Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
van thanh » ban thanh, van tuan
vien cay » vien cac, vien cao, vien xay
van hanh » ban hanh, van anh, van ban
cay thuc » cay thuoc, can thuc, day thuc
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

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 ty ((nang xa) OR (lang xa)) hoi. hieu vien cay thuc ((van hanh) or (van thanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang xa) OR (lang xa)) hoi. hieu vien cay thuc ((van hanh) OR (van thanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((nang xa) OR (lang xa)) hoi. hieu vien cay thuc ((van hanh) or (van thanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang xa) OR (lang xa)) hoi. hieu vien cay thuc ((van hanh) or (van thanh)) vi cua tre*.