首页 | 官方网站   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   1619篇
  免费   104篇
  国内免费   12篇
医药卫生   1735篇
  2021年   10篇
  2020年   12篇
  2019年   15篇
  2018年   26篇
  2017年   20篇
  2016年   13篇
  2015年   24篇
  2014年   38篇
  2013年   33篇
  2012年   62篇
  2011年   50篇
  2010年   53篇
  2009年   59篇
  2008年   42篇
  2007年   40篇
  2006年   55篇
  2005年   52篇
  2004年   45篇
  2003年   40篇
  2002年   45篇
  2001年   38篇
  2000年   29篇
  1999年   23篇
  1998年   84篇
  1997年   87篇
  1996年   93篇
  1995年   59篇
  1994年   61篇
  1993年   50篇
  1992年   27篇
  1991年   39篇
  1990年   27篇
  1989年   50篇
  1988年   36篇
  1987年   49篇
  1986年   30篇
  1985年   39篇
  1984年   26篇
  1983年   23篇
  1982年   18篇
  1981年   21篇
  1980年   14篇
  1979年   9篇
  1978年   8篇
  1977年   8篇
  1976年   12篇
  1975年   11篇
  1973年   6篇
  1972年   4篇
  1971年   6篇
排序方式: 共有1735条查询结果,搜索用时 0 毫秒
1.
2.
Originally described by Rosen in 1983, syringomatous nipple adenoma (SAN) is a tumor of disputed histogenesis, which can be problematic both diagnostically and therapeutically. 1 It is a benign primary tumor of breast epithelium with histology similar to that of the syringoma. In the current case, we describe a 40-year-old female with this lesion occurring within a supernumerary breast. This case represents, to our knowledge, the first such reported case, and represents a significant finding as its presence could lend some confusion as to whether or not this represents a benign primary process of breast or a potentially infiltrative tumor of the skin.  相似文献   
3.
Homozygous familial hypercholesterolemia (HFH) is a very rare autosomal dominant disease characterized by accelerated severe atherosclerosis. We examined 18 patients from 9 families with HFH. The age range was 6-30 years (mean = 16 years). Male to female ratio was equal. All patients had huge, multiple tuberous xanthomas on the skin and tendons. Mean +/- standard deviation of plasma cholesterol, triglycerides, low-density lipoproteins (LDL), and high-density lipoproteins (HDL) cholesterol levels were 608 +/- 89, 122 +/- 39, 550 +/- 88, and 26 +/- 8 mg/dl, respectively. Five patients (28%) had angina pectoris, two sustained a myocardial infarction, and one died at the age of 15 years. Two-dimensional echocardiography demonstrated supravalvular aortic stenosis in 3 of the 13 patients (23%). Coronary arteriography performed in 11 patients demonstrated significant obstruction in 6 patients, 2 each with single-, double-, and triple-vessel disease. Left main stenosis was present in 3 patients (27%). Supravalvular aortic narrowing was demonstrated in 6 patients (54%) and was associated with a gradient in 2 (25 and 35 mmHg, respectively). Segmental contraction abnormalities were detected in 2 of the 11 patients (18%). It is concluded that coronary artery disease is prevalent in patients with HFH and, based on the data presented, we recommend the performance of noninvasive technique, coronary arteriography and supravalvular aortography at an early age to detect and to follow the progression of the disease.  相似文献   
4.
5.
Previous reports in the literature have described correlation of increasing repeat length with severity of the phenotype, in Kennedy syndrome. We describe male siblings with different repeat lengths, with lack of expression of the phenotype in the sibling with the longer repeat length. The phenotype was identical to motor neurone disease. There is variability of expression in Kennedy syndrome and repeat length even in siblings cannot be taken as a conclusive indicator of severity. CAG repeat length cannot be used to predict the natural history of Kennedy disease. The diagnosis of Kennedy syndrome should be considered in male patients presenting with atypical motor neurone disease.  相似文献   
6.
Role of collagenase in colonic anastomoses: a reappraisal   总被引:7,自引:0,他引:7  
Increased collagenolysis, with reduction in collagen concentration, has been incriminated in the breakdown of colonic anastomoses but previous studies have measured only collagen levels and non-specific collagenolytic activity. Collagenase, the initiating enzyme in collagen degradation, is synthesized on demand and controlled by tissue inhibitor of metalloproteinases (TIMP). Antibodies to collagenase and TIMP were applied to colonic anastomoses in rabbits to investigate the role of the enzyme during healing. Within 12 h of operation, secreting cells and extracellular collagenase were identified at the everted edges of the bowel wall. After 24 h, collagenase activity was accompanied by TIMP secretion in the same localized regions, and by the third postoperative day very few cells were still synthesizing enzyme in these areas, although extracellular activity remained visible. TIMP-secreting cells, however, were seen in a layer of connective tissue sealing the serosal surface of the anastomosis. At 7 days, both enzyme and inhibitor were found only in small aggregates of secreting cells in the deeper layers. The localization and extent of collagenase and TIMP activity accorded well with a normal healing response as, at all times, the enzyme was confined to the immediate vicinity of the suture line.  相似文献   
7.
Chronic low back pain: comparison of bone SPECT with radiography and CT   总被引:1,自引:0,他引:1  
Ryan  PJ; Evans  PA; Gibson  T; Fogelman  I 《Radiology》1992,182(3):849
  相似文献   
8.
9.
Uroscopy in the 21st century: high-field NMR spectroscopy   总被引:1,自引:1,他引:0  
From the experiments described, it can be seen that there are different research approaches that can be taken and these are summarized in Table 1. Whereas much scientific research is principally hypothesis led, there remains, nevertheless, an important place for exploratory research. High resolution NMR can measure, directly and simultaneously, a wide range of endogenous metabolites in biological fluids and has the unique capability of providing structural information on the metabolites detected. It has proved to be a powerful research tool with which to study inherited metabolic diseases, renal disease, drug metabolism, and toxicity, and can be used to monitor the effects of drug therapy. For instance, by using a library of experimental toxins one can map the metabolic profile of site-specific nephron injury. With this approach in man one could eventually take an unknown disease such as Balkan nephropathy and predict the initial site of tubular injury, the mode of injury and therefore the kind of toxin capable of producing that injury. NMR spectroscopic techniques are still advancing rapidly, with ever increasing sensitivity and sophistication of NMR pulse sequences to enhance structural elucidation in complex mixtures. Given the advances in directly coupled HPLC-NMR and even HPLC-NMR-mass spectroscopy it is likely that these technologies in conjunction with pattern recognition will make major contribution to our understanding of renal processes and provide new diagnostic insights in the 21st century.   相似文献   
10.
Leukotriene B4 (LTB4) and the protein kinase C activator, 4-beta-phorbol dibutyrate (PDBu), both induced a pronounced and concentration-dependent stimulation of hydrogen peroxide (H2O2) generation by purified guinea pig peritoneal eosinophils in the concentration range 1 nM-1 microM. The LTB4 response was inhibited competitively by the specific LTB4 receptor antagonist, U-75302, with a KB of 25 nM, while the concentration-response curves for both stimuli were shifted rightwards (3.8-fold and 2.8-fold for LTB4 and PDBu, respectively) by the competitive protein kinase C inhibitor, 1-O-hexadecyl-2-O-methylglycerol at a concentration of 300 microM. LTB4 appears, therefore, to induce respiratory burst in eosinophils via a receptor-mediated mechanism involving protein kinase C.  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-23

京公网安备 11010802026262号