Perhaps you should try some spelling variations:
duc ngan » duc ngon, luc ngan, dung ngan
duc nhan » duc phan, dac nhan, luc nhan
su sach » so sach, vu sach
ty hang » ly hang, thi hang, thu hang
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
vi cua » vai cua, di cua
cua te » cua tu

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 ((ty hang) or (ty xang)) xa hoi. hieu ve cam ((duc ngan) OR (duc nhan)) hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ty hang) OR (ty xang)) xa hoi. hieu ve cam ((duc ngan) OR (duc nhan)) hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty hang) or (ty xang)) xa hoi. hieu ve cam ((duc ngan) OR (duc nhan)) hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty hang) or (ty xang)) xa hoi. hieu ve cam ((duc ngan) OR (duc nhan)) hanh vi cua te*.