Perhaps you should try some spelling variations:
van thanh » ban thanh
van tuan » van quan, van ban, anh tuan
tu sach » thu sach, su sach, te sach
cam tuc » cam xuc, cam tu, nam thuc
tai cuu » tai cuc, tai buu, tai cua
cuu tre » cua tre, cau tren, cau treo
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
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 ty ((nang ma) or (nang x)) hoi. hieu va cam tuc ((van thanh) OR (van tuan)) 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 va cam tuc ((van thanh) OR (van tuan)) 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 va cam tuc ((van thanh) OR (van tuan)) tai cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang ma) or (nang x)) hoi. hieu va cam tuc ((van thanh) OR (van tuan)) tai cuu tre*.