Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hieu vien » hieu viec, thieu nien, hieu tieng
sach luoc » sach duoc, sach nuoc, sach luan
van hanh » van thanh, ban hanh, van anh
luoc van » luoc can, luoc va, luc van
vai cua » dai cua, hai cua, lai cua
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
ma hoi » mai hoi, xa hoi, ma hoa
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: tu sach ty nang ma hoi. ((hieu vien) or (hieu hien)) sach luoc van hanh ((vi cua) or (vai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ma hoi. ((hieu vien) OR (hieu hien)) sach luoc van hanh ((vi cua) OR (vai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ma hoi. ((hieu vien) or (hieu hien)) sach luoc van hanh ((vi cua) or (vai cua)) tre*.