Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
toc sach » hoc sach, doc sach, thuoc sach
nay tang » nam tang, tay tang, anai tang
tang cho » trang cho, sang cho, hang cho
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
cac luc » cau luc, coc luc, cac cuoc
hieu ve » hieu va, hieu van
cho hoc » co hoc, khoa hoc
cua cay » cua 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: ((te sach) OR (toc sach)) nay tang cho hoc. hieu ve ((cac luc) or (cac nuoc)) van hanh vi cua cay~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) nay tang cho hoc. hieu ve ((cac luc) OR (cac nuoc)) van hanh vi cua cay*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) nay tang cho hoc. hieu ve ((cac luc) or (cac nuoc)) van hanh vi cua cay*".