Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
thanh ke » thanh ket, thanh ve, thanh de
dau tren » dau tien, dat tren, dau tieng
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
ke dau » ke cau, ke dan, ke dam

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 ky ((nang ma) or (nang x)) hoi. hieu va pham duc va thanh ke dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang ma) OR (nang x)) hoi. hieu va pham duc va thanh ke dau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang ma) or (nang x)) hoi. hieu va pham duc va thanh ke dau tren*.