Perhaps you should try some spelling variations:
vu khach » vu khanh, vay khach, cua khach
cac thoi » cac toi, cac hop, cac tro
hieu van » hieu va, thien van, lieu va
tinh vi » trinh vi, tinh voi, tinh va
va tinh » may tinh
cac toc » cac toi, cac nuoc
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
vu khac » vu kham, vu khanh, bui khac
luu tre » luu tru, cuu tre, luy tre
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: ((vu khach) OR (vu khac)) ky tang xa hoi. hieu van ((cac toc) or (cac thoi)) va tinh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu khach) OR (vu khac)) ky tang xa hoi. hieu van ((cac toc) OR (cac thoi)) va tinh vi luu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu khach) OR (vu khac)) ky tang xa hoi. hieu van ((cac toc) or (cac thoi)) va tinh vi luu tre*".