Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
nang mai » nang ma, nang tai, lang mai
dua tren » dung tren
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
cuu tre » cua tre, cau tren, cau treo
ve cac » va cac
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 mai hoi. hieu ((ve cac) OR (vien cac)) xuc va hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang mai hoi. hieu ((ve cac) OR (vien cac)) xuc va hanh vi ((dua tren) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang mai hoi. hieu ((ve cac) OR (vien cac)) xuc va hanh vi ((dua tren) or (cuu tre))*".