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   409篇
  免费   29篇
  国内免费   4篇
儿科学   25篇
妇产科学   1篇
基础医学   27篇
口腔科学   9篇
临床医学   68篇
内科学   69篇
皮肤病学   8篇
神经病学   20篇
特种医学   85篇
外科学   53篇
综合类   6篇
预防医学   29篇
眼科学   3篇
药学   14篇
  2篇
肿瘤学   23篇
  2023年   4篇
  2022年   2篇
  2020年   4篇
  2019年   7篇
  2018年   8篇
  2017年   5篇
  2016年   8篇
  2015年   10篇
  2014年   16篇
  2013年   15篇
  2012年   14篇
  2011年   11篇
  2010年   16篇
  2009年   19篇
  2008年   10篇
  2007年   6篇
  2006年   14篇
  2005年   6篇
  2004年   11篇
  2003年   5篇
  2002年   8篇
  2001年   8篇
  2000年   5篇
  1999年   14篇
  1998年   19篇
  1997年   20篇
  1996年   16篇
  1995年   16篇
  1994年   15篇
  1993年   10篇
  1992年   4篇
  1991年   13篇
  1990年   14篇
  1989年   12篇
  1988年   5篇
  1987年   8篇
  1986年   7篇
  1985年   8篇
  1984年   3篇
  1983年   8篇
  1982年   3篇
  1981年   1篇
  1980年   5篇
  1979年   6篇
  1978年   5篇
  1977年   5篇
  1976年   7篇
  1975年   4篇
  1958年   2篇
排序方式: 共有442条查询结果,搜索用时 234 毫秒
51.
52.
Human breast cancer in vivo: H-1 and P-31 MR spectroscopy at 1.5 T   总被引:3,自引:0,他引:3  
To assess the potential of in vivo magnetic resonance (MR) spectroscopy for breast cancer, hydrogen-1 and phosphorus-31 MR spectra of five malignant human breast tumors were compared with those of unaffected breast tissue. The water-to-fat ratio was high in the tumors (average, 2.2) but low in the unaffected tissue (average, 0.3). The P-31 spectrum of normal breast tissue showed low levels of phosphomonoesters (PMEs), inorganic phosphate, phosphodiesters (PDEs), and ATP. In addition, an intense phosphocreatine (PCr) signal was observed in breast tissue of young women: The relative intensities of the PCr and ATP signals had a mean value of 1.9. The tumor spectrum showed elevated levels of PMEs, Pi, and PDEs, while no PCr was seen (PCr/ATP less than 0.2). In two breast cancers treated with radiation therapy, resulting in a decrease of tumor volume of more than 50%, a similar change in the tumor P-31 spectrum was observed: An intense PCr signal developed (PCr/ATP = 1.1). Control experiments indicated that the appearance of PCr after radiation therapy was the result of a radiation-induced metabolic change in the tumor itself.  相似文献   
53.
54.
Sympathetic nervous control of cat ileocecal sphincter   总被引:1,自引:0,他引:1  
  相似文献   
55.
Non-invasive methods for assessment of the vascular effects of antimigraine drugs were evaluated with respect to their utility, variability and sensitivity in a double-blind, placebo-controlled, three-period crossover study in six healthy volunteers using an intravenous vasoconstrictor, methoxamine, as a probe drug. Changes in the internal diameter of the brachial and radial arteries were measured using ultrasound which had low between-day and within-day coefficients of variation. Peak systolic velocity (PSV), time-averaged velocity (TAV), total flow, resistance (RI) and pulsatility indices (PI) were measured by Doppler from one arterial wave form. Whilst PSV and TAV increased with methoxamine, because of bradycardia, changes in PI and RI were difficult to interpret. An automatic oscillametric cuff, a mercury-in-silastic strain gauge method and the "Finapres", finger arterial blood pressure monitor were used to follow changes in systolic blood pressure (SBP). The strain gauge technique underestimated arm SBP compared to the oscillometric method but clearly showed drug-related increases whilst the Finapres did not reflect changes in blood pressure detected by the other methods.  相似文献   
56.
Multidimensional analysis of peak pain symptoms and experiences   总被引:1,自引:0,他引:1  
Peak pain symptoms and experiences were explored within a group of 243 intractable pain patients seen consecutively at a pain clinic. Using a 5-point scale, patients rated the frequency with which 99 symptom adjectives occurred when their pain was at its worst. Key cluster analysis identified 11 reliable, conceptually clear symptom clusters: Four affective symptom categories, Angry Depression, Diminished Drive, Intropunitive Depression and Anxiety, describing emotional states concomitant with peak pain; two somatic symptom categories, Ecto-Pain and Endo-Pain, describing surface and deep bodily pain, respectively; and five additional symptom categories including Cognitive Dysfunction, Sleep Disturbance, Fatigue, Withdrawal and Disequilibrium. Among the affective symptom clusters, symptoms of Angry Depression were reported to occur frequently by 32% of the patients while only 11% reported the frequent occurrence of Intropunitive Depression. For the somatic symptom clusters, 25 and 52% reported the frequent occurrence of Ecto-Pain and Endo-Pain, respectively. Pain reports measured by Ecto-Pain and Endo-Pain were nearly independent of all other symptom categories. The results suggest that the experiential context of pain differs widely among intractable pain patients. The study derived a Pain Symptom Checklist to measure each symptom cluster as one way to identify coping styles among chronic pain patients.  相似文献   
57.
58.
59.
60.
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