Perhaps you should try some spelling variations:
ngang cho » nang cho, ngang tho, sang cho
duc manh » suc manh, duc anh, duc minh
sach ty » sach tu, sach thu, xach tay
cho hoc » co hoc, khoa hoc
hieu ve » hieu va, hieu van
duc van » duc va, duc tan, duc phan
hanh di » hanh vi, hanh de, hang di
cua cau » cua cac, cua chu, cua cay
ve cac » va cac, vien cac
di cua » dai cua, doi cua, de cua

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