Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
thu sac » thu sach, thu san, thu xac
cac lap » cac lop, cac cap, cac tap
va hanh » van hanh, va thanh, va danh
dinh cu » dinh cuu, dinh chuc, dinh chau
sac ky » cac ky, sai ky
co hoi » co loi
lap va » tap va
vi cuu » vi luu, vinh cuu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sac ky nang ((co hoi) OR (co hoc)). hieu vien cac lap va hanh ((vi cuu) or (dinh cu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sac ky nang ((co hoi) OR (co hoc)). hieu vien cac lap va hanh ((vi cuu) OR (dinh cu)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sac ky nang ((co hoi) OR (co hoc)). hieu vien cac lap va hanh ((vi cuu) or (dinh cu)) tre".
• Adding a wildcard symbol may retrieve word variants: thu sac ky nang ((co hoi) OR (co hoc)). hieu vien cac lap va hanh ((vi cuu) or (dinh cu)) tre*.