首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6448篇
  免费   367篇
  国内免费   226篇
耳鼻咽喉   17篇
儿科学   87篇
妇产科学   47篇
基础医学   1122篇
口腔科学   121篇
临床医学   342篇
内科学   1087篇
皮肤病学   76篇
神经病学   429篇
特种医学   123篇
外国民族医学   4篇
外科学   425篇
综合类   865篇
现状与发展   1篇
预防医学   347篇
眼科学   52篇
药学   1021篇
中国医学   305篇
肿瘤学   570篇
  2023年   57篇
  2022年   58篇
  2021年   152篇
  2020年   128篇
  2019年   230篇
  2018年   207篇
  2017年   173篇
  2016年   134篇
  2015年   163篇
  2014年   306篇
  2013年   412篇
  2012年   338篇
  2011年   459篇
  2010年   345篇
  2009年   372篇
  2008年   395篇
  2007年   442篇
  2006年   325篇
  2005年   302篇
  2004年   244篇
  2003年   230篇
  2002年   171篇
  2001年   135篇
  2000年   128篇
  1999年   104篇
  1998年   73篇
  1997年   69篇
  1996年   59篇
  1995年   73篇
  1994年   60篇
  1993年   63篇
  1992年   44篇
  1991年   33篇
  1990年   34篇
  1989年   25篇
  1988年   26篇
  1987年   20篇
  1986年   23篇
  1985年   55篇
  1984年   69篇
  1983年   32篇
  1982年   54篇
  1981年   42篇
  1980年   42篇
  1979年   30篇
  1978年   27篇
  1977年   18篇
  1976年   17篇
  1975年   13篇
  1974年   13篇
排序方式: 共有7041条查询结果,搜索用时 15 毫秒
1.
《Vaccine》2022,40(32):4296-4300
Advanced computational methodologies suggested SARS-CoV-2, nonstructural proteins ORF1AB, ORF3a, as the source of immunodominant peptides for T cell presentation. T cell immunity is long-lasting and compatible with COVID-19 pathology. Based on the supporting clinical data, nonstructural SARS-CoV-2 protein vaccines could provide global immunity against COVID-19.  相似文献   
2.
肺癌是世界上发病率最高的癌症之一,且尚无二线进展后的标准治疗方案,而肿瘤血管生成目前已被确定为恶性肿瘤的重要治疗靶点,小分子多靶点血管激酶抑制剂可通过抑制血管生成相关信号通路,抑制肿瘤血管的生成。目前已开展多项小分子抗血管生成药物治疗非小细胞肺癌的临床试验,且已有部分血管内皮生长因子受体酪氨酸激酶抑制剂(vascular endothelial growth factor receptor-tyrosine kinase inhibitors, VEGFR-TKIs)获批治疗晚期非小细胞肺癌,本文基于国内外多项小分子抗血管生成药物治疗非小细胞肺癌的发展现状,归纳了多个VEGFR-TKIs及成纤维细胞生长因子受体(fibroblast growth factor receptor, FGFR)-TKI单药或联合[包括分别与化疗、表皮生长因子受体(epidermal growth factor receptor, EGFR)-TKIs、免疫治疗、放疗等联合)]治疗非小细胞肺癌的疗效与安全性研究,同时探讨了VEGFR-TKIs可能存在的耐药机制及疗效预测指标等,并对未来抗血管治疗非小细胞肺癌的发展趋势以及存在的潜在问题进行展望,同时为肺癌后续的精准治疗及个体化治疗提供新的思路。  相似文献   
3.
《Vaccine》2021,39(45):6601-6613
AKS-452 is a biologically-engineered vaccine comprising an Fc fusion protein of the SARS-CoV-2 viral spike protein receptor binding domain antigen (Ag) and human IgG1 Fc (SP/RBD-Fc) in clinical development for the induction and augmentation of neutralizing IgG titers against SARS-CoV-2 viral infection to address the COVID-19 pandemic. The Fc moiety is designed to enhance immunogenicity by increasing uptake via Fc-receptors (FcγR) on Ag-presenting cells (APCs) and prolonging exposure due to neonatal Fc receptor (FcRn) recycling. AKS-452 induced approximately 20-fold greater neutralizing IgG titers in mice relative to those induced by SP/RBD without the Fc moiety and induced comparable long-term neutralizing titers with a single dose vs. two doses. To further enhance immunogenicity, AKS-452 was evaluated in formulations containing a panel of adjuvants in which the water-in-oil adjuvant, Montanide™ ISA 720, enhanced neutralizing IgG titers by approximately 7-fold after one and two doses in mice, including the neutralization of live SARS-CoV-2 virus infection of VERO-E6 cells. Furthermore, ISA 720-adjuvanted AKS-452 was immunogenic in rabbits and non-human primates (NHPs) and protected from infection and clinical symptoms with live SARS-CoV-2 virus in NHPs (USA-WA1/2020 viral strain) and the K18 human ACE2-trangenic (K18-huACE2-Tg) mouse (South African B.1.351 viral variant). These preclinical studies support the initiation of Phase I clinical studies with adjuvanted AKS-452 with the expectation that this room-temperature stable, Fc-fusion subunit vaccine can be rapidly and inexpensively manufactured to provide billions of doses per year especially in regions where the cold-chain is difficult to maintain.  相似文献   
4.
5.
6.

Background

The ZOE-50 (NCT01165177) and ZOE-70 (NCT01165229) phase 3 clinical trials showed that the adjuvanted recombinant zoster vaccine (RZV) was ≥90% efficacious in preventing herpes zoster in adults. Here we present a comprehensive overview of the safety data from these studies.

Methods

Adults aged ≥50 (ZOE-50) and ≥70 (ZOE-70) years were randomly vaccinated with RZV or placebo. Safety analyses were performed on the pooled total vaccinated cohort, consisting of participants receiving at least one dose of RZV or placebo. Solicited and unsolicited adverse events (AEs) were collected for 7 and 30?days after each vaccination, respectively. Serious AEs (SAEs) were collected from the first vaccination until 12?months post-last dose. Fatal AEs, vaccination-related SAEs, and potential immune-mediated diseases (pIMDs) were collected during the entire study period.

Results

Safety was evaluated in 14,645 RZV and 14,660 placebo recipients. More RZV than placebo recipients reported unsolicited AEs (50.5% versus 32.0%); the difference was driven by transient injection site and solicited systemic reactions that were generally seen in the first week post-vaccination. The occurrence of overall SAEs (RZV: 10.1%; Placebo: 10.4%), fatal AEs (RZV: 4.3%; Placebo: 4.6%), and pIMDs (RZV: 1.2%; Placebo: 1.4%) was balanced between groups. The occurrence of possible exacerbations of pIMDs was rare and similar between groups. Overall, except for the expected local and systemic symptoms, the safety results were comparable between the RZV and Placebo groups irrespective of participant age, gender, or race.

Conclusions

No safety concerns arose, supporting the favorable benefit-risk profile of RZV.  相似文献   
7.
《Vaccine》2019,37(44):6696-6706
Live attenuated viral vaccine/vector candidates are inherently unstable and infectivity titer losses can readily occur without defining appropriate formulations, storage conditions and clinical handling practices. During initial process development of a candidate vaccine against HIV-1 using a recombinant Human Cytomegalovirus vector (rHCMV-1), large vector titer losses were observed after storage at 4 °C and after undergoing freeze-thaw. Thus, the goal of this work was to develop candidate frozen liquid formulations of rHCMV-1 with improved freeze-thaw and short-term liquid stability for potential use in early clinical trials. To this end, a virus stability screening protocol was developed including use of a rapid, in vitro cell-based immunofluorescence focus assay to quantitate viral titers. A library of ∼50 pharmaceutical excipients (from various known classes of additives) were evaluated for their effect on vector stability after freeze-thaw cycling or incubation at 4 °C for several days. Certain additives including sugars and polymers (e.g., trehalose, sucrose, sorbitol, hydrolyzed gelatin, dextran 40) as well as removal of NaCl (lower ionic strength) protected rHCMV-1 against freeze-thaw mediated losses in viral titers. Optimized solution conditions (e.g., solution pH, buffers and sugar type) slowed the rate of rHCMV-1 titer losses in the liquid state at 4 °C. After evaluating various excipient combinations, three new candidate formulations were designed and rHCMV-1 stability was benchmarked against both the currently-used and a previously reported formulation. The new candidate formulations were significantly more stable in terms of reducing rHCMV-1 titer losses after 5 freeze-thaw cycles or incubation at 4 °C for 30 days. This case study highlights the utility of semi-empirical design of frozen liquid formulations of a live viral vaccine candidate, where protection against infectivity titer losses due to freeze-thaw and short-term liquid storage are sufficient to enable more rapid initiation of early clinical trials.  相似文献   
8.
目的探讨GATA6基因启动区-493(rs144923558)G/A、-172(rs146748749)G/A 2个位点单核苷酸多态性(SNP)与急性心肌梗死(AMI)之间的关系及其相关的危险因素。方法采用病例-对照研究方法,收集328例AMI患者和344例正常对照;应用聚合酶链反应-限制性内切酶片段长度多态性技术结合DNA测序后的序列比对进行数据统计;运用Hardy-Weinberg平衡检验后,应用χ~2检验进行相关分析;利用Logistic回归对多种危险因素以及2个SNP位点与AMI发病进行关联性分析;利用Haplovview4.2软件和SHEsis网站进行连锁不平衡及单倍体分析。结果 2个SNP位点共检测出3种基因型为GG、GA和AA,其基因型分布均符合Hardy-Weinberg平衡(P0.05),同时在AMI组与对照组间差异无显著性(P0.05)。多因素Logistic回归分析:增龄、高血压病、吸烟、低密度脂蛋白胆固醇(LDLC)和甘油三酯(TG)升高是AMI发病的独立危险因素(P0.05),HDLC为保护因素(P0.05)。在显性、隐性和加性3种不同遗传模式下进行Logistic回归分析发现,2个SNP位点与AMI发病无关联性。进行连锁不平衡和单倍型分析提示,该2个SNP位点处于同一个连锁不平衡区域(D′=1.000,r~2=1.000),单倍型GG和AA均未增加AMI易感性(P0.05)。结论 GATA6基因启动区-493(rs144923558)G/A与-172(rs146748749)G/A两个SNP位点为完全连锁不平衡,其中GG为主要单倍型。该2个SNP位点及其单倍体型与AMI发病无相关性,但提供了GATA6基因启动区多态性的群体遗传学资料。  相似文献   
9.
Glioblastoma (GBM) with primitive neuronal component (GBM‐PNC) is a rare GBM subtype recently categorized by the World Health Organization in the revised classification system of 2016. Extracranial metastases originating from GBM‐PNC are rare and metastasis to solid organs has never been reported. Herein, we present the first case of metastasis of GBM‐PNC to the lung. A 49‐year‐old man presenting with headache was diagnosed with multiple tumors adhering to the dura matter in the right temporal lobe. Despite surgery and chemoradiotherapy, 2 months after the initial therapy, the patient presented with CSF dissemination and lung metastases. The patient succumbed to the disease 12 months after the first surgery. We discuss the possibility that GBM‐PNC may constitute a subtype of glioma with particularly poor prognosis, tending to dissemination and metastasis. Our results suggest that a complementary regular inspection of the whole body via CT may be recommended for the follow‐up of patients with GBM‐ PNC.  相似文献   
10.
BackgroundZoonotic Salmonella enterica serovar Choleraesuis (S. Choleraesuis), causing paratyphoid in pigs and bacteremia in humans, commonly carry a virulence plasmid and sometimes a separate antimicrobial-resistant plasmid or merging together. This study aimed to analyze the likely mechanism of how to form a virulence-resistance chimera of plasmid in S. Choleraesuis.MethodsWhole plasmid sequence of pOU7519 in S. Choleraesuis strain OU7519 was determined using shotgun cloning and sequencing. Sequence annotation and comparison were performed to determine the sequence responsible for the formation of a chimeric virulence-resistance pOU7519. Other chimeric plasmids among the collected strains of S. Choleraesuis were also confirmed.ResultsThe sequence of pOU719, 127,212 bp long, was identified to be a chimera of the virulence plasmid pSCV50 and a multidrug-resistant plasmid pSC138 that have been found in S. Choleraesuis strain SC-B67. The pOU7519 is a conjugative plasmid carrying various mobile DNAs, including prophages, insertion sequences, integrons and transposons, especially a Tn6088-like transposon. By dissecting the junction site of the pSCV50-pSC138 chimera in pOU7519, defective sequences at integrase gene scv50 (int) and its attachment site (att) were found, and that likely resulted in a stable chimera plasmid due to the failure of excision from the pSCV50-pSC138 chimera. Similar structure of chimera was also found in other large plasmids.ConclusionThe deletion of both the int and att sties could likely block chimera excision, and result in an irreversible, stable pSCV50-pSC138 chimera. The emergence of conjugative virulence and antimicrobial-resistant plasmids in S. Choleraesuis could pose a threat to health public.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号