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   14285篇
  免费   972篇
  国内免费   211篇
耳鼻咽喉   69篇
儿科学   364篇
妇产科学   188篇
基础医学   981篇
口腔科学   262篇
临床医学   1852篇
内科学   2348篇
皮肤病学   155篇
神经病学   585篇
特种医学   219篇
外国民族医学   4篇
外科学   1065篇
综合类   1644篇
一般理论   1篇
预防医学   1810篇
眼科学   251篇
药学   1485篇
  14篇
中国医学   1551篇
肿瘤学   620篇
  2024年   129篇
  2023年   417篇
  2022年   729篇
  2021年   852篇
  2020年   784篇
  2019年   1395篇
  2018年   1037篇
  2017年   615篇
  2016年   351篇
  2015年   401篇
  2014年   948篇
  2013年   791篇
  2012年   708篇
  2011年   744篇
  2010年   555篇
  2009年   496篇
  2008年   423篇
  2007年   360篇
  2006年   292篇
  2005年   238篇
  2004年   156篇
  2003年   124篇
  2002年   91篇
  2001年   80篇
  2000年   58篇
  1999年   44篇
  1998年   26篇
  1997年   21篇
  1996年   23篇
  1995年   24篇
  1994年   18篇
  1993年   8篇
  1992年   6篇
  1991年   6篇
  1989年   12篇
  1988年   9篇
  1986年   5篇
  1985年   205篇
  1984年   296篇
  1983年   268篇
  1982年   262篇
  1981年   257篇
  1980年   200篇
  1979年   197篇
  1978年   140篇
  1977年   146篇
  1976年   170篇
  1975年   140篇
  1974年   101篇
  1973年   98篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
The present paper reports on the inaugural meeting of the Mental Health Special Interest Research Group (SIRG) of the International Association for the Scientific study of Intellectual disability which was held at Fitzwilliam College, Cambridge, UK, in March 1998. The meeting was organized in conjunction with the Ninth Annual SIRG on ageing and intellectual disability. Representatives from North America, several European and Scandinavian countries, Australia, and Israel attended. Two broad themes had been determined prior to the meeting: ‘Improving the detection of mental health problems’ and ‘Research strategies for identifying risk factors for mental health problems’. In the presentations and subsequent discussions, it was apparent that there were extrenely diverse perspectives both across and within the different countries represented. Not only were individuals' experiences very different, but most strikingly, the theoretical frameworks were very diverse. This was partly a function of there being understandable differences in perspectives across disciplines, but at its most marked, there were fundamental differences in the way both intellectual disability and mental health were conceptualized.  相似文献   
22.
背景 农村订单定向医学生(简称定向医学生)的免费培养工作是缓解农村地区基层医生匮乏、提升基层医疗卫生队伍整体素质和水平的重要举措。目的 探索我国定向医学生培养的研究热点、研究动态和未来趋势,为后续研究提供参考。方法 于2022-02-15,在中国知网、万方数据知识服务平台、维普网中检索2010-01-01至2021-12-31发表的关于定向医学生培养相关论文,统计其发文量,运用Cite Space软件对样本文献作者、研究机构、关键词进行知识图谱的可视化分析。结果 共纳入598篇文献,关于定向医学生培养研究的文献量呈上升趋势,2018年达到历年顶峰(n=81)。该领域存在5个大的作者群,发文量排在前3位的机构为赣南医学院[113篇(18.9%)]、广西医科大学[40篇(6.7%)]及新乡医学院[28篇(4.7%)]。关键词词频排在前3位的分别是“订单定向”(70次)、“定向生”(57次)、“人才培养”(44次)。关键词聚类图谱得到“#0学习动力”“#1教学模式”“#2定向培养”“#3影响因素”“#4全科医学”“#5基层”“#6医学院”“#7医学生”8个聚类主题。最强突现词显示,排在前3位...  相似文献   
23.
背景 小儿遗尿症是儿科常见病之一,有效的小儿遗尿症诊疗指南有助于症状的规范化控制和缓解,而制定高质量的临床实践指南是提高小儿遗尿症诊疗水平的重要方式。目的 基于AGREEⅡ和RIGHT工具,评价2010年以来国内外发布的小儿遗尿症指南和专家共识的质量,以期为临床实践及后续指南的制订提供参考。方法 检索中国知网、万方数据知识服务平台、维普网、中国生物医学文献数据库和PubMed(补充检索医脉通、世界卫生组织以及英国国家临床示范研究所等数据库)2010-01-01至2022-01-31公开发表的小儿遗尿症相关的诊疗指南和专家共识。采用AGREEⅡ和RIGHT工具评价纳入文献的方法学和报告质量。根据AGREE Ⅱ工具评价结果,将各指南/共识推荐等级评定为“推荐(A级)”“更新后推荐(B级)”和“不推荐(C级)”。使用组内相关系数(ICC)进行一致性评价。结果 纳入8部指南和5部专家共识。共形成推荐意见185条,其中44条为诊断评估方面的意见,140条为治疗方面的推荐意见,1条为随访推荐意见。AGREEⅡ工具评价结果显示,范围和目的、参与人员、严谨性、清晰性、应用性和独立性6个领域的总得分(报...  相似文献   
24.
Chromosome banding analyses were made on 10 cases of Ph1-positive AML (7 M1 and 3 M2). The standard type Ph1 translocation, t(9q +;22q -), was identified in all of them. Karyotypically normal cells were observed in 6-65% of bone marrow metaphases at the initial cytogenetic examination of 7 patients, whereas the remaining 3 patients had only Ph1-positive cells at diagnosis. Follow-up studies performed in 5 cases indicated that the frequency of karyotypically normal cells increased up to 81-100% when the patients were in remission, whereas it was much reduced in relapse. In 5 cases, there was observed a clone of cells in which the Ph1 translocation was the sole karyotypic abnormality. Various types of other chromosome abnormalities, in addition to the Ph1, were observed in all cases, among which-7 was the most frequent, being found in three cases as a stem line. Other additional changes encountered were + Ph1, del(5), i(17q), - 10, + 18, + X, and various numerical and structural changes including certain secondary translocations that occurred in the Ph1 (22q -) or its partner (9q +). The types and frequencies of these additional changes appeared to be different from those found in the acute phase of CML or in Ph1-positive ALL.  相似文献   
25.
Male wild (Cavia aperea) and domestic (C. porcellus) guinea pigs were tested in two-bottle choice tests for preferences between glucose solutions of different concentrations and de-ionized water. Wild males showed significant preferences for concentrations between 0.025 and 0.4 M glucose while domestic males preferred only the 0.2 M glucose solution to de-ionized water. C. aperea males also consumed significantly greater volumes of liquid per kg body wt.34 during the glucose tests than did the C. porcellus males. These comparative results contrast sharply with those obtained by other authors with wild and domestic Norway rats.  相似文献   
26.
27.
28.
The cytogenetic findings by G- and C-banding in a primary breast carcinoma are reported. The tumor is characterized by a high modal number of chromosomes (79) and 14 markers of ten different origins. Chromosome #1 is more frequently involved in structural and numerical aberrations than is any other chromosome; nine copies of 1q were present in each cell examined. This observation supports the hypothesis that duplication of chromosome 1q may play an important role in the progression of malignant tumors.  相似文献   
29.
The neurotoxic hexacarbon 2,5-hexanedione (2,5-HD) produces testicular atrophy in experimental animals. To examine the morphogenesis of the testicular lesion, 1.0% 2,5-HD was provided in the drinking water of adult F-344 rats for up to 6 weeks. After 3 weeks of administration, there were occasional large vacuoles in the basal region of the germinal epithelium. At 4 weeks, these vacuoles were much larger and more numerous; electron microscopy demonstrated that they were derived from the smooth endoplasmic reticulum. The vacuoles were preferentially associated with stages 12, 13, 14, and 1 of the spermatogenic cycle. Additionally, at 4 weeks there was a significant decrease in the number of tubules in stages 7 and 13, and a concomitant increase in the percentage of tubules in stages 3, 5, and 6. By Week 5, most Golgi-phase and cap-phase spermatids were visibly affected, showing margination of nuclear chromatin, and were becoming dissociated from Sertoli cells. Frequent multinucleated giant cells were seen and electron microscopy of these cells suggested that they were derived from fused spermatocytes or spermatids. After 6 weeks, fewer giant cells were present, most tubules contained cellular debris, and many showed empty lumina encircled by a thin ring of cytoplasm near the basement membrane. Interstitial tissue appeared unaffected. These studies indicate that the Sertoli cell is probably an initial target for 2,5-HD action in the testis.  相似文献   
30.
A portable device for the rapid concentration of viruses from natural freshwaters described and its performance in field use is evaluated. The system handled up to 500 litres of water in less than 90 min at a cost of only 2 pounds per sample. Where the samples contained sufficient bacteriophages for detection by direct plating the apparent phage recoveries were greater than 75%. Plant and animal viruses were also concentrated from waters with this system.  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