Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
ky lang » ky nang, ky tang, tay lang
ky dang » ky nang, ky danh
van cau » van dau, van hau, van chat
truc va » thuc va, thuc vat, trung va
va danh » va dinh, va dan, va hanh
vai cua » dai cua, hai cua, lai 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: thu sach ((ky lang) OR (ky dang)) xa hoi. hieu van cau truc va danh ((vai cua) or (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ky lang) OR (ky dang)) xa hoi. hieu van cau truc va danh ((vai cua) OR (di cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ky lang) OR (ky dang)) xa hoi. hieu van cau truc va danh ((vai cua) or (di cua)) tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ((ky lang) OR (ky dang)) xa hoi. hieu van cau truc va danh ((vai cua) or (di cua)) tre*.