Perhaps you should try some spelling variations:
cau treo » cau theo, cau tren, cau triet
hanh tai » thanh tai, hang tai, han tai
hieu va » lieu va, hieu qua
tai cau » tai cac, tai cao
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, cam tu, nam thuc
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu van
tuc va » thuc va, truc va, tuc xa

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