Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
cac thuc » cach thuc, cac thu, can thuc
den cua » dien cua, de cua, ben cua
cua tre » cua te, cuu tre, cua triet
vu sai » vu san, vu dai, vu tai
vu hai » su hai, vu ha
vat ba » vat va, vat da, hat ba
ba den » ban den, va den, ba don
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: ((vu sai) OR (vu hai)) ky nang x hoi. hieu vien cac thuc vat ba den cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sai) OR (vu hai)) ky nang x hoi. hieu vien cac thuc vat ba den cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu sai) OR (vu hai)) ky nang x hoi. hieu vien cac thuc vat ba den cua tre*.