Perhaps you should try some spelling variations:
sach ky » sac ky, sach ty, sach kem
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
luu tre » luu tru, luy tre
cuu tre » cua tre, cau tren, cau treo
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: doc ((sach ky) or (sach y)) nang cao hoi. hieu ve cam xuc va hanh vi ((luu tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sach ky) OR (sach y)) nang cao hoi. hieu ve cam xuc va hanh vi ((luu tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((sach ky) or (sach y)) nang cao hoi. hieu ve cam xuc va hanh vi ((luu tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: doc ((sach ky) or (sach y)) nang cao hoi. hieu ve cam xuc va hanh vi ((luu tre) OR (cuu tre))*.