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   168342篇
  免费   11765篇
  国内免费   7359篇
耳鼻咽喉   2274篇
儿科学   2721篇
妇产科学   1601篇
基础医学   25271篇
口腔科学   6135篇
临床医学   15352篇
内科学   23875篇
皮肤病学   2226篇
神经病学   19071篇
特种医学   4412篇
外国民族医学   28篇
外科学   17990篇
综合类   23995篇
现状与发展   34篇
一般理论   4篇
预防医学   7637篇
眼科学   4192篇
药学   16572篇
  35篇
中国医学   5191篇
肿瘤学   8850篇
  2023年   1929篇
  2022年   4093篇
  2021年   5568篇
  2020年   5033篇
  2019年   5325篇
  2018年   5262篇
  2017年   5226篇
  2016年   5304篇
  2015年   5747篇
  2014年   9821篇
  2013年   11439篇
  2012年   9394篇
  2011年   10613篇
  2010年   8571篇
  2009年   8330篇
  2008年   8691篇
  2007年   8632篇
  2006年   7630篇
  2005年   7038篇
  2004年   5932篇
  2003年   5222篇
  2002年   4141篇
  2001年   3672篇
  2000年   3028篇
  1999年   2766篇
  1998年   2487篇
  1997年   2229篇
  1996年   1912篇
  1995年   1621篇
  1994年   1497篇
  1993年   1251篇
  1992年   1226篇
  1991年   1100篇
  1990年   984篇
  1989年   811篇
  1988年   744篇
  1987年   724篇
  1986年   663篇
  1985年   1444篇
  1984年   1464篇
  1983年   1090篇
  1982年   1303篇
  1981年   1237篇
  1980年   1013篇
  1979年   896篇
  1978年   621篇
  1977年   561篇
  1976年   599篇
  1975年   470篇
  1974年   333篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
《Vaccine》2021,39(26):3498-3508
Adenovirus infections are a major cause of epidemic keratoconjunctivitis (EKC), which can lead to corneal subepithelial infiltrates and multifocal corneal opacity. In the current study, we investigated the use of an E1/E3-deleted adenovirus serotype 5 (Ad5) vector as a vaccine administered intramuscularly (IM) or intranasally (IN) against subsequent challenges with a luciferase-expressing Ad5 (Ad5-Luci) vector via eyedrop. We evaluated the adaptive immune response to Ad5 vector vaccination and confirmed a robust polyfunctional CD8 T cell response in splenic cells. Neutralizing Ad5 antibodies were also measured in the sera of vaccinated mice as well as Ad5 antibody in the eye wash solutions. Upon challenge with Ad5-Luci vector 8 weeks post the primary immunization, transduction was significantly reduced by > 70% in the vaccinated mice, which was slightly better in IM- vs. that in IN-vaccinated animals. Resistance to subsequent challenge was observed 10 months post primary IM vaccination, with sustained reduction up to 60% in the Ad5-Luci vector transduction. Passive immunization of naive mice with antisera from IM to vaccinated mice subsequently challenged with the Ad5-Luci vector resulted in approximately 40% loss in transduction efficiency. Furthermore, the mice that received IM immunization with or without CD8 T cell depletion showed > 40% and 70% reductions, respectively, in Ad8 genomic copies after Ad8 topical challenge. We conclude that Ad-vector vaccination successfully induced an adaptive immune response that prevented subsequent Ad transduction in the cornea and conjunctiva-associated tissues in a mouse model of adenovirus keratoconjunctivitis, and that both cellular and humoral immunity play an important role in preventing Ad transduction.  相似文献   
42.
聚酰胺—胺树枝状聚合物(PAMAM)作为一种新型超支化大分子聚合物,因其出色的化学和生物学特性,一直被众学者称之为“人工蛋白”。 PAMAM的特点是存在内部空腔,并含有大量的反应性末端基团,这些结构使得PAMAM可以被用作仿生大分子,模拟天然有机基质在牙体组织表面进行仿生矿化,即PAMAM作为有机模板调控矿物质成核以及晶体的生长,以此来建造比传统的异体材料更加理想的牙体修复材料。本文就 PAMAM 诱导牙体硬组织仿生矿化的研究进展作一综述。  相似文献   
43.
Ovarian carcinoma is one of the most lethal malignancies, but only very few prognostic biomarkers are known. The degradome, comprising proteases, protease non-proteolytic homologues and inhibitors, have been involved in the prognosis of many cancer types, including ovarian carcinoma. The prognostic significance of the whole degradome family has not been specifically studied in high-grade serous ovarian cancer. A targeted DNA microarray known as the CLIP-CHIP microarray was used to identify potential prognostic factors in ten high-grade serous ovarian cancer women who had early recurrence (<1.6 years) or late/no recurrence after first line surgery and chemotherapy. In women with early recurrence, we identified seven upregulated genes (TMPRSS4, MASP1/3, SPC18, PSMB1, IGFBP2, CFI – encoding Complement Factor I – and MMP9) and one down-regulated gene (ADAM-10). Using immunohistochemistry, we evaluated the prognostic effect of these 8 candidate genes in an independent cohort of 112 high-grade serous ovarian cancer women. Outcomes were progression, defined according to CA-125 criteria, and death. Multivariate Cox proportional hazard regression models were done to estimate the associations between each protein and each outcome. High ADAM-10 expression (intensity of 2–3) was associated with a lower risk of progression (adjusted hazard ratio (HR): 0.51; 95% confidence interval (CI): 0.29-0.87). High complement factor I expression (intensity 2–3) was associated with a higher risk of progression (adjusted HR: 2.30, 95% CI: 1.17–4.53) and death (adjusted HR: 3.42; 95% CI: 1.72–6.79). Overall, we identified the prognostic value of two proteases, ADAM-10 and complement factor I, for high-grade serous ovarian cancer which could have clinical significance.  相似文献   
44.
《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   
45.
46.
47.
BackgroundDifferent studies have reported the efficacy of percutaneous tibial nerve stimulation (PTNS) and transcutaneous tibial nerve stimulation (TTNS) in treating idiopathic overactive bladder (OAB). However, no study has compared the effectiveness of PTNS and TTNS added to bladder training (BT) in idiopathic OAB.ObjectiveTo compare the efficacy of PTNS and TTNS added to BT in women with idiopathic OAB.MethodsWe randomised 60 women with idiopathic OAB into 3 groups. Group 1 (n = 19) received BT, Group 2 (n = 19) received PTNS in addition to BT, and Group 3 (n = 20) received TTNS in addition to BT. PTNS and TTNS were performed 2 days a week, for 30 min a day, for a total of 12 sessions for 6 weeks. Patients were evaluated by incontinence severity (pad test), a 3-day voiding diary (frequency of voiding, incontinence episodes, nocturia and number of pads used), symptom severity, quality of life, treatment success (positive response rate), treatment satisfaction (Likert scale), discomfort level and preparation time for stimulation (sec).ResultsAt the end of treatment; severity of incontinence, frequency of voiding, incontinence episodes, nocturia, number of pads used, symptom severity and quality of life were significantly improved in Groups 2 and 3 versus Group 1 (P < 0.0167). Treatment success and treatment satisfaction were higher in Groups 2 and 3 than Group 1 (P < 0.001 and P < 0.0167, respectively). Level of discomfort was lower, treatment satisfaction was higher and preparation time for stimulation was shorter in Group 3 than Group 2 (P < 0.05).ConclusionBoth the PTNS plus BT and TTNS plus BT were more effective than BT alone in women with idiopathic OAB. These 2 tibial nerve stimulation methods had similar clinical efficacy but with slight differences: TTNS had shorter preparation time, less discomfort level and higher patient satisfaction than PTNS.  相似文献   
48.
49.
目的 研究凉血通瘀方对高血压大鼠急性脑出血模型脑组织miRNA表达的影响,对差异表达的miRNA靶基因进行分析,探索凉血通瘀方可能的药效机制。方法 将自发性高血压大鼠随机分成对照组(B)和实验组(C)。适应性饲养一周后,C组灌胃凉血通瘀方,B组灌胃等体积生理盐水,连续5天,每天1次。构建脑出血模型后收集脑组织,借助全转录组测序技术获得miRNA表达量,与miRBase数据库比对获取已知miRNA,使用miRDeep2预测新miRNA。差异分析软件为DESeq2,筛选阈值为|log2FC| ≥1 并且P <0.05。对显著差异表达的miRNA进行靶基因预测,对靶基因进行GO功能、KEGG通路富集和PPI网络分析。结果 实验组和对照组对比,共发现21个显著差异表达的miRNA,上调有9个,下调有12个,共预测得到1243个有统计学意义的靶基因。GO富集分析发现,生物过程中突触囊泡分泌的调节、神经递质分泌的调节和神经递质运输的调节占前三位,神经元投射终点、全膜、质膜区域和细胞投射则是主要的细胞成分。分子功能分别为小GTPase绑定、底物特异性跨膜转运蛋白活性和离子跨膜转运体活性。通路分析结果显示,靶基因在癌证通路、pI3K-Akt信号通路、人类乳头瘤病毒感染、神经活性配体-受体相互作用和MAPK通路等分布广泛。采用STRING网站和Cytoscape软件,根据MCC算法筛选出ADRA2C、CASR、CCL28、CCR1、DRD2、GNAT3、GRM2、DYNC1LI1、GABBR1、GNAI1等核心靶基因。结论 凉血通瘀方对脑出血急性期鼠脑组织内miRNA的表达有重要影响;显著差异表达miRNAs可能通过靶向核心基因调控凉血通瘀方干预急性脑出血的病理过程及预后。  相似文献   
50.
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