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   1545篇
  免费   1篇
化学工业   4篇
轻工业   4篇
一般工业技术   1篇
冶金工业   1536篇
原子能技术   1篇
  2020年   1篇
  2017年   1篇
  2011年   1篇
  2009年   1篇
  2007年   1篇
  2006年   2篇
  1999年   58篇
  1998年   459篇
  1997年   258篇
  1996年   174篇
  1995年   94篇
  1994年   84篇
  1993年   102篇
  1992年   10篇
  1991年   17篇
  1990年   13篇
  1989年   28篇
  1988年   19篇
  1987年   22篇
  1986年   10篇
  1985年   8篇
  1983年   5篇
  1982年   5篇
  1981年   7篇
  1980年   9篇
  1979年   1篇
  1978年   4篇
  1977年   38篇
  1976年   111篇
  1975年   1篇
  1963年   1篇
  1961年   1篇
排序方式: 共有1546条查询结果,搜索用时 0 毫秒
101.
In ten patients breast reconstruction was done after surgical treatment for a premalignant or malignant breast disease. In six of these, prophylactic subcutaneous mastectomy and implant reconstruction were carried out, and in the remaining four reconstruction was done after simple or modified radical mastectomy. It is suggested that these procedures should be considered by those physicians and surgeons who undertake evaluation and treatment of breast disease in women. Breast reconstruction should be considered and offered to patients who suffer from the severe personal and emotional trauma attendant to surgical operation for breast disease.  相似文献   
102.
103.
The development of independence in daily living skills of 256 patients with spina bifida was assessed by means of a new Functional Activities scoring system. The score was derived from nine categories of activity; five are to do with self-care, three with locomotion and one with social interaction. The reasons for the variation in achievement between individuals with the same degree of paralysis are discussed, as are the differences in learning curves for single activities. The scoring system enables a quantitative assessment to be made of the current status of an individual patient, and enables more realistic therapeutic goals to be set.  相似文献   
104.
105.
The esophageal airway has gained increasing acceptance in airway management during cardiopulmonary resuscitation, and its enthusiastic advocates are urging expansion of its use. A fatal case of esophageal perforation following the use of an esophageal airway is presented. Possible contributing factors are discussed. A modified esophageal airway which seems safer and more versatile, effective, and economic is described.  相似文献   
106.
The ratio of pulmonary to systemic vascular resistance (Rp/Rs) largely determines the amount of left-to-right shunting and pulmonary to systemic flow rat (Qp/Qs) in the presence of a large isolated ventricular septal defect. The possibility that pharmacologic reduction of systemic vascular resistance with alpha-adrenergic receptor blockade or beta-adrenergic receptor stimulation would increase the ratio Rp/Rs, and therefore reduce the ratio Qp/Qs, was studied in dogs in which ventricular septal defects had been surgically created. Administration of phentolamine and phenoxybenzamine caused a 42% reduction in Rs and no reduction in Rp. Qs was unchanged and Qp declined by 24% and the ratio Qp/Qs fell by 32%. Infusion of the beta-adrenergic receptor stimulant isoproterenol also reduced Qp/Qs. However, this was accomplished as a result of an increase in Qs and at the expense of an increase in heart rate. As a decline in the ratio Qp/Qs has been shown to be beneficial to patients with large left-to-right shunts, pharmacologic reduction of systemic vascular resistance may prove to be helpful in treating congestive heart failure in those patients with large left-to-right shunts at the ventricular level who are refractory to the usual decongestive measures.  相似文献   
107.
Myocardial imaging with technetium-99m stannous polyphosphate was performed on 46 patients. Eleven patients had no cardiac disease, 22 had acute myocardial infarction, and 13 had stable arteriosclerotic heart disease. Distinct patterns of myocardial activity were noted: (1) the patients with no obvious cardiac disease showed no cardiac activity; (2) stable arteriosclerotic heart disease showed faint, ill-defined cardiac activity, primarily in the anterior or inferior aspect of the left ventricle; (3) acute myocardial infarction showed intense, focal, well-defined activity, with a shape that characterized the location of the infarct.  相似文献   
108.
Patterns of ambulatory health care in five different delivery systems   总被引:2,自引:0,他引:2  
Few empirical investigations permit systematic comparison of the impact of widely-varying delivery systems within a single population sample. This study provides such a comparison, describing patterns of ambulatory care among patients using five different systems in Washington, D.C. as a regular source of health care: solo practice, fee-for-service group practice, prepaid group practice, public clinics, and hospital outpatient departments or emergency rooms. Comparisons are adjusted statistically to account for major patient group variations, and the results reveal substantial differences among the five systems. Sources used primarily by the poor--hospital outpatient departments, emergency rooms, and public clinics--contained important structural and financial barriers, and had the lowest rates of patient-initiated use. The prepaid system, in contrast, maximized patient's access to both preventive care and symptomatic care, and did not seem to inhibit physician-controlled follow-up care. The results suggest some perverse effects of fee-for-service payment: patients, especially poor patients, appeared to be deterred from seeking preventive and symptomatic care, while physicians were encouraged to expand follow-up services. Moreover, services in fee-for-service systems were distributed less equitably relative to both income and medical need than in the prepaid system. These findings have direct implications for policy decisions concerning organizational and financial arrangements for the delivery of ambulatory care.  相似文献   
109.
110.
The purpose of this paper is to verify if we may use the rat glomerular basement membrane (GBM) as antigen, in indirect immunofluorescent test in isolated GBM (IIT-BGM) to detect human anti GBM antibodies. Rabbit anti-human GBM serum (A-H-GBMS) were obtained by rabbit's immunization with human GBM or rat GBM respectively. The content of anti-GBM antibodies in rabbit's sera was determined in IIT-GBM. The titer of the A-H-GBMS was 1/10 when determined in IIT-GBM performed in human GBM and only weakly positive in IIT-GBM performed in rat GBM. The titer of A-R-GBMS was 1/60 and 1/20 when determined respectively in rat GBM and in human GBM. All the reactions performed with sera absorbed with autologous GBM were negative; the absorption of sera with heterologous GBM reduced sera titer. In conclusion: a) rat and human GBM have common and different antigenic components; b) to detect human anti-GBM antibodies we must not employ rat GBM in IIT-GBM.  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