Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
thu sach » tu sach, thuat sach, thuoc sach
lang vai » lang van, lang dai, lang hai
vai cua » dai cua, hai cua, lai cua
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
tuc va » thuc va, truc va, duc va
cua tu » cua tuc, cua su, cua cu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (thu sach)) ky nang ma hoa. hieu vien cac ((tuc va) OR (tuc xa)) lang vai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (thu sach)) ky nang ma hoa. hieu vien cac ((tuc va) OR (tuc xa)) lang vai cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (thu sach)) ky nang ma hoa. hieu vien cac ((tuc va) OR (tuc xa)) lang vai cua tu".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (thu sach)) ky nang ma hoa. hieu vien cac ((tuc va) OR (tuc xa)) lang vai cua tu*.