Perhaps you should try some spelling variations:
dan thuong » dang thuong, dan phuong, han thuong
sach truc » cach thuc, sach tren, sach thu
truc thuc » truc thuoc, thuc thuc, truc thuy
hieu thuc » hieu thuoc, hieu tuc, lieu thuc
hien thuc » kien thuc, bien thuc, hien thu
thuc dan » thuc hanh, hoc dan, thuc vat
tu sach » thu sach, su sach, te sach

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 truc thuc dan thuong ((hieu thuc) OR (hien thuc)) giai~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach truc thuc dan thuong ((hieu thuc) OR (hien thuc)) giai".
• Adding a wildcard symbol may retrieve word variants: tu sach truc thuc dan thuong ((hieu thuc) OR (hien thuc)) giai*.