汗牛充栋 (汗牛充棟) hàn niú chōng dòng

hàn niú chōng dòng set phrase enough books to make a pack-ox sweat or to fill a house to the rafters
Domain: Idiom 成语
Notes: (CC-CEDICT '汗牛充棟'; Guoyu '汗牛充棟')