Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, gian cac
tinh vai » tinh va, tinh hai, tinh bai
su sach » so sach, vu sach
va tinh » may tinh
cua tre » cua te, cua triet, dua tren
vien da » vien dai, hien dai
sach ky » sac ky, sach y, sach ty
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
cuu tre » cau tren, cau treo
luc va » duc va, tuc va, loc va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky dang xa hoi. hieu ((vien cac) OR (vien da)) luc va tinh vai ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky dang xa hoi. hieu ((vien cac) OR (vien da)) luc va tinh vai ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky dang xa hoi. hieu ((vien cac) OR (vien da)) luc va tinh vai ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su sach ky dang xa hoi. hieu ((vien cac) OR (vien da)) luc va tinh vai ((cua tre) or (cuu tre))*.