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   385篇
  免费   0篇
综合类   1篇
建筑科学   1篇
无线电   2篇
一般工业技术   2篇
冶金工业   377篇
自动化技术   2篇
  2018年   3篇
  2017年   2篇
  2013年   1篇
  2006年   1篇
  1999年   10篇
  1998年   119篇
  1997年   62篇
  1996年   48篇
  1995年   22篇
  1994年   15篇
  1993年   23篇
  1991年   5篇
  1990年   5篇
  1989年   3篇
  1988年   7篇
  1987年   3篇
  1986年   1篇
  1985年   2篇
  1982年   3篇
  1981年   3篇
  1980年   8篇
  1978年   1篇
  1977年   9篇
  1976年   27篇
  1975年   2篇
排序方式: 共有385条查询结果,搜索用时 0 毫秒
111.
Twenty two patients with inflammatory respiratory tract infection were treated with cefpirome. Among the patients 14 were with severe pneumonia, 4 with exacerbated obstructive chronic purulent bronchitis and 4 with mucoviscidosis. All the patients were subjected to clinical, laboratory and x-ray examinations, electrocardiography, estimation of the external respiration and sputum bacteriological tests. The cefpirome susceptibility was determined by the agar diffusion assay with standard disks from Roussel Uclaf. Cefpirome was administered by slow intravenous infusion in a daily dose of 2 to 4 g every 12 hours depending on the disease severity. After 2 or 3 days of the patient afebrile temperature and normal differential blood count the therapy was discontinued. The favourable time course of the disease was recorded in 12 out of the 14 patients with pneumonia. Recovery and clinical improvement were stated in 64.3 and 21.4 per cent of the cases respectively. In 2 patients the treatment failed. In all the patients with exacerbated severe chronic purulent bronchitis the cefpirome therapy resulted in the disease remission. The clinical effect of the mucoviscidosis treatment was observed in 3 out of the 4 patients. The drug tolerance in the doses used was good.  相似文献   
112.
Escalating reinforcement for sustained abstinence has been effective in treating cocaine abuse. Under this schedule, patients receive vouchers for cocaine-free urine samples; vouchers have monetary values that increase with the number of consecutive cocaine-free urine samples. Cocaine-abusing methadone patients were randomly assigned to receive vouchers for 12 weeks under (a) an escalating schedule (n = 20), (b) an escalating schedule with start-up bonuses (n = 20), or (c) a noncontingent schedule (n = 19). Start-up bonuses were designed to provide added reinforcement for initiating abstinence; however, they did not improve outcomes. Both contingent interventions significantly increased cocaine abstinence. In addition, the contingent interventions increased abstinence from opiates and decreased reports of cocaine craving. These results replicate the efficacy of cocaine abstinence reinforcement and show that it can have broad beneficial effects.  相似文献   
113.
Although many anecdotal reports indicate that marijuana and its active constituent, delta-9-tetrahydrocannabinol (delta-9-THC), may reduce pain sensation, studies of humans have produced inconsistent results. In animal studies, the apparent pain-suppressing effects of delta-9-THC and other cannabinoid drugs are confounded by motor deficits. Here we show that a brainstem circuit that contributes to the pain-suppressing effects of morphine is also required for the analgesic effects of cannabinoids. Inactivation of the rostral ventromedial medulla (RVM) prevents the analgesia but not the motor deficits produced by systemically administered cannabinoids. Furthermore, cannabinoids produce analgesia by modulating RVM neuronal activity in a manner similar to, but pharmacologically dissociable from, that of morphine. We also show that endogenous cannabinoids tonically regulate pain thresholds in part through the modulation of RVM neuronal activity. These results show that analgesia produced by cannabinoids and opioids involves similar brainstem circuitry and that cannabinoids are indeed centrally acting analgesics with a new mechanism of action.  相似文献   
114.
PURPOSE: Calcium channel blockers have been reported to increase the risk of gastrointestinal bleeding. We tested this hypothesis, and also assessed whether beta blockers decrease this risk. SUBJECTS AND METHODS: A nested case-control design within a population-based cohort of all 34,074 new users of beta blockers, angiotensin-converting enzyme (ACE) inhibitors, or calcium channel blockers in Saskatchewan, from 1990 to 1993 and followed up to March 1995, was used. We identified all 311 subjects hospitalized because of gastrointestinal bleeding during this period, each of whom was matched to 10 randomly selected controls. RESULTS: The rate of hospitalization for gastrointestinal bleeding was 3.0 per 1,000 per year. The adjusted rate ratio of gastrointestinal bleeding for current use of calcium channel blockers was 1.1 (95% confidence interval [CI] 0.8 to 1.4) and 0.66 (95% CI 0.44 to 0.98) for beta blockers compared with no current use of anti-hypertensive drugs. The adjusted rate ratio for ACE inhibitor use was 1.0 (95% CI 0.7 to 1.3) while that for diuretic use was 1.4 (95% CI 1.0 to 2.0). CONCLUSIONS: The use of calcium channel blockers does not appear to increase the risk of gastrointestinal bleeding in the first five years of treatment, while beta blockers may prevent this adverse event. The unexpected elevated risk associated with the use of diuretics needs to be investigated further.  相似文献   
115.
A new form of representation of clinical data concerning a state of alcoholic patients during different periods of consumption and withdrawal of alcohol was considered according to factor quantitative data expression. Metalcoholic clinical signs, i.e. clinical manifestations of the changed reactivity to alcohol withdrawal were analysed. Separate symptoms and phases are estimated in terms of factors loading. The factors were considered as some primary components of symptoms and phasic states (so called primary disorders), because they show a vector of pathophysiologic processes in the course of the disease development. This form reflect both a clinical state of a patient and specificity of the disease course as a diagnostic physician's image during process of the making of diagnostic and therapeutic decisions. This might be widely used in therapeutic matching of patients as well as in validization of classification and systematization of alcoholism. In terms of scientific application the method provides modelling of the disease.  相似文献   
116.
117.
118.
119.
A technique which allows colony growth of haematologically normal human bone marrow cells is described. The cells are supported by semi-solid-agar-medium inside modified Millipore diffusion chambers implanted in the peritoneal cavity of irradiated mice. After 9 days incubation colonies containing up to 1000 cells are found in these Agar Diffusion Chambers. All haematologically normal patients studied so far produced colonies, the majority with between 10 and 40 colonies per 2 X 10(5) bone marrow cells inoculated. This culture system therefore provides a convenient and reliable clonal assay for human bone marrow cells which, in contrast to the agar colony assay in vitro, does not require a source of Colony Stimulating Factor (CSF).  相似文献   
120.
Cell walls prepared from vegetative yeast cells and from hormone-induced conjugation tubes of the basidiomycete Tremella mesenterica had similar compositions. Evidence was found for 1,3-alpha-glucan (yeast 38%, tube 25%), 1,3-beta-1,6-beta-glucan (yeast 33%, tube 48%) and chitin (both less than 3%) in the walls. The walls also contained xylose (5 to 7%), mannose (6%), glucuronic acid (approx. 2%), and traces of galactose. Protein amounted to less than 2% of the wall weight. The cell capsule was very insoluble and could not be removed from the cell wall. The conjugation hormone did not appear to exert its effect on cell shape by causing gross changes in wall composition.  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