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   2830篇
  免费   5篇
电工技术   5篇
综合类   16篇
化学工业   38篇
金属工艺   3篇
机械仪表   13篇
建筑科学   16篇
矿业工程   9篇
能源动力   2篇
轻工业   10篇
水利工程   5篇
石油天然气   2篇
武器工业   2篇
无线电   4篇
一般工业技术   34篇
冶金工业   2658篇
原子能技术   2篇
自动化技术   16篇
  2024年   1篇
  2019年   1篇
  2014年   5篇
  2013年   4篇
  2012年   9篇
  2011年   19篇
  2010年   10篇
  2009年   13篇
  2008年   20篇
  2007年   46篇
  2006年   11篇
  2005年   12篇
  2004年   2篇
  2003年   13篇
  2002年   6篇
  2001年   1篇
  2000年   4篇
  1999年   75篇
  1998年   774篇
  1997年   450篇
  1996年   255篇
  1995年   165篇
  1994年   150篇
  1993年   170篇
  1992年   13篇
  1991年   45篇
  1990年   35篇
  1989年   32篇
  1988年   34篇
  1987年   29篇
  1986年   37篇
  1985年   23篇
  1983年   10篇
  1982年   13篇
  1981年   28篇
  1980年   25篇
  1979年   2篇
  1978年   15篇
  1977年   97篇
  1976年   171篇
  1975年   7篇
  1959年   1篇
  1955年   2篇
排序方式: 共有2835条查询结果,搜索用时 16 毫秒
11.
12.
13.
14.
In experiments on 50 dogs with toxic acute edema of the lung, induced with intravenous injection of 0.1% silver nitrate, the authors have studied the efficacy of accessory artificial circulation and "conservative" therapy. During the perfusion a discharge of the right portions, adequate extracorporeal gas metabolism, normalization of blood gas and acid-base balance were noted; an intensity of pulmonary edema is descreased. An intensive therapy for pulmonary edema was found to be more effective in association of "conservative" treatment with venoarterial perfusion and blood oxygenation.  相似文献   
15.
The histochemical changes in succinate dehydrogenase (SDH) were investigated in pectoralis major muscle of guinea pig, rat and mouse after low level X-irradiation (72 R and 240 R) and compared with control animals. Biochemical studies were carried out on liver, kidney, muscle (pectoralis major), adrenal and spleen of these animals after low dose local X-irradiation and compared with control animals. Changes in SDH activity were studied up to 72-h post-irradiation, which shows that low dose local X-irradiation leads to increased enzymic activity. The increase in enzymic activity was remarkable in mouse tissues as compared with guinea pig and rat. Adrenals of all the three animals showed significant activation after all the doses of radiation studied. The significance of these results, with special reference to oxidative metabolism, has been discussed.  相似文献   
16.
17.
Random noise beyond the maximum signal frequency of the imaging system can be removed by low-pass filtering without compromising signal transmission.  相似文献   
18.
The effect of prostaglandin E1 (PGE1) on central and peripheral hemodynamics was studied in seven conscious dogs under conditions of normoxia and hypobaric hypoxia to ascertain if hypoxia attenuated the cardiovascular actions of PGE1. Silastic catheters were chronically implanted in the pulmonary artery, left atrium, and aorta. Acute hypoxia was produced in a hypobaric chamber maintained at 446 mmHg pressure (14,000 feet). PGE1 at sea level (normoxia) resulted in significant increases in heart rate, cardiac output, left ventricular stroke work and pulmonary blood volume as well as significant decreases in aortic, pulmonary arterial, and left atrial pressures. During hypobaric hypoxia, PGE1 produced essentially identical effects on all hemodynamic parameters except pulmonary blood volume and pulmonary arterial pressure where marked attenuation of PGE1 action occurred.  相似文献   
19.
Four hundred seventy blood access procedures performed on 170 dialysis patients during the period 1962-1975 have been analyzed according to survival of access with respect to age, sex and cause of failure. Subcutaneous forms of blood access have a significantly longer life and are more free of complications than external shunts. Although the mode of access can now be tailored to the individual patient, the arterio-venous fistula remains the least expensive and simplest surgical procedure. It should therefore remain as the first choice of access for most patients.  相似文献   
20.
Serum lysozyme activity was measured in groups of untreated patients with malignant melanoma, hyperneophroma and breast carcinoma. Significant elevation of serum levels of the enzyme was confined to patients with localized disease. In the presence of metastatic disease such elevation was not detected. The rise in serum lysozyme activity was not due to renal damage or any infective process and in the case of malignant melanoma was shown to be associated with infiltration of the tumour mass by macrophages. In vitro studies demonstrated that the macrophages resident in a tumour mass are responsible for relasing lysozyme in large amounts. It is proposed that the elevation of serum lysozyme in these cases may be an indicator of macrophage-mediated host resistance and that the measurement of macrophage products such as lysozyme in the extracellular fluid may under well defined conditions provide useful clinical information concerning host reactions.  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