Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
hanh cua » manh cua, hang cua, hanh sua
tu sach » su sach, te sach, tu cach
ty nang » ky nang, ty xang, ty hang
hieu va » hieu qua
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, x ho
nuoc » quoc, duoc, ngoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) OR (tu sach)) ty nang x hoi. ((hieu va) or (lieu va)) dat nuoc va van hanh cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ty nang x hoi. ((hieu va) OR (lieu va)) dat nuoc va van hanh cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (tu sach)) ty nang x hoi. ((hieu va) or (lieu va)) dat nuoc va van hanh cua tre*".