Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
van chao » van chat, van hao, van cho
doc sach » hoc sach, nuoc sach, dac sac
cau tren » cu tren, dau tren, ca tren
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
dan vai » dan va, dan tai, dan vat
cuu tre » cua tre, cau treo
va dan » ca dan, va dao, va dau
xu va » xu van, tu va, su va

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) or (doc sach)) ky lang xa hoi. hieu van chao xu va dan vai ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky lang xa hoi. hieu van chao xu va dan vai ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) ky lang xa hoi. hieu van chao xu va dan vai ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ky lang xa hoi. hieu van chao xu va dan vai ((cuu tre) OR (cau tren))*.