Perhaps you should try some spelling variations:
nang doc » nang luc
vu sach » vu bach, su sach, vu khach
nang co » nang cao, nang noi, nang hoc
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
va nam » van nam, ha nam, va nay
thu va » thuc va, thue va, tu va
vi cua » vai 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: ((vu sach) or (vay khach)) ky ((nang co) OR (nang doc)) loi. hieu va nam thu va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (vay khach)) ky ((nang co) OR (nang doc)) loi. hieu va nam thu va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) or (vay khach)) ky ((nang co) OR (nang doc)) loi. hieu va nam thu va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) or (vay khach)) ky ((nang co) OR (nang doc)) loi. hieu va nam thu va hanh vi cua tre*.