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