Perhaps you should try some spelling variations:
dan thanh » dang thanh, danh thanh, ban thanh
hieu van » thien van, lieu va, hieu ve
so sach » so sanh, bo sach, co sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cam thu » nam thu, cac thu, ca thu
thu dan » thuc dan, thu dang, thu ban
doi cua » hoi cua
y nang » ky nang, ly nang, v nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y nang xa hoi. ((hieu van) OR (hieu va)) cam thu dan thanh ((doi cua) or (dai cua)) cu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y nang xa hoi. ((hieu van) OR (hieu va)) cam thu dan thanh ((doi cua) OR (dai cua)) cu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y nang xa hoi. ((hieu van) OR (hieu va)) cam thu dan thanh ((doi cua) or (dai cua)) cu".
• Adding a wildcard symbol may retrieve word variants: so sach y nang xa hoi. ((hieu van) OR (hieu va)) cam thu dan thanh ((doi cua) or (dai cua)) cu*.