user20758: In the guidelines of asking questions it is said that the op should show some previous research. I would like to want should be written in questions whose googling or Wikipedia doesn't show any literature about it?

user32402: You could explain "I have tried searching the web and Wikipedia and I haven't found any literature about it", and add what search terms you have used, that at least shows previous research. Add a link, or links, to any pages that you feel would be useful to illustrate how you are getting some of the way to answering your question, but how they don't quite do it for you.
Importantly though I would also add my thoughts/intuition about the subject to at least show that I have done some thinking about it, this also has the desired effect of maybe showing where you have become 'stuck' in your thought processes which may help the answerer to shape their answer for you.

user27148: I think the request for "research" has less to do with necessarily looking for an answer to the problem, and more to do with showing that you understand what the problem actually is.
I very much dislike the questions that ask a simple question and then say "I haven't found anything so please help."
I hope @canadianer doesn't mind me using their example and disagreeing heavily that there is "no research effort", see: Can beavers control the direction a tree falls?
There isn't any attempt there to find an answer, but it shows a good description of the problem, including an explanation of how humans would make strategic cuts, good reasoning for why such behavior might be useful to a beaver, and picture evidence that shows what could be a hinge made by the beaver.
Similarly: Why is EcoRI supplied with a unique buffer when it is allegedly 100% active in universal buffers?
This question contains information on the buffer provided with EcoR1, and examples of two other buffers said to work fine with EcoR1 and yet not packaged with it. Honestly, I care nothing at all about EcoR1, it doesn't come up in my research ever, I don't care much about it except for its importance in the history of biology, but the question was interesting because with just the information in the question, it was clear that a) these solutions are fairly similar with some differences, and b) the answer isn't immediately obvious. If the question had no body, it would look like @canadianer wasn't actually interested or curious in the answer, but maybe just had that as a question on a lab exam or something.
This all counts to me as "research" even if it isn't "I searched Google and found nothing..." I think it's sometimes okay to have Googleable questions here, as long as they aren't just incredibly dull and boring questions (for example, questions that are effectively requesting a definition are always boring to me).
For you specifically, a lot of your questions don't have much background or basis. It doesn't make sense why you want to know an answer besides curiosity or maybe studying for an exam. If you can't find an answer, at least try to motivate why it's worth someone's time to answer your question.

20758: <p>In the guidelines of asking questions it is said that the op should show some previous research. I would like to want should be written in questions whose googling or Wikipedia doesn't show any literature about it?</p>
 32402: <p>You could explain <em>"I have tried searching the web and Wikipedia and I haven't found any literature about it"</em>, and add what search terms you have used, that at least shows previous research. Add a link, or links, to any pages that you feel would be useful to illustrate how you are getting some of the way to answering your question, but how they don't quite do it for you.</p>

<p>Importantly though I would also add my thoughts/intuition about the subject to at least show that I have done some thinking about it, this also has the desired effect of maybe showing where you have become 'stuck' in your thought processes which may help the answerer to shape their answer for you.</p>
 27148: <p>I think the request for "research" has less to do with necessarily looking for an answer to the problem, and more to do with showing that you understand what the problem actually is.</p>

<p>I very much dislike the questions that ask a simple question and then say "I haven't found anything so please help."</p>

<p>I hope @canadianer doesn't mind me using their example and disagreeing heavily that there is "no research effort", see: <a href="https://biology.stackexchange.com/questions/35921/can-beavers-control-the-direction-a-tree-falls">Can beavers control the direction a tree falls?</a></p>

<p>There isn't any attempt there to find an answer, but it shows a good description of the problem, including an explanation of how humans would make strategic cuts, good reasoning for why such behavior might be useful to a beaver, and picture evidence that shows what could be a hinge made by the beaver.</p>

<p>Similarly: <a href="https://biology.stackexchange.com/questions/58533/why-is-ecori-supplied-with-a-unique-buffer-when-it-is-allegedly-100-active-in-u">Why is EcoRI supplied with a unique buffer when it is allegedly 100% active in universal buffers?</a></p>

<p>This question contains information on the buffer provided with EcoR1, and examples of two other buffers said to work fine with EcoR1 and yet not packaged with it. Honestly, I care nothing at all about EcoR1, it doesn't come up in my research ever, I don't care much about it except for its importance in the history of biology, but the question was interesting because with just the information in the question, it was clear that a) these solutions are fairly similar with some differences, and b) the answer isn't immediately obvious. If the question had no body, it would look like @canadianer wasn't actually interested or curious in the answer, but maybe just had that as a question on a lab exam or something.</p>

<p>This all counts to me as "research" even if it isn't "I searched Google and found nothing..." I think it's sometimes okay to have Googleable questions here, as long as they aren't just incredibly dull and boring questions (for example, questions that are effectively requesting a definition are always boring to me).</p>

<p>For you specifically, a lot of your questions don't have much background or basis. It doesn't make sense why you want to know an answer besides curiosity or maybe studying for an exam. If you can't find an answer, at least try to motivate why it's worth someone's time to answer your question.</p>
