Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
va triet » va thiet, va trien, ve triet
manh hai » lanh hai, minh hai, thanh hai
ban manh » ban hanh, van manh, ban mach
duc ban » duc tan, duc van, dua ban
su sach » so sach, vu sach
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
xay hoi » xa hoi, tay hoi, cay phoi
ky danh » ky anh
ky dang » ky nang
ve cac » va cac, vien cac

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 ((ky dang) OR (ky danh)) xay hoi. hieu ve cac duc ban manh hai ((cua triet) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky dang) OR (ky danh)) xay hoi. hieu ve cac duc ban manh hai ((cua triet) OR (va triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky dang) OR (ky danh)) xay hoi. hieu ve cac duc ban manh hai ((cua triet) or (va triet))".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky dang) OR (ky danh)) xay hoi. hieu ve cac duc ban manh hai ((cua triet) or (va triet))*.