Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
thanh dam » thanh dat, thanh nam, thanh tam
thanh day » thanh dat, thanh tay, thanh dan
nang dai » nang dau, nang tai, lang dai
dai khoa » da khoa, tai khoa, dac khoa
vien cac » vien bach, vien dai, vien da
so sach » so sanh, bo sach, co sach
cuu tre » cua tre, cau tren, cau treo
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
luc va » tuc va, loc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty nang dai khoa. hieu vien cac ((luc va) or (duc va)) ((thanh day) OR (thanh dam)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty nang dai khoa. hieu vien cac ((luc va) OR (duc va)) ((thanh day) OR (thanh dam)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty nang dai khoa. hieu vien cac ((luc va) or (duc va)) ((thanh day) OR (thanh dam)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: so sach ty nang dai khoa. hieu vien cac ((luc va) or (duc va)) ((thanh day) OR (thanh dam)) cuu tre*.