Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
cua tre » cua te, cua triet, dua tren
hieu ve » hieu va, hieu van
cuu tre » cau tren, cau treo
lang xa » lang ha, dang xay, lang van
dam tu » nam tu, cam tu, tam tu
tu van » tu va
y lang » o lang, _ lang, tay lang
ve dam » ven dam, ke dam, va dam

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)) y lang xa hoi. hieu ve dam tu van hanh vi ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y lang xa hoi. hieu ve dam tu van hanh vi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) y lang xa hoi. hieu ve dam tu van hanh vi ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) y lang xa hoi. hieu ve dam tu van hanh vi ((cua tre) OR (cuu tre))*.