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   1186篇
  免费   0篇
化学工业   7篇
金属工艺   1篇
机械仪表   4篇
建筑科学   1篇
矿业工程   4篇
能源动力   1篇
轻工业   1篇
无线电   5篇
一般工业技术   13篇
冶金工业   1145篇
原子能技术   3篇
自动化技术   1篇
  2022年   1篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2018年   1篇
  2017年   2篇
  2016年   5篇
  2015年   1篇
  2013年   2篇
  2012年   5篇
  2011年   3篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2007年   2篇
  2006年   1篇
  2005年   1篇
  2003年   2篇
  2002年   1篇
  1999年   5篇
  1998年   272篇
  1997年   203篇
  1996年   162篇
  1995年   86篇
  1994年   73篇
  1993年   59篇
  1992年   13篇
  1991年   13篇
  1990年   1篇
  1989年   9篇
  1988年   7篇
  1987年   3篇
  1986年   4篇
  1985年   2篇
  1984年   1篇
  1983年   2篇
  1982年   7篇
  1981年   10篇
  1980年   18篇
  1979年   1篇
  1978年   3篇
  1977年   70篇
  1976年   123篇
  1975年   3篇
  1961年   1篇
  1955年   2篇
排序方式: 共有1186条查询结果,搜索用时 15 毫秒
11.
CT scans of 9 patients with orbital pseudotumor (bilateral in 6 and unilateral in 3) showed findings distinct from those observed in Graves' ophthalmopathy. In bilateral involvement, they ranged from localized mass lesions to complete obiliteration of normal orbital CT anatomical landmarks; diffuse or multifocal lesions involving the posterior globe and muscle insertions were most typical of the diagnosis. However, findings in unilateral psedotumor may be indistinguishable from orbital mass lesions other than Graves' ophthalmopathy. Serial CT scans were used to show progression of disease and response to treatment.  相似文献   
12.
In experiments with unanaesthetized rabbits the influences of electric stimulation of the dentate fascia (DF) on the extracellularly recorded spontaneous and evoked activity of the CA3 neurones were investigated. Stimulation of a fixed locus in the DF during recording in the CA3 by a microelectrode, shifted along the longitudinal axis of the hippocampus, supported the notion of the topical, "segmental" organization of connections between the DF and CA3. A relatively narrow "active zone" (approximately 700 nm) appeared in the CA3 during the threshold DF stimulation: it was bordered by zones with predominantly inhibitory responses to stimulation. The CA3 neurones in the "active zone" rapidly lost their reactivity to sensory stimuli. In the "inhibitory" and "zero" zones the normal level of reactivity to sensory stimuli was preserved.  相似文献   
13.
Forty patients with temporal epilepsy were operated on with a stereotaxic technique. Eleven patients had a unilateral localization of the epileptic focus, and in 29 bitemporal foci were diagnosed. In evaluating the results of the treatment the dynamics of the epileptic fits, the peculiarities of changes in the mental status, and the degree of social adaptation were taken into consideration. A postoperative improvement was achieved in 73% of the patients with monotemporal lesions, while in those with bitemporal epilepsy and distinct persistent mental disorders the state was improved in 44% of the cases. Indications for the choice of the zone of destruction depending on the clinical peculiarities of the lesion are presented.  相似文献   
14.
Some indexes of nitrogen metabolism in blood, rumen content and urine of bull-calves fed on urea were studied as affected by UV-radiation. The content of protein, nonprotein, amine nitrogen, urea and ammonia in the rumen content and blood as well as as intensity of urea nitrogen and ammonia excretion with urine were determined. It is established that when 25% of protein necessary for the organism was replaced in the ration by urea, UV-radiation with a dose of 120 merg/h-m2 lowers already at the beginning of irradiation the amount of amine nitrogen and further the protein one in the young cattle rumen content. In blood of the irradiated bull-calves at the beginning of irradiation the level of amine nitrogen decreases, the level of nonprotein nitrogen lowers with a longer irradiation. The content of protein nitrogen in blood at that time increases. It was found that the content of ammonia in the bull-calves rumen during the first twenty-hours lowers, the amount of urea in blood does not change essentially. Simultaneously the ammonia excretion with urine intensifies, at the same time the excretion of urea nitrogen with urine does not differ essentially from that in the control bull-calves. In the bull-calves under study the nitrogen balance and average daily gains increase that may testify to the fact that UV-radiation in the applied dose stimulates a more complete utilization of urea nitrogen for the synthesis processes in the organism.  相似文献   
15.
The isoenzyme composition of lactate dehydrogenase of soleus and plantaris muscles of rats flown for 20.5 d aboard the biosatellite Cosmos-690 and irradiated with a dose of 800 rad was investigated. The muscles exposed to weightlessness per se and weightlessness combined with radiation showed similar changes in their carbohydrate metabolism. On return to 1 G, readaptation of irradiated rats developed less rapidly than of animals exposed to weightlessness alone.  相似文献   
16.
Identical distribution of C2- and Cx-cellulase activities of enzyme complexes produced by Trichoderma lignorum on a medium with lactose, a soluble "inductor", and on a medium with cellulose was found by means of disc elestrophoresis in polyacrylamide gel. The maximum rate of synthesis of cellulases on the medium with lactose was registered during the highest deceleration, and even complete cessation, of the fungal growth. During this phase, only one electrophoretically homogeneous cellulase component with Rf of 0.44 possessing all types of the cellulase activity is present in the cultural broth. In the course of growth of the fungus on cellulose after 48 hours, also only one electrophoretically homogeneous component with Rf of 0.44 was found in the cultural broth when the rate of the substrate degradation was highest. The appearance of minor protein components with the activity of cellulase at later stages of cultivation after cessation of the fungal growth is supposed to be caused by modification of the main cellulase component with Rf of 0.44 by the growth medium.  相似文献   
17.
18.
An efficient pilot‐scale process was developed to produce nutraceutical products from fresh sea buckthorn (Hippophae rhamnoides) berries. Fresh berries were subjected to high‐pressure dewatering using a continuous screw press. The separated liquid phase containing 80–90% of pulp oil was clarified at 80 °C and centrifuged to obtain pulp oil, clear juice and sludge. The pulp oil yield was 2.7–2.8% of fresh berry weight with 66–70% extraction efficiency. The pulp oil was remarkably rich in carotenoids (2450–2810 mg kg?1), tocopherols (1409–1599 mg kg?1) and sterols (4096–4403 mg kg?1), with a characteristic fresh berry flavour and 16:1 as the major fatty acid (45.6–49.1%). The clear juice obtained was free from oil and contained high amounts of vitamin C (1683–1840 mg kg?1) and phytochemicals such as polyphenols (2392–2821 mg kg?1) and flavonoids (340–401 mg kg?1). Isorhamnetin (251–310 mg kg?1) was the major flavonoid in the juice, along with quercetin (77–81 mg kg?1) and kaempherol (12–16 mg kg?1). The juice was very acidic (pH 3), with high concentrations of organic acids (30.8–36.0 g kg?1). High‐performance liquid chromatography profiling of organic acids revealed quinic acid (18.1–19.9 g kg?1) as the major acid in the juice. The seeds in the pressed cake were separated and extracted for oil using supercritical CO2. Copyright © 2006 Society of Chemical Industry  相似文献   
19.
20.
We successfully synthesized 13X zeolite using a hydrothermal method. Then, composites of polyaniline (PANI) with 13X zeolite and PANI–13X with platinum were prepared by chemical oxidative polymerization and chemical reduction, respectively. Field emission scanning electron microscopy, X‐ray diffraction, Raman spectroscopy and Brunauer–Emmett–Teller techniques were used to characterize the PANI–Pt and PANI–Pt–13X composites. Further, the electrocatalytic activity towards methanol oxidation of the synthesized catalysts was explored using cyclic voltammetry in 1 mol L?1 CH3OH + 0.5 mol L?1 H2SO4 solution. From the obtained results, PANI–Pt–13X shows superior performance compared to PANI–Pt towards methanol oxidation and electrical conductivity. Hence, the 13X zeolite‐incorporated PANI–Pt composite could be an efficient catalyst for direct methanol fuel cell applications. © 2019 Society of Chemical Industry  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