Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach y, sach ty
va hang » van hang, va nang, va lang
tu sach » thu sach, su sach, te sach
nam luc » nang luc, nhan luc, nam duoc
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
doi cu » doi cua, doi co, doi su
doi ca » doi cua, doi cay, duoi ca

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 tang xa hoi. hieu van ((nam luc) or (nam thuc)) va hang ((doi cu) OR (doi ca)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky tang xa hoi. hieu van ((nam luc) OR (nam thuc)) va hang ((doi cu) OR (doi ca)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky tang xa hoi. hieu van ((nam luc) or (nam thuc)) va hang ((doi cu) OR (doi ca)) tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ky tang xa hoi. hieu van ((nam luc) or (nam thuc)) va hang ((doi cu) OR (doi ca)) tren*.