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   84篇
  免费   2篇
工业技术   86篇
  2021年   1篇
  2018年   1篇
  2017年   1篇
  2016年   3篇
  2015年   9篇
  2013年   4篇
  2012年   7篇
  2011年   2篇
  2010年   1篇
  2009年   1篇
  2008年   5篇
  2006年   5篇
  2005年   2篇
  2002年   1篇
  1998年   3篇
  1997年   3篇
  1996年   1篇
  1995年   2篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1987年   3篇
  1985年   1篇
  1984年   1篇
  1982年   1篇
  1981年   2篇
  1980年   3篇
  1979年   1篇
  1978年   5篇
  1977年   2篇
  1976年   2篇
  1975年   3篇
  1973年   1篇
  1972年   1篇
  1971年   2篇
  1966年   1篇
排序方式: 共有86条查询结果,搜索用时 534 毫秒
1.
The present study was designed to determine if spinal calcium channels, calmodulin, and calcium/calmodulin-dependent protein kinase II were involved in the production of antinociception induced by cold water swimming stress (CWSS). The effects of intrathecal (i.t.) injection of nimodipine, omega-conotoxin GVIA, calmidazolium, or (S)-5-isoquinolinesulfonic acid, 4-[2-[(5-isoquinolinyl-sulfonyl)methylamino]-3-oxo-3-(4-phenyl-1-piperaz inyl)-propyl]phenyl ester (KN-62) on CWSS-induced antinociception were studied in ICR mice. The antinociception was assessed by the tail-flick test. CWSS produced inhibition of the tail-flick response. Various doses of nimodipine (10-40 ng), omega-conotoxin GVIA (5-40 ng), calmidazolium (10-40 ng), or KN-62 (5-40 ng) injected i.t. alone did not show any antinociceptive effect in the tail-flick test. I.t. pretreatment with omega-conotoxin GVIA, calmidazolium, or KN-62 dose dependently attenuated the CWSS-induced inhibition of the tail-flick response. However, i.t. pretreatment with nimodipine did not affect the inhibition of the tail-flick response induced by CWSS. Our results suggest that spinal N-type calcium channel, calmodulin and calcium/calmodulin-dependent protein kinase II may be involved in the production of antinociception induced by CWSS. On the other hand, CWSS-induced antinociception appears not to be mediated via the spinal L-type calcium channel.  相似文献   
2.
3.
Advances in computation challenge established design approaches in architecture through a much deeper integration of form generation and materialisation. Tobias Schwinn , Research Associate at the Institute for Computational Design (ICD), University of Stuttgart, and Guest-Editor Achim Menges , Director of the ICD, introduce how the potentials and constraints of robotic fabrication can now be explored as generative drivers in agent-based design. This enables architectural innovation in unison with fabricability, structural capacity and spatial performance, as demonstrated by the Landesgartenschau Exhibition Hall in Schwäbisch Gmu"nd, Germany, the world's first building with a robotically fabricated segmented timber shell as its primary structure.  相似文献   
4.
Aggregate architectures are full-scale spatial formations made from loose granular matter. Especially if the individual grain is custom-designed, the range of behaviours can be calibrated to match a wide range of architectural and structural performance criteria. The aggregate becomes programmable matter. The relevance of loose granular systems for architecture is on the one hand their rapid re-configurability, allowing for a system not to be destroyed but rather to be recycled. On the other hand aggregates per se can be functionally graded either within one and the same particle type or through mixing different particle geometries. This enables the variation of architectural properties throughout one and the same material system, which is one of the core postulates of current architectural design research. However, very few examples of designed granular matter in architecture exist. The results presented here are thus one of the first coherent bodies of comprehensive research in this field compiled over a period of five years. Methodologically aggregate systems challenge conventional architectural design principles: whereas an architect generally precisely defines local and global geometry of a structure, in a designed granular system he can only calibrate the particle geometry in order to tune the overall behaviour of the aggregate formation. Thus new design methods have been developed throughout the research projects, which are informed by the related fields of granular physics and behaviour-based robotics. In this context the article provides an introduction to both designed particle systems and suitable fabrication approaches in an architectural context. Case study projects serve to verify the applicability of the concepts introduced. The research findings are discussed with regards to their practical, methodological and design theoretical contributions. To conclude, further directions of research are highlighted.  相似文献   
5.
Sintering of PVC     
Although PVC is counted as one of the amorphous plastics it possesses a distinct powder grain structure. This structure is responsible for various effects; for example it is impossible to sinter thick pieces of rigid PVC dryblend possessing satisfactory mechanical properties. For this application, it is necessary to break down this powder structure into smaller parts, called primary particles, by mechanical shearing and covering these particles with processing auxiliaries enabling it to be sintered. PVC can then be melted by the influence of temperature and pressure in the same way as other thermoplastic materials. For this reason, tests were carried out to determine the best material configuration and the necessary data for the compounding and shearing process, and the sinter conditions. A continuously working roll mill was used to break down the structure. The rolls of this equipment are provided with grooves inclined at a certain angle. With this construction it is possible to achieve a high shearing rate at a low mass-temperature. Furthermore, all additives can be added during the rolling process, so that no additional mixing process is necessary. These gelable pellets, made by the roll mill, can thus be formed in a die into plates of different thicknesses. Samples were pressed by varying compounding and sintering conditions and these were tested for mechanical properties.  相似文献   
6.
Several components are responsible for circulatory control at the central, regional, and microcirculatory level. Angiotensin-converting enzyme (ACE) inhibitors are known to act beneficially on circulation by various mechanisms. The influence of continuous i.v. administration of the ACE inhibitor enalaprilat on regulators of circulation was studied in 45 critically ill patients. According to a prospective randomized sequence, either 0.25 mg/h (group 1, n = 15) or 0.5 mg/h (group 2, n = 15) of enalaprilat or saline solution as placebo (control group, n = 15) were continuously given. Infusion was started on the day of admission to the intensive care unit (ICU) and continued for the next 5 days. From arterial blood samples, plasma levels of endothelin-1 (ET), atrial natriuretic peptide (ANP), renin, vasopressin, angiotensin-II, and catecholamines (epinephrine, norepinephrine) were measured. All measurements were carried out before infusion (= baseline values) and during the next 5 days. In both enalaprilat groups, mean arterial blood pressure (MAP) decreased similarly; heart rate (HR) and central venous pressure (CVP) did not change, and were without differences in comparison to the untreated control. Except for ET, plasma levels of all vasoactive substances exceeded normal range at baseline. Angiotensin-II plasma concentrations significantly decreased during enalaprilat infusion (0.25 mg/h: from 53.1 +/- 11.3 to 22.1 +/- 9.3 pg/ml; 0.50 mg/h: 62.1 +/- 14.4 to 17.9 +/- 7.9 pg/ml), but they remained significantly elevated in the untreated control patients. Vasopressin plasma level increased only in the control group (p < 0.01) and decreased in the patients in whom 0.50 mg/h of enalaprilat was infused.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
7.
This article considers two topics: (1) Cooling of the film bubble and (2) Production of shrinkable film. Heat is transported by conduction, convection, and radiation, but only convection and radiation are relevant for the cooling results. Heat radiation can be calculated with known surface area, temperatures, and emission coefficient. Here we learn that the emission coefficient depends on the film thickness. Heat transfer by radiation amounts to about 15 percent of the total heat transfer. Heat transfer by convection normally can be calculated by known methods assuming ideal flow conditions. Because the flow conditions of the cooling air differ considerably from ideal conditions, known heat-transfer laws give incorrect results. Therefore, a new formula was set-up by determining the heat transfer conditions in real experiments. Each blown film is shrinkable, but in most cases the influence of the die on the shrinkage is disregarded. The die causes an important anisotropy in the elastic behavior of the film. Further on, shrinkage is influenced by the degree of bubble deformation, the temperature profile, and the deformation velocity between die exit and freeze line. This is discussed qualitatively. A calculations is not yet possible because of the unknown relaxation behavior of the melt. The shrinkage of an LDPE blown film depends on time and temperature. Time and temperature are exchangeable variables.  相似文献   
8.
Allelopathic volatiles associated with the weed Palmer amaranth (Amaranthus palmeri S. Wats.; AMAPA) were trapped on Tenax GC, thermally desorbed, and identified by gas chromatography-mass spectroscopy. Methyl ketones and alcohols (C4–C11) were the principal components of the volatiles mixture. Seedheads, stems, or roots were placed in a glass container and incubated at 31 °C (10 hr)/21 °C (14 hr) for three days prior to trapping the volatiles. Seedheads were rich in 2-heptanone which was consistently found, together with 2-heptanol, in all AMAPA tissues. Vapors of authentic 2-heptanone and (±)-2-heptanol at concentrations of 1 ppm or higher strongly inhibited the germination of onion and carrot and almost completely suppressed the germination of tomato and AMAPA seeds.Names of companies or commercial products are given solely for the purpose of providing specific information; their mention does not imply recommendation or endorsement by the U.S. Department of Agriculture over others not mentioned.  相似文献   
9.
49 students in an undergraduate educational psychology course designed and conducted behavioral self-modification projects. They were prepared to undertake the projects through preliminary instruction and a system of computer-delivered mastery tests on operant psychology. Project outcomes were measured by goal-attainment scaling, a technique that permits individuality of self-change goals and produces standardized outcome scores for the group of participants. Correlation and regression analyses indicated weak but significant relationships between self-modification outcomes and a linear combination of dogmatism (Rokeach Dogmatism Scale), sex, and mathematical aptitude (Scholastic Aptitude Test) variables. The effects of demand characteristics in the instructional setting were negligible. (l7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
10.
A case of malignant degeneration in a right parapontine epidermoid cyst giving rise to leptomeningeal carcinomatosis in a 57 year old woman is presented. The malignant tissue had infiltrated the right cerebellar hemisphere and produced a symptomatic trigeminal neuralgia, a change in the psychological state of the patient, and an acute conus and cauda syndrome following metastasis implantation. Only eight unequivocal previous reports of malignant transformation of intracranial epidermoid cyst have been reported in the literature with metastases in four.  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