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   405743篇
  免费   27687篇
  国内免费   4753篇
耳鼻咽喉   5400篇
儿科学   8492篇
妇产科学   10272篇
基础医学   55674篇
口腔科学   12221篇
临床医学   33313篇
内科学   81722篇
皮肤病学   8832篇
神经病学   28517篇
特种医学   14972篇
外国民族医学   97篇
外科学   63107篇
综合类   16124篇
一般理论   64篇
预防医学   19314篇
眼科学   10270篇
药学   34344篇
  45篇
中国医学   4375篇
肿瘤学   31028篇
  2021年   3770篇
  2020年   2934篇
  2019年   3604篇
  2018年   5350篇
  2017年   4420篇
  2016年   4294篇
  2015年   5475篇
  2014年   7641篇
  2013年   9112篇
  2012年   12627篇
  2011年   12853篇
  2010年   8060篇
  2009年   7367篇
  2008年   11089篇
  2007年   11847篇
  2006年   11709篇
  2005年   10477篇
  2004年   9784篇
  2003年   9619篇
  2002年   9013篇
  2001年   28963篇
  2000年   29298篇
  1999年   24123篇
  1998年   5287篇
  1997年   4416篇
  1996年   3905篇
  1995年   3674篇
  1994年   3264篇
  1993年   2926篇
  1992年   16137篇
  1991年   14904篇
  1990年   14211篇
  1989年   14001篇
  1988年   12636篇
  1987年   12098篇
  1986年   11132篇
  1985年   10342篇
  1984年   6920篇
  1983年   5608篇
  1982年   2719篇
  1979年   5479篇
  1978年   3345篇
  1977年   2963篇
  1975年   2632篇
  1974年   3062篇
  1973年   2862篇
  1972年   2823篇
  1971年   2763篇
  1970年   2507篇
  1969年   2540篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Clinical Oral Investigations - To analyze differences in variation of orthodontic diagnostic measurements on lateral cephalograms reconstructed from ultra low dose-low dose (ULD-LD) cone beam...  相似文献   
3.
PurposeThis study aimed to describe the spectrum of cancers observed in Bloom Syndrome and the observed survival and age of first cancer diagnosis in Bloom syndrome as these are not well-defined.MethodsData from the Bloom Syndrome Registry (BSR) was used for this study. Cancer history, ages of first cancer diagnosis, and ages of death were compiled from the BSR and analyzed.ResultsAmong the 290 individuals in the BSR, 155 (53%) participants developed 251 malignant neoplasms; 100 (65%) were diagnosed with 1 malignancy, whereas the remaining 55 (35%) developed multiple malignancies. Of the 251 neoplasms, 83 (33%) were hematologic and 168 (67%) were solid tumors. Hematologic malignancies (leukemia and lymphoma) were more common than any of the solid tumors. The most commonly observed solid tumors were colorectal, breast, and oropharyngeal. The cumulative incidence of any malignancy by age 40 was 83%. The median survival for all participants in the BSR was 36.2 years. There were no significant differences in time to first cancer diagnosis or survival by genotype among the study participants.ConclusionWe describe the spectrum of cancers observed in Bloom syndrome and the observed survival and age of first cancer diagnosis in Bloom syndrome. We also highlight the significant differences in survival and age of diagnosis seen among different tumor types and genotypes.  相似文献   
4.
Information regarding the impact of the coronavirus disease 2019 (COVID-19) pandemic on cervical cancer in mainland China is lacking. We explored its impact on the hospital attendance of patients with primary cervical cancer. We included 1918 patients with primary cervical cancer who initially attended Harbin Medical University Cancer Hospital between January 23, 2019, and January 23, 2021. Attendance decreased by 31%, from 1135 in 2019 to 783 in 2020, mainly from January to June (𝜒2 = 73.362, P < .001). The percentage of patients detected by screening decreased from 12.1% in January-June 2019 to 5.8% in January-June 2020 (𝜒2 = 7.187, P = .007). Patients with stage I accounted for 28.4% in 2020 significantly lower than 36.6% in 2019 (𝜒2 = 14.085, P < .001), and patients with stage III accounted for 27.1% in 2020 significantly higher than 20.5% in 2019 (𝜒2 = 11.145, P < .001). Waiting time for treatment was extended from 8 days (median) in January-June and July-December 2019 to 16 days in January-June (𝜒2 = 74.674, P < .001) and 12 days in July-December 2020 (𝜒2 = 37.916, P < .001). Of the 179 patients who delayed treatment, 164 (91.6%) were for the reasons of the healthcare providers. Compared to 2019, the number of patients in Harbin or non-Harbin in Heilongjiang Province and outside the province decreased, and cross-regional medical treatment has been hindered. The COVID-19 pandemic has negatively impacted cervical cancer patient attendance at the initial phase. These results are solid evidence that a strategy and mechanism for the effective attendance of cervical cancer patients in response to public health emergencies is urgently needed.  相似文献   
5.
目的探讨肿瘤坏死因子相关激活蛋白(CD40L)、CD4+/CD8+、白细胞介素-4(IL-4)与儿童细菌性社区获得性肺炎(CAP)经典炎症标志物的关系及预测抗菌治疗效果的效能。方法选取300例儿童细菌性CAP患儿,均给予化痰、止咳、平喘及抗感染治疗, 其中43例治疗无效(观察组)及257例治疗有效(对照组),比较2组治疗前白细胞计数(WBC)、C反应蛋白(CRP)、降钙素原(PCT)及CD40L、CD4+/CD8+、IL-4,采用Pearson分析CD40L、CD4+/CD8+、IL-4与经典炎症标志物的关系及CD40L、CD4+/CD8+、IL-4之间的关系,采用logistic回归方程分析CD40L、CD4+/CD8+、IL-4与治疗无效的关系,采用受试者工作特征曲线(ROC)及ROC下面积(AUC)分析CD40L、CD4+/CD8+、IL-4预测抗菌治疗效果的效能。结果观察组WBC、CRP、PCT、CD40L、IL-4水平均高于对照组(P < 0.01),CD4+/CD8+低于对照组(P < 0.01);CD40L与WBC、CRP、PCT均呈正相关(r=0.720、0.433、0.832,P < 0.01),CD4+/CD8+与WBC、CRP、PCT呈负相关(r=-0.709、-0.449、-0.698,P < 0.01),IL-4与WBC、CRP、PCT呈正相关(r=0.889、0.760、0.723,P < 0.01);CD40L、CD4+/CD8+、IL-4均与治疗无效的相关性具有统计学意义(P < 0.01);CD40L与CD4+/CD8+呈负相关(r=-0.776,P < 0.01),与IL-4呈正相关(r=0.554,P < 0.01);CD4+/CD8+与IL-4呈负相关(r=-0.538,P < 0.01);单一指标中IL-4预测抗菌治疗效果的AUC最大为0.805,各指标联合预测抗菌治疗效果的AUC为0.867,敏感度达79.07%,大于任一单一指标(P < 0.01)。结论CD40L、IL-4、CD4+/CD8+与经典炎症标志物存在一定相关性,可在一定程度上反映细菌性CAP患儿病情程度,治疗期间进行动态监测可及早预测疗效,为细菌性CAP患儿后续治疗提供参考依据。  相似文献   
6.
目的:探究术前预后营养指数(prognostic nutritional index,PNI)和中性粒-淋巴细胞比值(neutrophil-lymphocyte ratio,NLR)对于非肌层浸润性膀胱癌(non-muscular invasive bladder cancer,NMIBC)患者在术后复发中的预测价值。方法:回顾性分析我院2016年01月-2019年12月期间182例住院行手术治疗的 NMIBC患者,根据术前1周内血常规和生化的结果计算PNI值和NLR值,并根据ROC曲线确定术前PNI和NLR的最佳临界值,分别分析PNI、NLR与NMIBC患者病理特征以及术后复发的关系。结果:根据ROC曲线,确定本研究中高PNI组(≥47.18)116例,低PNI组(<47.18)66例,高NLR组(≥2.50)77例,低NLR组(<2.50)105例;PNI组在年龄、复发及病理T分期上存在明显差异,P<0.05;NLR组在复发、病理T分期上存在明显差异,P<0.05;Kaplan-Meier生存曲线显示,低PNI组RFS显著差于高PNI组(P<0.001),高NLR组RFS显著差于低NLR组(P<0.001);Cox单因素分析结果提示:患者的吸烟史、肿瘤分期、组织学分级、PNI<47.18、NLR≥2.50是影响NMIBC患者复发的危险因素;Cox多因素分析结果提示:患者的吸烟史、肿瘤分期、PNI<47.18、NLR≥2.50是影响NMIBC患者复发的独立危险因素;Pearson相关性分析显示PNI与NLR值在NMIBC患者中存在负相关(P<0.001);低PNI/高NLR与患者术后复发、高PNI/低NLR与患者术后未复发具有相关性(P<0.001)。结论:术前PNI、NLR是预测NMIBC患者术后复发的有效指标,47.18、2.50可分别作为PNI、NLR的最佳分界值,低PNI、高NLR是NMIBC复发的独立危险因素,同时具有低PNI、高NLR患者更易出现术后复发,联合使用PNI、NLR两项指标,可以更有效地预测NMIBC患者术后复发。  相似文献   
7.
Whether the underlying mutations are homozygous, heterozygous, or co-inherited with other hemoglobinopathies, sickle cell disease is known to afflict the kidneys, leading to the clinical entity known as sickle cell nephropathy (SCN). Although common, SCN remains diagnostically elusive. Conventional studies performed in the context of renal disorders often fail to detect early stage SCN. This makes the quest for early diagnosis and treatment more challenging, and it increases the burden of chronic kidney disease-related morbidity among patients. Novel diagnostic tools have been employed to overcome this limitation. In this study, we discuss various biomarkers of SCN, including those employed in clinical practice and others recently identified in experimental settings, such as markers of vascular injury, endothelial dysfunction, tubulo-glomerular damage, and oxidative stress. These include kidney injury molecule-1, monocyte chemoattractant protein-1, N-acetyl-B-D-glucosaminidase, ceruloplasmin, orosomucoid, nephrin, and cation channels, among others. Furthermore, we explore the potential of novel biomarkers for refining diagnostic and therapeutic approaches and describe some obstacles that still need to be overcome. We highlight the importance of a collaborative approach to standardize the use of promising new biomarkers. Finally, we outline the limitations of conventional markers of renal damage as extensions of the pathogenic process occurring at the level of the organ and its functional subunits, with a discussion of the expected pattern of clinical and biochemical progression among patients with SCN.  相似文献   
8.
9.
绦虫病是由猪带绦虫、牛带绦虫和亚洲带绦虫寄生于人体肠道所引起的食源性人兽共患寄生虫病。人类是唯一的最终宿主。该文报道一例绦虫感染致急腹症患者的诊治经过。该例28岁男性患者主要表现为腹痛,入院后行血常规、生化、影像学等检查,阑尾炎表现不典型,考虑其他原因的急腹症,经禁饮、禁食、灌肠、抗炎、补液等保守治疗后,患者恢复排便排气,腹痛明显缓解,由患者排出的粪便中见绦虫的带节片,确诊为绦虫感染致不完全性肠梗阻,诊断明确后予阿苯达唑驱虫治疗并顺利出院。该例的诊治过程提示,临床医师应提高对肠道寄生虫病的认识,拓宽诊断思路,减少漏诊和误诊。  相似文献   
10.
目的 对手卫生行为量表(Hand Hygiene Behaviour Questionnaire,HHBQ)进行汉化,并检验其信效度。方法 根据跨文化调试指南,对HHBQ进行前译、前译综合、回译、回译综合、原作者审核、专家咨询、预测试,形成中文版HHBQ。2021年7月—10月对杭州市3所三级甲等医院的537名医务人员进行调查,评价中文版HHBQ的信效度。 结果 中文版HHBQ包含3个维度,分别是手卫生能力(5个条目)、手卫生机会(7个条目)、手卫生动机(5个条目)。总量表内容效度指数为0.995,量表各条目内容效度指数为0.923~1.000。探索性因子分析共提取3个公因子,累计方差贡献率为68.741%。验证性因子分析显示模型拟合度良好。总量表的Cronbach’s α系数为0.918,各维度的Cronbach’s α系数为0.871~0.906。量表的重测信度为0.739。 结论 中文版HHBQ具有良好的信效度,可全面评估医务人员手卫生的影响因素。  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