看到最近很多“paper helps", 其实这边之前总结过有很多免费查文献的方法，我摘抄
一下，版主能不能置顶？
下次再要文章的话，能不能最好都自己查过没有再要？
1) put a doi/PMID in this search engine http://gen.lib.rus.ec/scimag/ (it finds books too)
2) For the popular journals, such as nature、springerlink、sciencedirect、
wiley, if you add “sci-hub.io” after the journal name, you can get the
full text.
For example; the original paper: http://www.nature.com/nchembio/journal/v11/n7/full/nchembio.1837.html
