Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
danh vai » danh sai, danh va, doanh van
hieu ve » hieu va, hieu van
tu nang » tru nang, tu nano, tu lang
vai cua » dai cua, hai cua, lai cua
tu nong » tu dong, tu cong, tu tong
va danh » va dinh, va dan, va hanh
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 ((tu nang) OR (tu nong)) ((xa hoi) or (o hai)). hieu ve pham duc va danh vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((tu nang) OR (tu nong)) ((xa hoi) OR (o hai)). hieu ve pham duc va danh vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((tu nang) OR (tu nong)) ((xa hoi) or (o hai)). hieu ve pham duc va danh vai cua te".
• Adding a wildcard symbol may retrieve word variants: hoc sach ((tu nang) OR (tu nong)) ((xa hoi) or (o hai)). hieu ve pham duc va danh vai cua te*.