Perhaps you should try some spelling variations:
va doanh » van doanh, vay doanh, va danh
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cac xuc » cam xuc, cac nuoc, chat xuc
cuc tre » cua tre, cuu tre, cuc thue
duc tre » duoc tren, duc tien
sac ky » cac ky, sai ky
xuc va » duc va, tuc va, luc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc ((sach ky) OR (sac ky)) nang xa hoi. hieu va cac xuc va doanh tai ((cuc tre) or (duc tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc ((sach ky) OR (sac ky)) nang xa hoi. hieu va cac xuc va doanh tai ((cuc tre) OR (duc tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc ((sach ky) OR (sac ky)) nang xa hoi. hieu va cac xuc va doanh tai ((cuc tre) or (duc tre))".
• Adding a wildcard symbol may retrieve word variants: thuoc ((sach ky) OR (sac ky)) nang xa hoi. hieu va cac xuc va doanh tai ((cuc tre) or (duc tre))*.