Perhaps you should try some spelling variations:
dua tren » dung tren
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
hieu van » hieu va, thien van, lieu va
sach ly » sach y, sach lo, sach ty
lua tre » cua tre, luy tre, luat tri
te sach » toc sach
cac luc » cau luc, coc luc, cac cuoc
ly nang » ky nang, ly hang, ly vang
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va

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 ly nang x ho. hieu van ((cac luc) OR (cac nuoc)) va dan vi ((lua tre) or (dua tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ly nang x ho. hieu van ((cac luc) OR (cac nuoc)) va dan vi ((lua tre) OR (dua tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ly nang x ho. hieu van ((cac luc) OR (cac nuoc)) va dan vi ((lua tre) or (dua tren))".
• Adding a wildcard symbol may retrieve word variants: te sach ly nang x ho. hieu van ((cac luc) OR (cac nuoc)) va dan vi ((lua tre) or (dua tren))*.