Perhaps you should try some spelling variations:
van phong » van dong, hai phong
van phan » van thanh, luan phan, van ban
hanh vai » hanh vi, hanh va, hanh tai
sach ky » sac ky, sach ty, sach kem
cao hoc » co hoc, cho hoc, chat hoc
va hanh » van hanh, va thanh, va danh
vai cua » dai cua, hai cua, lai cua
cua te » cua tu

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) OR (sach y)) nang cao hoc. hieu ((van phan) or (van phong)) duc va hanh vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang cao hoc. hieu ((van phan) OR (van phong)) duc va hanh vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sach y)) nang cao hoc. hieu ((van phan) or (van phong)) duc va hanh vai cua te".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sach y)) nang cao hoc. hieu ((van phan) or (van phong)) duc va hanh vai cua te*.