Perhaps you should try some spelling variations:
cau trung » cau truong, cac trung, cao trung
hieu van » thien van, lieu va, hieu ve
hanh vai » hanh vi, hanh va, hanh tai
thu sach » thuat sach, thuoc sach, thu hoach
trung va » truong va, trang va, trung ha
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
tu sach » su sach, te sach, tu cach
nang ma » tang ma, sang ma, nang cao
vai hoa » van hoa, va hoa, dai hoa
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) OR (thu sach)) ky nang ma hoi. ((hieu van) or (hieu va)) cau trung va hanh vai hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang ma hoi. ((hieu van) OR (hieu va)) cau trung va hanh vai hoa viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ky nang ma hoi. ((hieu van) or (hieu va)) cau trung va hanh vai hoa viet*".