Perhaps you should try some spelling variations:
ninh viet » sinh vien, anh viet
hoc sach » hoc sinh, hoc cac, hoc anh
nano cau » nang cau, bang cau, nano va
cam luc » cam xuc, cau luc
dinh vi » dinh ve, dinh viet, dinh tri
sach ty » sach y, sach tu, sach thu
hieu va » lieu va
ty nano » tu nano, day nano, tao nano
luc va » duc va, tuc va, loc va
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: hoc sach ty nano cau hoi. ((hieu va) OR (hieu qua)) cam luc va ((dinh vi) or (ninh viet)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ty nano cau hoi. ((hieu va) OR (hieu qua)) cam luc va ((dinh vi) OR (ninh viet)) cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ty nano cau hoi. ((hieu va) OR (hieu qua)) cam luc va ((dinh vi) or (ninh viet)) cua te".
• Adding a wildcard symbol may retrieve word variants: hoc sach ty nano cau hoi. ((hieu va) OR (hieu qua)) cam luc va ((dinh vi) or (ninh viet)) cua te*.