Perhaps you should try some spelling variations:
khang thuoc » khong thuoc, dang thuoc, hanh thuoc
van khang » van khanh, van thanh, van quang
sach hoc » cach hoc, sach hoi, mach hoc
thuoc ma » hoc ma, duoc ma
cua khau » cua khu, xuat khau, cua khach
khau tai » pham tai, nhan tai
su sach » so sach, vu sach
mon hoc » toan hoc, dong hoc
hoa cua » hoa chat, hoa xuat
mo hoc » co hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach hoc tap, nghien cuu ((mo hoc) OR (mon hoc)) van khang thuoc ma hoa cua khau tai~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach hoc tap, nghien cuu ((mo hoc) OR (mon hoc)) van khang thuoc ma hoa cua khau tai".
• Adding a wildcard symbol may retrieve word variants: su sach hoc tap, nghien cuu ((mo hoc) OR (mon hoc)) van khang thuoc ma hoa cua khau tai*.