Perhaps you should try some spelling variations:
nghien huu » nghien cuu, nguyen huu, nhiem huu
phuong hoa » huong hoa, phuong hoang, phung ho
hoc thanh » hoc nhanh, hoan thanh, hoc phan
sach hoc » cach hoc, sach hoi, mach hoc
huu tuan » huu han, huu tung
tuan hoc » toan hoc, luan hoc, than hoc
hung hoa » hang hoa, ung hoa, trung hoa
cau gian » cau giay, hau giang, dan gian
gian dan » gian lang
tu sach » thu sach, su sach, te sach
hoi cau » hoi chu, hoc cau, hoa cau

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 hoc tap, nghien huu tuan hoc thanh ((phuong hoa) or (hung hoa)) xa hoi cau gian dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach hoc tap, nghien huu tuan hoc thanh ((phuong hoa) OR (hung hoa)) xa hoi cau gian dan.
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien huu tuan hoc thanh ((phuong hoa) or (hung hoa)) xa hoi cau gian dan*.