Perhaps you should try some spelling variations:
manh hanh » xanh hanh, danh thanh, minh thanh
hieu van » hieu va, thien van, lieu va
te sach » toc sach
cao duc » dao duc, cao suc, giao duc
cac duc » cac du, cac dac, cac nuoc
cao hoc » co hoc, cho hoc, chat hoc
ty nang » ky nang, ty hang, ly nang
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 ((ty nang) OR (ty xang)) cao hoc. hieu van ((cac duc) or (cao duc)) manh hanh vi cua cay~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ty nang) OR (ty xang)) cao hoc. hieu van ((cac duc) OR (cao duc)) manh hanh vi cua cay*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ty nang) OR (ty xang)) cao hoc. hieu van ((cac duc) or (cao duc)) manh hanh vi cua cay*".