Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
toc sach » hoc sach, doc sach, thuoc sach
cua tre » cua te, cua triet, dua tren
dinh vi » dinh ve, dinh viet, dinh tri
thuc va » thuc vat, thuc dan, thuc day
sach ty » sach y, sach tu, sach thu
ve pham » vi pham, v pham, ve phan
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
cuu tre » cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ty nang xa hoi. hieu ve pham thuc va ((dinh vi) or (chinh tri)) ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang xa hoi. hieu ve pham thuc va ((dinh vi) OR (chinh tri)) ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty nang xa hoi. hieu ve pham thuc va ((dinh vi) or (chinh tri)) ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang xa hoi. hieu ve pham thuc va ((dinh vi) or (chinh tri)) ((cua tre) OR (cuu tre))*.