Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cuu cong » cua cong, thu cong, cac cong
cong hoc » dong hoc, cong hoa, cong coc
san khoa » toan khoa, hang khoa, da khoa
khoa hoc » hoa hoc
nhan dan » phan dau, gian dan, nhan tai
hoc san » hoc dan, toc san, hoc can
va nhan » van nhan, ca nhan, va phan
hoc xa » hoc ma
sinh » dinh, minh, kinh

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (hoc sinh)) hoc tap, nghien cuu cong hoc san khoa hoc xa hoi va nhan dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sinh)) hoc tap, nghien cuu cong hoc san khoa hoc xa hoi va nhan dan.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sinh)) hoc tap, nghien cuu cong hoc san khoa hoc xa hoi va nhan dan*.