Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
nong cho » dong cho, rong cho, cong cho
cac nuoc » cap nuoc, dat nuoc, cua nuoc
vai cua » dai cua, hai cua, lai cua
te cach » te sach, tu cach, te cac
cho hoc » co hoc, khoa hoc
tu nong » tu dong, tu cong, tu tong
ve cach » va cach, ve cac, ve canh
cua cau » cua cac, cua chu, cua cay

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

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