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   22299篇
  免费   2036篇
  国内免费   719篇
耳鼻咽喉   89篇
儿科学   213篇
妇产科学   177篇
基础医学   1245篇
口腔科学   627篇
临床医学   2867篇
内科学   3667篇
皮肤病学   425篇
神经病学   743篇
特种医学   3085篇
外国民族医学   2篇
外科学   1865篇
综合类   2390篇
现状与发展   2篇
预防医学   910篇
眼科学   761篇
药学   4274篇
  9篇
中国医学   266篇
肿瘤学   1437篇
  2023年   262篇
  2022年   365篇
  2021年   710篇
  2020年   759篇
  2019年   817篇
  2018年   806篇
  2017年   825篇
  2016年   863篇
  2015年   925篇
  2014年   1277篇
  2013年   2027篇
  2012年   1283篇
  2011年   1358篇
  2010年   1073篇
  2009年   1091篇
  2008年   1131篇
  2007年   1140篇
  2006年   1000篇
  2005年   904篇
  2004年   779篇
  2003年   756篇
  2002年   626篇
  2001年   518篇
  2000年   373篇
  1999年   315篇
  1998年   275篇
  1997年   319篇
  1996年   197篇
  1995年   228篇
  1994年   196篇
  1993年   196篇
  1992年   155篇
  1991年   149篇
  1990年   120篇
  1989年   113篇
  1988年   116篇
  1987年   123篇
  1986年   86篇
  1985年   115篇
  1984年   119篇
  1983年   82篇
  1982年   79篇
  1981年   60篇
  1980年   58篇
  1979年   49篇
  1978年   54篇
  1977年   41篇
  1976年   43篇
  1974年   18篇
  1973年   22篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
IntroductionThe sofosbuvir-velpatasvir (SOF/VEL) combination is a direct-acting antiviral therapy that is authorized and available in Mexico, making the performance of a real-world multicenter study that evaluates the sustained virologic response at 12 weeks post-treatment a relevant undertaking.MethodsA retrospective review of the case records of 241 patients seen at 20 hospitals in Mexico was conducted to assess hepatitis C treatment with the SOF/VEL combination (n = 231) and the sofosbuvir/velpatasvir/ribavirin (SOF/VEL/RBV) combination (n = 10). The primary efficacy endpoint was the percentage of patients that achieved SVR at 12 weeks after the end of treatment.ResultsOverall SVR was 98.8% (95% CI 97.35-100%). Only three patients did not achieve SVR, two of whom had cirrhosis and a history of previous treatment with peg-IFN. Of the subgroups analyzed, all the patients with HIV coinfection, three patients with genotype 3, and the patients treated with the SOF/VEL/RBV combination achieved SVR. The subgroups with the lower success rates were patients that were treatment-experienced (96.8%) and patients with F1 fibrosis (95.5%). The most frequent adverse events were fatigue, headache, and insomnia. No serious adverse events were reported.ConclusionTreatments with SOF/VEL and SOF/VEL/RBV were highly safe and effective, results coinciding with those of other international real-world studies.  相似文献   
4.
Oxidative stress and inflammation are two possible mechanisms related to nephrotoxicity caused by environmental pollutants. Ellagic acid, a powerful antioxidant phytochemical, may have great relevance in mitigating pollutant-induced nephrotoxicity and preventing the progression of kidney disease. This review discusses the latest findings on the protective effects of ellagic acid, its metabolic derivatives, the urolithins, against kidney toxicity caused by heavy metals, pesticides, mycotoxins, and organic air pollutants. We describe the chelating, antioxidant, anti-inflammatory, antifibrotic, antiautophagic, and antiapoptotic properties of ellagic acid to attenuate nephrotoxicity. Furthermore, we present the molecular targets and signaling pathways that are regulated by these antioxidants, and suggest some others that should be explored. Nevertheless, the number of reports is still limited to establish the efficacy of ellagic acid against kidney damage induced by environmental pollutants. Therefore, additional preclinical studies on this topic are required, as well as the development of well-designed clinical trials.  相似文献   
5.
This work describes a measurement method for assessing dose-related image-quality of CT scans based on the difference detail curve (DDC) method, and showcases its use in a low contrast setting. The method is based on a phantom consisting of elliptical slices of different sizes into which contrast object modules can be inserted. These modules contain contrast objects based on (synthetic) resin mixtures with sucrose (native) or sodium iodine (contrast medium). Mixing ratios are provided to achieve a range of clinically relevant CT-numbers with these materials. The phantom is characterized in terms of contrast accuracy, energy dependency and long-term drift with satisfying results. Contrast accuracy and energy dependency are similar to that of water or soft tissue. Image quality of 655 scans of the phantom acquired at 30 different clinical institutions and with 16 different CT scanner models from 4 manufacturers was assessed by calculating a difference detail curve (DDC) from evaluation of up to 5 human observers using a custom-made software (RadiVates) described in this work. Based on these measurements, inter-observer variability was quantified using a bootstrap method and was shown to be a large contributor to the overall variability. This work demonstrates that assessment of CT image quality is feasible with the aforementioned phantom and DDC method.  相似文献   
6.
7.
目的探究腹腔镜精准肝切除术治疗原发性肝癌的临床效果。方法选择2019年1月—2020年6月期间在医院接受腹腔镜肝切除术治疗的80例原发性肝癌患者作为实验分析对象,依据手术治疗方案的不同将患者分为腹腔镜常规肝切除组(对照组)40例和腹腔镜精准肝切除组(观察组)40例,对两组患者手术各项指标、手术前后肝功能指标改善情况及术后并发症发生率进行对比分析。结果观察组患者手术时间明显长于对照组,组间比较进行t检验,差异具有统计学意义(P<0.05);观察组患者术中出血量及术中输血量均少于对照组患者,术后恢复时间明显短于对照组患者,组间比较进行t检验,差异具有统计学意义(P<0.05);术后,两组患者ALT、AST、ALB及TBIL水平均显著降低,组内比较进行t检验,差异具有统计学意义(P<0.05),观察组患者ALT、AST、ALB及TBIL水平降低幅度显著大于对照组患者,组间比较进行t检验,差异具有统计学意义(P<0.05);观察组患者术后并发症发生率为10.00%,对照组患者术后并发症发生率为27.50%,组间比较进行χ2检验,差异具有统计学意义(χ2=4.021;P=0.045)。结论与腹腔镜常规肝切除术比较,腹腔镜精准肝切除术操作精细,手术时间相对较长,患者术中出血量更少,术后恢复时间更短,能够最大限度保护患者的肝脏,减低患者术后并发症发生率,提高手术治疗效果,改善患者预后。  相似文献   
8.
Erythema induratum of Bazin (EIB) is a form of tuberculid resulting from hypersensitivity to tuberculosis antigen. EIB occurs most commonly in middle‐aged women and is not typically seen in children. Here, we present a rare case of EIB, presenting as a chronic nodular panniculitis, in a 10‐year‐old Korean boy.  相似文献   
9.
[摘要] 目的 评估直接抗病毒药物(direct antivirus agent, DAA)治疗肝移植术后HCV感染复发的有效性和安全性。方法?回顾性分析首都医科大学附属北京佑安医院2011年2月—2018年12月收治的14例肝移植术后HCV感染复发患者的DAA治疗临床数据,比较患者基线与治疗结束后肝肾功能、血常规、凝血功能、病毒学水平以及无创纤维化评分天冬氨酸转氨酶血小板比率指数(aspartate aminotransferase-platelet ratio index, APRI)的差异。利用电子病历系统和电话随访收集患者治疗期间不良反应发生情况。结果?所有患者均在治疗结束时达到病毒学清除,12周、24周持续病毒学应答率均为100%,DAA治疗后随访17~44个月,期间均未见病毒学复发。与基线水平相比,治疗终点时ALT、AST、TBIL、γ-谷氨酰转移酶以及无创纤维化评分APRI显著下降,WBC、HGB、PLT、CRE、肾小球滤过率和血糖等指标均未见显著变化。DAA治疗期间共3例患者发生不良反应,均为轻度,可自然缓解。结论?肝移植术后HCV感染复发的DAA治疗是安全有效的。  相似文献   
10.
ObjectivesThe detection of SARS-CoV-2 RNA in blood and platelet concentrates from asymptomatic donors, and the detection of viral particles on the surface and inside platelets during in vitro experiments, raised concerns over the potential risk for transfusion-transmitted-infection (TTI). The objective of this study was to assess the efficacy of the amotosalen/UVA pathogen reduction technology for SARS-CoV-2 in human platelet concentrates to mitigate such potential risk.Material and methodsFive apheresis platelet units in 100% plasma were spiked with a clinical SARS-CoV-2 isolate followed by treatment with amotosalen/UVA (INTERCEPT Blood System), pre- and posttreatment samples were collected as well as untreated positive and negative controls. The infectious viral titer was assessed by plaque assay and the genomic titer by quantitative RT-PCR. To exclude the presence of infectious particles post-pathogen reduction treatment below the limit of detection, three consecutive rounds of passaging on permissive cell lines were conducted.ResultsSARS-CoV-2 in platelet concentrates was inactivated with amotosalen/UVA below the limit of detection with a mean log reduction of > 3.31 ± 0.23. During three consecutive rounds of passaging, no viral replication was detected. Pathogen reduction treatment also inhibited nucleic acid detection with a log reduction of > 4.46 ± 0.51 PFU equivalents.ConclusionSARS-CoV-2 was efficiently inactivated in platelet concentrates by amotosalen/UVA treatment. These results are in line with previous inactivation data for SARS-CoV-2 in plasma as well as MERS-CoV and SARS-CoV-1 in platelets and plasma, demonstrating efficient inactivation of human coronaviruses.  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