Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien dao » vien dai, vien da, vien cao
va trinh » van trinh, va tinh, lap trinh
doi cua » dai cua, hoi cua
dao tuc » dao duc
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
tuc va » thuc va, truc va, tuc xa
di cua » dai cua, de cua, do 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 ky ((nang ma) or (tang ma)) hoi. hieu vien dao tuc va trinh ((di cua) OR (doi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang ma) OR (tang ma)) hoi. hieu vien dao tuc va trinh ((di cua) OR (doi cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang ma) or (tang ma)) hoi. hieu vien dao tuc va trinh ((di cua) OR (doi cua)) tre*".