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   140532篇
  免费   12473篇
  国内免费   8682篇
耳鼻咽喉   1383篇
儿科学   2021篇
妇产科学   2606篇
基础医学   15508篇
口腔科学   2615篇
临床医学   18850篇
内科学   20265篇
皮肤病学   1324篇
神经病学   6928篇
特种医学   4954篇
外国民族医学   44篇
外科学   14133篇
综合类   24357篇
现状与发展   39篇
一般理论   20篇
预防医学   9400篇
眼科学   3656篇
药学   14824篇
  107篇
中国医学   7750篇
肿瘤学   10903篇
  2024年   280篇
  2023年   1743篇
  2022年   3524篇
  2021年   6492篇
  2020年   4802篇
  2019年   4159篇
  2018年   4510篇
  2017年   4001篇
  2016年   3816篇
  2015年   5872篇
  2014年   7545篇
  2013年   7127篇
  2012年   10655篇
  2011年   11691篇
  2010年   7777篇
  2009年   6215篇
  2008年   7784篇
  2007年   8063篇
  2006年   7762篇
  2005年   7622篇
  2004年   5586篇
  2003年   5111篇
  2002年   4516篇
  2001年   3604篇
  2000年   3422篇
  1999年   3175篇
  1998年   1859篇
  1997年   1784篇
  1996年   1535篇
  1995年   1348篇
  1994年   1129篇
  1993年   714篇
  1992年   1074篇
  1991年   872篇
  1990年   721篇
  1989年   649篇
  1988年   623篇
  1987年   527篇
  1986年   431篇
  1985年   334篇
  1984年   211篇
  1983年   159篇
  1982年   85篇
  1981年   98篇
  1980年   84篇
  1979年   115篇
  1978年   53篇
  1977年   56篇
  1975年   44篇
  1974年   45篇
排序方式: 共有10000条查询结果,搜索用时 467 毫秒
11.
12.
The research and development of penicillin started with difficulty before 1949 and achieved certain results. In 1951, after the founding of the People's Republic of China, Zhang Weishen, as the only Chinese scientist who had been trained and worked in a penicillin research and development center in the United States for many years, overcame many difficulties and returned to China. In 1953, with the efforts of Zhang Weishen and his colleagues, China realized the industrialized production of penicillin, alleviating the urgent needs of the masses. Antibiotics has also become the first discipline to achieve major scientific and technological achievements after the founding of the New China. In the mid-1950s, the technical breakthrough in the localization of lactose substitutes marked the localization of the raw materials of the penicillin-producing culture medium, which paved the way for the industrialized production of penicillin with Chinese characteristics. Antibiotics have become one of the most widely used and affordable drugs for hundreds of millions of patients in China, and China has since ended the humiliating history of the “Sick Man of East Asia".  相似文献   
13.
癫痫发作后状态(PIS)是指癫痫发作停止到恢复至发病前水平的异常状态,包括认知、运动、感觉、自主神经和精神行为等异常,症状多样,严重程度不一,持续数秒至数天不等,对患者的健康和生活质量产生很大影响。然而,目前国内外相关的研究较少,临床医生对此缺乏正确认识,容易误诊误治。本文将从PIS的定义、病理生理机制、临床表现、诊断和鉴别诊断、临床意义以及干预策略等进行综述,以提高临床医生的认识,并为今后临床研究提供参考。  相似文献   
14.
15.
杜玫洁  黄素芳  熊杰  储备 《护理学杂志》2022,27(10):110-113
以过渡期护理内涵为基础对文献进行干预措施内容提取,以干预时间点为标准对ICU转科患者家属迁移应激的过渡期护理措施进行综述,护理干预措施包括干预前准备、转科前干预、转科中干预、转科后干预,并总结护理干预效果评价,以期为临床护理人员开展相关实践提供具体参考,推进以家庭为中心的护理工作,改善临床护理质量。  相似文献   
16.
Inappropriate use of acetaminophen (APAP) can lead to morbidity and mortality secondary to hepatic necrosis. Ginsenoside Rg1 is a major active ingredient in processed Panax ginseng, which is proved to elicit biological effects. We hypothesized the beneficial effect of Rg1 on APAP-mediated hepatotoxicity was through Nrf2/ARE pathway. The study was conducted in cells and mice, comparing the actions of Rg1. Rg1 significantly improved cell survival rates and promoted the expression of antioxidant proteins. Meanwhile, Rg1 reduced the excessive ROS and the occurrence of cell apoptosis, which were related to Nrf2/ARE pathway. Expression of Nrf2 has a certain cell specificity.

  相似文献   

17.
18.
目的探讨人工弓状线切开技术在变异弓状线病例腹腔镜全腹膜外腹股沟疝修补术(TEP)应用的可靠性、安全性和有效性。 方法回顾性分析2016年7月至2019年8月广东医科大学茶山医院施行TEP的60例弓状线变异患者资料,在脐与耻骨联合连线中点人为切开腹直肌后鞘及其后面的腹横筋膜创建一条人工弓状线,并对其后面的腹膜前间隙进分离。影像记录弓状线的形态和手术步骤。 结果低位弓状线50例(83.3%),位于脐下8~12 cm,表现为不完整的腹直肌后鞘,向下呈逐渐变薄、变少的散在纤维。无弓状线10例(16.7%),有完整的腹直肌后鞘并一直延伸至耻骨。以人工弓状线为界分为两个层面,前面的是腹直肌后间隙,后面是腹膜前间隙,位于腹横筋膜(含有后鞘)与腹膜前筋膜浅层之间,是TEP理想的分离层面,沿此间隙向下分离与Retzius间隙相连,然后向外分离Bogros间隙。本组平均手术时间(130±15)min,术中腹膜损伤率8.3%(5/60)。术后发生血肿3例,血清肿2例,皮下气肿3例,无慢性疼痛病例。术后平均随访25个月,无复发病例。 结论人工弓状线切开技术在低位和无弓状线患者的TEP手术中安全有效、简单可靠,值得推广。  相似文献   
19.
ABSTRACT

In clinical trials, selection of appropriate study endpoints is critical for an accurate and reliable evaluation of safety and effectiveness of a test treatment under investigation. In practice, however, there are usually multiple endpoints available for measurement of disease status and/or therapeutic effect of the test treatment under study. For example, in cancer clinical trials, overall survival, response rate, and/or time to disease progression are usually considered as primary clinical endpoints for evaluation of safety and effectiveness of the test treatment under investigation. Once the study endpoints have been selected, sample size required for achieving a desired power is then determined. It, however, should be noted that different study endpoints may result in different sample sizes. In practice, it is usually not clear which study endpoint can best inform the disease status and measure the treatment effect. Moreover, different study endpoints may not translate one another although they may be highly correlated one another. In this article, we intend to develop an innovative endpoint namely therapeutic index based on a utility function to combine and utilize information collected from all study endpoints. Statistical properties and performances of the proposed therapeutic index are evaluated theoretically. A numerical example concerning a cancer clinical trial is given to illustrate the use of the proposed therapeutic index.  相似文献   
20.

Objective

Comparative survival between neoadjuvant chemotherapy and adjuvant chemotherapy for patients with cT2-4N0-1M0 non–small cell lung cancer has not been extensively studied.

Methods

Patients with cT2-4N0-1M0 non–small cell lung cancer who received platinum-based chemotherapy were retrospectively identified. Exclusion criteria included stage IV disease, induction radiotherapy, and targeted therapy. The primary end point was disease-free survival. Secondary end points were overall survival, chemotherapy tolerance, and ability of Response Evaluation Criteria In Solid Tumors response to predict survival. Survival was estimated using the Kaplan–Meier method, compared using the log-rank test and Cox proportional hazards models, and stratified using matched pairs after propensity score matching.

Results

In total, 330 patients met the inclusion criteria (n = 92/group after propensity-score matching; median follow-up, 42 months). Five-year disease-free survival was 49% (95% confidence interval, 39-61) for neoadjuvant chemotherapy versus 48% (95% confidence interval, 38-61) for adjuvant chemotherapy (P = .70). On multivariable analysis, disease-free survival was not associated with neoadjuvant chemotherapy or adjuvant chemotherapy (hazard ratio, 1.1; 95% confidence interval, 0.64-1.90; P = .737), nor was overall survival (hazard ratio, 1.21; 95% confidence interval, 0.63-2.30; P = .572). The neoadjuvant chemotherapy group was more likely to receive full doses and cycles of chemotherapy (P = .014/0.005) and had fewer grade 3 or greater toxicities (P = .001). Response Evaluation Criteria In Solid Tumors response to neoadjuvant chemotherapy was associated with disease-free survival (P = .035); 15% of patients receiving neoadjuvant chemotherapy (14/92) had a major pathologic response.

Conclusions

Timing of chemotherapy, before or after surgery, is not associated with an improvement in overall or disease-free survival among patients with cT2-4N0-1M0 non–small cell lung cancer who undergo complete surgical resection.  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