Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu san » hieu van, hieu sau, chieu sang
va triet » va thiet, va trien, cua triet
ve triet » va trien, su triet
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
duc van » duc tan, duc manh, duc phan
minh vi » minh voi, dinh vi, minh va
pham » phan

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 san pham ((duc van) or (duc va)) minh vi ((va triet) OR (ve triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang xa hoi. hieu san pham ((duc van) OR (duc va)) minh vi ((va triet) OR (ve triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty nang xa hoi. hieu san pham ((duc van) or (duc va)) minh vi ((va triet) OR (ve triet))".
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang xa hoi. hieu san pham ((duc van) or (duc va)) minh vi ((va triet) OR (ve triet))*.