Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
nang cho » nang chon, ngang cho, nang cao
cac duc » cac du, cao duc, cac dac
cua cau » cua cac, cua chu, cua can
hanh di » hanh vi, hanh de, hang di
duc van » duc va, duc tan, duc manh
cua cay » cua cac
sach ty » sach tu, sach thu, xach tay
hieu ve » hieu va, hieu van
cho hoc » co hoc, khoa hoc
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((sach ty) or (sach y)) nang cho hoc. hieu ve cac duc van hanh di ((cua cau) OR (cua cay))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sach ty) OR (sach y)) nang cho hoc. hieu ve cac duc van hanh di ((cua cau) OR (cua cay))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((sach ty) or (sach y)) nang cho hoc. hieu ve cac duc van hanh di ((cua cau) OR (cua cay))*".