Perhaps you should try some spelling variations:
khoa hoc » hoa hoc
toc sach » hoc sach, doc sach, thuoc sach
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
lang xa » lang ha, dang xay, lang van
v lang » va lang, o lang, _ lang
cham o » cham soc
ca dan » cac dan, ca dao
dan di » danh di, dan da, dan de
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) v lang xa hoi. hieu ve ((khoa hoc) or (cham o)) ca dan di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) v lang xa hoi. hieu ve ((khoa hoc) OR (cham o)) ca dan di cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) v lang xa hoi. hieu ve ((khoa hoc) or (cham o)) ca dan di cua tre*.