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   943613篇
  免费   68951篇
  国内免费   5885篇
耳鼻咽喉   12960篇
儿科学   29016篇
妇产科学   26604篇
基础医学   130711篇
口腔科学   25428篇
临床医学   80668篇
内科学   188174篇
皮肤病学   19339篇
神经病学   73288篇
特种医学   38438篇
外国民族医学   358篇
外科学   147305篇
综合类   29403篇
现状与发展   6篇
一般理论   253篇
预防医学   67865篇
眼科学   21507篇
药学   69233篇
  59篇
中国医学   5314篇
肿瘤学   52520篇
  2021年   8000篇
  2019年   8184篇
  2018年   10982篇
  2017年   8931篇
  2016年   9422篇
  2015年   11352篇
  2014年   15621篇
  2013年   22321篇
  2012年   30369篇
  2011年   32085篇
  2010年   19997篇
  2009年   18505篇
  2008年   29106篇
  2007年   30626篇
  2006年   30566篇
  2005年   29844篇
  2004年   27819篇
  2003年   26780篇
  2002年   26062篇
  2001年   42111篇
  2000年   43132篇
  1999年   36749篇
  1998年   9768篇
  1997年   8903篇
  1996年   8777篇
  1995年   8686篇
  1994年   8301篇
  1993年   7699篇
  1992年   28309篇
  1991年   27112篇
  1990年   26528篇
  1989年   25433篇
  1988年   23635篇
  1987年   23235篇
  1986年   22309篇
  1985年   21201篇
  1984年   15822篇
  1983年   13472篇
  1982年   8062篇
  1979年   14580篇
  1978年   10191篇
  1977年   8604篇
  1976年   8124篇
  1975年   8945篇
  1974年   10686篇
  1973年   10174篇
  1972年   9665篇
  1971年   8911篇
  1970年   8579篇
  1969年   8021篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
81.
82.
Salivary glands tumours are uncommon tumours showing a large diversity of histological types. This article presents a synthesis of patterns and paths of invasion of parotid glands tumours in order to propose an approach of the delineation of primary tumour clinical target volumes and of the selection of lymph nodes target volumes. This article does not discuss treatment indications but defines clinical target volumes to treat if radiotherapy is indicated. Postoperative situation being the most frequent, the delineation of primary tumour clinical target volume is based on an anatomical approach.  相似文献   
83.

Objective

To investigate the efficacy and safety of an influenza vaccination in patients with myasthenia gravis with acetylcholine receptor antibodies (AChR MG).

Methods

An influenza vaccination or placebo was administered to 47 AChR MG patients. Before and 4?weeks after administration blood samples and clinical outcome scores were obtained. Antibodies to the vaccine strains A/California/7/2009 (H1N1)pdm09, A/Hong Kong/4801/14 (H3N2) and B/Brisbane/060/08 were measured using the hemagglutination-inhibition (HI) assay and disease-specific AChR antibody titers were measured with a radio-immunoprecipitation assay. Forty-seven healthy controls (HC) were vaccinated with the same influenza vaccine to compare antibody titers.

Results

A post-vaccination, seroprotective titer (HI?≥?1:40) was achieved in 89.4% of MG patients vs. 93.6% in healthy controls for the H3N2 strain, 95.7% vs 97.9% for the H1N1 strain and 46.8 vs 51% for the B-strain. A seroprotective titer for all three strains of the seasonal influenza vaccine was reached in 40.4% (19/47) of the MG group and in 51% (24/47) of the HC group. Immunosuppressive medication did not significantly influence post geomean titers (GMT). The titers of disease-specific AChR antibodies were unchanged 4?weeks after vaccination. The clinical outcome scores showed no exacerbation of MG symptoms.

Conclusion

The antibody response to an influenza vaccination in patients with AChR MG was not different from that in healthy subjects, even in AChR MG patients using immunosuppressive medication. Influenza vaccination does not induce an immunological or clinical exacerbation of AChR MG.

Clinical trial registry

The influenza trial is listed on clinicaltrialsregister.eu under 2016-003138-26.  相似文献   
84.

Background

Programmed death ligand-1 (PD-L1) is a potential predictive biomarker for immunotherapy in several malignancies. However, the expression level and clinical significance of PD-L1 in von Hippel–Lindau (VHL)-associated hereditary clear-cell renal cell carcinoma (ccRCC) remain unclear.

Patients and Methods

Surgical specimens were recruited from 129 patients with sporadic ccRCC and 26 patients with VHL-associated hereditary ccRCC. The PD-L1 expression level was assessed using immunohistochemistry. Correlations between PD-L1 expression and clinicopathological features were analyzed.

Results

In sporadic ccRCC, the positive expression rate of PD-L1 was 47.3% (61/129). Positive PD-L1 expression was correlated with advanced tumor T stage (P = .011), higher Fuhrman nuclear grade (P = .022), poor disease-free survival (P = .037), and sex (P = .025). In the VHL-associated hereditary ccRCC, positive PD-L1 expression rate was 34.6% (9/26), lower than that in sporadic ccRCC. Positive PD-L1 was correlated with higher Fuhrman nuclear grade (P = .008), but not with sex, age, tumor stage, or the onset age of VHL-associated tumors.

Conclusion

Positive PD-L1 expression was correlated with the aggressive clinicopathological features in sporadic and VHL-associated hereditary ccRCC. Whether PD-L1 expression level in ccRCC is related to the effectiveness of programmed death-1/PD-L1 checkpoint inhibitor immunotherapy needs to be further investigated.  相似文献   
85.
86.
87.
Uptake of colorectal cancer screening remains suboptimal. Mailed fecal immunochemical testing (FIT) offers promise for increasing screening rates, but optimal strategies for implementation have not been well synthesized. In June 2019, the Centers for Disease Control and Prevention convened a meeting of subject matter experts and stakeholders to answer key questions regarding mailed FIT implementation in the United States. Points of agreement included: 1) primers, such as texts, telephone calls, and printed mailings before mailed FIT, appear to contribute to effectiveness; 2) invitation letters should be brief and easy to read, and the signatory should be tailored based on setting; 3) instructions for FIT completion should be simple and address challenges that may lead to failed laboratory processing, such as notation of collection date; 4) reminders delivered to initial noncompleters should be used to increase the FIT return rate; 5) data infrastructure should identify eligible patients and track each step in the outreach process, from primer delivery through abnormal FIT follow-up; 6) protocols and procedures such as navigation should be in place to promote colonoscopy after abnormal FIT; 7) a high-quality, 1-sample FIT should be used; 8) sustainability requires a program champion and organizational support for the work, including sufficient funding and external policies (such as quality reporting requirements) to drive commitment to program investment; and 9) the cost effectiveness of mailed FIT has been established. Participants concluded that mailed FIT is an effective and efficient strategy with great potential for increasing colorectal cancer screening in diverse health care settings if more widely implemented.  相似文献   
88.
89.
目的比较正常剂量盐酸氨溴索联合排痰仪与大剂量盐酸氨溴索联合支气管镜在治疗老年重症肺炎中的临床疗效。方法通过计算机检索PubMed、The Cochrane Library、Web of Science、CNKI、万方数据库、维普数据库和中国生物医学文献服务系统,搜索国内外公开发表的有关盐酸氨溴索联合排痰仪与大剂量盐酸氨溴索联合支气管镜治疗老年重症肺炎的相关文章,检索时限从建库起到2019年5月。分别由两名作者根据文献纳入和排除标准对文献进行筛选以及数据提取,使用RevMan 5.3软件进行Meta分析。结果经筛选后共有27篇文献最终被纳入分析。Meta分析结果表明,大剂量盐酸氨溴索联合支气管镜治疗能减少患者ICU住院时间(MD=-1.84,95%CI:-2.21~-1.48)、呼吸机使用时间(MD=-3.93,95%CI:-4.17~-3.69)、治疗期间死亡率(O^R=0.42,95%CI:0.33~0.53)、急性生理学与慢性健康状况(APACHEⅡ)评分(MD=-0.67,95%CI:-1.05~-0.29)、多器官功能衰竭(MOF)发生率(O^R=0.41,95%CI:0.32~0.53)、C反应蛋白(CRP)浓度(MD=-10.35,95%CI:-11.29~-9.41)以及血清降钙素原(PCT)浓度(MD=-0.37,95%CI:-0.40~-0.33),增加患者动脉血氧分压(PaO_2)(MD=4.85,95%CI:3.83~5.86)、经皮动脉血氧饱和度(SpO_2)(MD=6.47,95%CI:5.65~7.29)和氧合指数(OI)(PaO_2/FiO_2)(MD=31.88,95%CI:29.21~34.54)。结论大剂量使用盐酸氨溴索联合支气管镜治疗老年重症肺炎是安全可行的,且与常规治疗方法相比,在所测指标中均具有一定的优势,有望成为治疗老年重症肺炎的优先选择。  相似文献   
90.
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