Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
va trien » va truyen, va thiet, va tuyen
nang xa » nang x, lang xa, nang ma
cam tuc » cam xuc, cam tu, nam thuc
va hanh » van hanh, va thanh, va danh
hanh ke » hanh kem, thanh ke, hanh ky
v nang » va nang, vu nang, van nang
sach v » sach va, sach y, sach 2
tuc va » thuc va, truc va, tuc xa
ke va » te va

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach v nang xa hoi. ((((hieu va) or (hieu qua))) or (lieu va)) cam tuc va hanh ke va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach v nang xa hoi. ((((hieu va) OR (hieu qua))) OR (lieu va)) cam tuc va hanh ke va trien.
• Adding a wildcard symbol may retrieve word variants: doc sach v nang xa hoi. ((((hieu va) or (hieu qua))) or (lieu va)) cam tuc va hanh ke va trien*.