Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach vuc » sach duoc, sach nuoc, sach truc
vuc nang » cuc nang, vu nang, chuc nang
danh di » danh du, xanh di, danh dien
cua tre » cua te, cuu tre, cua triet
nang co » nang cao, nang doc, nang noi
va cam » va cham, va cao, va cai
co hoi » co hoc, co loi
dan di » dan da, dan de, dan li

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 vuc nang co hoi. hieu ((va cam) or (va cac)) duc va ((dan di) OR (danh di)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach vuc nang co hoi. hieu ((va cam) OR (va cac)) duc va ((dan di) OR (danh di)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach vuc nang co hoi. hieu ((va cam) or (va cac)) duc va ((dan di) OR (danh di)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach vuc nang co hoi. hieu ((va cam) or (va cac)) duc va ((dan di) OR (danh di)) cua tre*.