Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
tinh lai » tinh lao, tinh hai, minh lai
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cua triet, dua tren
va tinh » may tinh
tu sach » thu sach, su sach, te sach
ty nang » ky nang, ty xang, ty hang
cuu tre » cau tren, cau treo
xuc va » duc va, tuc va, luc va
ve cac » va cac
x hoi » xa hoi, o hoi, x ho

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 ty nang x hoi. hieu ((ve cac) OR (vien cac)) xuc va tinh lai ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang x hoi. hieu ((ve cac) OR (vien cac)) xuc va tinh lai ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang x hoi. hieu ((ve cac) OR (vien cac)) xuc va tinh lai ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang x hoi. hieu ((ve cac) OR (vien cac)) xuc va tinh lai ((cua tre) or (cuu tre))*.