Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
tinh dai » trinh dai, tinh da, tinh hai
sach thu » sach thue, sach thieu, sach tham
lang xa » lang ha, dang xay, lang van
sach ty » sach y, sach tu, xach tay
cac loc » cac lop, cac hoc, cac nuoc
cac toc » cac toi, cac nuoc, cac thoi
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: thu ((sach ty) OR (sach thu)) lang xa hoi. hieu vien ((cac loc) or (cac toc)) may tinh dai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ty) OR (sach thu)) lang xa hoi. hieu vien ((cac loc) OR (cac toc)) may tinh dai cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ty) OR (sach thu)) lang xa hoi. hieu vien ((cac loc) or (cac toc)) may tinh dai cua tu".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ty) OR (sach thu)) lang xa hoi. hieu vien ((cac loc) or (cac toc)) may tinh dai cua tu*.