Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
thanh vi » hanh vi, thanh va, thanh ve
va thanh » gia thanh, ban thanh, va tinh
su viet » so viet
chai tu » cai tu, choi tu, chay tu
va chai » va cai, va chat, va cham
sach ly » sach y, sach lo, sach ty
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
hieu va » lieu va, hieu qua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ly ((nang xa) OR (nang ma)) hoi. hieu va chai tu va thanh vi ((su viet) or (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly ((nang xa) OR (nang ma)) hoi. hieu va chai tu va thanh vi ((su viet) OR (va trien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly ((nang xa) OR (nang ma)) hoi. hieu va chai tu va thanh vi ((su viet) or (va trien))".
• Adding a wildcard symbol may retrieve word variants: su sach ly ((nang xa) OR (nang ma)) hoi. hieu va chai tu va thanh vi ((su viet) or (va trien))*.