全文获取类型
收费全文 | 25242篇 |
免费 | 2221篇 |
国内免费 | 2311篇 |
专业分类
29774篇 |
出版年
2024年 | 44篇 |
2023年 | 219篇 |
2022年 | 478篇 |
2021年 | 755篇 |
2020年 | 655篇 |
2019年 | 754篇 |
2018年 | 781篇 |
2017年 | 670篇 |
2016年 | 898篇 |
2015年 | 1467篇 |
2014年 | 1657篇 |
2013年 | 1840篇 |
2012年 | 2335篇 |
2011年 | 1994篇 |
2010年 | 1424篇 |
2009年 | 1294篇 |
2008年 | 1622篇 |
2007年 | 1476篇 |
2006年 | 1397篇 |
2005年 | 1285篇 |
2004年 | 1191篇 |
2003年 | 1051篇 |
2002年 | 896篇 |
2001年 | 570篇 |
2000年 | 482篇 |
1999年 | 447篇 |
1998年 | 302篇 |
1997年 | 225篇 |
1996年 | 203篇 |
1995年 | 182篇 |
1994年 | 159篇 |
1993年 | 118篇 |
1992年 | 143篇 |
1991年 | 115篇 |
1990年 | 92篇 |
1989年 | 90篇 |
1988年 | 59篇 |
1987年 | 73篇 |
1986年 | 56篇 |
1985年 | 29篇 |
1984年 | 20篇 |
1983年 | 37篇 |
1982年 | 16篇 |
1981年 | 18篇 |
1979年 | 18篇 |
1978年 | 14篇 |
1977年 | 13篇 |
1976年 | 13篇 |
1972年 | 12篇 |
1970年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Zhang Z Sun H Zhang Y Zhao Y Shi B Sun S Lu H Bu D Ling L Chen R 《Journal of theoretical biology》2006,240(2):200-208
As a powerful tool for gene function prediction, gene fusion has been widely studied in prokaryotes and certain groups of eukaryotes, but it has been little applied in studies of mammalian genomes. With the first fully sequenced mammalian genomes (human, mouse, rat) now available, we defined and collected a set of fusion/fission event-linked segments (FFLS) based on structured organized genomic alignment. The statistics of the sequence features highlighted the FFLSs against their random context. We found that there are three groups of FFLSs with different component pairs (i.e. gene-gene, gene-noncoding and noncoding-noncoding) in all three mammalian genomes. The proteins encoded by the components of FFLSs in the first group shown a strong tendency to interact with each other. The segmental components in the last two groups which did not contain any protein-coding genes, were found not only to be transcribed to some level, but also more conserved than the random background. Thus, these segments are possibly carrying certain biologically functional elements. We propose that FFLS may be a potential tool for prediction and analysis of function and functional interaction of genetic elements, including both genes and noncoding elements, in mammalian genomes. The full list of the FFLSs in the genomes of the three mammals is available as supporting information at doi:10.1016/j.jtbi.2005.09.016. 相似文献
103.
104.
105.
106.
High Performance Flexible Supercapacitor Electrodes Composed of Ultralarge Graphene Sheets and Vanadium Dioxide 下载免费PDF全文
Little is known regarding the effect of the graphene lateral size on the electrochemical performance of hybrid graphene electrode. This work examines the electrochemical performance of a flexible hybrid supercapacitor electrode composed of ultralarge graphene oxide (UGO; mean lateral size of 47 ± 22 μm) and vanadium dioxide (VO2) nanobelts, referring to a reference electrode composed of small scale graphene oxide (SGO; mean lateral size of 0.8 ± 0.5 μm) and VO2.Thermal treatment converts UGO/VO2 and SGO/VO2 to URGO/VO2 (denoted VURGO) and SRGO/VO2 (denoted VSRGO) electrodes, respectively. The sheet resistance of the VURGO film (0.57 ± 0.03 kΩ sq.–1) was two orders of magnitude lower than that of the VSRGO (55.74 ± 9.35 kΩ sq.–1). The VURGO hybrid electrode showed a specific capacitance of 769 F g?1, which was significantly better than the corresponding values for the VSRGO electrode (385 F/g). These results support the notion that the use of ultralarge graphene sheets (≈22 500 μm2) lowers the intersheet resistance due to the presence of fewer intersheet tunneling barriers. This article highlights the potential utility of URGO (as a conductive support) in hybrid electrode containing VO2 nanobelts for high performance flexible hybrid supercapacitor. 相似文献
107.
Auweter SD Yu HB Arena ET Guttman JA Finlay BB 《Microbes and infection / Institut Pasteur》2012,14(2):148-154
Effectors translocated into the host cell by Salmonella enterica serovar Typhimurium are critical for bacterial virulence. For many effectors, the mechanisms of their interactions with host pathways are not yet understood. We have recently found an interaction between the SPI-2 effector SseL and oxysterol-binding protein (OSBP). We show here that SseL binds the N-terminus of OSBP and that S. Typhimurium infection results in redistribution of OSBP. We furthermore demonstrate that OSBP is required for efficient replication of intracellular S. Typhimurium. This suggests that S. Typhimurium hijacks OSBP-dependent pathways to benefit its intracellular life-style, possibly by SseL- and OSBP-mediated manipulation of host lipid metabolism. 相似文献
108.
转基因在玉米中的遗传分离与整合特性的研究 总被引:23,自引:0,他引:23
用PCR和DNA分子杂交方法研究了转基因Bt在3种不同方法获得的8个转化体后代中的遗传分离、整合性质及其稳定性,结果表明:(1)转基因在大多数转化体后中呈简单的孟德尔遗传;在R1至R2代,部分家系中转化体比例偏低,有的发生转基因丢失,但到R3代以后均趋于正常的孟德尔遗传方式,在群体中固定下来;(2)转基因在不同转化体中的整合类型有一定差异,但整合的位点和拷贝数都较少,且多呈串联或紧密连锁的整合;( 相似文献
109.
110.
Underiner TL Ruggeri B Aimone L Albom M Angeles T Chang H Hudkins RL Hunter K Josef K Robinson C Weinberg L Yang S Zulli A 《Bioorganic & medicinal chemistry letters》2008,18(7):2368-2372
Orally bioavailable, dual inhibitors of TIE-2/VEGF-R2 were identified by elaborating the C3/N13 SAR around a fused pyrrolodihydroindazolocarbazole scaffold. Analogs bearing a C3-thiophencarbonyl group were evaluated in enzymatic and cellular biochemical assays; two orally bioavailable analogs were further profiled in functional assays and found to inhibit microvessel growth in rat aortic explant cultures and inhibit Ang-1-stimulated chemotaxis of HUVECs. 相似文献