Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cau nuoc » cap nuoc, cac nuoc, dau nuoc
va trinh » van trinh, va tinh, lap trinh
trinh he » trinh han, trinh hoa, trinh thi
sach ty » sach tu, sach thu, xach tay
van cau » van dau, van hau, van chat
ang xa » lang xa, mang xa, dang xay
cua tu » cua tuc, cua cu, cua te
cua su » qua su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ty) or (sach y)) ang xa hoi. hieu van cau nuoc va trinh he ((cua tu) OR (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach y)) ang xa hoi. hieu van cau nuoc va trinh he ((cua tu) OR (cua su)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) or (sach y)) ang xa hoi. hieu van cau nuoc va trinh he ((cua tu) OR (cua su))".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sach y)) ang xa hoi. hieu van cau nuoc va trinh he ((cua tu) OR (cua su))*.