中国科学技术信息研究所--国家工程技术数字图书馆

harvard university.(11)

iowa state university.(9)

the university of wisconsin - madison.(8)

university of california los angeles.(8)

cornell university.(6)

university of california berkeley.(5)

university of minnesota.(5)

university of pennsylvania.(5)

yale university.(5)

north dakota state university.(4)

rutgers the state university of new jersey school of graduate studies.(4)

the university of north carolina at chapel hill(4)

washington state university.(4)

california institute of technology.(3)

colorado state university.(3)

michigan state university.(3)

south dakota state university.(3)

the george washington university.(3)

the ohio state university.(3)

university of california davis.(3)

university of california san diego.(3)

university of california santa cruz.(3)

university of michigan.(3)

university of notre dame.(3)

university of toronto (canada).(3)

boston university.(2)

clemson university(2)

emory university.(2)

harvard university(2)

new mexico state university.(2)