Perhaps you should try some spelling variations:
nghien huu » nghien cuu, nguyen huu, nhiem huu
dang thuoc » dung thuoc
khong hoc » khung hoc, thong hoc, khong thuoc
hoc nhanh » hoc nganh, hoc phan
van phan » van phong, van thanh, luan phan
phan dau » phan tu, hang dau
sach doi » sach hoi, sach moi, sach dao
toan hoc » toan khoa, van hoc, hoa hoc
huu toan » huu tuan, cuu toan, huy toan
hoi van » hoi va, hoi dan, hai van
doi tap » doi tac, doi dap, doi tai
tu sach » thu sach, su sach, te sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach doi tap, nghien huu toan hoc nhanh ((khong hoc) or (dang thuoc)) xa hoi van phan dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach doi tap, nghien huu toan hoc nhanh ((khong hoc) OR (dang thuoc)) xa hoi van phan dau.
• Adding a wildcard symbol may retrieve word variants: tu sach doi tap, nghien huu toan hoc nhanh ((khong hoc) or (dang thuoc)) xa hoi van phan dau*.