Perhaps you should try some spelling variations:
cay thuoc » cua thuoc, nam thuoc, va thuoc
lam duoc » nam duoc, luat duoc, lam thuoc
thu sach » thuat sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
vai cay » va cay, vai cac, vai gay
va dinh » van dinh, va kinh, va tinh
va danh » va dan, va hanh, dia danh
tu sach » su sach, te sach, tu cach
van lam » van nam
nang o » nang co, nang ho, nang ro
o hoc » co hoc, mo hoc, so hoc

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) or (thu sach)) ky nang o hoc. hieu van lam duoc ((va danh) or (va dinh)) vai cay thuoc~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang o hoc. hieu van lam duoc ((va danh) OR (va dinh)) vai cay thuoc.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang o hoc. hieu van lam duoc ((va danh) or (va dinh)) vai cay thuoc*.