全文获取类型
收费全文 | 976篇 |
免费 | 77篇 |
专业分类
1053篇 |
出版年
2023年 | 7篇 |
2022年 | 11篇 |
2021年 | 41篇 |
2020年 | 11篇 |
2019年 | 17篇 |
2018年 | 13篇 |
2017年 | 7篇 |
2016年 | 17篇 |
2015年 | 53篇 |
2014年 | 43篇 |
2013年 | 46篇 |
2012年 | 76篇 |
2011年 | 55篇 |
2010年 | 31篇 |
2009年 | 22篇 |
2008年 | 47篇 |
2007年 | 33篇 |
2006年 | 41篇 |
2005年 | 31篇 |
2004年 | 24篇 |
2003年 | 26篇 |
2002年 | 29篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1997年 | 5篇 |
1994年 | 5篇 |
1989年 | 5篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1973年 | 11篇 |
1972年 | 6篇 |
1971年 | 9篇 |
1970年 | 8篇 |
1969年 | 6篇 |
1967年 | 9篇 |
1961年 | 5篇 |
1959年 | 6篇 |
1930年 | 6篇 |
1910年 | 5篇 |
1909年 | 7篇 |
1896年 | 5篇 |
1857年 | 5篇 |
排序方式: 共有1053条查询结果,搜索用时 10 毫秒
111.
Mathara JM Schillinger U Kutima PM Mbugua SK Guigas C Franz C Holzapfel WH 《Current microbiology》2008,56(4):315-321
Lactobacillus plantarum was the major species among the lactic acid bacterial strains isolated from traditional fermented milk of the Maasai in Kenya.
Selected strains were characterized for their functional properties using in vitro standard procedures. All strains expressed
acid tolerance at pH 2.0 after 2-h exposure of values that ranged from 1% to 100%, while bile tolerance of acid-stressed cells
at 0.3% oxgal varied from 30% to 80%. In vitro adhesion to the mucus-secreting cell line HT 29 MTX and binding capacity to
extracellular protein matrices was demonstrated for several strains. The four strains tested in a simulated stomach duodenum
passage survived with recovery rates ranging from 17% to 100%. Strains were intrinsically resistant to several antibiotics
tested. From these in vitro studies, a number of Lb. plantarum strains isolated from the Maasai traditional fermented milk showed probiotic potential. The strains are good candidates for
multifunctional starter culture development. 相似文献
112.
Anaerobic Respiration on Tellurate and Other Metalloids in Bacteria from Hydrothermal Vent Fields in the Eastern Pacific Ocean 下载免费PDF全文
This paper reports the discovery of anaerobic respiration on tellurate by bacteria isolated from deep ocean (1,543 to 1,791 m) hydrothermal vent worms. The first evidence for selenite- and vanadate-respiring bacteria from deep ocean hydrothermal vents is also presented. Enumeration of the anaerobic metal(loid)-resistant microbial community associated with hydrothermal vent animals indicates that a greater proportion of the bacterial community associated with certain vent fauna resists and reduces metal(loid)s anaerobically than aerobically, suggesting that anaerobic metal(loid) respiration might be an important process in bacteria that are symbiotic with vent fauna. Isolates from Axial Volcano and Explorer Ridge were tested for their ability to reduce tellurate, selenite, metavanadate, or orthovanadate in the absence of alternate electron acceptors. In the presence of metal(loid)s, strains showed an ability to grow and produce ATP, whereas in the absence of metal(loid)s, no growth or ATP production was observed. The protonophore carbonyl cyanide m-chlorophenylhydrazone depressed metal(loid) reduction. Anaerobic tellurate respiration will be a significant component in describing biogeochemical cycling of Te at hydrothermal vents. 相似文献
113.
Julius Halaschek-Wiener Mahsa Amirabbasi-Beik Nasim Monfared Markus Pieczyk Christian Sailer Anita Kollar Ruth Thomas Georgios Agalaridis So Yamada Lisa Oliveira Jennifer A. Collins Graydon Meneilly Marco A. Marra Kenneth M. Madden Nhu D. Le Joseph M. Connors Angela R. Brooks-Wilson 《PloS one》2009,4(8)
Individuals who live to 85 and beyond without developing major age-related diseases may achieve this, in part, by lacking disease susceptibility factors, or by possessing resistance factors that enhance their ability to avoid disease and prolong lifespan. Healthy aging is a complex phenotype likely to be affected by both genetic and environmental factors. We sequenced 24 candidate healthy aging genes in DNA samples from 47 healthy individuals aged eighty-five years or older (the ‘oldest-old’), to characterize genetic variation that is present in this exceptional group. These healthy seniors were never diagnosed with cancer, cardiovascular disease, pulmonary disease, diabetes, or Alzheimer disease. We re-sequenced all exons, intron-exon boundaries and selected conserved non-coding sequences of candidate genes involved in aging-related processes, including dietary restriction (PPARG, PPARGC1A, SIRT1, SIRT3, UCP2, UCP3), metabolism (IGF1R, APOB, SCD), autophagy (BECN1, FRAP1), stem cell activation (NOTCH1, DLL1), tumor suppression (TP53, CDKN2A, ING1), DNA methylation (TRDMT1, DNMT3A, DNMT3B) Progeria syndromes (LMNA, ZMPSTE24, KL) and stress response (CRYAB, HSPB2). We detected 935 variants, including 848 single nucleotide polymorphisms (SNPs) and 87 insertion or deletions; 41% (385) were not recorded in dbSNP. This study is the first to present a comprehensive analysis of genetic variation in aging-related candidate genes in healthy oldest-old. These variants and especially our novel polymorphisms are valuable resources to test for genetic association in models of disease susceptibility or resistance. In addition, we propose an innovative tagSNP selection strategy that combines variants identified through gene re-sequencing- and HapMap-derived SNPs. 相似文献
114.
Paul Nieuwenhuysen Julius Clauwaert 《Journal of biochemical and biophysical methods》1981,5(5):279-286
It is impossible to measure the diffusion coefficient of macromolecules directly and accurately by quasi—elastic light scattering, when aggregates cannot be eliminated from the solutions to be investigated. Nevertheless, a simple method can be applied to overcome this problem in many cases. Aggregates are separated from the monomeric macromolecules by rate-zonal sedimentation in a CsCl density gradient in a transparent centrifugation tube; the monomers are then located by laser light scattering intensity measurements; photon correlation spectroscopy of the scattered light finally yields their diffusion coefficient. The viscosity of aqueous CsCl solutions at different temperatures and concentrations allows a good separation by centrifugation and a low uncertainty in the reduction of the measured diffusion coefficient to standard conditions.The application of the method to eukaryotic large ribosomal subunits is described as an example. 相似文献
115.
Topologically associating domains and chromatin loops depend on cohesin and are regulated by CTCF,WAPL, and PDS5 proteins 下载免费PDF全文
Roman R Stocsits Wen Tang Stefan Schoenfelder Gregor Jessberger Matthias Muhar M Julius Hossain Nike Walther Birgit Koch Moritz Kueblbeck Jan Ellenberg Johannes Zuber Peter Fraser Jan‐Michael Peters 《The EMBO journal》2017,36(24):3573-3599
Mammalian genomes are spatially organized into compartments, topologically associating domains (TADs), and loops to facilitate gene regulation and other chromosomal functions. How compartments, TADs, and loops are generated is unknown. It has been proposed that cohesin forms TADs and loops by extruding chromatin loops until it encounters CTCF, but direct evidence for this hypothesis is missing. Here, we show that cohesin suppresses compartments but is required for TADs and loops, that CTCF defines their boundaries, and that the cohesin unloading factor WAPL and its PDS5 binding partners control the length of loops. In the absence of WAPL and PDS5 proteins, cohesin forms extended loops, presumably by passing CTCF sites, accumulates in axial chromosomal positions (vermicelli), and condenses chromosomes. Unexpectedly, PDS5 proteins are also required for boundary function. These results show that cohesin has an essential genome‐wide function in mediating long‐range chromatin interactions and support the hypothesis that cohesin creates these by loop extrusion, until it is delayed by CTCF in a manner dependent on PDS5 proteins, or until it is released from DNA by WAPL. 相似文献
116.
Sigit D. Sasmito Mriadec Sillanp Matthew A. Hayes Samsul Bachri Meli F. Saragi‐Sasmito Frida Sidik Bayu B. Hanggara Wolfram Y. Mofu Victor I. Rumbiak Hendri Sartji Taberima Suhaemi Julius D. Nugroho Thomas F. Pattiasina Nuryani Widagti Barakalla Joeni S. Rahajoe Heru Hartantri Victor Nikijuluw Rina N. Jowey Charlie D. Heatubun Philine zu Ermgassen Thomas A. Worthington Jennifer Howard Catherine E. Lovelock Daniel A. Friess Lindsay B. Hutley Daniel Murdiyarso 《Global Change Biology》2020,26(5):3028-3039
Globally, carbon‐rich mangrove forests are deforested and degraded due to land‐use and land‐cover change (LULCC). The impact of mangrove deforestation on carbon emissions has been reported on a global scale; however, uncertainty remains at subnational scales due to geographical variability and field data limitations. We present an assessment of blue carbon storage at five mangrove sites across West Papua Province, Indonesia, a region that supports 10% of the world's mangrove area. The sites are representative of contrasting hydrogeomorphic settings and also capture change over a 25‐years LULCC chronosequence. Field‐based assessments were conducted across 255 plots covering undisturbed and LULCC‐affected mangroves (0‐, 5‐, 10‐, 15‐ and 25‐year‐old post‐harvest or regenerating forests as well as 15‐year‐old aquaculture ponds). Undisturbed mangroves stored total ecosystem carbon stocks of 182–2,730 (mean ± SD: 1,087 ± 584) Mg C/ha, with the large variation driven by hydrogeomorphic settings. The highest carbon stocks were found in estuarine interior (EI) mangroves, followed by open coast interior, open coast fringe and EI forests. Forest harvesting did not significantly affect soil carbon stocks, despite an elevated dead wood density relative to undisturbed forests, but it did remove nearly all live biomass. Aquaculture conversion removed 60% of soil carbon stock and 85% of live biomass carbon stock, relative to reference sites. By contrast, mangroves left to regenerate for more than 25 years reached the same level of biomass carbon compared to undisturbed forests, with annual biomass accumulation rates of 3.6 ± 1.1 Mg C ha?1 year?1. This study shows that hydrogeomorphic setting controls natural dynamics of mangrove blue carbon stocks, while long‐term land‐use changes affect carbon loss and gain to a substantial degree. Therefore, current land‐based climate policies must incorporate landscape and land‐use characteristics, and their related carbon management consequences, for more effective emissions reduction targets and restoration outcomes. 相似文献
117.
118.
Claudia Eichenberger Silke Oeljeklaus Julia Bruggisser Jan Mani Beat Haenni Iosif Kaurov Moritz Niemann Benoît Zuber Julius Luke Hassan Hashimi Bettina Warscheid Bernd Schimanski Andr Schneider 《Molecular microbiology》2019,112(6):1731-1743
The mitochondrial contact site and cristae organization system (MICOS) mediates the formation of cristae, invaginations in the mitochondrial inner membrane. The highly diverged MICOS complex of the parasitic protist Trypanosoma brucei consists of nine subunits. Except for two Mic10‐like and a Mic60‐like protein, all subunits are specific for kinetoplastids. Here, we determined on a proteome‐wide scale how ablation of individual MICOS subunits affects the levels of the other subunits. The results reveal co‐regulation of TbMic10‐1, TbMic10‐2, TbMic16 and TbMic60, suggesting that these nonessential, integral inner membrane proteins form an interdependent network. Moreover, the ablation of TbMic34 and TbMic32 reveals another network consisting of the essential, intermembrane space‐localized TbMic20, TbMic32, TbMic34 and TbMic40, all of which are peripherally associated with the inner membrane. The downregulation of TbMic20, TbMic32 and TbMic34 also interferes with mitochondrial protein import and reduces the size of the TbMic10‐containing complexes. Thus, the diverged MICOS of trypanosomes contains two subcomplexes: a nonessential membrane‐integrated one, organized around the conserved Mic10 and Mic60, that mediates cristae formation, and an essential membrane‐peripheral one consisting of four kinetoplastid‐specific subunits, that is required for import of intermembrane space proteins. 相似文献
119.
120.
Stefan Zielonka Martin Empting Julius Grzeschik Doreen K?nning Caroline J Barelle Harald Kolmar 《MABS-AUSTIN》2015,7(1):15-25
In addition to antibodies with the classical composition of heavy and light chains, the adaptive immune repertoire of sharks also includes a heavy-chain only isotype, where antigen binding is mediated exclusively by a small and highly stable domain, referred to as vNAR. In recent years, due to their high affinity and specificity combined with their small size, high physicochemical stability and low-cost of production, vNAR fragments have evolved as promising target-binding scaffolds that can be tailor-made for applications in medicine and biotechnology. This review highlights the structural features of vNAR molecules, addresses aspects of their generation using immunization or in vitro high throughput screening methods and provides examples of therapeutic, diagnostic and other biotechnological applications. 相似文献