全文获取类型
收费全文 | 12096篇 |
免费 | 25篇 |
国内免费 | 40篇 |
专业分类
系统科学 | 57篇 |
丛书文集 | 206篇 |
教育与普及 | 45篇 |
理论与方法论 | 64篇 |
现状及发展 | 5281篇 |
研究方法 | 646篇 |
综合类 | 5618篇 |
自然研究 | 244篇 |
出版年
2013年 | 112篇 |
2012年 | 241篇 |
2011年 | 495篇 |
2010年 | 98篇 |
2008年 | 268篇 |
2007年 | 296篇 |
2006年 | 286篇 |
2005年 | 301篇 |
2004年 | 271篇 |
2003年 | 256篇 |
2002年 | 271篇 |
2001年 | 291篇 |
2000年 | 294篇 |
1999年 | 191篇 |
1992年 | 180篇 |
1991年 | 152篇 |
1990年 | 156篇 |
1989年 | 160篇 |
1988年 | 169篇 |
1987年 | 159篇 |
1986年 | 169篇 |
1985年 | 229篇 |
1984年 | 145篇 |
1983年 | 144篇 |
1982年 | 100篇 |
1981年 | 116篇 |
1980年 | 150篇 |
1979年 | 378篇 |
1978年 | 286篇 |
1977年 | 304篇 |
1976年 | 222篇 |
1975年 | 220篇 |
1974年 | 341篇 |
1973年 | 279篇 |
1972年 | 303篇 |
1971年 | 312篇 |
1970年 | 422篇 |
1969年 | 369篇 |
1968年 | 367篇 |
1967年 | 336篇 |
1966年 | 293篇 |
1965年 | 214篇 |
1964年 | 70篇 |
1959年 | 117篇 |
1958年 | 212篇 |
1957年 | 169篇 |
1956年 | 160篇 |
1955年 | 132篇 |
1954年 | 132篇 |
1948年 | 105篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
A genome-wide association study for celiac disease identifies risk variants in the region harboring IL2 and IL21 总被引:14,自引:0,他引:14
van Heel DA Franke L Hunt KA Gwilliam R Zhernakova A Inouye M Wapenaar MC Barnardo MC Bethel G Holmes GK Feighery C Jewell D Kelleher D Kumar P Travis S Walters JR Sanders DS Howdle P Swift J Playford RJ McLaren WM Mearin ML Mulder CJ McManus R McGinnis R Cardon LR Deloukas P Wijmenga C 《Nature genetics》2007,39(7):827-829
We tested 310,605 SNPs for association in 778 individuals with celiac disease and 1,422 controls. Outside the HLA region, the most significant finding (rs13119723; P = 2.0 x 10(-7)) was in the KIAA1109-TENR-IL2-IL21 linkage disequilibrium block. We independently confirmed association in two further collections (strongest association at rs6822844, 24 kb 5' of IL21; meta-analysis P = 1.3 x 10(-14), odds ratio = 0.63), suggesting that genetic variation in this region predisposes to celiac disease. 相似文献
142.
RNA polymerase is poised for activation across the genome 总被引:2,自引:0,他引:2
Muse GW Gilchrist DA Nechaev S Shah R Parker JS Grissom SF Zeitlinger J Adelman K 《Nature genetics》2007,39(12):1507-1511
143.
Saenz HL Engel P Stoeckli MC Lanz C Raddatz G Vayssier-Taussat M Birtles R Schuster SC Dehio C 《Nature genetics》2007,39(12):1469-1476
The bacterial genus Bartonella comprises 21 pathogens causing characteristic intraerythrocytic infections. Bartonella bacilliformis is a severe pathogen representing an ancestral lineage, whereas the other species are benign pathogens that evolved by radial speciation. Here, we have used comparative and functional genomics to infer pathogenicity genes specific to the radiating lineage, and we suggest that these genes may have facilitated adaptation to the host environment. We determined the complete genome sequence of Bartonella tribocorum by shotgun sequencing and functionally identified 97 pathogenicity genes by signature-tagged mutagenesis. Eighty-one pathogenicity genes belong to the core genome (1,097 genes) of the radiating lineage inferred from genome comparison of B. tribocorum, Bartonella henselae and Bartonella quintana. Sixty-six pathogenicity genes are present in B. bacilliformis, and one has been lost by deletion. The 14 pathogenicity genes specific for the radiating lineage encode two laterally acquired type IV secretion systems, suggesting that these systems have a role in host adaptability. 相似文献
144.
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
145.
Huntington’s disease: from huntingtin function and dysfunction to therapeutic strategies 总被引:3,自引:0,他引:3
Borrell-Pagès M Zala D Humbert S Saudou F 《Cellular and molecular life sciences : CMLS》2006,63(22):2642-2660
Huntington’s disease (HD) is a neurodegenerative disorder that usually starts in middle age and is characterized by involuntary
movements (chorea), personality changes and dementia, leading to death within 10–20 years. The defective gene in HD contains
a trinucleotide CAG repeat expansion within its coding region that expresses a polyglutamine repeat in the protein huntingtin.
Together with the characteristic formation of aggregates in HD, aberrant protein interactions and several post-translational
modifications affect huntingtin during disease progression and lead to the dysfunction and death of selective neurons in the
brains of patients. The exact molecular mechanisms by which mutant huntingtin induces cell death are not completely understood
but may involve the gain of new toxic functions and the loss of the beneficial properties of huntingtin. This review focuses
on the cellular functions in which huntingtin is involved and how a better understanding of pathogenic pathways can lead to
new therapeutic approaches.
Received 24 May 2006; received after revision 5 July 2006; accepted 23 August 2006 相似文献
146.
Ethanol, 3 g/kg i.p., did not significantly alter the acute toxicity of amphetamine in the mouse. However, the urinary metabolite pattern was changed, suggesting that ethanol suppressed metabolism of the stimulant during the initial 6 h period. After 24 h, the mouse metabolized the same fraction of a given dose of amphetamine, whether it was given as amphetamine alone or amphetamine mixed with 2,3 or 4 g/kg ethanol. 相似文献
147.
5-Methylcytosine localised in mammalian constitutive heterochromatin 总被引:26,自引:0,他引:26
148.
<正> This paper shows how the so called von Karman model can be obtained as a singular limitof a modified Mindlin-Timoshenko system when the modulus of elasticity in shear k tends to infinity,provided a regularizing term through a fourth order dispersive operator is added.Introducing dampingmechanisms,the authors also show that the energy of solutions for this modified Mindlin-Timoshenkosystem decays exponentially,uniformly with respect to the parameter k.As k→∞,the authors obtainthe damped von Karman model with associated energy exponentially decaying to zero as well. 相似文献
149.
150.
Zhang F.Wu Q.Zeng G. 《复杂系统与复杂性科学》2017,(1):81-87
We consider an SIRS epidemic model with a general direct immunization rate on networks. By constructing suitable Lyapunov functions, we find that the dynamical behvaior of the model is completely determined by the epidemic threshold λc. When λ≤λc, the disease-free equilibrium is globally asymptotically stable; when λ>λc, the endemic equilibrium is globally asymptotically stable. In addition, we propose a uniform direct immunization and a targeted direct immunization. The results show that under the same average immunization rate s there exists a critical immunization-lost rate δc so that the epidemic threshold of the targeted direct immunization is smaller (larger) than that of the uniform direct immunization if δ<δc(δ>δc). © 2017, The Journal of Agency of Complex Systems and Complexity Science. All right reserved. 相似文献