全文获取类型
收费全文 | 657篇 |
免费 | 92篇 |
出版年
2021年 | 7篇 |
2020年 | 5篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 18篇 |
2014年 | 17篇 |
2013年 | 38篇 |
2012年 | 32篇 |
2011年 | 29篇 |
2010年 | 20篇 |
2009年 | 22篇 |
2008年 | 27篇 |
2007年 | 25篇 |
2006年 | 28篇 |
2005年 | 29篇 |
2004年 | 21篇 |
2003年 | 30篇 |
2002年 | 16篇 |
2001年 | 19篇 |
2000年 | 24篇 |
1999年 | 20篇 |
1998年 | 11篇 |
1997年 | 9篇 |
1996年 | 10篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 15篇 |
1991年 | 15篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 14篇 |
1987年 | 17篇 |
1986年 | 19篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 15篇 |
1979年 | 9篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1974年 | 13篇 |
1971年 | 4篇 |
1967年 | 4篇 |
1965年 | 7篇 |
1963年 | 5篇 |
1957年 | 3篇 |
1956年 | 3篇 |
排序方式: 共有749条查询结果,搜索用时 733 毫秒
41.
Ergosterol, episterol, 4α-methyl-5α-ergosta-8,24(28)-dien-3β-ol and 24-methylene-24,25-dihydrolanosterol, isolated from Phycomyces blakesleeanus grown in the presence of methionine-[methyl-2H3], each contained two deuterium atoms; lanosterol, however, was unlabelled. The 14C:3H atomic ratio of the following sterols isolated from P. blakesleeanus grown in the presence of mevalonic acid-[2-14C,(4R)-4-3H1], was: ergosterol, 5:3; episterol, 5:4; ergosta-5,7,24(28)-trien-3β-ol, 5:3; 4α-methyl-5α-ergosta-8,24(28)-dien-3β-ol, 5:4; 24-methylene-24,25-dihydrolanosterol, 6:5; lanosterol, 6:5. The significance of these results in terms of ergosterol biosynthesis is discussed. 相似文献
42.
Albert L. Harting Michelle M. Barbieri Jason D. Baker Tracy A. Mercer Thea C. Johanos Stacie J. Robinson Charles L. Littnan Katie M. Colegrove Dave S. Rotstein 《Marine Mammal Science》2021,37(1):235-250
Identifying, assessing, and ranking the impact of individual threats is fundamental to the conservation and recovery of rare and endangered species. In this analysis, we quantify not only the frequency of specific causes-of-death (CODs) among Main Hawaiian Island (MHI) monk seals, but also assess the impact of individual CODs on the intrinsic growth rate, λ, of the MHI population. We used gross necropsy results, histopathology, and other evidence to assign probabilities of 11 COD types to each mortality and then used Monte Carlo sampling to evaluate the influence of each COD on λ. By right censoring realizations involving specific CODs, we were able to estimate λ (and its associated uncertainty) when CODs were selectively removed from influencing survival. Applying the analysis to all known and inferred deaths believed to have occurred 2004–2019, the CODs with the largest influence on λ were anthropogenic trauma, anthropogenic drowning, and protozoal disease. In aggregate, anthropogenic CODs had a larger effect on the growth rate than either natural or disease CODs. Possible bias associated with differential carcass detection, recovery, and COD classification are discussed. 相似文献
43.
Herbert C. Lee Piyush Kumar Leonard I. Wiebe Robert McDonald John R. Mercer Kazue Ohkura 《Nucleosides, nucleotides & nucleic acids》2013,32(9):1995-2016
Abstract The stereospecific synthesis of 1-(5-deoxy-5-iodo-α-D-arabino-furanosyl)-2-aminoimidazole (iodoaminoimidazole arabinoside: IAIA, 2) is described. The reaction of the protected sugar bromide (8) and trifluoroacetamidoimidazole (10B) gave the coupled product (11B), which gave the free nucleoside (4) on deblocking. It was identical with AIA obtained by reduction of AZA (azomycin arabinoside), whose anomeric configuration was found to be a by the X-ray crystallography. 相似文献
44.
45.
Shuiliang Shi Scott Mercer George J. Eckert Stephen B. Trippel 《Journal of cellular biochemistry》2013,114(4):908-919
Adult articular chondrocytes lack an effective repair response to correct damage from injury or osteoarthritis. Polypeptide growth factors that stimulate articular chondrocyte proliferation and cartilage matrix synthesis may augment this response. Gene transfer is a promising approach to delivering such factors. Multiple growth factor genes regulate these cell functions, but multiple growth factor gene transfer remains unexplored. We tested the hypothesis that multiple growth factor gene transfer selectively modulates articular chondrocyte proliferation and matrix synthesis. We tested the hypothesis by delivering combinations of the transgenes encoding insulin‐like growth factor I (IGF‐I), fibroblast growth factor‐2 (FGF‐2), transforming growth factor beta1 (TGF‐β1), bone morphogenetic protein‐2 (BMP‐2), and bone morphogenetic protien‐7 (BMP‐7) to articular chondrocytes and measured changes in the production of DNA, glycosaminoglycan, and collagen. The transgenes differentially regulated all these chondrocyte activities. In concert, the transgenes interacted to generate widely divergent responses from the cells. These interactions ranged from inhibitory to synergistic. The transgene pair encoding IGF‐I and FGF‐2 maximized cell proliferation. The three‐transgene group encoding IGF‐I, BMP‐2, and BMP‐7 maximized matrix production and also optimized the balance between cell proliferation and matrix production. These data demonstrate an approach to articular chondrocyte regulation that may be tailored to stimulate specific cell functions, and suggest that certain growth factor gene combinations have potential value for cell‐based articular cartilage repair. J. Cell. Biochem. 114: 908–919, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
46.
Unlike humans, certain adult vertebrates such as newts and zebrafish possess extraordinary abilities to functionally regenerate lost appendages and injured organs, including cardiac muscle. Here, we present new evidence that a remodeled extracellular matrix (ECM) directs cell activities essential for cardiac muscle regeneration. Comprehensive mining of DNA microarrays and Gene Ontology term enrichment analyses for regenerating newt and zebrafish hearts revealed that distinct ECM components and ECM-modifying proteases are among the most significantly enriched genes in response to local injury. In contrast, data analyses for mammalian cardiac injury models indicated that inflammation and metabolic processes are the most significantly activated gene groups. In the regenerating newt heart, we show dynamic spatial and temporal changes in tenascin-C, hyaluronic acid, and fibronectin ECM distribution as early as 3 days postamputation. Linked to distinct matrix remodeling, we demonstrate a myocardium-wide proliferative response and radial migration of progenitor cells. In particular, we report dramatic upregulation of a regeneration-specific matrix in the epicardium that precedes the accumulation and migration of progenitor cells. For the first time, we show that the regenerative ECM component tenascin-C significantly increases newt cardiomyocyte cell cycle reentry in vitro. Thus, the engineering of nature-tested extracellular matrices may provide new strategic opportunities for the enhancement of regenerative responses in mammals. 相似文献
47.
Swati P. Mercer Anthony J. Roecker Susan Garson Duane R. Reiss C. Meacham Harrell Kathy L. Murphy Joseph G. Bruno Rodney A. Bednar Wei Lemaire Donghui Cui Tamara D. Cabalu Cuyue Tang Thomayant Prueksaritanont George D. Hartman Steven D. Young Christopher J. Winrow John J. Renger Paul J. Coleman 《Bioorganic & medicinal chemistry letters》2013,23(24):6620-6624
The orexin (or hypocretin) system has been identified as a novel target for the treatment of insomnia due to the wealth of biological and genetic data discovered over the past decade. Recently, clinical proof-of-concept was achieved for the treatment of primary insomnia using dual (OX1R/OX2R) orexin receptor antagonists. However, elucidation of the pharmacology associated with selective orexin-2 receptor antagonists (2-SORAs) has been hampered by the lack of orally bioavailable, highly selective small molecule probes. Herein, the discovery and optimization of a novel series of 2,5-diarylnicotinamides as potent and orally bioavailable orexin-2 receptor selective antagonists is described. A compound from this series demonstrated potent sleep promotion when dosed orally to EEG telemetrized rats. 相似文献
48.
A PBX1 transcriptional network controls dopaminergic neuron development and is impaired in Parkinson's disease
下载免费PDF全文
![点击此处可从《The EMBO journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J Carlos Villaescusa Bingsi Li Enrique M Toledo Pia Rivetti di Val Cervo Shanzheng Yang Simon RW Stott Karol Kaiser Saiful Islam Daniel Gyllborg Rocio Laguna‐Goya Michael Landreh Peter Lönnerberg Anna Falk Tomas Bergman Roger A Barker Sten Linnarsson Licia Selleri Ernest Arenas 《The EMBO journal》2016,35(18):1963-1978
49.
Santini Nadia S. Lovelock Catherine E. Hua Quan Zawadzki Atun Mazumder Debashish Mercer Tim R. Muñoz-Rojas Miriam Hardwick Simon A. Madala Bindu Swapna Cornwell William Thomas Torsten Marzinelli Ezequiel M. Adam Paul Paul Swapan Vergés Adriana 《Ecosystems》2019,22(8):1803-1822
Ecosystems - Saltmarshes provide many valuable ecosystem services including storage of a large amount of ‘blue carbon’ within their soils. To date, up to 50% of the world’s... 相似文献
50.
Schneider Céline M. Steeves Katherine L. Mercer Grace V. George Hannah Paranavitana Leah Simpson Myrna J. Simpson André J. Cahill Lindsay S. 《Metabolomics : Official journal of the Metabolomic Society》2022,18(1):1-11
Metabolomics - The study of lipoprotein metabolism at the population level can provide valuable information for the organisation of lipoprotein related processes in the body. To use this... 相似文献