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   264363篇
  免费   12714篇
  国内免费   959篇
耳鼻咽喉   3179篇
儿科学   8039篇
妇产科学   6155篇
基础医学   38083篇
口腔科学   8912篇
临床医学   18533篇
内科学   58920篇
皮肤病学   7005篇
神经病学   23267篇
特种医学   6428篇
外国民族医学   2篇
外科学   28050篇
综合类   1157篇
一般理论   73篇
预防医学   29477篇
眼科学   6014篇
药学   19808篇
中国医学   1031篇
肿瘤学   13903篇
  2023年   1767篇
  2022年   2753篇
  2021年   6006篇
  2020年   3565篇
  2019年   5768篇
  2018年   8207篇
  2017年   5535篇
  2016年   5968篇
  2015年   6591篇
  2014年   8007篇
  2013年   11267篇
  2012年   18350篇
  2011年   19225篇
  2010年   9975篇
  2009年   7875篇
  2008年   15561篇
  2007年   16185篇
  2006年   15216篇
  2005年   14517篇
  2004年   13272篇
  2003年   12277篇
  2002年   11406篇
  2001年   5466篇
  2000年   5878篇
  1999年   4777篇
  1998年   1508篇
  1997年   1100篇
  1996年   999篇
  1992年   2514篇
  1991年   2194篇
  1990年   2175篇
  1989年   1864篇
  1988年   1783篇
  1987年   1652篇
  1986年   1712篇
  1985年   1573篇
  1984年   1174篇
  1983年   1031篇
  1979年   1278篇
  1978年   883篇
  1975年   927篇
  1974年   1184篇
  1973年   1206篇
  1972年   1144篇
  1971年   1104篇
  1970年   1035篇
  1969年   1107篇
  1968年   1127篇
  1967年   1002篇
  1966年   898篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
The recognition that neurogenesis does not stop with adolescence has spun off research towards the reduction of brain disorders by enhancing brain regeneration. Adult neurogenesis is one of the tougher problems of developmental biology as it requires the generation of complex intracellular and pericellular anatomies, amidst the danger of neuroinflammation. We here review how a multitude of regulatory pathways optimized for early neurogenesis has to be revamped into a new choreography of time dependencies. Distinct pathways need to be regulated, ranging from neural growth factor induced differentiation to mitochondrial bioenergetics, reactive oxygen metabolism, and apoptosis. Requiring much Gibbs energy consumption, brain depends on aerobic energy metabolism, hence on mitochondrial activity. Mitochondrial fission and fusion, movement and perhaps even mitoptosis, thereby come into play. All these network processes are interlinked and involve a plethora of molecules. We recommend a deep thinking approach to adult neurobiology.  相似文献   
73.
器官移植术是20世纪出现的针对器官功能衰竭的最有效治疗方法,每年拯救全球超过12万例患者。但供器官短缺的现状,与器官移植技术和辅助药物的发展不匹配,制约了器官移植事业的发展。我国自2015年起已成为全球器官捐献和移植大国之一,2017年公民逝世后器官捐献数量超过5 000例,占全球捐献总量的15%以上。黄洁夫教授总结的器官捐献与移植"中国模式"得到了世界卫生组织、国际移植界的高度重视和充分肯定。本文通过整理全球及各国的器官捐献与移植数据,剖析全球现状与发展趋势,进一步探索我国公民器官捐献的影响因素并提出针对性的应对策略,以期实现我国器官捐献和移植的"自给自足"。  相似文献   
74.
Background: Most theoretical models of self-determination suggest that both environmental and personal factors influence the development of self-determination. The design and implementation of interventions must be conducted with foreknowledge of such mediating and moderating factors if the intervention is to be successful.

Methods: The purpose of this study was to examine the degree to which several personal factors and school characteristics affect and explain students’ self-determination. A total of 232 students with intellectual disability from Spain participated. Their self-determination level was assessed by the ARC-INICO Scale.

Results: Students with moderate levels of intellectual disability obtained significantly lower scores on self-determination than their peers with mild intellectual disability. There were significant differences in relation to the level of support needs and their experience with transition programs. The level of support needs was a significant predictor.

Conclusion: These findings contribute to current research in this field and practical implications were discussed.  相似文献   

75.
76.
Journal of Digital Imaging - Vertebral Compression Fracture (VCF) occurs when the vertebral body partially collapses under the action of compressive forces. Non-traumatic VCFs can be secondary to...  相似文献   
77.
78.
79.
80.
Melatonin, the main hormone produced by the pineal gland, is secreted in a circadian manner (24‐hr period), and its oscillation influences several circadian biological rhythms, such as the regulation of clock genes expression (chronobiotic effect) and the modulation of several endocrine functions in peripheral tissues. Assuming that the circadian synchronization of clock genes can play a role in the regulation of energy metabolism and it is influenced by melatonin, our study was designed to assess possible alterations as a consequence of melatonin absence on the circadian expression of clock genes in the epididymal adipose tissue of male Wistar rats and the possible metabolic repercussions to this tissue. Our data show that pinealectomy indeed has impacts on molecular events: it abolishes the daily pattern of the expression of Clock, Per2, and Cry1 clock genes and Pparγ expression, significantly increases the amplitude of daily expression of Rev‐erbα, and affects the pattern of and impairs adipokine production, leading to a decrease in leptin levels. However, regarding some metabolic aspects of adipocyte functions, such as its ability to synthesize triacylglycerols from glucose along 24 hr, was not compromised by pinealectomy, although the daily profile of the lipogenic enzymes expression (ATP‐citrate lyase, malic enzyme, fatty acid synthase, and glucose‐6‐phosphate dehydrogenase) was abolished in pinealectomized animals.  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