Conjunctions are of three kinds, coordinating, subordinating and correlative.

1. Coordinating conjunctions connect two pieces of language of equal syntactic importance.

Geldi ve gidebildik. (MAIN CLAUSE + MAIN CLAUSE)

My guess is this is just about what bağlaç means. 

2. Subordinating conjunctions connect two pieces of language. One of them governs the other one syntactically.

Hasta olduğu için eve gelecek. (SUBCLAUSE/ADVERBIAL + MAIN CLAUSE)

This is edat. The same word also has a postposition use when seen together with a noun phrase.

3. Correlative conjunctions work in pairs to join pieces of language of equal value.

Ne çalışır ne çalıştırır. (MAIN CLAUSE + MAIN CLAUSE)

Our original example is of the type 2, SUBCLAUSE/ADVERBIAL + MAIN CLAUSE.

Daha önceki çalışmaları incelemedikleri sürece iyi bir proje hazırlamaları imkansız görünüyor. 

And yes daha önceki çalışmaları incelemedikleri is a sentence, why not? There is a subject and a predicate, and even an object. But it is a subordinated (embedded) sentence. The marking of subordination in Turkish is DIK. You can make any sentence a constituent of another sentence (here adverbial) after you have marked it with DIK.

Two sentences are connected with a conjunction, one of the sentences syntactically governs the other.

1. Think twice before you call someone very lucky while standing next to someone who has the device of luck.

2. Destiny is like a rug in a tent. Allah gives its yarn, you are the one who weaves it. You have the design, the colors are from Him.

3. It is impossible for a human being to learn something that he believes he knows already.

I do not quite get the first sentence, so probably there is a mistake...

In addition to porpoises and ordinary dolphins there are some 60 to 70 bottle-nosed dolphins living in the Bosphorus.

A two-year research project has revealed that the dolphin community of the Bosphorus suffers greatly from the large volume of shipping in the strait. Biologist Aylın Akkaya says the dolphins cannot prey effectively and they waste a lot of energy escaping from vessels. Also the noise of engines disturb their echolocation.

The researches suggest that for the welfare of the dolphins Bosphorus traffic should be restricted at certain times of the year by speed limits and different routings.

source

He is never ignored.

Kolay gelsin çabuk geçsin.

I love such arguments.

Wow you found it in half an hour. This is the power of a community like this. My friend will be so surprised.

Thank you ikicihan, thank you Kelowna.

A friend of mine praised an old Turkish movie  -  probably from the 1980´s  - where four Kurdish prisoners get a vacation and each one of them goes to their villages. She does not remember the name of the movie or the director, so it is very difficult to search. I was hoping the composition would ring a bell for someone.

Daha önceki çalışmaları incelemedikleri sürece iyi bir proje hazırlamaları imkansız görünüyor.

The bits connected by sürece are

                  "Daha önceki çalışmaları incelemiyorlar"

                                      AND

                  "iyi bir proje hazırlamaları imkansız görünüyor".

Two sentences, the first one is subordinate to the other (and thus marked with DIK). What defines its syntactic and semantic position in accordance with the main clause is the conjunction sürece.

It changes into an adverbial clause, yes yes, but the inner structure of the clause is this.

Makes very much sense. Probably this is how it came into being.