Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc anh
hanh doi » thanh doi, hanh noi, hang doi
van hanh » van thanh, ban hanh, van anh
nong cho » dong cho, rong cho, cong cho
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
cac vuc » cac vung, cac cuoc, cac quoc
doi cua » dai cua, hoi cua
cua cau » cua cac, cua chu, cua cay
hieu ve » hieu va, hieu van
cho hoc » co hoc, khoa hoc
tu nong » tu dong, tu cong, tu tong
hoc cac » hoc cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc sach) OR (hoc cac)) tu nong cho hoc. hieu ve ((cac vuc) or (cac nuoc)) van hanh doi cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (hoc cac)) tu nong cho hoc. hieu ve ((cac vuc) OR (cac nuoc)) van hanh doi cua cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc sach) OR (hoc cac)) tu nong cho hoc. hieu ve ((cac vuc) or (cac nuoc)) van hanh doi cua cau*".