Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, lieu vien
toc sach » hoc sach, doc sach, thuoc sach
thi nang » ki nang, thi hanh
thi cong » tai cong, thien cong
van hanh » van thanh, ban hanh, van anh
cao hoc » co hoc, cho hoc, chat hoc
vien da » vien dai, hien dai
xuc van » duc van, luc van, vuc van
vi cua » vai cua
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 ((thi nang) OR (thi cong)) cao hoc. hieu vien da xuc van hanh ((vi cua) or (di cua)) cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((thi nang) OR (thi cong)) cao hoc. hieu vien da xuc van hanh ((vi cua) OR (di cua)) cac*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((thi nang) OR (thi cong)) cao hoc. hieu vien da xuc van hanh ((vi cua) or (di cua)) cac*".