Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
ly hoang » le hoang, ly hong, ly hoan
va thanh » gia thanh, ban thanh, va tinh
ly hang » ly quang
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
san cua » sang cua, ban cua, nan cua
dan cua » dan ca, ban cua, dai cua

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 ((ly hoang) or (ly hang)) xa hoi. hieu va pham duc va thanh ((san cua) OR (dan cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((ly hoang) OR (ly hang)) xa hoi. hieu va pham duc va thanh ((san cua) OR (dan cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((ly hoang) or (ly hang)) xa hoi. hieu va pham duc va thanh ((san cua) OR (dan cua)) tre".
• Adding a wildcard symbol may retrieve word variants: hoc sach ((ly hoang) or (ly hang)) xa hoi. hieu va pham duc va thanh ((san cua) OR (dan cua)) tre*.