全文获取类型
收费全文 | 1006篇 |
免费 | 2篇 |
国内免费 | 2篇 |
专业分类
系统科学 | 13篇 |
理论与方法论 | 5篇 |
现状及发展 | 259篇 |
研究方法 | 100篇 |
综合类 | 567篇 |
自然研究 | 66篇 |
出版年
2018年 | 4篇 |
2016年 | 4篇 |
2014年 | 3篇 |
2013年 | 8篇 |
2012年 | 31篇 |
2011年 | 98篇 |
2010年 | 6篇 |
2008年 | 39篇 |
2007年 | 37篇 |
2006年 | 36篇 |
2005年 | 37篇 |
2004年 | 34篇 |
2003年 | 31篇 |
2002年 | 34篇 |
2001年 | 20篇 |
2000年 | 44篇 |
1999年 | 16篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 18篇 |
1991年 | 10篇 |
1990年 | 19篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 19篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1983年 | 12篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 10篇 |
1979年 | 16篇 |
1978年 | 19篇 |
1977年 | 20篇 |
1976年 | 15篇 |
1975年 | 20篇 |
1974年 | 23篇 |
1973年 | 17篇 |
1972年 | 20篇 |
1971年 | 31篇 |
1970年 | 44篇 |
1969年 | 15篇 |
1968年 | 27篇 |
1967年 | 26篇 |
1966年 | 22篇 |
1965年 | 10篇 |
1964年 | 8篇 |
1963年 | 2篇 |
1961年 | 2篇 |
排序方式: 共有1010条查询结果,搜索用时 15 毫秒
981.
Role for the p53 homologue p73 in E2F-1-induced apoptosis 总被引:20,自引:0,他引:20
982.
Warm-coding deficits and aberrant inflammatory pain in mice lacking P2X3 receptors 总被引:25,自引:0,他引:25
Souslova V Cesare P Ding Y Akopian AN Stanfa L Suzuki R Carpenter K Dickenson A Boyce S Hill R Nebenuis-Oosthuizen D Smith AJ Kidd EJ Wood JN 《Nature》2000,407(6807):1015-1017
ATP activates damage-sensing neurons (nociceptors) and can evoke a sensation of pain. The ATP receptor P2X3 is selectively expressed by nociceptors and is one of seven ATP-gated, cation-selective ion channels. Here we demonstrate that ablation of the P2X3 gene results in the loss of rapidly desensitizing ATP-gated cation currents in dorsal root ganglion neurons, and that the responses of nodose ganglion neurons to ATP show altered kinetics and pharmacology resulting from the loss of expression of P2X(2/3) heteromultimers. Null mutants have normal sensorimotor function. Behavioural responses to noxious mechanical and thermal stimuli are also normal, although formalin-induced pain behaviour is reduced. In contrast, deletion of the P2X3 receptor causes enhanced thermal hyperalgesia in chronic inflammation. Notably, although dorsal-horn neuronal responses to mechanical and noxious heat application are normal, P2X3-null mice are unable to code the intensity of non-noxious 'warming' stimuli. 相似文献
983.
D O Morgan J C Edman D N Standring V A Fried M C Smith R A Roth W J Rutter 《Nature》1987,329(6137):301-307
The primary structure of human insulin-like growth factor II receptor, predicted from the complementary DNA sequence, reveals a transmembrane receptor molecule with a large extracellular domain made up of fifteen repeat sequences and a small region homologous to the collagen-binding domain of fibronectin. The structural and biochemical features of the IGF-II receptor appear identical to those of the cation-independent mannose-6-phosphate receptor. 相似文献
984.
Deletion of genes on chromosome 1 in endocrine neoplasia 总被引:22,自引:0,他引:22
C G Mathew B A Smith K Thorpe Z Wong N J Royle A J Jeffreys B A Ponder 《Nature》1987,328(6130):524-526
Recent studies have identified normal cellular DNA sequences which are lost in the development of embryonal and adult tumours. These tumours are thought to arise after a primary mutation in one allele of such a sequence is followed by loss of its normal homologue. In familial cases, the primary mutation is transmitted in the germ line. The secondary mutation may involve a substantial loss of chromosomal material and thus lead to identification of the site of the inherited mutation. We have examined constitutional and tumour genotypes of medullary thyroid carcinomas and phaeochromocytomas which develop in the dominantly inherited cancer syndrome multiple endocrine neoplasia type 2 (MEN2) to locate the predisposing gene in this syndrome. We observed deletion of a hypervariable region of DNA on the short arm of chromosome 1 in seven out of fourteen tumours. Analysis of the parental origin of the deleted allele in two families showed that it was derived from the affected parent in one case, which suggests that the deletion does not reflect the site of the inherited mutation in MEN2. The deleted region is distal to the breakpoint commonly detected in neuroblastomas, which share with the tumours of MEN2 embryological origin from neuroectoderm. 相似文献
985.
Mutations in COL11A2 cause non-syndromic hearing loss (DFNA13) 总被引:13,自引:0,他引:13
McGuirt WT Prasad SD Griffith AJ Kunst HP Green GE Shpargel KB Runge C Huybrechts C Mueller RF Lynch E King MC Brunner HG Cremers CW Takanosu M Li SW Arita M Mayne R Prockop DJ Van Camp G Smith RJ 《Nature genetics》1999,23(4):413-419
We report that mutation of COL11A2 causes deafness previously mapped to the DFNA13 locus on chromosome 6p. We found two families (one American and one Dutch) with autosomal dominant, non-syndromic hearing loss to have mutations in COL11A2 that are predicted to affect the triple-helix domain of the collagen protein. In both families, deafness is non-progressive and predominantly affects middle frequencies. Mice with a targeted disruption of Col11a2 also were shown to have hearing loss. Electron microscopy of the tectorial membrane of these mice revealed loss of organization of the collagen fibrils. Our findings revealed a unique ultrastructural malformation of inner-ear architecture associated with non-syndromic hearing loss, and suggest that tectorial membrane abnormalities may be one aetiology of sensorineural hearing loss primarily affecting the mid-frequencies. 相似文献
986.
Conservation of a sex-determining gene 总被引:34,自引:0,他引:34
987.
The dynamics of chromosome evolution in birds and mammals 总被引:20,自引:0,他引:20
Burt DW Bruley C Dunn IC Jones CT Ramage A Law AS Morrice DR Paton IR Smith J Windsor D Sazanov A Fries R Waddington D 《Nature》1999,402(6760):411-413
Comparative mapping, which compares the location of homologous genes in different species, is a powerful tool for studying genome evolution. Comparative maps suggest that rates of chromosomal change in mammals can vary from one to ten rearrangements per million years. On the basis of these rates we would expect 84 to 600 conserved segments in a chicken comparison with human or mouse. Here we build comparative maps between these species and estimate that numbers of conserved segments are in the lower part of this range. We conclude that the organization of the human genome is closer to that of the chicken than the mouse and by adding comparative mapping results from a range of vertebrates, we identify three possible phases of chromosome evolution. The relative stability of genomes such as those of the chicken and human will enable the reconstruction of maps of ancestral vertebrates. 相似文献
988.
Nanog safeguards pluripotency and mediates germline development 总被引:3,自引:0,他引:3
Chambers I Silva J Colby D Nichols J Nijmeijer B Robertson M Vrana J Jones K Grotewold L Smith A 《Nature》2007,450(7173):1230-1234
989.
990.