Perhaps you should try some spelling variations:
cham duc » pham duc, cham soc, pham duy
su sach » so sach, vu sach
va tinh » may tinh
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
tu nano » truc nano
tu nang » tru nang, tu nong, tu lang
va chu » va che, va chi
va cau » van cau, va cac, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((tu nang) or (tu nano)) xa hoi. hieu vu cham duc va tinh ((va chu) OR (va cau)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((tu nang) OR (tu nano)) xa hoi. hieu vu cham duc va tinh ((va chu) OR (va cau)) te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((tu nang) or (tu nano)) xa hoi. hieu vu cham duc va tinh ((va chu) OR (va cau)) te*".