Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
cam duc » cam xuc, cao duc, pham duc
hieu ve » hieu va, hieu van
sang ma » tang ma, nang ma, sang tao
nang xa » nang x, lang xa, nang ma
cuu tre » cau tren, cau treo
ve cam » ve cham, ve cac, va cam

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 y ((nang xa) or (sang ma)) hoi. hieu ve cam duc va hanh vi ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang xa) OR (sang ma)) hoi. hieu ve cam duc va hanh vi ((cua tre) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang xa) or (sang ma)) hoi. hieu ve cam duc va hanh vi ((cua tre) OR (cuu tre))*".