Perhaps you should try some spelling variations:
va thieu » va thiet, va hieu, va tieu
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
han mai » han tai, ban mai, han mac
cam tuc » cam xuc, cam tu, dam thuc
tu sach » thu sach, su sach, tu cach
nang xa » nang x, lang xa, nang ma
te sach » toc sach
va han » va phan, van han, va hanh

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 (te sach)) ky nang xa hoi. hieu van ((cam tuc) OR (nam thuc)) va han mai va thieu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky nang xa hoi. hieu van ((cam tuc) OR (nam thuc)) va han mai va thieu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) ky nang xa hoi. hieu van ((cam tuc) OR (nam thuc)) va han mai va thieu".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ky nang xa hoi. hieu van ((cam tuc) OR (nam thuc)) va han mai va thieu*.