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   160篇
  免费   9篇
  国内免费   1篇
化学工业   27篇
机械仪表   2篇
建筑科学   8篇
矿业工程   8篇
能源动力   8篇
轻工业   29篇
无线电   10篇
一般工业技术   15篇
冶金工业   56篇
原子能技术   1篇
自动化技术   6篇
  2023年   1篇
  2022年   2篇
  2021年   1篇
  2020年   3篇
  2019年   2篇
  2018年   4篇
  2017年   3篇
  2016年   5篇
  2015年   7篇
  2014年   8篇
  2013年   15篇
  2012年   3篇
  2011年   7篇
  2010年   3篇
  2009年   7篇
  2008年   5篇
  2007年   3篇
  2006年   2篇
  2005年   3篇
  2004年   4篇
  2002年   3篇
  2001年   1篇
  2000年   2篇
  1999年   2篇
  1998年   14篇
  1997年   10篇
  1996年   6篇
  1995年   9篇
  1994年   4篇
  1993年   5篇
  1992年   6篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1984年   2篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1971年   1篇
排序方式: 共有170条查询结果,搜索用时 9 毫秒
71.
The occurrence of chondrocalcinosis in patients with Bartter's syndrome has been reported as a typical example of hypomagnesemia-associated calcium pyrophosphate dihydrate crystal (CPPD) deposition disease. However, hypomagnesemia is a feature of Gitelman's variant of Bartter's syndrome, whereas serum magnesium levels are normal in Bartter's syndrome strictly speaking. We managed four patients with chondrocalcinosis and hypomagnesemia who met criteria for Gitelman's disease, including hypomagnesemia, hypokalemia with normal or high urinary potassium excretion, hypocalciuria, and normal blood pressure. Based on our experience with these patients, we argue that many cases of chondrocalcinosis and hypomagnesemia ascribed in previously published articles to Bartter's syndrome were due to Gitelman's syndrome.  相似文献   
72.
In breast cancer, DNA amplification of the oncogene c-erbB-2, encoding for the p185 protein, is associated with a poor prognosis. A retrospective study on a population of 220 cases of primary breast cancer permitted a quantitative measure of p185 oncoprotein overexpression by an immunoenzymetric assay and the determination of c-erbB-2 amplification by the Southern blot method. A correlation existed between the two measurements (r=0.85) using the double cut-off: DNA 2 copies and p185 400 U/mg protein, and only 2.7% of the cases were discordant. 13.2% of the tumors showed p185 overexpression. The percentage of tumors overexpressing p185 was significantly different between the groups with amplified and non-amplified c-erbB-2. We observed a significant correlation between p185 levels and tumor grade (p=0.03), and an inverse correlation with hormonal receptors (p=0.0001). The p185 assay could be an additional prognostic factor to better define patient subgroups with node negative, grade II, and positive or negative hormonal receptors.  相似文献   
73.
Ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) was purified from an obligately autotrophic hydrogen-oxidizing bacterium, Hydrogenovibrio marinus MH-110. The protein has a M(r) value of approximately 110,000, and is composed of two identical subunits of 55,000. To our knowledge, the existence of L2-form RubisCO in a chemolithoautotrophic bacterium is first reported in this paper. The N-terminal amino acid sequence determination of the purified enzyme showed high homology with those of the L2-form RubisCO of Rhodospirillum rubrum and the Lx-form RubisCO from Rhodobacter sphaeroides.  相似文献   
74.
75.
Landslides are recognized as one of the most damaging natural hazards in Italy. Campania region represents a complex geological setting, where mass movements of different types are widespread, and urban expansion can be increasingly seen by the presence of buildings and infrastructure in landslide-prone areas. In such a context, monitoring of unstable slopes represents a key activity in the process of landslide risk prevention and mitigation, in order to correctly establish a cause–effect correlation and to predict the possible reactivation phases that may result in high costs for the human society. This article focuses on the application of different methods of landslide analysis and monitoring, including those developed more recently and based on data acquired by satellites and processed by synthetic aperture radar (SAR) interferometric techniques. The study area is a small town, Calitri, known worldwide for the large landslide reactivated by the 23 November 1980 earthquake that destroyed a large sector of the historical centre. The site has been investigated by two ground-monitoring campaigns, the analysis of which allowed identification of the evolution of landslide activity over time. Furthermore, differential SAR interferometry (DInSAR), based upon two different approaches, allowed us to produce point-wise and wide area deformation maps after processing data sets of Earth Resource Satellite 1/2 (ERS-1/2) images, respectively acquired in 1992–2001 and 1992–1995. The results obtained from this analysis highlighted the potentiality of remote-sensing tools in landslide hazard assessment and led to development of a research project based on the installation of corner reflectors along unstable slopes and aimed at creating a field–Earth observation monitoring system.  相似文献   
76.
Drug-in-adhesive matrix-type transdermal therapeutic systems for indomethacin (IND) were formulated and evaluated. Silicone and two types of polyacrylates were used as the bases of matrices. Terpinolene was used as a penetration enhancer. The physicochemical properties of matrices were determined. The bioavailability study of IND was performed in rats. The presence of IND in blood was demonstrated for each system. The calculated pharmacokinetics parameters for IND mainly depend on the solubility of IND in the adhesive layer. The positive influence of a penetration enhancer on IND bioavailability was observed only for one type of polyacrylate matrices.  相似文献   
77.
This study applies a systems thinking approach to sustainment-phase redesign planning for large-scale, complex, sustainment-dominated systems (SDSs) found in the airline, aerospace and defense, healthcare, and utilities industries. Maintaining the SDS’s effectiveness throughout its long life presents a significant engineering and business challenge. This research contributes to the literature by developing an academically rigorous redesign-planning framework (RPF) through the lens of management and systems theories and the use of the grounded theory, research methodology. With the RPF, engineering managers can now simultaneously consider key issues, improvement opportunities, and risks of SDSs to develop and execute strategic, sustainment redesign plans that improve SDS performance at a lower lifecycle cost.  相似文献   
78.
Previous investigations of attitude change in counseling based on S. R. Strong's (see PA, Vol 42:12025) social influence model have yielded mixed and inconclusive results. Such findings resemble the state of attitude change research that until recently existed in social psychology. In this article we introduce a model of attitude change from social psychology, the Elaboration Likelihood Model (ELM) of persuasion, which has served to unify some of the conflicting results in social psychology. The ELM may potentially account for the inconsistent findings within counseling psychology, providing a reconceptualization of the social influence process that builds upon Strong's (1968) theory and subsequent research. We also provide guidelines for the integration of recent social and counseling literatures in regard to the interpersonal influence process as represented by the ELM. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
79.
The E7 protein from human papillomavirus (HPV) plays a key role in oncogenesis; for this reason, it is a target of great biomedical interest. To date, no high resolution information is available for the full protein. We present here the NMR characterization of the entire E7 from HPV16, one of the most oncogenic variants of the virus. The protein is very heterogeneous in terms of structural and dynamic properties with a highly flexible N‐terminal module and a more structured C terminus. This opens possibilities for studies of molecular‐level interactions and post‐translational modifications of the protein to unravel functional details that might be linked to its highly oncogenic potential.  相似文献   
80.
A new algorithm for the calculation of monomer partitioning in emulsion copolymer systems is presented. The algorithm can be applied both to monodisperse and polydisperse systems and the outputs of the algorithm include the distribution of the volume fractions of the monomers according to the particle size distribution, the volume fractions of the monomers in the monomer droplets, and the aqueous phase and the total volumes of all the phases in the system. The algorithm can handle both Interval II and Interval III conditions, using the same set of equations. This results in substantial computer time savings during the simulation of emulsion copolymerization systems. Examples of applications are given. © 1994 John Wiley & Sons, Inc.  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