Perhaps you should try some spelling variations:
vien dai » hien dai
van hanh » van thanh, ban hanh, van anh
chat xuc » chat huu, cam xuc, chat cua
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
tang ma » mang may, tang van
luu tre » luu tru, cuu tre, luy tre
dai ky » dan ky, dai ly, sai ky
vi luu » vi lua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vien dai ky ((nang xa) or (tang ma)) hoi. hieu va ((chat xuc) OR (chao xu)) van hanh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vien dai ky ((nang xa) OR (tang ma)) hoi. hieu va ((chat xuc) OR (chao xu)) van hanh vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vien dai ky ((nang xa) or (tang ma)) hoi. hieu va ((chat xuc) OR (chao xu)) van hanh vi luu tre".
• Adding a wildcard symbol may retrieve word variants: vien dai ky ((nang xa) or (tang ma)) hoi. hieu va ((chat xuc) OR (chao xu)) van hanh vi luu tre*.