Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
toc sach » hoc sach, doc sach, thuoc sach
van hanh » ban hanh, van anh, van ban
ngan cho » ngang cho, ngang tho, nganh che
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
cho hoc » co hoc, khoa hoc
ly ngan » ly nhan
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: ((te sach) OR (toc sach)) ly ngan cho hoc. hieu ve cac duc ((van hanh) or (van thanh)) di cua cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ly ngan cho hoc. hieu ve cac duc ((van hanh) OR (van thanh)) di cua cac*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ly ngan cho hoc. hieu ve cac duc ((van hanh) or (van thanh)) di cua cac*".