Perhaps you should try some spelling variations:
thieu quang » hieu quang, thien quan, trien quang
lang van » dang van, tang van, hoang van
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
vat dan » va dan, van dan, vat ran
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
dan vi » doan vi, don vi, dan va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty ((lang van) or (van xay)) hoi. thieu quang nam thuc vat dan vi ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((lang van) OR (van xay)) hoi. thieu quang nam thuc vat dan vi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((lang van) or (van xay)) hoi. thieu quang nam thuc vat dan vi ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((lang van) or (van xay)) hoi. thieu quang nam thuc vat dan vi ((cua tre) OR (cuu tre))*.