Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cua triet, dua tren
hanh va » hang va, hanh vi
thuc va » thuc vat, thuc dan, thuc day
cuu tre » cau tren, cau treo
van cam » van nam, van lam, van cau
lang xa » lang ha, dang xay, lang van
ty lang » tay lang, ty xang, ty hang
tuc va » truc va, tuc xa, duc 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 ty lang xa hoi. hieu van cam ((tuc va) OR (thuc va)) hanh va ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty lang xa hoi. hieu van cam ((tuc va) OR (thuc va)) hanh va ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty lang xa hoi. hieu van cam ((tuc va) OR (thuc va)) hanh va ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: toc sach ty lang xa hoi. hieu van cam ((tuc va) OR (thuc va)) hanh va ((cua tre) or (cuu tre))*.