Perhaps you should try some spelling variations:
cham tuc » nham thuc, pham thuc, tham thuc
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
nang ro » nang co, nang ho, nang ra
nang va » nang van, hang va, nang ma
hieu va » lieu va, hieu qua
va cham » va chat, va tham
tuc van » thuc van, truc van, tuc va
cuc te » cua te, cuc thue, cuc tieu

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 ty ((nang ro) or (nang va)) hoi. hieu va cham tuc van hanh tai cuc te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang ro) OR (nang va)) hoi. hieu va cham tuc van hanh tai cuc te.
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang ro) or (nang va)) hoi. hieu va cham tuc van hanh tai cuc te*.