全文获取类型
收费全文 | 3921篇 |
免费 | 426篇 |
专业分类
4347篇 |
出版年
2022年 | 33篇 |
2021年 | 48篇 |
2020年 | 36篇 |
2019年 | 47篇 |
2018年 | 47篇 |
2017年 | 52篇 |
2016年 | 74篇 |
2015年 | 120篇 |
2014年 | 129篇 |
2013年 | 172篇 |
2012年 | 192篇 |
2011年 | 199篇 |
2010年 | 143篇 |
2009年 | 116篇 |
2008年 | 159篇 |
2007年 | 207篇 |
2006年 | 160篇 |
2005年 | 118篇 |
2004年 | 145篇 |
2003年 | 133篇 |
2002年 | 130篇 |
2001年 | 119篇 |
2000年 | 133篇 |
1999年 | 106篇 |
1998年 | 60篇 |
1996年 | 50篇 |
1995年 | 53篇 |
1994年 | 29篇 |
1993年 | 39篇 |
1992年 | 68篇 |
1991年 | 63篇 |
1990年 | 70篇 |
1989年 | 67篇 |
1988年 | 62篇 |
1987年 | 64篇 |
1986年 | 48篇 |
1985年 | 45篇 |
1984年 | 43篇 |
1983年 | 51篇 |
1982年 | 33篇 |
1981年 | 35篇 |
1979年 | 47篇 |
1978年 | 32篇 |
1977年 | 36篇 |
1976年 | 37篇 |
1975年 | 44篇 |
1974年 | 29篇 |
1973年 | 37篇 |
1971年 | 36篇 |
1970年 | 34篇 |
排序方式: 共有4347条查询结果,搜索用时 0 毫秒
1.
2.
—A resolution of the enhancement of protein synthesis in the visual cortex of rats during first exposure to light (Richardson and Rose , 1972) was achieved by polyacrylamide gel electrophoresis using a double-labelling technique. Differential incorporation of lysine was established between exposed and control animals in two fractions of the soluble proteins and seven fractions of the insoluble proteins. This suggests that exposure to a new experience of this type involves a specific effect on protein synthesis, rather than a general stimulation across all fractions. 相似文献
3.
J H Richardson L L Steinmetz S B Deutscher W A Bookless W L Schmelzinger 《Analytical biochemistry》1979,97(1):17-23
A synchronously pumped krypton ion dye laser fluorescence system is shown to provide tunable, polarized, subnanosecond pulses at high repetition rates, modest peak powers, and low energy. Such a source is uniquely suited to fluorescence investigations of biochemical mechanisms. Applications of this fluorescence excitation source to analysis, life-time determination, and depolarization effects are discussed. 相似文献
4.
A double antibody radioimmunoassay technique is described for the measurement of anti-zona antibodies in the peripheral plasma of marmosets actively immunized against intact cow zonae pellucidae. The method has been shown to be a reliable, repeatable indicator of antibody titer, enabling direct comparison of the response obtained between marmosets. This is the first report of a procedure describing the active immunization of a primate against zona antigens, and the first time a radioimmunoassay technique has been used to monitor profiles of anti-cow zona antibody production following active immunization. The method should prove to be a useful tool in the evaluation of zona antigens as agents for immunocontraception. 相似文献
5.
6.
Shreaya Chakroborty Clark Briggs Megan B. Miller Ivan Goussakov Corinne Schneider Joyce Kim Jaime Wicks Jill C. Richardson Vincent Conklin Benjamin G. Cameransi Grace E. Stutzmann 《PloS one》2012,7(12)
Alzheimer’s disease (AD) is a devastating neurodegenerative condition with no known cure. While current therapies target late-stage amyloid formation and cholinergic tone, to date, these strategies have proven ineffective at preventing disease progression. The reasons for this may be varied, and could reflect late intervention, or, that earlier pathogenic mechanisms have been overlooked and permitted to accelerate the disease process. One such example would include synaptic pathology, the disease component strongly associated with cognitive impairment. Dysregulated Ca2+ homeostasis may be one of the critical factors driving synaptic dysfunction. One of the earliest pathophysiological indicators in mutant presenilin (PS) AD mice is increased intracellular Ca2+ signaling, predominantly through the ER-localized inositol triphosphate (IP3) and ryanodine receptors (RyR). In particular, the RyR-mediated Ca2+ upregulation within synaptic compartments is associated with altered synaptic homeostasis and network depression at early (presymptomatic) AD stages. Here, we offer an alternative approach to AD therapeutics by stabilizing early pathogenic mechanisms associated with synaptic abnormalities. We targeted the RyR as a means to prevent disease progression, and sub-chronically treated AD mouse models (4-weeks) with a novel formulation of the RyR inhibitor, dantrolene. Using 2-photon Ca2+ imaging and patch clamp recordings, we demonstrate that dantrolene treatment fully normalizes ER Ca2+ signaling within somatic and dendritic compartments in early and later-stage AD mice in hippocampal slices. Additionally, the elevated RyR2 levels in AD mice are restored to control levels with dantrolene treatment, as are synaptic transmission and synaptic plasticity. Aβ deposition within the cortex and hippocampus is also reduced in dantrolene-treated AD mice. In this study, we highlight the pivotal role of Ca2+ aberrations in AD, and propose a novel strategy to preserve synaptic function, and thereby cognitive function, in early AD patients. 相似文献
7.
P.Mick Richardson 《Biochemical Systematics and Ecology》1982,10(2):197-199
Published results of the distribution of anthocyanins in the Sterculiaceae have been re-interpreted on the basis of the phylogenetic status of the compounds present. A flavonoid score system was less useful than a cladistic interpretation based on Hennigian arguments. 相似文献
8.
A monoclonal antibody (RBU/01) was raised against human thyroglobulin and its suitability for the immunohistochemical staining of thyroglobulin was determined on fixed, wax-embedded tissue, using the peroxidase anti-peroxidase (PAP) method. The antibody was then used to demonstrate the expression of human thyroglobulin in sections of a human follicular carcinoma of the thyroid which had been grown in immunodeficient mice. It is concluded that the immunohistochemical evaluation of the xenografts with the antibody provides useful information on this xenograft system as a potential model for thyroid carcinoma. 相似文献
9.
10.
Platinum(II) binding to metallothioneins 总被引:1,自引:0,他引:1
The reaction of equine renal metallothionein (MT) with excess K2PtCl4 at pH 2 results in a polymeric adduct containing 17 +/- 2 mol Pt/mol MT. A monomeric adduct containing 7 mol Pt/mol MT is obtained at neutral pH. Rates of reaction of Pt7MT with DTNB and iodoacetic acid are consistent with Pt2+ to cysteine thiolate coordination, and the extent of reaction in both cases is 11 +/- 2 mol cys/mol MT. Adducts from the reaction of K2PtCl4 with apoMT chemically modified at the N-terminal methionine residue, Cd7MT, and native MT are also reported. A structural model of Pt7MT is proposed in which the square planar tetrathiolate Pt(II) unit is incorporated into a three-metal beta cluster. Implications for the metabolism of platinum anticancer drugs are discussed. 相似文献