Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
so sanh » do sanh
sanh tu » anh tu, danh tu, hanh tu
tu mang » tu manh, tu lang, tu quang
mang xa » lang xa, mang may, dang xay
vien da » vien dai, hien dai
cuu tre » cua tre, cau tren, cau treo
xac va » tac va, ac va, bac va
tuc va » thuc va, truc va, duc va
vi cuu » vi luu, vinh cuu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sanh tu mang xa hoi. hieu vien da ((xac va) or (((tuc va) OR (tuc xa)))) hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sanh tu mang xa hoi. hieu vien da ((xac va) OR (((tuc va) OR (tuc xa)))) hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sanh tu mang xa hoi. hieu vien da ((xac va) or (((tuc va) OR (tuc xa)))) hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: so sanh tu mang xa hoi. hieu vien da ((xac va) or (((tuc va) OR (tuc xa)))) hanh vi cuu tre*.