全文获取类型
收费全文 | 381篇 |
免费 | 23篇 |
专业分类
404篇 |
出版年
2023年 | 2篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 16篇 |
2014年 | 23篇 |
2013年 | 28篇 |
2012年 | 20篇 |
2011年 | 15篇 |
2010年 | 24篇 |
2009年 | 29篇 |
2008年 | 14篇 |
2007年 | 14篇 |
2006年 | 13篇 |
2005年 | 13篇 |
2004年 | 15篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 13篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 11篇 |
1997年 | 12篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 1篇 |
1991年 | 6篇 |
1989年 | 2篇 |
1988年 | 7篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 16篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有404条查询结果,搜索用时 15 毫秒
101.
JM Mcnulty 《Biotechnic & histochemistry》2013,88(5-6):191-196
Zirconyl hematoxylin stains acidic mucins darkly and specifically using a solution of 100 mg hematoxylin, 5 ml ethanol, 5 ml 0.5% sodium iodate, 400 mg zirconyl chloride octahydrate, and 30 ml 25% aqueous glycerol. The stain is especially advantageous for studying goblet cells and Paget cells. 相似文献
102.
The evolutionary analysis of the Tnt1 retrotransposon in Nicotiana species reveals the high variability of its regulatory sequences 总被引:2,自引:0,他引:2
We studied the evolution of the tobacco Tnt1 retrotransposon by analyzing
Tnt1 partial sequences containing both coding domains and U3 regulatory
sequences obtained from a number of Nicotiana species. We detected three
different subfamilies of Tnt1 elements, Tnt1A, Tnt1B, and Tnt1C, that
differ completely in their U3 regions but share conserved flanking coding
and LTR regions. U3 divergence between the three subfamilies is found in
the region that contains the regulatory sequences that control the
expression of the well-characterized Tnt1-94 element. This suggests that
expression of the three Tnt1 subfamilies might be differently regulated.
The three Tnt1 subfamilies were present in the Nicotiana genome at the time
of species divergence, but have evolved independently since then in the
different genomes. Each Tnt1 subfamily seems to have conserved its ability
to transpose in a limited and different number of Nicotiana species. Our
results illustrate the high variability of Tnt1 regulatory sequences. We
propose that this high sequence variability could allow these elements to
evolve regulatory mechanisms in order to optimize their coexistence with
their host genome.
相似文献
103.
Background
The leukocyte common antigen related receptor (LAR) protein has been shown to modulate the signal transduction of a number of different growth factors, including insulin and insulin-like growth factor 1. Splice variants exhibit differing roles and are expressed according to tissue type and developmental stage. 相似文献104.
Wei Qi Haiyan Bu Kun Liu Wenjin Li Johannes M. H. Knops Juhong Wang Wenlong Li Guozhen Du 《Plant Ecology》2014,215(10):1187-1198
Plants that share the same habitat often exhibit similar biological traits. As climatic conditions change with increasing elevation, biological traits are expected to vary among plant species with temperate endemic, alpine endemic, or widespread elevational distributions. On a northeast Tibetan flora including temperate (1,850–2,800 m a.s.l.), subalpine (2,800–3,400 m a.s.l.), and alpine (3,400–4,150 m a.s.l.) vegetations, we analyzed patterns of change for ten traits of 326 annual and perennial herbaceous species using both univariate and multivariate analyses. The traits selected for this study fit in different groups, i.e., traits related to light competition, photosynthesis, reproduction, defense, and dispersal. We found that plant shape (plant height and leaf distribution along stem) and leaf traits (specific leaf area and leaf area) were significant predictors of plants’ elevational distributions, suggesting an important role for a trade-off between light competition and biomass costs in support structures, and between photosynthetic efficiency and leaf defense. Moreover, species with a broad distribution had significantly higher seed germination and shorter first germination time, as compared to species with narrow distributions, which indicates that rapid regeneration may be crucial for widespread species. However, dispersal-related traits may not be the main factor in shaping plants’ elevational distribution because no significant difference was detected in wind- and animal-dispersal ability. In addition, annual species potentially may have different strategies and adaptive mechanisms because we detected no differences in trait related to the elevational distributions. 相似文献
105.
106.
Rick Brouwer Wilma TM Vree Egberts Gerald JD Hengstman Reinout Raijmakers Baziel GM van Engelen Hans Peter Seelig Manfred Renz Rudolf Mierau Ekkehard Genth Ger JM Pruijn Walther J van Venrooij 《Arthritis research & therapy》2001,4(2):1-5
The autoantigenic polymyositis/scleroderma (PM/Scl) complex was recently shown to be the human homologue of the yeast exosome, which is an RNA-processing complex. Our aim was to assess whether, in addition to targeting the known autoantigens PM/Scl-100 and PM/Scl-75, autoantibodies also target recently identified components of the PM/Scl complex. The prevalence of autoantibodies directed to six novel human exosome components (hRrp4p, hRrp40p, hRrp41p, hRrp42p, hRrp46p, hCsl4p) was determined in sera from patients with idiopathic inflammatory myopathy (n = 48), scleroderma (n = 11), or the PM/Scl overlap syndrome (n = 10). The sera were analyzed by enzyme-linked immunosorbent assays and western blotting using the affinity-purified recombinant proteins. Our results show that each human exosome component is recognized by autoantibodies. The hRrp4p and hRrp42p components were most frequently targeted. The presence of autoantibodies directed to the novel components of the human exosome was correlated with the presence of the anti-PM/Scl-100 autoantibody in the sera of patients with idiopathic inflammatory myopathy (IIM), as was previously found for the anti-PM/Scl-75 autoantibody. Other clear associations between autoantibody activities were not found. These results further support the conception that the autoimmune response may initially be directed to PM/Scl-100, whereas intermolecular epitope spreading may have caused the autoantibody response directed to the associated components. 相似文献
107.
Ori Elkayam Refael Segal Daniele Bendayan Robert van Uitert Carla Onnekink Ger JM Pruijn 《Arthritis research & therapy》2010,12(1):R12
Introduction
Patients with tuberculosis (TB) frequently produce anti-citrullinated protein antibodies (ACPA). The objective of this study is to characterize the citrulline-dependence of the ACPA reactivity in sera of patients with mycobacterium infections. 相似文献108.
109.
Inference for imputation estimators 总被引:16,自引:0,他引:16
110.