Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hanh trinh » canh tranh, hanh chinh
hoc thuat » hoc thuyet, hoc thuc, hoc chat
trinh han » trinh quan
cong cong » cong dong, trong cong, dung cong
dang cong » dung cong
thang van » tang van, thanh van, thong van
van dau » van dao, phan dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thuat sach - hanh trinh han ((cong cong) or (dang cong)) thang van dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thuat sach - hanh trinh han ((cong cong) OR (dang cong)) thang van dau*.