Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, lieu vien
vien cac » vien bach, vien dai, vien da
van hanh » van thanh, ban hanh, van anh
thi hang » thi hanh, thi nang, thi hong
vai cua » dai cua, hai cua, lai cua
vuc van » duc van, luc van, thuc van
cac vuc » cac nuoc, cac vung, cac cuoc
te sach » toc sach
cho hoc » co hoc, khoa hoc
ty hang » ly hang, ty xang, thu hang
vi 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 hang) or (thi hang)) cho hoc. hieu vien cac vuc van hanh ((vi cua) OR (vai cua)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ty hang) OR (thi hang)) cho hoc. hieu vien cac vuc van hanh ((vi cua) OR (vai cua)) cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ty hang) or (thi hang)) cho hoc. hieu vien cac vuc van hanh ((vi cua) OR (vai cua)) cau*".