Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
cham hoi » cham voi, cham h'roi, pham hoai
cham hoc » cham soc, chat hoc, cho hoc
lang van » dang van, tang van, hoang van
te sach » toc sach
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
mang xa » lang xa, mang may, dang xay
luu tre » luu tru, cuu tre, luy tre
vi luu » vi lua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky ((mang xa) or (lang van)) hoi. hieu va ((cham hoc) OR (cham hoi)) van hanh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((mang xa) OR (lang van)) hoi. hieu va ((cham hoc) OR (cham hoi)) van hanh vi luu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky ((mang xa) or (lang van)) hoi. hieu va ((cham hoc) OR (cham hoi)) van hanh vi luu tre*".