Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dang mat » dang vat, dang mau, dung mat
va triet » va thiet, va trien, ve triet
sach ty » sach y, sach tu, sach thu
truc va » thuc va, thuc vat, trung va
dan mat » dan dat, dan lat, dan vat
ty nang » ky nang, ty xang, ty hang
ve cam » ve cham, va cam, ve cai
ve cac » va cac, vien cac
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: hoc sach ty nang x hoi. hieu ((ve cam) OR (ve cac)) truc va ((dan mat) or (dang mat)) va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ty nang x hoi. hieu ((ve cam) OR (ve cac)) truc va ((dan mat) OR (dang mat)) va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ty nang x hoi. hieu ((ve cam) OR (ve cac)) truc va ((dan mat) or (dang mat)) va triet".
• Adding a wildcard symbol may retrieve word variants: hoc sach ty nang x hoi. hieu ((ve cam) OR (ve cac)) truc va ((dan mat) or (dang mat)) va triet*.