全文获取类型
收费全文 | 5007篇 |
免费 | 24篇 |
国内免费 | 36篇 |
专业分类
系统科学 | 77篇 |
丛书文集 | 108篇 |
教育与普及 | 207篇 |
理论与方法论 | 10篇 |
现状及发展 | 302篇 |
研究方法 | 691篇 |
综合类 | 3670篇 |
自然研究 | 2篇 |
出版年
2019年 | 6篇 |
2017年 | 5篇 |
2014年 | 7篇 |
2012年 | 365篇 |
2011年 | 426篇 |
2010年 | 94篇 |
2009年 | 20篇 |
2008年 | 335篇 |
2007年 | 419篇 |
2006年 | 367篇 |
2005年 | 427篇 |
2004年 | 379篇 |
2003年 | 367篇 |
2002年 | 333篇 |
2001年 | 277篇 |
2000年 | 407篇 |
1999年 | 105篇 |
1998年 | 17篇 |
1997年 | 13篇 |
1996年 | 18篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1993年 | 19篇 |
1992年 | 12篇 |
1991年 | 22篇 |
1990年 | 27篇 |
1989年 | 19篇 |
1988年 | 20篇 |
1987年 | 18篇 |
1986年 | 27篇 |
1985年 | 26篇 |
1984年 | 27篇 |
1983年 | 24篇 |
1982年 | 26篇 |
1981年 | 34篇 |
1980年 | 8篇 |
1979年 | 13篇 |
1978年 | 9篇 |
1977年 | 7篇 |
1972年 | 4篇 |
1971年 | 12篇 |
1970年 | 27篇 |
1966年 | 9篇 |
1959年 | 38篇 |
1958年 | 53篇 |
1957年 | 42篇 |
1956年 | 27篇 |
1955年 | 32篇 |
1954年 | 30篇 |
1948年 | 15篇 |
排序方式: 共有5067条查询结果,搜索用时 28 毫秒
21.
22.
Gout AM;ADPKD Gene Variant Consortium Ravine D Harris PC Rossetti S Peters D Breuning M Henske EP Koizumi A Inoue S Shimizu Y Thongnoppakhun W Yenchitsomanus PT Deltas C Sandford R Torra R Turco AE Jeffery S Fontes M Somlo S Furu LM Smulders YM Mercier B Ferec C Burtey S Pei Y Kalaydjieva L Bogdanova N McCluskey M Geon LJ Wouters CH Reiterova J Stekrová J San Millan JL Aguiari G Del Senno L 《Nature genetics》2007,39(4):427-428
23.
Mutations in the gene encoding the basal body protein RPGRIP1L, a nephrocystin-4 interactor, cause Joubert syndrome 总被引:7,自引:0,他引:7
Arts HH Doherty D van Beersum SE Parisi MA Letteboer SJ Gorden NT Peters TA Märker T Voesenek K Kartono A Ozyurek H Farin FM Kroes HY Wolfrum U Brunner HG Cremers FP Glass IA Knoers NV Roepman R 《Nature genetics》2007,39(7):882-888
Protein-protein interaction analyses have uncovered a ciliary and basal body protein network that, when disrupted, can result in nephronophthisis (NPHP), Leber congenital amaurosis, Senior-L?ken syndrome (SLSN) or Joubert syndrome (JBTS). However, details of the molecular mechanisms underlying these disorders remain poorly understood. RPGRIP1-like protein (RPGRIP1L) is a homolog of RPGRIP1 (RPGR-interacting protein 1), a ciliary protein defective in Leber congenital amaurosis. We show that RPGRIP1L interacts with nephrocystin-4 and that mutations in the gene encoding nephrocystin-4 (NPHP4) that are known to cause SLSN disrupt this interaction. RPGRIP1L is ubiquitously expressed, and its protein product localizes to basal bodies. Therefore, we analyzed RPGRIP1L as a candidate gene for JBTS and identified loss-of-function mutations in three families with typical JBTS, including the characteristic mid-hindbrain malformation. This work identifies RPGRIP1L as a gene responsible for JBTS and establishes a central role for cilia and basal bodies in the pathophysiology of this disorder. 相似文献
24.
Loss of GLIS2 causes nephronophthisis in humans and mice by increased apoptosis and fibrosis 总被引:4,自引:0,他引:4
25.
26.
Birnbaum RY Zvulunov A Hallel-Halevy D Cagnano E Finer G Ofir R Geiger D Silberstein E Feferman Y Birk OS 《Nature genetics》2006,38(7):749-751
We describe an Israeli Jewish Moroccan family presenting with autosomal dominant seborrhea-like dermatosis with psoriasiform elements, including enhanced keratinocyte proliferation, parakeratosis, follicular plugging, Pityrosporum ovale overgrowth and dermal CD4 lymphocyte infiltrate. We mapped the disease gene to a 0.5-cM region overlapping the PSORS2 locus (17q25) and identified a frameshift mutation in ZNF750, which encodes a putative C2H2 zinc finger protein. ZNF750 is normally expressed in keratinocytes but not in fibroblasts and is barely detectable in CD4 lymphocytes. 相似文献
27.
Common variation in three genes, including a noncoding variant in CFH, strongly influences risk of age-related macular degeneration 总被引:12,自引:0,他引:12
Maller J George S Purcell S Fagerness J Altshuler D Daly MJ Seddon JM 《Nature genetics》2006,38(9):1055-1059
Age-related macular degeneration (AMD) is a common, late-onset disease with seemingly typical complexity: recurrence ratios for siblings of an affected individual are three- to sixfold higher than in the general population, and family-based analysis has resulted in only modestly significant evidence for linkage. In a case-control study drawn from a US-based population of European descent, we have identified a previously unrecognized common, noncoding variant in CFH, the gene encoding complement factor H, that substantially increases the influence of this locus on AMD, and we have strongly replicated the associations of four other previously reported common alleles in three genes (P values ranging from 10(-6) to 10(-70)). Despite excellent power to detect epistasis, we observed purely additive accumulation of risk from alleles at these genes. We found no differences in association of these loci with major phenotypic categories of advanced AMD. Genotypes at these five common SNPs define a broad spectrum of interindividual disease risk and explain about half of the classical sibling risk of AMD in our study population. 相似文献
28.
29.
Ross P Weinhouse H Aloni Y Michaeli D Weinberger-Ohana P Mayer R Braun S de Vroom E van der Marel GA van Boom JH Benziman M 《Nature》1987,325(6101):279-281
Cellulose is the most abundant renewable carbon resource on earth and is an indispensable raw material for the wood, paper, and textile industries. A model system to study the mechanism of cellulose biogenesis is the bacterium Acetobacter xylinum which produces pure cellulose as an extracellular product. It was from this organism that in vitro preparations which possessed high levels of cellulose synthase activity were first obtained in both membranous and soluble forms. We recently demonstrated that this activity is subject to a complex multi-component regulatory system, in which the synthase is directly affected by an unusual cyclic nucleotide activator enzymatically formed from GTP, and indirectly by a Ca (2+) -sensitive phosphodiesterase which degrades the activator. The cellulose synthase activator (CSA) has now been identified as bis-(3' 5')-cyclic diguanylic acid (5'G3'p5'G3'p) on the basis of mass spectroscopic data, nuclear magnetic resonance analysis and comparison with chemically synthesized material. We also report here on intermediary steps in the synthesis and degradation of this novel circular dinucleotide, which have been integrated into a model for the regulation of cellulose synthesis. 相似文献
30.