Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
cam truc » cau truc, nam truc, lam truoc
tu sach » su sach, te sach, tu cach
hieu va » lieu va, hieu qua
buu tre » cuu tre
nang ma » tang ma, sang ma, nang cao
va cam » va cham, va cac, va cao

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