Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
tru nang » tra nang, truc nano, thi nang
danh hai » dang hai, lanh hai, manh hai
tri nang » thi nang, tra nang, tri bang
hai cua » thai cua, dai cua, hoi cua
va danh » va dinh, va dan, va hanh
bao luc » bao thuc
cao luc » cao duc, cao suc, cau luc
cua te » cua tu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ((tru nang) or (tri nang)) xa hoi. hieu qua ((cao luc) OR (bao luc)) va danh hai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ((tru nang) OR (tri nang)) xa hoi. hieu qua ((cao luc) OR (bao luc)) va danh hai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ((tru nang) or (tri nang)) xa hoi. hieu qua ((cao luc) OR (bao luc)) va danh hai cua te".
• Adding a wildcard symbol may retrieve word variants: doc sach ((tru nang) or (tri nang)) xa hoi. hieu qua ((cao luc) OR (bao luc)) va danh hai cua te*.