Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
cham hoc » cham soc, chat hoc, cham hoi
van hanh » ban hanh, van anh, van ban
vai cua » dai cua, hai cua, lai cua
va cham » va chat, va tham
sach ty » sach tu, sach thu, xach tay
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ty) OR (sach y)) nang ma hoa. hieu va cham hoc ((van hanh) or (van thanh)) vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach y)) nang ma hoa. hieu va cham hoc ((van hanh) OR (van thanh)) vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) OR (sach y)) nang ma hoa. hieu va cham hoc ((van hanh) or (van thanh)) vai cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) OR (sach y)) nang ma hoa. hieu va cham hoc ((van hanh) or (van thanh)) vai cua tre*.