Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuoc sinh
thuat sach » thuat lanh, thuat san
day nano » dan nano, day nang, day nhanh
hai cua » thai cua, dai cua, hoi cua
dan hai » doan hai, dang hai, dan khai
cau luc » cau truc, cau phuc
hieu va » lieu va, hieu qua
ty nano » tu nano, tao nano
va cau » van cau, va cac, va dau
luc va » duc va, tuc va, loc va
va dan » ca dan, va dao, va dau
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuoc sach) or (thuat sach)) ((ty nano) OR (day nano)) xa hoi. hieu va cau luc va dan hai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (thuat sach)) ((ty nano) OR (day nano)) xa hoi. hieu va cau luc va dan hai cua tu*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (thuat sach)) ((ty nano) OR (day nano)) xa hoi. hieu va cau luc va dan hai cua tu*".