Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
vai cua » dai cua, hai cua, lai cua
va dinh » van dinh, va kinh, va tinh
va danh » va dan, va hanh, dia danh
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
cua te » cua tu
o hai » co hai, so hai, o lai

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 thu nang ((xa hoi) or (o hai)). hieu ve pham duc ((va danh) OR (va dinh)) vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach thu nang ((xa hoi) OR (o hai)). hieu ve pham duc ((va danh) OR (va dinh)) vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach thu nang ((xa hoi) or (o hai)). hieu ve pham duc ((va danh) OR (va dinh)) vai cua te".
• Adding a wildcard symbol may retrieve word variants: hoc sach thu nang ((xa hoi) or (o hai)). hieu ve pham duc ((va danh) OR (va dinh)) vai cua te*.