Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
cac loc » cac lop, cac toc, cac hoc
hanh di » hanh de, hang di, danh di
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
y lang » o lang, _ lang, tay lang
loc va » hoc va, luc 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 y lang xa hoi. hieu va cac loc va ((hanh di) or (hanh vi)) ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y lang xa hoi. hieu va cac loc va ((hanh di) OR (hanh vi)) ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y lang xa hoi. hieu va cac loc va ((hanh di) or (hanh vi)) ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: toc sach y lang xa hoi. hieu va cac loc va ((hanh di) or (hanh vi)) ((cua tre) OR (cuu tre))*.