Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
sach ky » sach y, sach ty, sach kem
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
sac ky » cac ky, sai ky
ve cam » ve cham, ve cac, va cam
xuc va » duc va, tuc va, luc va
vi cau » va cau, ve cau, di cau

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