Top 20 countries in physics 1997-2007

	Country/Territory	Papers	Citations	Impact
1	Switzerland	22,231	304,182	13.68
2	Denmark	7,925	101,350	12.79
3	US	218,045	2,719,244	12.47
4	Netherlands	17,407	206,652	11.87
5	Austria	9,137	105,854	11.59
6	Germany	104,592	1,100,855	10.53
7	Israel	14,040	147,556	10.51
8	England	55,085	577,457	10.48
9	Sweden	15,431	149,739	9.70
10	Canada	24,759	238,065	9.62
11	France	74,124	683,324	9.22
12	Spain	28,461	261,164	9.18
13	Italy	49,700	449,636	9.05
14	Belgium	12,265	105,694	8.62
15	Australia	15,189	1,456	8.39
16	Japan	117,017	899,691	7.69
17	Poland	24,529	168,958	6.89
18	Brazil	19,956	121,789	6.10
19	South Korea	32,313	191,334	5.92
20	Russia	80,575	458,682	5.69

Essential Science Indicators lists nations ranked in the top 50 per cent for a field over a given period, based on total citations. In physics, 87 nations are listed, meaning 174 were surveyed. Twenty-two nations earned at least 100,000 citations. Those not included in the ranking above are India and China, ranked 21st and 22nd respectively. India’s 28,786 papers attracted 162,061 citations, for a cites/paper score of 5.63, whereas China’s 86,679 papers collected 371,287 citations, for a cites/paper score of 4.28. China ranks fourth in output and eighth in total citations worldwide. India ranks 10th in output and 15th in citations. Both are clearly prodigious producers, but they have not yet become international competitors in impact. As we have seen with other fields, Switzerland, Denmark, and The Netherlands, although relatively small in output, show strongly in per paper influence.

The data above were extracted from Thomson Scientific’s Essential Science Indicators database. This database, currently covering the period January 1997 to December 2007, surveys only journal articles (original research reports and review articles) indexed by Thomson Scientific. Articles are assigned to a category based on the journals in which they were published and Thomson Scientific’s journal-to-category field definition scheme. Both articles tabulated and citation counts to those articles are for the period indicated. Here our ranking in physics is by citations per paper – among nations that collected 100,000 or more citations – to reveal weighted impact. For articles with multiple authors from different nations, each nation receives full, not fractional, citation credit. For more information on Thomson Scientific’s Essential Science Indicators, see http://scientific.thomson.com/products/esi.

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