Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
chua tre » chua tri, cua tre, chua trieu
tu sach » su sach, te sach, tu cach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
vi chua » va chua, vi khuan, chi chua
ma hoi » mai hoi, xa hoi, ma hoa
ve cam » ve cham, ve cac, va cam
xuc va » tuc va, luc va, xac va

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 ve cam ((xuc va) OR (duc va)) hanh vi chua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang ma hoi. hieu ve cam ((xuc va) OR (duc va)) hanh vi chua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang ma hoi. hieu ve cam ((xuc va) OR (duc va)) hanh vi chua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang ma hoi. hieu ve cam ((xuc va) OR (duc va)) hanh vi chua tre*.