Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dinh duc » minh duc, tinh duc, sinh duoc
ninh duc » minh duc, tinh duc, sinh duoc
cau tren » cu tren, dau tren, ca tren
nang xa » nang x, lang xa, nang ma
y nang » ky nang, ly nang, v nang
va cam » va cham, va cao, va cai
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 nang xa hoi. lieu ((va cam) or (va cac)) loc va ((dinh duc) OR (ninh duc)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang xa hoi. lieu ((va cam) OR (va cac)) loc va ((dinh duc) OR (ninh duc)) cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang xa hoi. lieu ((va cam) or (va cac)) loc va ((dinh duc) OR (ninh duc)) cau tren".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang xa hoi. lieu ((va cam) or (va cac)) loc va ((dinh duc) OR (ninh duc)) cau tren*.