Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
cau tren » cu tren, dau tren, ca tren
long ha » dong ha, cong ha, dong hoa
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
dan vai » dan va, dan vat, den vai
dan tai » van tai, dan thi, han tai
va nam » van nam, ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky ((lang xa) or (long ha)) hoi. hieu va nam thuc va ((dan vai) or (dan tai)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((lang xa) OR (long ha)) hoi. hieu va nam thuc va ((dan vai) OR (dan tai)) cau tren.
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((lang xa) or (long ha)) hoi. hieu va nam thuc va ((dan vai) or (dan tai)) cau tren*.