Perhaps you should try some spelling variations:
van thinh » van thanh, van chinh, van minh
cau tren » cu tren, dau tren, ca tren
viet cau » viet chau, viet ca, viet chu
va trinh » van trinh, va tinh, lap trinh
hieu van » hieu va, thien van, lieu va
lam tuc » lam thuoc, lam truoc, luat tuc
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
mang xa » lang xa, mang may, dang xay
van lam » van nam

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 ky ((mang xa) or (nang x)) hoi. hieu van lam tuc ((va trinh) or (van thinh)) viet cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((mang xa) OR (nang x)) hoi. hieu van lam tuc ((va trinh) OR (van thinh)) viet cau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((mang xa) or (nang x)) hoi. hieu van lam tuc ((va trinh) or (van thinh)) viet cau tren*.