in this sense you should use 中文 since 我研究中国 is "I research China" and 我学习中国 is "I learn from China" 学习 is to study, or learning 研究 is to research but in terms of usage 学习would not be used as direct translation. 学习 actually refers to 2 seperate things. 學or 学 is to learn via self study or being taught/acquire knowledge, 習or 习 is the action take to consolidate the knowledge or skills so we would usually say :我正在学中文. " I am learning Chinese" the am is quite important otherwise we'd have no way of telling what's going on it is possible to say 我正在学习中文."I am studying Chinese" but this suggests you are physically "studying" when you are saying so, which if you are saying such make sense. people use 研究, to research for a deeper understanding so if you are doing more advance Chinese is would be wise to use this term as it suggests you are tackling something hard and deeper than common knowledge. eg.我正在研究中文 "I am researching into Chinese" hope that helps

学习的意思是还没有掌握，有一个从有到无的过程。而研究是有在掌握了相关知识的情况下进一步加深探索学习的意味。

If you want to tell other you are studying English, you can say"我在学汉语“。 ”我学习中国“, it have a little problem to make sense, you can use this way"我在学中国的语言和**” “我研究中国” the way more likely a scholar research Chinese culture or language. That's just my idea.

И хочу добать разница между "学习" и "研究" “学习“ на русском языке “учить”, например я учу китайский язык. ”研究“ на русскоя языке ”изучать“ , например я изучаю китайский язык.

we human have known that 1+1 = 2 but you don't know because you are too young. The process of you knowing that 1+1=2 is "学习". BUT we human haven't known that 1+2=3, and you work hard, do some research, and finally you know that 1+2=3, this process is 研究. people 学习 to know old and current knowledge. According to what people have 学习, people 研究, get some new results which people in the future could 学习. so how do we human develop? 学习 --- 研究 --- 学习 --- 研究..............................