Perhaps you should try some spelling variations:
pham duy » pham duc
va doanh » van doanh, vay doanh, va danh
cau tren » cu tren, dau tren, ca tren
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
hieu vu » hieu va, hieu ve, hieu su
vu pham » su pham, vi pham, vu kham
cua tre » cua te, cuu tre, cua triet
duy va » duy vat, duy van, day 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 xa hoi. hieu vu pham duy va doanh tai ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty nang xa hoi. hieu vu pham duy va doanh tai ((cua tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: so sach ty nang xa hoi. hieu vu pham duy va doanh tai ((cua tre) or (cau tren))*.