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