Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
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
nang xa » nang x, lang xa, nang ma
xa danh » va danh, dia danh, nam danh
sai cua » hai cua, lai cua, bai cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (hoc sach)) ky nang xa hoi. hieu van cham tuc xa danh ((sai cua) OR (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ky nang xa hoi. hieu van cham tuc xa danh ((sai cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (hoc sach)) ky nang xa hoi. hieu van cham tuc xa danh ((sai cua) OR (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) ky nang xa hoi. hieu van cham tuc xa danh ((sai cua) OR (dai cua)) tre*.