Perhaps you should try some spelling variations:
nghien huu » nghien cuu, nguyen huu, nhiem huu
tang khoa » hang khoa, dang khoa, tang kha
hoc sach » hoc sinh, hoc cac, hoc anh
sach hoc » cach hoc, sach hoi, mach hoc
hoc tang » hoc bang, hoc tan, hoc tieng
khoa hoc » hoa hoc
huu mot » cuu mot, huy mot, hieu mot
mot hoc » mon hoc, mo hoc, mot goc
va nhan » van nhan, ca nhan, va nha
va phan » van phan, va phat, va phap
hoc xa » hoc ma

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

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