Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
tinh di » tinh doi, trinh di, tinh da
va tinh » may tinh
cao suc » cao su
so sach » so sanh, bo sach, co sach
vu khac » vu kham, vu khanh, bui khac
cao duc » dao duc, giao duc, tao duoc
di cau » da cau, diem cau
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (vu khac)) ky nang x hoi. hieu van ((cao duc) or (cao suc)) va tinh di cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (vu khac)) ky nang x hoi. hieu van ((cao duc) OR (cao suc)) va tinh di cau tren.
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (vu khac)) ky nang x hoi. hieu van ((cao duc) or (cao suc)) va tinh di cau tren*.