Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
lang van » dang van, tang van, hoang van
cau treo » cau theo, cau tren, cau triet
lang ha » long ha
qua nam » quan nam, cua nam, quang nam
thuc va » thuc vat, thuc dan, thuc day
dan vai » dan va, dan vat, den vai
dan tai » van tai, dan thi, han tai

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

• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((lang van) OR (lang ha)) hoi. hieu qua nam thuc va ((dan vai) OR (dan tai)) cau treo~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y ((lang van) or (lang ha)) hoi. hieu qua nam thuc va ((dan vai) OR (dan tai)) cau treo~".
• Adding a wildcard symbol may retrieve word variants: toc sach y ((lang van) or (lang ha)) hoi. hieu qua nam thuc va ((dan vai) OR (dan tai)) cau treo*.