全文获取类型
收费全文 | 2351篇 |
免费 | 240篇 |
国内免费 | 226篇 |
专业分类
2817篇 |
出版年
2024年 | 16篇 |
2023年 | 55篇 |
2022年 | 93篇 |
2021年 | 138篇 |
2020年 | 111篇 |
2019年 | 131篇 |
2018年 | 159篇 |
2017年 | 93篇 |
2016年 | 125篇 |
2015年 | 175篇 |
2014年 | 191篇 |
2013年 | 180篇 |
2012年 | 212篇 |
2011年 | 171篇 |
2010年 | 98篇 |
2009年 | 83篇 |
2008年 | 119篇 |
2007年 | 91篇 |
2006年 | 78篇 |
2005年 | 65篇 |
2004年 | 59篇 |
2003年 | 65篇 |
2002年 | 81篇 |
2001年 | 40篇 |
2000年 | 28篇 |
1999年 | 23篇 |
1998年 | 23篇 |
1997年 | 13篇 |
1996年 | 16篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 15篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1985年 | 4篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有2817条查询结果,搜索用时 0 毫秒
51.
Chavan SS Huerta PT Robbiati S Valdes-Ferrer S Ochani M Dancho M Frankfurt M Volpe BT Tracey KJ Diamond B 《Molecular medicine (Cambridge, Mass.)》2012,18(9):930-937
Severe sepsis, a syndrome that complicates infection and injury, affects 750,000 annually in the United States. The acute mortality rate is approximately 30%, but, strikingly, sepsis survivors have a significant disability burden: up to 25% of survivors are cognitively and physically impaired. To investigate the mechanisms underlying persistent cognitive impairment in sepsis survivors, here we developed a murine model of severe sepsis survivors following cecal ligation and puncture (CLP) to study cognitive impairments. We observed that serum levels of high mobility group box 1 (HMGB1), a critical mediator of acute sepsis pathophysiology, are increased in sepsis survivors. Significantly, these levels remain elevated for at least 4 wks after CLP. Sepsis survivors develop significant, persistent impairments in learning and memory, and anatomic changes in the hippocampus associated with a loss of synaptic plasticity. Administration of neutralizing anti-HMGB1 antibody to survivors, beginning 1 wk after onset of peritonitis, significantly improved memory impairments and brain pathology. Administration of recombinant HMGB1 to na?ve mice recapitulated the memory impairments. Together, these findings indicate that elevated HMGB1 levels mediate cognitive decline in sepsis survivors, and suggest that it may be possible to prevent or reverse cognitive impairments in sepsis survivors by administration of anti-HMGB1 antibodies. 相似文献
52.
Park SH Hanning I Jarquin R Moore P Donoghue DJ Donoghue AM Ricke SC 《FEMS microbiology letters》2011,316(1):7-15
Three pathogens, Campylobacter, Salmonella, and Shiga-toxin-producing Escherichia coli, are leading causes of bacterial gastroenteritis in the United States and worldwide. Although these three bacteria are typically considered food-borne pathogens, outbreaks have been reported due to contaminated drinking water and irrigation water. The aim of this research was to develop two types of PCR assays that could detect and quantify three pathogens, Campylobacter spp., E. coli O157:H7, and Salmonella spp., in watershed samples. In conventional PCR, three target strains were detected by multiplex PCR (m-PCR) using each specific primer pair simultaneously. Under optimized m-PCR conditions, the assay produced a 90-bp product for Campylobacter jejuni, a 150-bp product for E. coli O157:H7, and a 262-bp product for Salmonella Typhimurium, and the limitation of detection was approximately 700 copies for all three bacteria. In addition, real-time PCR was performed to quantify the three pathogens using SYBR green fluorescence. The assay was designed so that each target had a different melting temperature [C. jejuni (80.1 °C), E. coli O157:H7 (83.3 °C), and S. Typhimurium (85.9 °C)]. Therefore, this system could quantify and distinguish three pathogens simultaneously in a single reaction. 相似文献
53.
Yang CH Liu XM Si JJ Shi HS Xue YX Liu JF Luo YX Chen C Li P Yang JL Wu P Lu L 《PloS one》2012,7(6):e39696
The inhibitor κB protein kinase/nuclear factor κB (IKK/NF-κB) signaling pathway is critical for synaptic plasticity. However, the role of IKK/NF-κB in drug withdrawal-associated conditioned place aversion (CPA) memory is unknown. Here, we showed that inhibition of IKK/NF-κB by sulphasalazine (SSZ; 10 mM, i.c.v.) selectively blocked the extinction but not acquisition or expression of morphine-induced CPA in rats. The blockade of CPA extinction induced by SSZ was abolished by sodium butyrate, an inhibitor of histone deacetylase. Thus, the IKK/NF-κB signaling pathway might play a critical role in the extinction of morphine-induced CPA in rats and might be a potential pharmacotherapy target for opiate addiction. 相似文献
54.
中国南海侧扁软柳珊瑚中孕甾烷类化学成分的研究(英文) 总被引:1,自引:0,他引:1
从南海侧扁软柳珊瑚Subergorgia suberosa的二氯甲烷-甲醇提取物中首次分离鉴定了8个孕甾烷类化合物,经波谱鉴定为3β-O-palmitoyl-pregn-5-ene-20-one-3-ol (1),3β-O-palmitoyl-5α-pregn-20-one-3-ol (2),5α-pregn-1-ene-3,20-dione (3),3β,5α-pregn-20-one-3-ol (4),3β-pregn-5-ene-20-one-3-ol (5),3β,5β-pregn-20-one-3-ol (6),5β-pregn-3,20-dione (7),pregn-4-ene-3,20-dione (8).其中化合物1,2为新化合物. 相似文献
55.
56.
57.
Aim: To determine whether assessing the penetration of solutions with different concentrations of ethanol (alcohol percentage test: APT) on fungal surfaces is effective in characterization of hydrophobicity on fungal surfaces. Methods and Results: APT and contact angle (CA) measurements were conducted on nine hydrophobic and two hydrophilic fungal strains from the phyla of Ascomycota, Basidiomycota and Zygomycota. There was a strong positive correlation (R2 = 0·95) between the APT and CA measurements from eight of the nine hydrophobic stains (four pathogenic and mycotoxigenic Fusarium taxa, one melanosporaceous biotrophic taxon, Alternaria sp, Penicillium aurantiogriseum and Cladosporium cladosporioides). Hydrophilic control strains, Mortierella hyalina and Laccaria laccata, had CAs <90° and no measurable degree of hydrophobicity using the APT method. Conclusions: The APT method was effective in measuring the degree of hydrophobicity and can be conducted on different zones of fungal growth. Significance and Impact of the Study: Characterization of fungal surface hydrophobicity is important for understanding of its particular role and function in fungal morphogenesis and pathogenesis. APT is a simple method that can be utilized for fungal hydrophobicity measurements when CA cannot be measured because of obscured view from aerial mycelia growth. 相似文献
58.
Hai‐Fan Yu Lian‐Wen Zheng Zhan‐Qing Yang Yu‐Si Wang Ji‐Cheng Huang Shu Liu Zhan‐Peng Yue Bin Guo 《Journal of cellular and molecular medicine》2020,24(12):7023-7033
Serpinb6b is a novel member of Serpinb family and found in germ and somatic cells of mouse gonads, but its physiological function in uterine decidualization remains unclear. The present study revealed that abundant Serpinb6b was noted in decidual cells, and advanced the proliferation and differentiation of stromal cells, indicating a creative role of Serpinb6b in uterine decidualization. Further analysis found that Serpinb6b modulated the expression of Mmp2 and Mmp9. Meanwhile, Serpinb6b was identified as a target of Bmp2 regulation in stromal differentiation. Treatment with rBmp2 resulted in an accumulation of intracellular cAMP level whose function in this differentiation program was mediated by Serpinb6b. Addition of PKA inhibitor H89 impeded the Bmp2 induction of Serpinb6b, whereas 8‐Br‐cAMP rescued the defect of Serpinb6b expression elicited by Bmp2 knock‐down. Attenuation of Serpinb6b greatly reduced the induction of constitutive Wnt4 activation on stromal cell differentiation. By contrast, overexpression of Serpinb6b prevented this inhibition of differentiation process by Wnt4 siRNA. Moreover, blockage of Wnt4 abrogated the up‐regulation of cAMP on Serpinb6b. Collectively, Serpinb6b mediates uterine decidualization via Mmp2/9 in response to Bmp2/cAMP/PKA/Wnt4 pathway. 相似文献
59.
60.
Histone deacetylases (HDACs) belong to a group of epigenetic regulatory enzymes that participate in modulating the acetylation level of histone lysine residues as well as non‐histone proteins, and they play a key role in the regulation of gene expression. HDACs are potential anticancer drug targets highly expressed in various kinds of cancer cells. So far, five small molecules targeting HDACs have been approved for the therapy of cancer, and over 20 inhibitors of HDACs are under different phases of clinical trials. Among them, hydroxamate‐based HDAC inhibitors (HDACis) represent a well‐investigated series of chemical entities. The current review covers the recent progress in the discovery process, form SAHA to hydroxamate HDAC inhibitors with branched CAP region and linear linker. At the same time, the pharmacological and structure‐activity relationship (SAR) studies of the specific derivatives from SAHA and the HDACis with branched CAP region and linear linker are also introduced. 相似文献