Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
cao hoc » co hoc, cho hoc, chat hoc
van cam » van nam, van lam, van cau
va hanh » van hanh, va thanh, va danh
luu tre » luu tru, cuu tre, luy tre
sac ky » cac ky, sai ky
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: doc ((sac ky) or (sach y)) nang cao hoc. hieu van cam xuc ((va hanh) or (ban thanh)) vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sac ky) OR (sach y)) nang cao hoc. hieu van cam xuc ((va hanh) OR (ban thanh)) vi luu tre.
• Adding a wildcard symbol may retrieve word variants: doc ((sac ky) or (sach y)) nang cao hoc. hieu van cam xuc ((va hanh) or (ban thanh)) vi luu tre*.