Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang cho » nang chon, ngang cho, nang cao
van hanh » van thanh, ban hanh, van ban
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
sach tu » sach thu, cach tu, sach ty
van anh » van thanh, tuan anh, van minh
cua cay » cua cac
cac vuc » cac vung, cac cuoc, cac quoc
hieu ve » hieu va, hieu van
cho hoc » co hoc, khoa hoc
tu nang » tru nang, tu nong, tu nano
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: toc sach tu nang cho hoc. hieu ve ((cac vuc) or (cac nuoc)) ((van hanh) OR (van anh)) di cua cay~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tu nang cho hoc. hieu ve ((cac vuc) OR (cac nuoc)) ((van hanh) OR (van anh)) di cua cay*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach tu nang cho hoc. hieu ve ((cac vuc) or (cac nuoc)) ((van hanh) OR (van anh)) di cua cay*".