Perhaps you should try some spelling variations:
thien van » thi van
hanh va » hanh vi
duc van » duc va, duc tan, duc manh
cau duc » cao duc, cau luc, chu duc
sach ky » sac ky, sach y, sach kem
van cau » van dau, van hau, van chat
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ky) or (sach ty)) nang x hoi. thien van cau duc van ((hanh va) OR (hang va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sach ty)) nang x hoi. thien van cau duc van ((hanh va) OR (hang va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) or (sach ty)) nang x hoi. thien van cau duc van ((hanh va) OR (hang va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) or (sach ty)) nang x hoi. thien van cau duc van ((hanh va) OR (hang va)) cua tre*.