Perhaps you should try some spelling variations:
sach tham » sach nha
van hanh » van thanh, ban hanh, van anh
sach nay » sach hay, sach vay, sach nang
cau duc » cao duc, cau luc, chu duc
van hoi » van hoc, van hoe, van loi
hieu ve » hieu va, hieu van
duc van » duc va, duc tan, duc manh
vi cua » vai cua, di cua
cua tu » cua tuc, cua su, cua cu
ve cau » ke cau, va cau, ve cac

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 tham) or (sach nay)) lang ((van hoi) OR (van hoa)). hieu ve cau duc van hanh vi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tham) OR (sach nay)) lang ((van hoi) OR (van hoa)). hieu ve cau duc van hanh vi cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach tham) or (sach nay)) lang ((van hoi) OR (van hoa)). hieu ve cau duc van hanh vi cua tu".
• Adding a wildcard symbol may retrieve word variants: tu ((sach tham) or (sach nay)) lang ((van hoi) OR (van hoa)). hieu ve cau duc van hanh vi cua tu*.