WHAT CONSTITUTES “STRONG TIES”?
Strong ties differ from country to country, city to city, individual to individual. Some examples of ties can be a job, a house, a family, a bank account.
Without knowing anything beyond that which you put in your question, let's look at the 4 examples listed.
You state you are currently unemployed. "I don't have a paid job now." So this example is false, you don't have a tie via a job.
You state you are resident in Turkey, but don't say your housing situation. If you are renting, month to month, that is no tie to cause you to leave before your visa expires.
If you are renting, based on a year or more lease, of if you own a home, in Turkey, that would be a reason to return. Since you were given a 214(b), I assume you do not, or did not prove you do.
So this reason is false, you do not have a strong tie to return to a domicile.
You state you are a Russian citizen with a current residency in Turkey. You don't state whether it is just you, or if your entire family is currently also resident in Turkey, or back in Russia. If they are in Russia, you don't have current strong ties of family to return to home, because they weren't strong enough to keep you there in the first place (you moved to Turkey.)
If you don't have family at all (they are all deceased), then you don't have family ties at all.
So this example is false, you have no strong family ties to return home.
A Bank Account
If all you have is a bank account, with your savings built up over time from working, this, in and of itself, would not constitute a strong tie, because you can either remove all your money before flying, or access it from overseas.
So, per the page I linked above, the immigration officer has to, by law, assume you are going to stay in the US, unless you prove your intent to be temporary, because you have multiple strong ties to cause you to want to return to your country of origin.
Going by the information, scant as it is, that you provide us, I would have to say you have no ties at all, therefore I would have to agree that you have not proven you case, and I would likely also deny you, based on 214(b).
Final Questions asked
Finally, you ask two questions.
So the most likely reason for the rejection was that I will get a job offer in the USA or get married there, right?
Exactly. You seem to want to come to the US specifically to learn better ways to get employment, and will be here for 2 months (!). Plenty of time to meet someone and start a relationship.
So I should not reapply unless I marry or get a job in another country or something along these lines to prove my intent to return?
Now you're asking for a truly personal response. And you've hit on the catch-22 conundrum that all 214(b) denials face. You're trying to improve yourself, so you hit upon this opportunity in the US to do so. Yet, to do so, you need to prove your ties to be let in. However, if your ties were proven, it would be more likely you wouldn't need to have come here in the first place.
It's not my place to say "get married" or "find a really good job", not really, but on the other hand, if you were married, or had a really good job, then letting you in the US as a temporary visitor isn't really a concern, because 60 days later, you'll return home. To your family/husband and your really good job.