Perhaps you should try some spelling variations:
thieu trang » thu trang, thi trang, hien trang
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, hoc dan, thuc vat
truc va » thuc va, thuc vat, trung va
van cau » van dau, van hau, van chat
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
luu tre » luu tru, cuu tre, luy tre
ma hoi » xa hoi, ma hoa, me hoi
vi luu » vi lua

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 thieu trang ((ma hoi) OR (mai hoi)). hieu van cau ((truc va) or (thuc dan)) hanh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thieu trang ((ma hoi) OR (mai hoi)). hieu van cau ((truc va) OR (thuc dan)) hanh vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thieu trang ((ma hoi) OR (mai hoi)). hieu van cau ((truc va) or (thuc dan)) hanh vi luu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach thieu trang ((ma hoi) OR (mai hoi)). hieu van cau ((truc va) or (thuc dan)) hanh vi luu tre*.