 
                       
                       
                    
                   
                  
                  
                  The impact factor was devised by Eugene Garfield, the founder of the Institute for Scientific Information (ISI), now part of Thomson Reuters. Impact factors are calculated yearly for those journals that are indexed in Thomson Reuter's Journal Citation Reports.
The following are the Impact Factors for some most cited scientific journals in 2007:
Abbreviated Journal Title  	(Impact Factor)
CA-CANCER J CLIN 	(69.026)
NEW ENGL J MED 	(52.589)
ANNU REV IMMUNOL 	(47.981)
REV MOD PHYS 	(38.403)
NAT REV MOL CELL BIO 	(31.921)
ANNU REV BIOCHEM 	(31.19)
CELL 	(29.887)
PHYSIOL REV 	(29.6)
NAT REV CANCER 	(29.19)
NATURE 	(28.751)
LANCET 	(28.638)
NAT REV IMMUNOL 	(28.3)
NAT MED 	(26.382)
SCIENCE 	(26.372)
NAT IMMUNOL 	(26.218)
ANNU REV NEUROSCI 	(26.077)
NAT GENET 	(25.556)
JAMA-J AM MED ASSOC 	(25.547)
NAT REV NEUROSCI 	(24.52)
CANCER CELL 	(23.858)
ANNU REV CELL DEV BI 	(23.545)
NAT REV DRUG DISCOV 	(23.308)
NAT BIOTECHNOL 	22.848
CHEM REV 	22.757
NAT REV GENET 	22.399
ANNU REV PHARMACOL 	21.696
PROG MATER SCI 	20.846
ANNU REV ASTRON ASTR 	20.29
PHYS REP 	20.263
NAT MATER 	19.782
IMMUNITY 	19.266
ANNU REV PHYSIOL 	18.875
PHARMACOL REV 	18.823
ANNU REV PLANT BIOL 	18.712
ENDOCR REV 	18.493
ANNU REV GENET 	18.302
ANNU REV BIOPH BIOM 	17.757
NAT CELL BIOL 	17.623
BEHAV BRAIN SCI 	17.462
CELL METAB 	17.148
J CLIN INVEST 	16.915
B AM MUS NAT HIST 	16.385
ACCOUNTS CHEM RES 	16.214
ARCH GEN PSYCHIAT 	15.976
CLIN MICROBIOL REV 	15.764
J NATL CANCER I 	15.678
NAT NEUROSCI 	15.664
J EXP MED 	15.612
ANN INTERN MED 	15.516
J CLIN ONCOL 	15.484
NAT METHODS 	15.478
TRENDS BIOCHEM SCI 	14.994
NAT REV MICROBIOL 	14.959
NAT NANOTECHNOL 	14.917
TRENDS ECOL EVOL 	14.797
GENE DEV 	14.795
NAT PHYS 	14.677
MICROBIOL MOL BIOL R 	14.629
MAT SCI ENG R 	14.4
ANNU REV MICROBIOL 	14.362
NAT CHEM BIOL 	13.683
TRENDS CELL BIOL 	13.527
PLOS BIOL 	13.501
CURR OPIN CELL BIOL 	13.444
ANNU REV MED 	13.415
NEURON 	13.41
ANNU REV PSYCHOL 	13.4
MOL CELL 	13.156
CHEM SOC REV 	13.082
ANNU REV NUCL PART S 	12.885
PROG POLYM SCI 	12.809
CIRCULATION 	12.755
PLOS MED 	12.601
TRENDS NEUROSCI 	12.479
DEV CELL 	12.436
LANCET ONCOL 	12.247
LANCET INFECT DIS 	12.058
ALDRICHIM ACTA 	11.929
SURF SCI REP 	11.923
CYTOKINE GROWTH F R 	11.816
GASTROENTEROLOGY 	11.673
ANNU REV BIOMED ENG 	11.567
REP PROG PHYS 	11.366
GENOME RES 	11.224
PROG LIPID RES 	11.194
AM J HUM GENET 	11.092
NAT STRUCT MOL BIOL 	11.085
J AM COLL CARDIOL 	11.054
MOL PHARM 	11.03
PSYCHOL BULL 	10.905
MOL PSYCHIATR 	10.9
BLOOD 	10.896
MASS SPECTROM REV 	10.896
ANNU REV PHYTOPATHOL 	10.778
HEPATOLOGY 	10.734
ANNU REV GENOM HUM G 	10.722
ANNU REV ENTOMOL 	10.68
CURR BIOL 	10.539
IMMUNOL REV 	10.536
PROG NEUROBIOL 	10.467
ANNU REV ECOL EVOL S 	10.34
LANCET NEUROL  	10.169
CURR OPIN GENET DEV 	10.15
CURR OPIN STRUC BIOL 	10.15
ANGEW CHEM INT EDIT 	10.031
GUT 	10.015
......