Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
hanh tai » thanh tai, hang tai, han tai
sang tao » hang tai
tai duc » tai cuc, mai duc, tai du
tu sach » thu sach, su sach, te sach
sang ma » tang ma, nang ma, mang may
duc tre » duoc tren, duc tien
tuc va » thuc va, truc va, tuc xa

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 y ((sang ma) or (sang tao)) hoi. hieu vien cac ((tuc va) or (duc va)) hanh tai duc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((sang ma) OR (sang tao)) hoi. hieu vien cac ((tuc va) OR (duc va)) hanh tai duc tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((sang ma) or (sang tao)) hoi. hieu vien cac ((tuc va) or (duc va)) hanh tai duc tre*.