Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van nang » van quang, van ban, van dong
cham loc » cham soc, chon loc, hau loc
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
v nang » va nang, vu nang, voi nang
cham o » cham soc
va dan » ca dan, va dao, va dau
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: toc sach ((v nang) OR (van nang)) xa hoi. hieu ve ((cham loc) or (cham o)) va dan di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((v nang) OR (van nang)) xa hoi. hieu ve ((cham loc) OR (cham o)) va dan di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((v nang) OR (van nang)) xa hoi. hieu ve ((cham loc) or (cham o)) va dan di cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((v nang) OR (van nang)) xa hoi. hieu ve ((cham loc) or (cham o)) va dan di cua tre*.