Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
van tuan » van quan, van ban, anh tuan
so sach » so sanh, bo sach, co sach
cam duc » cam xuc, cao duc, pham duc
vai cua » dai cua, hai cua, lai cua
duc van » duc va, duc tan, duc manh
nang co » nang cao, nang doc, nang noi
hieu va » lieu va, hieu qua
y nang » ky nang, ly nang, v nang
co hoi » co hoc, co loi
vi cua » di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y nang co hoi. ((hieu van) OR (hieu va)) cam duc van tuan ((vi cua) or (vai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y nang co hoi. ((hieu van) OR (hieu va)) cam duc van tuan ((vi cua) OR (vai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y nang co hoi. ((hieu van) OR (hieu va)) cam duc van tuan ((vi cua) or (vai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: so sach y nang co hoi. ((hieu van) OR (hieu va)) cam duc van tuan ((vi cua) or (vai cua)) tre*.