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   22764篇
  免费   2086篇
  国内免费   788篇
耳鼻咽喉   120篇
儿科学   128篇
妇产科学   87篇
基础医学   2444篇
口腔科学   1190篇
临床医学   1618篇
内科学   2235篇
皮肤病学   123篇
神经病学   967篇
特种医学   668篇
外科学   1203篇
综合类   3263篇
一般理论   3篇
预防医学   2878篇
眼科学   208篇
药学   5682篇
  27篇
中国医学   2446篇
肿瘤学   348篇
  2024年   14篇
  2023年   381篇
  2022年   490篇
  2021年   1011篇
  2020年   834篇
  2019年   780篇
  2018年   750篇
  2017年   812篇
  2016年   845篇
  2015年   937篇
  2014年   1443篇
  2013年   2146篇
  2012年   1526篇
  2011年   1586篇
  2010年   1196篇
  2009年   1228篇
  2008年   1297篇
  2007年   1145篇
  2006年   998篇
  2005年   919篇
  2004年   674篇
  2003年   600篇
  2002年   499篇
  2001年   455篇
  2000年   384篇
  1999年   330篇
  1998年   248篇
  1997年   222篇
  1996年   203篇
  1995年   152篇
  1994年   166篇
  1993年   156篇
  1992年   135篇
  1991年   120篇
  1990年   101篇
  1989年   110篇
  1988年   109篇
  1987年   89篇
  1986年   81篇
  1985年   77篇
  1984年   80篇
  1983年   55篇
  1982年   57篇
  1981年   41篇
  1980年   43篇
  1979年   25篇
  1978年   23篇
  1977年   18篇
  1976年   16篇
  1973年   7篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
2.
3.
ObjectivesPreclinical and clinical studies indicate a role for MLC901 (NeuroAiD II) in Alzheimer's disease (AD). The primary aim was to investigate its safety as add-on therapy to standard treatment and the secondary aims its effect on cognition and slowing disease progression.DesignRandomized double-blind placebo-controlled delayed-start study.Setting and ParticipantPatients with mild to moderate probable AD by NINCDS-ADRDA criteria, stable on acetylcholinesterase inhibitors or memantine (n = 125), were randomized to receive MLC901 (early starters) or placebo (delayed starters) for 6 months, followed by a further 6 months when all patients received MLC901, in a delayed-start design (clinical trial registration: ClinicalTrials.gov, NCT03038035).MethodsThe primary outcome measure was occurrence of serious adverse events (SAEs) at 6 months. Secondary outcomes included the Alzheimer's Disease Assessment Scale–Cognitive subscale (ADAS-Cog) and other assessment scales.ResultsThere was no significant difference in the risk of SAEs between early and delayed starters at month (M) 6 (22.6% vs 27.0%, risk difference ?4.4%, 90% CI –16.9% to 8.3%). Similarly, there was no significant difference in the risk of adverse events and the occurrence of stroke or vascular events between early and delayed starters throughout the 12-month study period. Early starters did not differ significantly on ADAS-Cog from delayed starters at M6 [mean difference (MD) ?1.0, 95% CI –3.3 to 1.3] and M12 (MD –2.35, 95% CI –5.45 to 0.74) on intention-to-treat analysis. Other cognitive assessment scales did not show significant differences.Conclusions and ImplicationsThis study of 125 persons with dementia found no evidence of a significant increase in adverse events between MLC901 and placebo, thus providing support for further studies on both efficacy and safety. Analyses suggest the potential of MLC901 in slowing down AD progression, but this requires further confirmation in larger and longer studies using biomarkers for AD.  相似文献   
4.
The Extracellular Vesicle Flow Cytometry Working Group ( http://www.evflowcytometry.org ) is formed by members of the International Society for Extracellular Vesicles (ISEV), the International Society for Advancement of Cytometry (ISAC), and the International Society on Thrombosis and Haemostasis (ISTH). This working group of flow cytometry experts develops guidelines for best practices regarding flow cytometry detection of extracellular vesicles. To improve rigor and standardization, this working group published a framework outlining the minimal information to report about a flow cytometry experiment on extracellular vesicles (MIFlowCyt-EV) in the Journal of Extracellular Vesicles, the ISEV journal, in 2020. In parallel, an article explaining MIFlowCyt-EV was published in Cytometry Part A, one of the ISAC journals, and now will be introduced to the ISTH as an SSC Communication in the Journal of Thrombosis and Haemostasis. The goal of this SSC Communication is to explain why flow cytometry is becoming the instrument of choice to characterize single extracellular vesicles, the obstacles that have been identified and (mostly) overcome by developing procedures to calibrate flow cytometers, and the relevance of reporting minimal information to improve reliability and reproducibility of experiments in which flow cytometers are used for characterization of extracellular vesicles.  相似文献   
5.
文章以温病的治法祛湿法为例,提出讨论式教学法的教学设计,包括建立"三人为师"规则、"发言签"规则,营造讨论气氛,角色分配包括向导、刺头、记录员、法官、汇报人,然后按照"领结模型"展开讨论,最后按照表达意愿、思维技能、学生间互动、内容知识掌握情况等进行评估,旨在培养学生温病学临床思维能力与团队协作能力。  相似文献   
6.
目的 研究成型工艺和结构设计对电子束选区熔化技术(SEBM)制备的菱形十二面体Ti6Al4V点阵材料相对密度、形貌和压缩性能的影响。方法 点阵的密度通过测定其尺寸和质量得出,采用电子万能试验机测试点阵结构的压缩性能,采用扫描电子显微镜观察点阵表面形貌。结果 SEBM成形Ti6Al4V支架的相对密度随着熔化功率增加和单胞尺寸减小而增大;以等离子旋转电极雾化技术制备的TC4粉末为原料成型的点阵结构具有优异的塑性,压缩应力—应变曲线平台区域波动小;TC4钛合金菱形十二面体多孔材料的密度与屈服强度和弹性模量的关系满足Gibson-Ashby方程,但指数分别为2.34和2.32。结论 通过调控点阵结构设计和SEBM成型工艺,可控制钛合金的孔隙率和压缩性能,满足骨科植入多孔材料需求。  相似文献   
7.
《Drug discovery today》2022,27(5):1367-1380
The tremendous advances in genomics, recombinant DNA technology, bioengineering and nanotechnology, in conjunction with the development of high-end computations, have been instrumental in the process of rational design of peptide-based vaccines. The use of peptide vaccines was limited owing to their inherent instability when systemically administered; however, advanced formulation techniques have been developed for their systemic delivery, thereby overcoming their degradation, clearance, cellular uptake and off-target effects. With the rise of sophisticated immunological predictors and experimental techniques, several methodological advances have occurred in this field. This review examines contemporary methods to identify and optimize epitopes, engineer their immunogenic properties and develop their safe and efficient delivery into the host.  相似文献   
8.
9.
10.
《Saudi Pharmaceutical Journal》2022,30(11):1603-1611
This study was performed with the main objective of formulating and evaluating the potential of ethosomesl gel (Etho gel) to deliver nimodipine (NiM) for cardiovascular disease, a potent water insoluble anti-hypertensive drug via skin to reach the deeper layers of skin. The Box-Behnken design (BBD) was used to optimize the NiM-Eth to determine the impact of the independent and depended variables. The effectiveness of drug entrapment, vesicle size, and cumulative drug release were assessed for the NiM loaded ethosomes and NiM-Eth gel using carbopol 934 as a gelling agent. Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), Power X-ray diffraction (PXRD), and scanning electron microscopy (SEM) analysis were performed and analysed their physicochemical characters. Rat abdomen skin was used to investigate drug permeability and deposition. As compared to marketed products, NiM-Eth gel produced an improved drug permeability in ex vivo experiments. The mean AUC0 to AUC0-∞ of NiM-Eth gel when compared to oral formulation (Nymalize oral preparation) was found to be increased from 4.1 to 5.9 folds which was found to be resulted from first pass effect. Histophatlogical findings revealed that the maximum amount of NiM penetrated the stratum corneum of the skin and create drug depots in the deep layer. In summary, it can be said that NiM might be successfully prepared in NiM-Eth gel for transdermal drug delivery.  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