Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
tuc van » thuc van, truc van, tuc va
cam tuc » cam xuc, cam tu, nam thuc
hieu va » lieu va
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
buu tre » cuu tre

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 ty ((nang ma) or (nang x)) hoi. ((hieu va) OR (hieu qua)) cam tuc van hanh tai buu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang ma) OR (nang x)) hoi. ((hieu va) OR (hieu qua)) cam tuc van hanh tai buu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((nang ma) or (nang x)) hoi. ((hieu va) OR (hieu qua)) cam tuc van hanh tai buu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang ma) or (nang x)) hoi. ((hieu va) OR (hieu qua)) cam tuc van hanh tai buu tre*.