Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
ve cam » ve cham, ve cac, va cam
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, duc 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: tu sach ky nang ma hoi. hieu ve cam ((((xuc va) OR (tuc va))) or (tuc xa)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoi. hieu ve cam ((((xuc va) OR (tuc va))) OR (tuc xa)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ma hoi. hieu ve cam ((((xuc va) OR (tuc va))) or (tuc xa)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoi. hieu ve cam ((((xuc va) OR (tuc va))) or (tuc xa)) hanh vi cua tre*.