Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
luu tre » cuu tre, luy tre
ve cam » ve cham, ve cac, va cam
xuc va » duc va, tuc va, luc va
tru » truc

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang x) OR (nang ma)) hoi. hieu ve cam xuc va hanh vi ((luu tre) OR (luu tru))~.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang x) or (nang ma)) hoi. hieu ve cam xuc va hanh vi ((luu tre) or (luu tru))*.