Yes....though "just nationalist subgroups" is a little over-simplified.
"Eastern Orthodox" is the church - the entire church. You can think of it as an umbrella that includes all of the patriarchates.
The Eastern Orthodox Church includes several "patriarchates", each more or less autonomous but all agreeing with each other on fundamentals of Christian doctrine
http://en.wikipedia.org/wiki/Eastern_Orthodox_Church#Eastern_Orthodox_churches_ in_communion
For one example of difference: different patriarchates include different Scriptures in their Bibles
http://www.bible-reviews.com/charts_scriptures_d.html
There are - naturally - several other differences between the patriarchates regarding what we might call less significant details of Christian doctrine, worship practices, celebrations (and ways that holy days are celebrated) and saints.
To give you an idea of a patriarchate, from the Eastern Orthodox point of view the Roman Catholic Church is merely another patriarchate - one that has chosen to leave the "communion" of the Eastern Orthodox Church.
They are both part of the One Holy Orthodox Catholic and Apostolic Church -- the Orthodox Church.
There are about 13 such jurisdictions of the church:
Constantinople
Alexandria
Antioch
Jerusalem
Cyprus
Georgia (the country)
Russia
Greece
Romania
Albania
Serbia
Bulgaria
Orthodox Church in America (Russian roots, audiophile not universally recognized)
Nationalist is not the proper term, since the churches are not so much ethnically based as territory based, but with heavy linguistic overtones, as such things go politically.
Doctrinally, they are identical. Each has its own chief bishop, often called the Patriarch (or in the case of Alexandria, Pope), or Archbishop. There is no "one bishop to rule them all". They stay in contact through meetings of their respective bishops.
The primary worship service is the Divine Liturgy (analogous to the Roman Mass), usually the version called he Divine Liturgy of Saint John Chrysostom. Periodically, especially during Lent, the longer Divine Liturgy of Saint Basil is used. Within these liturgies, there have developed over the past 1000 years minor variations in practice, but not in doctrine.
The Seventh-day Adventist Church strongly believes that Jesus is God (John 1:1-3,14). He is the MESSIAH. He is the Savior.
Isaiah 7:14 prophesied the Virgin Birth of Christ our Savior. Indeed he is the Messiah. He will return with power in glory at the end of time as he has promised(Acts 1:9-11).
This is a fact, not fiction. Beware of false teachers that tell you otherwise. Beware of those who deny the deity of Christ. Jesus died on the Cross for the Sins of the World(John 3:16). Jesus is God(John 1:1-3). He was one with God the Father in the Creation of the World (Genesis 1:1).
Special note to all Jews, Atheists and Agnostics:
According to the 19Th century Scholar Henry Liddon, Jesus fulfilled to the letter no fewer than 332 Old Testament Prophecies. 29 Messianic Prophecies were fulfilled in the final 24 hours of his life alone.
Note Fulfilled Prophecy by Christ: Tanakh/Hebrew Scripture/New Testament
His Prue-existence------Micah 5:2, John 1:1,14
Born of the seed of a woman--Genesis 3:15; Matthew 1:18
Born of the Seed of Abraham--Genesis 12:3; Matthew 1:1-16
All Nations blessed by Abraham's seed--Genesis 12:3; Matthew 8:5,10
God would provide himself a Lamb as an offering--Genesis 22:8; John 1:29: From the tribe of Judah---------Genesis 49:10; Matthew 1:1-3
Heir to the throne of David----Isaiah 9:6-7; Matthew 1:1
Called "the Mighty God, The everlasting Father" Isaiah 9:6; Matt 1:23
Born in Bethelehem---Micah 5:2; Matthew 2:1
Born of a Virgin--Isaiah 7:14; Matthew 1:18
His name called Immanuel, "God with us" Isaiah 7:14; Matthew 1:23
Declared to be the Son of God--Psalm 2:7; Matthew 3:17
His messenger before him in the spirit of Elijah--Malachi 4:5,6; Luke 1:17
Preceded by a messenger to prepare His way---Malachi 3:1; Matthew 11:7-11
Messenger crying "Prepare ye the way of the Lord" Isaiah 40:3; Matthew 3:3
Would be a Prophet of the Children of Israel--Deuteronomy 18:15; Matthew 2:15
Called out of Egypt--Hosea 11:1; Matthew 2:15
Slaughter of the children--Jeremiah 31:15; Matthew 2:18
Would be a Nazarene--Judges 13:5; Amos 2:11; Lamentations 4:7; Matthew 2:23
Brought light to Zabulon and Napthalim, Galilee of the Gentiles--Isaiah 9:1-2; Matthew 4:15
Presented with gifts--Psalm 72:10; Matthew 2:1,11
Rejected by His own--Isaiah 53:3, Matthew 21:42; Mark 8:31, 12:10; Luke 9:22; 17:25
He is the stone which the builders rejected which became the Headstone--Psalm 118:22-23; Isaiah 28:16, Matthew 21:42; 1 Peter 2:7
He is Lord of the Sabbath day--March 2:27
A stone of stumbling to Israel--Isaiah 8:14-15; 1 Peter 2:8
He entered Jerusalem as a King riding on an *** Zechariah 9:9; Matthew 21:5
Betrayed by a friend--Psalms 41:9; John 13:21
Sold for 30 pieces of silver--Zechariah 11:12; Matthew 27:9-10
The 30 pieces of silver given for the Potter's field--Zechariah 11:12; Matthew 27:9-10
The 30 pieces of silver thrown in the Temple--Zechariah 11:13; Matthew 27:5
Forsaken by his Disciples--Zechariah 13:7; Matthew 26:56
Accused by false witnesses--Psalm 35:11, Matthew 26:60
Silent to accusations--Isaiah 53:7; Matthew 27:14
Wounded for our Sins--Isaiah 53:5; John 6:51
He bore the Sins of many--Isaiah 53:10-12; Mark 10:45
Messiah not killed for himself--Daniel 9:26; Matthew 20:28
Gentiles flock to Him--Isaiah 55:5; 60:3, 65:1; Malachi 1:11; 1 Samuel 22:44-45; Psalm 2:7-8; Matthew 27:35
His body was pierced--Zechariah 12:10; Psalm 22:16; John 20:25,27
Thirsty during execution--Psalm 22:16; John 19:28
Given Vinegar and Gall for thirst--Psalm 69:21; Matthew 27:34
Soldiers gambled for his garment--Psalm 22:18; Matthew 27:35
People mocked, "He trusted in God, let Him deliver Him!" Psalm 22:7-8; Matthew 27:43
People sat there looking at Him--Psalm 22:17; Matthew 27:36
Cried, "My God, my God why hast thou forsaken me?" Psalm 22:1; Matthew 27:46
Darkness over the land--Amos 8:9; Matthew 27:45
No Bones broken--Psalm 34:20, Numbers 9:12; John 19:33-36
Side pierced--Zechariah 12:10; John 19:34
Buried with the rich--Isaiah 53:9, Matthew 27:57,60
Resurrected from the dead--Psalm 16:10-11; 49:15; Mark 16:6
Priest after the order of Melchizedek--Psalm 110:4, Hebrews 5:5-6; 6:20; 7:15-17
Ascended to the right hand of God--Psalm 68:18; Luke 24:51
LORD said unto Him, "Sit thou at my right hand, until I make thine enemies thy footstool--Psalm 110:1, Matthew 22:44; Mark 12:36; 16:19; Luke 20:42-43; Acts 2:34-35; Hebrews 1:13
His coming glory---Malachi 3:2-3, Luke 3:17
Jesus Christ without a doubt fulfilled all the Messianic Prophecies. He is Lord. He is sovereign. He is God. He intercedes for us in the Heavenly Sanctuary. He is coming back for His Chuch as He has promised (John 14:1-3).
Have faith dear friends in God. The Holy Bible is our only guide.
Are there differences between the Eastern Orthodox, Greek Orthodox and Russian Orthod
