Perhaps you should try some spelling variations:
kho tang » cao tang
hieu van » hieu va, thien van, lieu va
ky lang » ky nang, ky dang, ky tang
van cam » van nam, van lam, van cau
cam loc » cam lo
va hanh » van hanh, va thanh, va danh
su sach » so sach, vu sach
loc va » hoc va, luc va
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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 ((ky lang) or (kho tang)) xa hoi. hieu van cam loc va hanh ((vi cua) OR (di cua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky lang) OR (kho tang)) xa hoi. hieu van cam loc va hanh ((vi cua) OR (di cua)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky lang) or (kho tang)) xa hoi. hieu van cam loc va hanh ((vi cua) OR (di cua)) viet".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky lang) or (kho tang)) xa hoi. hieu van cam loc va hanh ((vi cua) OR (di cua)) viet*.