Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » thien van, lieu va, hieu ve
chat huu » pham huu
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va phan » van phan, va phat, va phap
va han » van han, va hanh, va hang
thiet » thieu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty nang xa hoi. ((hieu van) or (hieu va)) chat huu ((va han) or (va phan)) tri va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang xa hoi. ((hieu van) OR (hieu va)) chat huu ((va han) OR (va phan)) tri va thiet.
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang xa hoi. ((hieu van) or (hieu va)) chat huu ((va han) or (va phan)) tri va thiet*.