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   631篇
  免费   25篇
  国内免费   32篇
耳鼻咽喉   14篇
儿科学   10篇
妇产科学   10篇
基础医学   47篇
口腔科学   62篇
临床医学   50篇
内科学   99篇
皮肤病学   14篇
神经病学   13篇
特种医学   125篇
外科学   54篇
综合类   87篇
预防医学   12篇
眼科学   4篇
药学   50篇
中国医学   2篇
肿瘤学   35篇
  2023年   1篇
  2022年   7篇
  2021年   6篇
  2020年   9篇
  2019年   2篇
  2018年   17篇
  2017年   8篇
  2016年   11篇
  2015年   11篇
  2014年   9篇
  2013年   23篇
  2012年   23篇
  2011年   29篇
  2010年   15篇
  2009年   19篇
  2008年   29篇
  2007年   38篇
  2006年   26篇
  2005年   29篇
  2004年   15篇
  2003年   18篇
  2002年   14篇
  2001年   14篇
  2000年   17篇
  1999年   18篇
  1998年   33篇
  1997年   23篇
  1996年   21篇
  1995年   20篇
  1994年   19篇
  1993年   17篇
  1992年   1篇
  1991年   8篇
  1990年   9篇
  1989年   17篇
  1988年   17篇
  1987年   12篇
  1986年   11篇
  1985年   7篇
  1984年   9篇
  1983年   10篇
  1982年   7篇
  1981年   11篇
  1980年   8篇
  1979年   2篇
  1978年   6篇
  1977年   4篇
  1976年   1篇
  1975年   7篇
排序方式: 共有688条查询结果,搜索用时 0 毫秒
51.
Tissue infiltration is different in desmoid and fibroma tumours. Both produce high levels of transforming growth factor beta1 (TGFbeta1), which is related to extracellular matrix (ECM) accumulation which in turn regulates cell function and cell migration. Interactions between collagen, proteoglycans and cell surface fibronectin are involved in the assembly and functions of the ECM. As toremifene inhibits collagen and TGFbeta1 synthesis, we tested it in normal, desmoid and fibroma fibroblasts. We will report the changes in glycosaminoglycan (GAG) and collagen synthesis, TGFbeta1 activity, fibronectin mRNA expression and TGFbeta1 receptors after toremifene treatment in normal, fibroma and desmoid fibroblasts. We evaluated GAG and collagen synthesis with (3)H-glucosamine and (3)H-proline incorporation, TGFbeta1 activity with the ELISA method, TGFbeta1 receptor affinity with (125)I-TGFbeta1 binding and total RNA with Northern blot analysis. GAG and collagen synthesis, TGFbeta1 activity and fibronectin levels were higher in fibroma and desmoid than normal fibroblasts. The increase was greater in desmoid than fibroma tumour cells. Toremifene treatment reduced GAG and collagen synthesis, TGFbeta1 activity and fibronectin levels in all cell cultures. The percentage reduction in GAG was similar in all cultures; the reduction in collagen synthesis and TGFbeta1 activity was the highest in desmoid fibroblasts. TGFbeta1 receptors were higher in fibroma and desmoid cells than controls. Toremifene reduced TGFbeta1 receptors only in desmoid fibroblasts, with no effect on the changes in type I, II, and III receptors. Our data show that toremifene modifies the ECM components that regulate cytokine activity and cell migration. The reduction in receptor number only in desmoid cells suggests that toremifene may reduce TGFbeta1's affinity for its receptors. Synthesis of a substance regulating protein kinase activity, which is directly involved in the link between TGFbeta1 and its receptors, cannot be excluded.  相似文献   
52.
53.
Jaffe  RB; Orsmond  GS; Veasy  LG 《Radiology》1986,161(2):355-357
In five patients, aged 4 days to 20 months, the left pulmonary artery was inadvertently ligated at the time of attempted closure of the patent ductus arteriosus. The complication was recognized in these patients between 1 day and 5 years later from findings of chest radiography, two-dimensional echocardiography with spectral analysis of Doppler shifted echoes, and angiography. In three patients, the presence of asymmetric pulmonary blood flow on chest radiographs obtained after surgery initially suggested the diagnosis. In the other two patients with bronchopulmonary dysplasia, the diagnosis was made by means of two-dimensional echocardiography and Doppler spectra in one and angiography in the other. On angiograms, the left pulmonary artery distal to the ligation was visualized by delayed opacification from aortic collaterals in three patients and by means of pulmonary venous wedge injection in one. Radiographic and echocardiographic examination with Doppler spectra may permit prompt diagnosis and early correction of this complication.  相似文献   
54.
55.
56.
57.
The osmolar stimulation of vasopressin (AVP) release has been studied in 5 healthy subjects using two comparative protocols (infusion of 5% NaCl over 2 h vs 2.5% NaCl over 3 h). As AVP may be secreted by episodic bursts, AVP plasma concentrations were determined both in discrete plasma samples and in integrated samples drawn continuously by a pump over periods of 30 min. There was an earlier rise of plasma osmolality and AVP during the 5% NaCl infusion, but the final maximal value of plasma AVP did not differ in the two protocols. Plasma AVP rose from 1.3 +/- 0.7 to 3.8 +/- 1.5 during the 2.5% NaCl infusion and from 1.1 +/- 0.1 to 3.9 +/- 0.6 pg/ml during the 5% NaCl infusion. In both protocols a significant correlation obtained between the discrete and the integrated values of plasma AVP (r = 0.77 and r = 0.84 respectively, P less than 0.05). These results demonstrate that the two protocols of osmolar stimulation are equipotent in releasing AVP and do not induce episodic secretion.  相似文献   
58.
磷酸二酯酶5(PDE5)影响环磷酸鸟苷(cGMP)维持血管平滑肌紧张性的生理学效应,在阴茎海绵体的静脉系统和肺血管系统中尤为明显。  相似文献   
59.
Hospital evaluation is a fundamental process to identify medical units' objective compliance, to analyze efficiency of resource use and allocation, institutional values and mission alignment, patient safety and quality standards, contributions to research and medical education, and the degree of coordination among medical units and the health system as a whole. We propose an evaluation system for highly specialized regional hospitals through the monitoring of performance indicators. The following are established as base thematic elements in the construction of indicators: safe facilities and equipment, financial situation, human resources management, policy management, organizational climate, clinical activity, quality and patient safety, continuity of care, patients' and providers' rights and obligations, teaching, research, social responsibility, coordination mechanisms. Monitoring refers to the planned and systematic evaluation of valid and reliable indicators, aimed at identifying problems and opportunity areas. Moreover, evaluation is a powerful tool to strengthen decision-making and accountability in medical units.  相似文献   
60.
The installation of airbags in motor vehicles, in association with the use of seat belts, has reduced the incidence of head injuries, as well as significantly decreasing morbidity and mortality in motor vehicle accidents. Nevertheless, the literature on the subject increasingly refers to lesions related to airbag deployment. These are usually minor, but in certain circumstances, severe and fatal injuries can result. This is a case report of serious injury due to airbag deployment, involving a restrained driver who suffered occipital condylar injury when his airbag deployed in a frontal collision. The range of airbag associated injuries is reported and predisposing factors, such as the probable proximity to the airbag housing, is discussed.  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