Perhaps you should try some spelling variations:
nghien huu » nghien cuu, nguyen huu, nhiem huu
tran khoa » toan khoa, san khoa, nhan khoa
hoc sach » hoc sinh, hoc cac, hoc anh
sach hoc » cach hoc, sach hoi, mach hoc
hoc tran » hoc tan, hoc tren, boc tran
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 tran khoa hoc xa hoi ((va nhan) OR (va phan)) dan~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach hoc tap, nghien huu mot hoc tran 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 tran khoa hoc xa hoi ((va nhan) OR (va phan)) dan*.