Perhaps you should try some spelling variations:
van thanh » ban thanh
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
van tuan » van quan, van ban, anh tuan
hieu ve » hieu va, hieu van
cao hoc » co hoc, cho hoc, chat hoc
ty nang » ky nang, ty xang, ty hang
cua cay » cua cac
ve cac » va cac, vien cac
vi cua » vai cua, di cua

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

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