Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
sang tai » hang tai, sang tao, tang tai
thuat va » thuyet va, thuat xay, thuat bai
tu sach » su sach, te sach, tu cach
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
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)) ky nang ma hoi. hieu va cam ((thuat va) or (thuc vat)) sang tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang ma hoi. hieu va cam ((thuat va) OR (thuc vat)) sang tai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang ma hoi. hieu va cam ((thuat va) or (thuc vat)) sang tai cua tre*.