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   197843篇
  免费   18728篇
  国内免费   8530篇
耳鼻咽喉   3140篇
儿科学   4417篇
妇产科学   2057篇
基础医学   36753篇
口腔科学   6310篇
临床医学   16241篇
内科学   26846篇
皮肤病学   4569篇
神经病学   12586篇
特种医学   5143篇
外国民族医学   121篇
外科学   19181篇
综合类   29549篇
现状与发展   53篇
预防医学   5420篇
眼科学   4063篇
药学   15775篇
  33篇
中国医学   6008篇
肿瘤学   26836篇
  2024年   157篇
  2023年   2810篇
  2022年   3547篇
  2021年   6714篇
  2020年   6559篇
  2019年   6300篇
  2018年   6515篇
  2017年   6769篇
  2016年   7011篇
  2015年   7860篇
  2014年   11692篇
  2013年   13029篇
  2012年   11110篇
  2011年   12462篇
  2010年   10364篇
  2009年   9945篇
  2008年   10418篇
  2007年   10718篇
  2006年   9695篇
  2005年   8825篇
  2004年   7892篇
  2003年   6917篇
  2002年   5698篇
  2001年   4923篇
  2000年   4065篇
  1999年   3572篇
  1998年   2996篇
  1997年   2948篇
  1996年   2550篇
  1995年   2586篇
  1994年   2300篇
  1993年   1958篇
  1992年   1645篇
  1991年   1554篇
  1990年   1234篇
  1989年   1154篇
  1988年   1064篇
  1987年   867篇
  1986年   780篇
  1985年   1067篇
  1984年   922篇
  1983年   629篇
  1982年   722篇
  1981年   594篇
  1980年   490篇
  1979年   385篇
  1978年   304篇
  1977年   253篇
  1976年   209篇
  1975年   84篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
92.
皮肤鳞状细胞癌是具有发病率高、发展快、可转移、易误诊等特点的一种恶性肿瘤,对人类的健康造成威胁。随着中医的发展和现代医学实验研究技术的进步,中医药在皮肤鳞状细胞癌的现代研究方面也取得一定成果。目前临床上治疗鳞状细胞癌多采取手术及药物化疗等,因不良反应的存在,患者接受度低。中药具有多靶点、安全性高、不良反应少等优势,在治疗皮肤鳞状细胞癌中中医具有一定优势,本文将围绕中药单体、中药复方,以及针灸在治疗皮肤鳞状细胞癌的研究进展展开论述和思考。  相似文献   
93.
目的:探讨中性粒细胞/淋巴细胞比值(neutrophil to lymphocyte ratio,NLR)对初治前弥漫性大B细胞淋巴瘤(diffuse large B cell lymphoma,DLBCL)患者预后的意义。方法:回顾性分析2010年1月至2019年10月,新疆医科大学附属肿瘤医院收治的165例初治DLBCL患者,确定了NLR(>2.77)在预后预测中的最佳临界值,采用Log-rank检验和Cox回归模型进行分析,评价治疗前NLR对无进展生存期(progression free survival time,PFS)和总生存期(overall survival rate,OS)的影响。结果:在入选的165例患者中,有67例患者治疗前NLR升高(>2.77),NLR升高与PFS和OS较短的患者明显相关(P<0.001和P=0.003)。多变量分析进一步表明,NLR>2.77是PFS的独立预测因子。结论:治疗前NLR升高提示DLBCL患者预后不良。  相似文献   
94.
95.
96.
BackgroundConsiderable progress has been made in therapeutic options for multiple myeloma (MM). Understanding the current landscape of MM treatment options and associated outcomes in the real world is important in providing key insights into clinical and knowledge gaps which could be targeted for further optimization.MethodsThe Canadian Myeloma Research Group Database (CMRG-DB) is a prospectively maintained disease-specific database with >7000 patients. The objective of this study was to describe the trends in the treatment landscape and outcomes including early mortality, time to next treatment, and overall survival (OS) in each line of treatment stratified by autologous stem cell transplant (ASCT) receipt among newly-diagnosed MM patients in Canada between 2007 and 2018.ResultsA total of 5154 patients were identified among which 3030 patients (58.8%) received an upfront ASCT and 2124 (41.2%) did not. At diagnosis, the median age was 64 years and 58.6% were males. Bortezomib and lenalidomide were most frequently used (>50%) in first and second-line treatment respectively among both the ASCT and non-ASCT cohort. The median OS was 122.0 months (95% Cl 115.0-135.0 months) and 54.3 months (95% CI 50.8-58.8 months) for the ASCT and non-ASCT cohort respectively with an incremental decrease in OS in each subsequent line of treatment.ConclusionWe present the largest study to date in the Canadian landscape showing the characteristics, therapy usage, and outcomes among MM patients. This information will be critical in benchmarking current outcomes and provide key insight into areas of unmet needs and gaps for improvement of MM patients nationally.  相似文献   
97.
A high risk of developing second primary malignancy (SPM) has been reported among head and neck cancer patients. Here, we aimed to statistically quantify the impact of SPM development on the survival of head and neck cancer patients. Our study was conducted using the Surveillance, Epidemiology and End Results database to collect the data of 48 316 patients who received curative surgical resection for initial primary head and neck squamous cell carcinoma (IP-HNSCC) in 1975 to 2019. SPM diagnosis was treated as a time-varying covariate and multivariable Cox regression analysis was conducted to estimate the association between SPM development and survival, overall or by the subsite of IP-HNSCC. Of the included patients, 11 238 patients (23.3%) developed SPM during the follow-up period. A significant reduction in survival was observed among patients with SPM (hazard ratio [HR] for overall survival, 3.30; 95% confidence interval [CI]: 3.20-3.41). The impact of SPM development on reduced survival was more significant in patients with localized IP-HNSCC vs regional IP-HNSCC (HROS, 3.41; 95% CI: 3.24-3.6 vs HROS, 3.18; 95% CI: 3.05-3.31; P for interaction <.001). The survival impact of SPM development was more evident in younger patients than in older patients. SPM in lung and bronchus was associated with the most pronounced reduction in survival, overall and across all subsites of HNSCC. Our results indicated that SPM development led to a significant reduction in survival. A greater survival benefit may be achieved through intensive surveillance for SPM in lung and bronchus targeting younger patients and those with localized HNSCC.  相似文献   
98.
ObjectivesThe reduction of postoperative acute kidney injury in patients undergoing cardiopulmonary bypass surgery using an oxygen delivery-guided perfusion strategy (oxygen delivery strategy) for cardiopulmonary bypass management compared with a fixed flow perfusion (conventional strategy) remains controversial. The purpose of this study was to determine whether a oxygen delivery strategy would reduce the incidence of postoperative acute kidney injury in patients undergoing cardiopulmonary bypass surgery.MethodsWe randomly enrolled 300 patients undergoing cardiopulmonary bypass surgery. Patients were randomly assigned to a oxygen delivery strategy (maintaining a oxygen delivery index value >300 mL/min/m2 through pump flow adjustments during cardiopulmonary bypass) or a conventional strategy (a target pump flow was determined on the basis of the body surface area). The primary end point was the development of acute kidney injury. Secondary end points were the red blood cell transfusion rate and number of red blood cell units, intubation time, postoperative length of stay in the intensive care unit and the hospital, predischarge estimated glomerular filtration rate, and hospital mortality.ResultsAcute kidney injury occurred in 20 patients (14.6%) receiving the oxygen delivery strategy and in 42 patients (30.4%) receiving the conventional strategy (relative risk, 0.48; 95% confidence interval, 0.30-0.77; P = .002). The secondary end points were not significantly different between strategies. In a prespecified subgroup analysis of patients who had nadir hematocrit less than 23% or body surface area less than 1.40 m2, the oxygen delivery strategy seemed to be superior to the conventional strategy and the existence of quantitative interactions was suggested.ConclusionsAn oxygen delivery strategy for cardiopulmonary bypass management was superior to a conventional strategy with respect to preventing the development of acute kidney injury.  相似文献   
99.
目的:研究胸段食管鳞癌术后复发模式,为术后放疗靶区勾画提供参考。方法:回顾分析我院2012年7月至2017年5月收治术后复发的81例胸段食管鳞癌患者的临床资料,参照AJCC第八版食管癌分期,将第1-8M站定义为上中纵隔淋巴结区,8Lo、9、15站定义为下纵隔淋巴结区,16-20站定义为上腹部淋巴结区。标记患者的复发部位,并分析局部复发、区域复发和远处转移的模式。结果:中位复发时间为12个月(2~103个月)。6例(7.4%)患者发生单纯局部复发,64例(79.0%)患者发生区域复发,11例(13.6%)患者发生远处转移。区域淋巴结复发中最高危的复发区域为上中纵隔淋巴引流区,此区域包含了82.8%的复发淋巴结,其次为上腹部淋巴结引流区(13.6%)。11例患者发生上腹部淋巴结复发,其中10(90.9%)例为胸下段,7例(63.6%)患者术后分期≥Ⅲ_(b)期。结论:胸段食管鳞癌术后复发模式以区域淋巴结复发为主,上中纵隔淋巴引流区为最高危复发区域,术后放疗靶区应重点包含。对于术后分期较晚的胸下段食管鳞癌,上腹部淋巴结引流区可能需要涵盖在放疗靶区内。吻合口、瘤床和下纵隔复发风险低,可不必常规涵盖在放疗靶区内。  相似文献   
100.
In the United States, renal cell carcinoma (RCC) incidence and the prevalence of obesity, an established risk factor for RCC, have been increasing for several decades. RCC is more common among older individuals. We sought to quantify the contribution of excess adiposity to the rising incidence of RCC among individuals 60 years or older. National Institutes of Health-American Association of Retired Persons Diet and Health Study data (n = 453 859 participants, enrolled in 1995-1996, age at enrollment 50-71 years) were used to estimate multivariable-adjusted hazard ratios (HRs) for RCC across body mass index categories and HRs associated with smoking. Population attributable fractions (PAFs) were calculated using estimated HRs and annual overweight/obesity prevalence from the National Health Interview Survey (1985-2008). PAF estimates were combined with RCC incidence from Surveillance, Epidemiology and End Results-13 to calculate annual percent changes in RCC incidence attributable (and unrelated) to overweight/obesity. We found that between 1995 and 2018, among individuals aged 60 years and older, PAF for overweight/obesity increased from 18% to 29% for all RCCs. In comparison, the PAF for smoking declined from 12% to 9%. RCC incidence increased 1.8% per year (95% confidence interval [CI] 1.5%-2.1%) overall, while RCC incidence attributable to overweight/obesity increased 3.8% per year (95%CI 3.5%-4.2%) and RCC incidence unrelated to overweight/obesity increased 1.2% per year (95% CI 0.9%-1.4%). In conclusion, overweight/obesity appears to have contributed importantly to the rising incidence of RCC in the United States since the mid-1990s. Public health interventions focused on reducing overweight and obesity could help substantially in curbing this trend.  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