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   4185篇
  免费   544篇
  国内免费   92篇
耳鼻咽喉   15篇
儿科学   108篇
妇产科学   42篇
基础医学   438篇
口腔科学   98篇
临床医学   447篇
内科学   562篇
皮肤病学   67篇
神经病学   1216篇
特种医学   333篇
外科学   167篇
综合类   434篇
现状与发展   2篇
预防医学   261篇
眼科学   81篇
药学   309篇
  3篇
中国医学   166篇
肿瘤学   72篇
  2024年   15篇
  2023年   104篇
  2022年   149篇
  2021年   209篇
  2020年   211篇
  2019年   228篇
  2018年   208篇
  2017年   196篇
  2016年   215篇
  2015年   238篇
  2014年   318篇
  2013年   289篇
  2012年   246篇
  2011年   218篇
  2010年   199篇
  2009年   185篇
  2008年   181篇
  2007年   197篇
  2006年   153篇
  2005年   129篇
  2004年   101篇
  2003年   112篇
  2002年   92篇
  2001年   55篇
  2000年   51篇
  1999年   76篇
  1998年   35篇
  1997年   45篇
  1996年   49篇
  1995年   35篇
  1994年   29篇
  1993年   14篇
  1992年   28篇
  1991年   28篇
  1990年   18篇
  1989年   12篇
  1988年   15篇
  1987年   18篇
  1986年   9篇
  1985年   17篇
  1984年   19篇
  1983年   16篇
  1982年   13篇
  1981年   13篇
  1980年   9篇
  1979年   6篇
  1978年   5篇
  1977年   5篇
  1976年   5篇
  1973年   1篇
排序方式: 共有4821条查询结果,搜索用时 15 毫秒
1.
BackgroundThe goal of this study was to characterize contemporary performance benchmarks and risk factors associated with negative appendectomy (NA) in children with suspected appendicitis.MethodsA multicenter retrospective cohort analysis of children undergoing appendectomy for suspected appendicitis was performed using data from the 2016–2021 NSQIP-Pediatric Appendectomy Targeted Public Use Files. Multivariable regression was used to evaluate the influence of year, age, sex, and WBC count on NA rate, and to generate rate estimates for NA based on different combinations of demographic characteristics and WBC profiles.Results100,322 patients were included from 140 hospitals. The overall NA rate was 2.4%, and rates decreased significantly during the study period (2016: 3.1% vs. 2021: 2.3%, p < 0.001). In adjusted analyses, the highest risk for NA was associated with a normal WBC (<9000/mm3; OR 5.31 [95% CI: 4.87–5.80]), followed by female sex (OR 1.55 [95% CI: 1.42–1.68]) and age <5 years (OR 1.64 [95% CI 1.39, 1.94]). Model-estimated risk for NA varied significantly across demographic and WBC strata, with a 14.4-fold range in rates between subgroups with the lowest and highest predicted risk (males 13–17 years with elevated WBC [1.1%] vs. females 3–4 years with normal WBC [15.8%]).ConclusionsContemporary NA rates have decreased over time, however NA risk remains high in children without a leukocytosis, particularly for girls and children <5 years of age. These data provide contemporary performance benchmarks for NA in children with suspected appendicitis and identify high-risk populations where further efforts to mitigate NA risk should be targeted.Level of EvidenceIII.  相似文献   
2.
3.
The current literature suggests that the antibacterial effect of leukocyte- and platelet-rich plasma (L-PRP) is directly related to platelet and leukocyte concentrations. The aim of this study was twofold: first, to evaluate the antimicrobial effect of L-PRP against selected bacterial strains in vitro, and second, to correlate this effect with leukocyte and platelet content in the final concentration. Blood was collected from 20 healthy males, and L-PRP, acellular plasma (AP), and autologous thrombin were consecutively prepared. Flow cytometry analysis of the blood, L-PRP, and AP was performed. The L-PRP gel, liquid L-PRP, and thrombin samples were tested in vitro for their antibacterial properties against seven selected bacterial strains using the Kirby–Bauer disk-diffusion method. There was notable antimicrobial activity against selected bacterial strains. No statistically significant correlations between antimicrobial activities and the platelet concentration in L-PRP were observed. Statistically significant positive correlations between selected leukocyte subtypes and antimicrobial activity were noted. A negative correlation was found between elevated monocyte count and antimicrobial activity of L-PRP against one bacterial strain studied. L-PRP possesses antimicrobial activity and can be potentially useful in the fight against certain postoperative infections. The bactericidal effect of L-PRP is caused by leukocytes, and there exists a relationship among selected leukocyte subtypes and L-PRP antimicrobial activity.  相似文献   
4.
Congenital rubella syndrome (CRS) results from maternal rubella virus infection in early pregnancy. Abnormal neuroimaging findings have been analyzed in a small number of CRS patients in the past; however, their clinical significance has been poorly addressed. Therefore, we have investigated the neuroimaging findings of 31 patients with CRS from previous studies. The most common finding was parenchymal calcification, which was observed in 18 of 31 patients (58.1%). A multivariable logistic regression model showed that it was associated with psychomotor or mental retardation (p = 0.018), suggesting that parenchymal calcification in CRS could be a prognostic factor.  相似文献   
5.
目的探讨他克莫司联合308nm准分子激光在面部白癜风治疗中的应用效果。方法选取2017年2月-2019年2月医院84例面部白癜风患者为研究对象,根据入院单双号将受试者进行分组,其中对照组42例患者接受308nm准分子激光治疗,研究组42例患者在对照组的基础上联合他克莫司软膏治疗,比较两组患者治疗后1个月、3个月时的治疗总有效率以及治疗前后白斑面积与皮损区IL-17水平变化。结果研究组患者在治疗后1个月、3个月时的治疗总有效率均显著高于对照组(P<0.05),与治疗前相比,治疗后两组患者白斑面积及皮损区IL-17水平均显著减少,且研究组显著少于对照组(P<0.05)。结论他克莫司联合308nm准分子激光可有效缩小白斑面积,降低皮损区IL-17水平,疗效确切。  相似文献   
6.
Subacute sclerosing panencephalitis (SSPE) is a rare, slowly progressing but invariably fatal disease that is related to a prior measles virus infection and most commonly affects paediatric patients. Magnetic resonance (MR) imaging is the modality of choice for determining such changes in white matter. SSPE typically demonstrates bilateral but asymmetric periventricular and subcortical white matter involvement. We herein report a rare case of unilateral white matter involvement in a 13-year-old boy with SSPE that closely simulated Rasmussen’s encephalitis. To the best of our knowledge, this is the first report of an atypical presentation on MR imaging in which SSPE was a rare cause of unilateral brain parenchymal involvement in a patient with intractable seizures.  相似文献   
7.
8.
9.
目的观察分析水针疗法联合清热祛毒汤治疗寻常型银屑病(血热证)的疗效及其作用机制。方法选择2018年8月—2019年7月在我院接收治疗的112例寻常型银屑病患者作为分析对象,采取随机分组的办法将其分为对照组56例和研究组56例,对照组患者采取水针疗法治疗,研究组在对照组的基础上联合清热祛毒汤治疗。比较分析2组患者的疗效;治疗前后的中医证候评分、皮肤病生活质量指数(DLQI)评分;治疗前后皮损面积、浸润、鳞屑、红斑等评分;治疗前后肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)、血管内皮生长因子(VEGF)水平变化情况。结果研究组患者治疗总有效率89.29%明显高于对照组73.21%(P<0.05);治疗前,2组患者的中医证候评分、DLQI评分、皮损面积、浸润、鳞屑、红斑等评分及TNF-α、IL-6、VEGF等水平比较(P>0.05);研究组患者治疗后的中医证候评分与DLQI评分明显低于治疗前(P<0.05);研究组患者治疗后的皮损面积、浸润、鳞屑、红斑等评分明显低于对照组(P<0.05);研究组患者治疗后的TNF-α、IL-6、VEGF等水平明显低于对照组(P<0.05)。结论对寻常型银屑病患者采取水针疗法联合清热祛毒汤治疗的疗效显著,能有效改善中医证候表现,提高生活质量,减轻皮损程度,降低炎症反应,其作用机制可能与炎症因子水平、皮损血管增生相关。  相似文献   
10.
目的 比较枸橼酸咖啡因和氨茶碱对早产儿神经行为发育的影响,为早产儿早期合理干预提供临床依据。方法 选择2014年6月-2018年6月在中国西电集团医院新生儿科住院接受枸橼酸咖啡因治疗的原发性呼吸暂停(AOP)早产儿62例作为研究组;2011 年 12 月-2014年5月同在中国西电集团医院新生儿科住院采用氨茶碱治疗的AOP患儿69例作为对照组。出生3~8 d及矫正胎龄40周时分别行头颅MRI检查,评估脑白质损伤(WMD)并进行两组比较;6个月及12个月时应用Gesell婴幼儿发育量表测试比较两组神经行为发育水平。结果 两组患儿在性别、出生胎龄及体重、产前孕母糖皮质激素应用及分娩方式、5 min Apgar评分、辅助通气和表面活性物质的应用等方面差异均无统计学意义(P>0.05)。首次头颅MRI显示两组患儿WMD差异无统计学意义(P>0.05)。矫正胎龄40周时头颅MRI显示,咖啡因组WMD较氨茶碱组明显改善,差异有统计学意义(P<0.05);且6个月及12个月时Gessell婴幼儿发育量表测试,随访至校正6月龄时,咖啡因组患儿的大运动、精细运动及个人-社交评分均高于氨茶碱组(P<0.05);随访至校正12月龄时,咖啡因组患儿的大运动、精细运动、语言、适应性评分均高于氨茶碱组(P<0.05)。结论 枸橼酸咖啡可明显改善AOP患儿6个月及12个月时的神经行为发育。  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