Perhaps you should try some spelling variations:
manh hanh » xanh hanh, danh thanh, minh thanh
duc manh » suc manh, duc anh, duc minh
tu sach » thu sach, su sach, te sach
cua tre » cua te, cuu tre, cua triet
cam duc » cam xuc, cao duc, pham duc
cu tren » tu tren, dua tren
hieu ve » hieu va, hieu van
nang ro » nang co, nang ho, nang ra
nang o » nang co, nang ho, nang x
ve cam » ve cham, ve cac, va cam

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 o) OR (nang ro)) hoi. hieu ve cam duc manh hanh vi ((cua tre) OR (cu tren))~.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang o) or (nang ro)) hoi. hieu ve cam duc manh hanh vi ((cua tre) or (cu tren))*.