Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
cham tuc » nham thuc, pham thuc, tham thuc
xa thanh » va thanh, ha thanh, ta thanh
tu sach » thu sach, su sach, te sach
do cua » doi cua, co cua, dong cua
de cua » le cua, te cua, dieu cua
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: ((tu sach) or (hoc sach)) ky nang x hoi. hieu van cham tuc xa thanh ((do cua) OR (de cua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (hoc sach)) ky nang x hoi. hieu van cham tuc xa thanh ((do cua) OR (de cua)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (hoc sach)) ky nang x hoi. hieu van cham tuc xa thanh ((do cua) OR (de cua)) viet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (hoc sach)) ky nang x hoi. hieu van cham tuc xa thanh ((do cua) OR (de cua)) viet*.