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
sach ty » sach y, sach tu, sach thu
tai cuu » tai cuc, tai buu, tai cua
tuc van » thuc van, truc van, tuc va
cuu tre » cua tre, cau tren, cau treo
nang ma » tang ma, sang ma, nang cao
va cam » va cham, va cac, va cao
ve cam » ve cham, ve cac, ve cai

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