Perhaps you should try some spelling variations:
cham duc » pham duc, cham soc, pham duy
su sach » so sach, vu sach
ca chua » ca cua, sua chua
va chua » vua chua, va chu, a chua
va tinh » may tinh
va cham » va chat, va tham
hieu va » lieu va, hieu qua
tu nano » truc nano
tu nang » tru nang, tu nong, tu lang

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 va cham duc va tinh ((va chua) or (ca chua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((tu nang) OR (tu nano)) xa hoi. hieu va cham duc va tinh ((va chua) OR (ca chua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((tu nang) OR (tu nano)) xa hoi. hieu va cham duc va tinh ((va chua) or (ca chua)) te".
• Adding a wildcard symbol may retrieve word variants: su sach ((tu nang) OR (tu nano)) xa hoi. hieu va cham duc va tinh ((va chua) or (ca chua)) te*.