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   1923篇
  免费   99篇
  国内免费   17篇
耳鼻咽喉   16篇
儿科学   68篇
妇产科学   6篇
基础医学   228篇
口腔科学   23篇
临床医学   103篇
内科学   452篇
皮肤病学   196篇
神经病学   182篇
特种医学   38篇
外科学   346篇
综合类   18篇
预防医学   51篇
眼科学   13篇
药学   87篇
中国医学   3篇
肿瘤学   209篇
  2023年   5篇
  2022年   25篇
  2021年   42篇
  2020年   25篇
  2019年   47篇
  2018年   73篇
  2017年   65篇
  2016年   48篇
  2015年   54篇
  2014年   43篇
  2013年   80篇
  2012年   105篇
  2011年   119篇
  2010年   59篇
  2009年   46篇
  2008年   109篇
  2007年   129篇
  2006年   105篇
  2005年   130篇
  2004年   105篇
  2003年   96篇
  2002年   116篇
  2001年   13篇
  2000年   14篇
  1999年   23篇
  1998年   26篇
  1997年   17篇
  1996年   18篇
  1995年   21篇
  1994年   18篇
  1993年   26篇
  1992年   21篇
  1991年   25篇
  1990年   18篇
  1989年   25篇
  1988年   13篇
  1987年   16篇
  1986年   16篇
  1985年   5篇
  1984年   8篇
  1983年   7篇
  1982年   12篇
  1981年   11篇
  1980年   11篇
  1979年   5篇
  1978年   14篇
  1977年   5篇
  1976年   3篇
  1975年   6篇
  1963年   2篇
排序方式: 共有2039条查询结果,搜索用时 9 毫秒
31.
32.
The gracile axonal dystrophy (gad) mutation in Uch-l1, the gene encoding the ubiquitin carboxy-terminal hydrolase isozyme L1 (UCH-L1), causes selective dying back degeneration of dorsal root ganglion neuron in the medulla oblongata along with progressive sensory-motor ataxia. Axonal spheroids are observed within degenerating axons, and their contents may illuminate the pathogenic mechanisms leading to neurodegeneration in gad mice. To analyze changes in negatively charged lipid molecules in dystrophic axons of gad mice, we performed matrix-assisted laser desorption/ionization (MALDI)-imaging mass spectrometry (IMS), electron microscopy, and fluorescence immunohistochemistry on tissue sections from gad and wild-type mouse medulla. MALDI-IMS revealed that m/z 806.68 and 822.68 molecules, assigned to sulfatide (ST) C18:0 and ST C18:0(OH), respectively, were concentrated in the dorsomedial medulla. This spatial distribution overlapped significantly with that of axonal spheroids. Immunostaining revealed that spheroids accumulated myelin and lymphocyte protein, a known ST binding protein. Sulfatides with short-chain fatty acids (C16–C20) are generally localized in intracellular vesicles; therefore, ST C18:0 accumulation may reflect intracellular vesicle aggregation within spheroids. Ubiquitin system disruption apparently alters lipid metabolism, membrane organization, protein turnover, and axonal transport. Changes in membrane organization, particularly STs within lipid rafts, may disrupt cellular signaling pathways necessary for neuronal viability.  相似文献   
33.
34.
35.

Introduction

The glucagon provocative test is useful for the diagnosis of gastrinoma. The aim of this study was to determine the criteria for the glucagon provocative test.

Methods

This study reviewed 8 patients that underwent the glucagon provocative test preoperatively and in whom the diagnosis was confirmed as gastrinoma histologically. The glucagon provocative test was performed by administering glucagon (20 μg/kg) intravenously, followed by 20 μg/kg h for the next 30 min, and plasma gastrin levels were measured 3 and 1 min before and 3, 5, 7, 10, 15, 20, and 30 min after the administration of glucagon. This study evaluated the peak value of plasma gastrin and the time required to reach the peak.

Results

Two of the 8 patients had multiple endocrine neoplasm type 1. The basal plasma gastrin levels ranged from 524 to 10,300 pg/ml. The time required to reach the peak was 3–10 min for all patients. The increase in the peak from the basal value was 235–8,920 pg/ml, and the percentage of increase was 38–337 %.

Conclusions

These results suggest that a diagnosis of gastrinoma should thus be made when plasma gastrin levels peak within 10 min after glucagon administration, with an increase of greater than 200 pg/ml and greater than 35 % of the basal value.  相似文献   
36.

Purpose

The reduction of periosteal compression through the use of a locking plate may minimize disturbances of bone blood supply and may improve the rate of bone union. A single-centre, assessor blinded randomized controlled trial was conducted to compare the clinical effectiveness of a locking plate and a non-locking plate.

Methods

A total of 52 patients with AO/OTA 44B lateral malleolar fractures were included in this study. All patients underwent surgical fixation using a lag screw and neutralization plate. An identical treatment protocol was used in all patients, with exception of plate selection. The rate of radiographic bone union, defined as the complete disappearance of fracture lines confirmed through anteroposterior, lateral, and internal oblique views was compared at three, six, and 12 months following surgery. In addition, the Medical Outcomes 36-Item Short-Form Health Survey (SF-36) score, the time required for resolution of tenderness at the fracture site and the complication rate were evaluated.

Results

Twenty-three patients were randomly assigned to undergo fixation using a locking plate, and 29 patients were assigned to undergo fixation using a non-locking plate. Intention-to-treat analysis showed no difference in the radiographic bone union rate of fibula, SF-36 score, the time for resolution of tenderness at the fracture site and complication rates.

Conclusion

No differences were observed in patients with AO/OTA 44B lateral malleolar fractures undergoing fixation with a locking versus non-locking neutralization plate.  相似文献   
37.
38.
39.
There is the concern that adaptation range of depression is enlarged, because operation diagnosis methods of ICD-10 and DSM-IV-TR spread in a clinic of psychiatry. On the other hand, clinical condition of depressive state may diversify. This is a review of the pathogenesis, classification and diagnostic criteria of depression. In the pathogenesis, we discussed about the biological origin (a neurotransmitter-related model, a neuroendocrine model et al) and the psychosocial origin with focus on a historic flow and recent knowledge of the pathogenetic theory. In the classification and diagnostic criteria, we mainly explained the points to notice and the problems on ICD-10 and DSM-IV-TR. It is necessity to arise the problem such as clinical symptoms are inconsistent with the classification and diagnostic criteria of ICD-10 and DSM-IV-TR, because all the pathogenesis is not elucidated now. A development of the classification and criteria of depression is expected in future by scientific elucidation advancing.  相似文献   
40.
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