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   607篇
  免费   28篇
  国内免费   4篇
工业技术   639篇
  2023年   1篇
  2022年   5篇
  2021年   7篇
  2020年   7篇
  2019年   5篇
  2018年   9篇
  2017年   7篇
  2016年   7篇
  2015年   7篇
  2014年   6篇
  2013年   9篇
  2012年   10篇
  2011年   12篇
  2010年   6篇
  2009年   9篇
  2008年   10篇
  2007年   4篇
  2006年   5篇
  2005年   7篇
  2004年   4篇
  2003年   1篇
  2002年   7篇
  2001年   4篇
  2000年   5篇
  1999年   4篇
  1998年   119篇
  1997年   76篇
  1996年   64篇
  1995年   34篇
  1994年   23篇
  1993年   27篇
  1992年   5篇
  1991年   6篇
  1990年   2篇
  1989年   3篇
  1988年   3篇
  1987年   5篇
  1986年   5篇
  1985年   1篇
  1983年   1篇
  1982年   1篇
  1981年   4篇
  1980年   6篇
  1978年   5篇
  1977年   27篇
  1976年   61篇
  1975年   1篇
  1955年   2篇
排序方式: 共有639条查询结果,搜索用时 15 毫秒
41.
This paper describes nursing students' views of a supervision programme provided during the second semester of their education, which was their first period of nursing practice. A form with open questions and a 24-item questionnaire were completed by the 28 nursing students. The analysis of their responses was a combination of factor analysis and grounded theory approach, based on comparative analysis. The results indicate two specific effects of the programme: personal growth and integration of knowledge. The process of creating knowledge includes four stages: awareness of concepts and phenomena, development of a 'language of caring', development of a 'model' of communication, and reflection gained as an effect of the intervention. The nursing students reported that reflection was a way to bridge the gap between theory and practice. Their views of the effect of the supervision showed high values for the following three factors: improved interpersonal skills, improved professional skills, and improved communication skills.  相似文献   
42.
The structure of cardiac rhythm was studied with the help of specialized computers during digitalization in 60 patients with atrial fibrillation of different etiology. The reduction of the heart contractions rate under digitalization is accompanied by certain changes in the structure of cardiac rhythm: the arrhythmic pattern of the ventricular contractions increases with a predominant growth of the number of long R--R intervals, the transitions from short intervals to longer ones become sharper, and portions of a relatively stable ventricular rhythm appear. Three main types of dynamics of the rhythm structure were distinguished on the basis of the changes in the interval R--R histogram. The described changes in the structure of cardiac rhythm are not specific, but when Digitalis drugs are used alone they can be used as additional criteria for digitalization.  相似文献   
43.
The persistence of metatarsus adductus varus has been a problem in management. We have treated a series of selected patients with this problem and believe that our results have been better than with the procedure we have used in the past. Fowler has described a procedure which seems ideal for the patients in our series. Through personal communication the procedure and its application were discussed and the series was started eight years ago. Our series is small because our patients are responding to other forms of treatment at an earlier age. The few that do not respond are now considered for the operation described. The procedure is relatively simple to perform. Full correction should be obtained at the time of surgery. Casting is utilized to hold the correction and immobilize the extremity for healing. Our unsatisfactory results occurred because of errors in technique or poor selection of patients. We believe that this procedure should be considered in the older patient with metatarsus varus.  相似文献   
44.
45.
46.
47.
Recently, the use of a ferromagnetic material in a soft‐heating method has garnered much attention as a novel method for cancer treatment. By concurrently using this material as a thermal probe, we are currently developing a minimally invasive heating and wireless temperature measurement system. To make the approach feasible in a clinical setting, it is vital to overcome the key challenge of heating the local tumor at a constant temperature. In previous conventional approaches, it was necessary to switch the induction‐heating power supply on/off after the target tumor temperature was reached. However, it cannot determine the temperature of the material during the power‐off period. Therefore, we changed this approach and found that by adjusting the distance between the heating coil and the material while maintaining a constant current flow in heating coil, the drift problem, which happened just after power is supplied during the on/off operation, did not occur any longer. Accordingly, it was not required to use multiple sensors to reduce the drift, thereby minimizing the cost. This study verifies the validity of our wireless thermometry approach while performing rotary scanning and proposes a technique for determining achievement of the target temperature. This knowledge complements other approaches for cancer treatment utilizing hyperthermia. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.  相似文献   
48.
We suggest that toroidal structures in the state of psi-condensation of DNA may be caused by anisotropy on a meso-scale of several thousand A, the conformation of a DNA-molecule being determined by its elasticity and neutralization of phosphate charge. We model a molecule of B-DNA on an anisotropic elastic rod subject to a torque, and make the numerical simulation of the model that reveals that under appropriate conditions, which may be effected in experimental setting by changing the concentration of polymeric solutions, there are toroidal structures having the size of a few persistence lengths, in agreement with the experimental data. On changing the elastic modulii or characteristics of the counterion layer, we see the toroidal structures turn into the spherical ones. To understand the function of anisotropy it would be interesting to investigate the Z-DNA as regards psi-condensation.  相似文献   
49.
The effect of various concentrations of ofloxacin, ciprofloxacin and lomefloxacin on the morphokinetic parameters of the cellular elements of the lung tissue of intact animals (mice, guinea pigs and dogs) was studied under the conditions of the tissue culture. It was shown that in a concentration of 100 micrograms/ml and the exposure time of 24 hours the drugs had no effect on the mobility and structure of the lung tissue cellular elements. When the drugs were used in a concentration of 100 micrograms/ml the mobility rate of the lymphocytes and macrophages proved to by markedly retarded by the end of the 24th hour. In a concentration of 1000 micrograms/ml the drugs killed the cell culture. There were detected no specific differences in the effect of the fluoroquinolones on the cellular elements of the lung tissue of the intact animals.  相似文献   
50.
SiC_p/Cu梯度复合材料热疲劳性能研究   总被引:1,自引:0,他引:1  
采用粉末冶金方法制备了4种SiC颗粒呈渐变分布的梯度复合材料,应用扫描电子显微镜、X射线衍射仪、自动显微硬度计等,研究了梯度复合材料的显微组织、硬度分布和热疲劳性能。结果表明,SiCp/Cu梯度复合材料基体连续,梯度层过渡均匀,显微组织及硬度呈梯度分布;梯度复合材料的SiC颗粒渐变过渡越均匀,梯度复合材料抗热疲劳性能越好。  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