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   734篇
  免费   32篇
电工技术   12篇
化学工业   162篇
金属工艺   15篇
机械仪表   12篇
建筑科学   27篇
能源动力   6篇
轻工业   92篇
水利工程   4篇
石油天然气   1篇
武器工业   1篇
无线电   54篇
一般工业技术   128篇
冶金工业   121篇
原子能技术   9篇
自动化技术   122篇
  2023年   7篇
  2022年   5篇
  2021年   10篇
  2020年   14篇
  2019年   7篇
  2018年   8篇
  2017年   11篇
  2016年   20篇
  2015年   23篇
  2014年   14篇
  2013年   26篇
  2012年   20篇
  2011年   35篇
  2010年   28篇
  2009年   24篇
  2008年   33篇
  2007年   25篇
  2006年   31篇
  2005年   17篇
  2004年   27篇
  2003年   17篇
  2002年   15篇
  2001年   12篇
  2000年   13篇
  1999年   12篇
  1998年   50篇
  1997年   25篇
  1996年   25篇
  1995年   30篇
  1994年   12篇
  1993年   12篇
  1992年   5篇
  1991年   6篇
  1990年   7篇
  1989年   14篇
  1988年   6篇
  1987年   17篇
  1986年   6篇
  1983年   3篇
  1982年   6篇
  1981年   7篇
  1980年   11篇
  1979年   7篇
  1978年   4篇
  1977年   3篇
  1976年   12篇
  1975年   4篇
  1974年   5篇
  1972年   3篇
  1950年   3篇
排序方式: 共有766条查询结果,搜索用时 797 毫秒
91.
The secretion of growth hormone was studied in 25 severely injured persons during the adaptive and convalescent stage. The ages of the patients varied between 9--65 years. During the first few days after the trauma hormone concentrations rose to up to 7--15 times their normal upper limits (about 10 mU/l). In some cases the hormone levels subsequently fell to the lower limits of normal. No attempt was made to calculate average values and the reasons for the omission are stated. The results are discussed with reference to the metabolic condition of the severely injured persons.  相似文献   
92.
Embedded digital signal processors for software defined radio have stringent design constraints including high computational bandwidth, low power consumption, and low interrupt latency. Furthermore, due to rapidly evolving communication standards with increasing code complexity, these processors must be compiler-friendly, so that code for them can quickly be developed in a high-level language. In this paper, we present the design of the Sandblaster Processor, a low-power multithreaded digital signal processor for software defined radio. The processor uses a unique combination of token triggered threading, powerful compound instructions, and SIMD vector operations to provide real-time baseband processing capabilities with very low power consumption. We describe the processor’s architecture and microarchitecture, along with various techniques for achieving high performance and low power dissipation. We also describe the processor’s programming environment and the SB3010 platform, a complete system-on-chip solution for software defined radio. Using a super-computer class vectorizing compiler, the SB3010 achieves real-time performance in software on a variety of communication protocols including 802.11b, GPS, AM/FM radio, Bluetooth, GPRS, and WCDMA. In addition to providing a programmable platform for SDR, the processor also provides efficient support for a wide variety of digital signal processing and multimedia applications. Michael Schulte received a B.S. degree in Electrical Engineering from the University of Wisconsin-Madison in 1991, and M.S. and Ph.D. degrees in Electrical Engineering from the University of Texas at Austin in 1992 and 1996, respectively. From 1996 to 2002, he was an assistant and associate professor at Lehigh University, where he directed the Computer Architecture and Arithmetic Research Laboratory. He is currently an assistant professor at the University of Wisconsin-Madison, where he leads the Madison Embedded Systems and Architectures Group. His research interests include high-performance embedded processors, computer architecture, domain-specific systems, computer arithmetic, and wireless systems. He is a senior member of the IEEE and the IEEE Computer Society, and an associate editor for the IEEE Transactions on Computers and the Journal of VLSI Signal Processing. John Glossner is CTO & Executive Vice President at Sandbridge Technologies. Prior to co-founding Sandbridge, John managed the Advanced DSP Technology group, Broadband Transmission Systems group, and was Access Aggregation Business Development manager at IBM’s T.J. Watson Research Center. Prior to IBM, John managed the software effort in Lucent/Motorola’s Starcore DSP design center. John received a Ph.D. in Computer Architecture from TU Delft in the Netherlands for his work on a Multithreaded Java processor with DSP capability. He also received an M.S. degree in Engineering Management and an M.S.E.E. from NTU. John also holds a B.S.E.E. degree from Penn State. John has more than 60 publications and 12 issued patents. Dr. Sanjay Jinturkar is the Director of Software at Sandbridge and manages the systems software and communications software groups. Previously, he managed the software tools group at StarCore. He has a Ph.D in Computer Science from University of Virginia and holds 20 publications and 4 patents. Mayan Moudgill obtained a Ph.D. in Computer Science from Cornell University in 1994, after which he joined IBM at the Thomas J. Watson Research Center. He worked on a variety of computer architecture and compiler related projects, including the VLIW research compiler, Linux ports for the 40x series embedded processors and simulators for the Power 4. In 2001, he co-founded Sandbridge Technologies, a start-up that is developing digital signal processors targeted at 3G wireless phones. Suman Mamidi is a graduate student in the Department of Electrical and Computer Engineering at the University of Wisconsin-Madison. He received his M.S. degree from the University of Wisconsin-Madison in December, 2003 and is currently working towards his PhD. His research interests include low-power processors, hardware accelerators, multithreaded processors, reconfigurable hardware, and embedded systems. Stamatis Vassiliadis was born in Manolates, Samos, Greece, in 1951. He is currently a Chair Professor in the Electrical Engineering, Mathematics, and Computer Science (EEMCS) department of Delft University of Technology (TU Delft), The Netherlands. He previously served in the Electrical and Computer Engineering faculties of Cornell University, Ithaca, NY and the State University of New York (S.U.N.Y.), Binghamton, NY. For a decade, he worked with IBM, where he was involved in a number of advanced research and development projects. He received numerous awards for his work, including 24 publication awards, 15 invention awards, and an outstanding innovation award for engineering/scientific hardware design. His 73 USA patents rank him as the top all time IBM inventor. Dr. Vassiliadis is an ACM fellow, an IEEE fellow and a member of the Royal Netherlands Academy of Arts and Sciences (KNAW).  相似文献   
93.
The sensitivity, specificity, and positive and negative predictive values were compared for six methods of collecting or culturing milk samples for the diagnosis of chronic Streptococcus agalactiae intramammary infection. Cows in four dairy herds were cultured three times in 2 wk to determine infection status. At the second sample period, individual quarter and composite milk samples were taken before and immediately after milking, and two volumes of milk from the composite samples were streaked on culture plates. The sensitivity, specificity, and predictive values for these cultures ranged between 95 and 100% for all diagnostic methods, and no significant differences were found between methods. The results indicate that when either quarter or composite samples are collected before or immediately after milking, 95 to 100% of S. agalactiae culture-positive cows will be infected with S. agalactiae in herds with a prevalence of S. agalactiae between 35 and 55%. A similar proportion of culture-negative cows will be uninfected.  相似文献   
94.
To produce high-quality polyurethane-reaction injection moulding (PUR-RIM) of the sort used in automotive exterior applications, the essential requirements are high-performance machinery and equipment plus a thorough understanding of all the processing parameters. Successful production of blemish free articles at fast cycles, ready for painting and requiring no post-treatment is only possible if the interconnected chemical and technical processing sequences all function in perfect harmony. Working towards this goal, several teams of chemists, processing engineers and manufacturers have been co-operating on intensive programmes of research and development, and today it can justifiably be claimed that the RIM process is remarkably mature for such a young technology. A determined effort is now required to incorporate the latest findings into the design of new machinery and to modify existing machinery accordingly.

In this paper, a detailed discussion is presented of the two most important processing parameters (temperature and pressure) and the various factors which depend on them, and the need for accurate control of these parameters during the manufacturing process is stressed. Details are also given of a production line complete with tooling designed specifically for the process. Together with an appropriate system of measuring, monitoring and recording the processing parameters, this is an essential prerequisite for cost-efficient production.  相似文献   

95.
X-ray microbeam technique and recrystallization method were used to measure plastic zones around 20 kHz fatigue cracks in mild steel. Both methods render approximately the same extension of a plastic zone. In order to obtain the amount of deformation within a plastic zone measurements of integral line breadth and recrystallization temperature were calibrated by specimens deformed with known per cent static tension. But since static and cyclic loading cause different dislocation structures (especially the dislocation density is much more inhomogeneous in fatigued specimens) quantitative comparison is difficult. Furthermore the two methods display different values of the actual amount of deformation. X-ray line broadening indicates an average dislocation density, whereas recrystallization displays a maximum amount of deformation, which corresponds to the local dislocation concentrations.  相似文献   
96.
A national sample of 251 1st- and 2nd-yr doctoral students in school psychology responded to a questionnaire measuring demographic characteristics, preferences among applied specialties in professional psychology, graduate program applications, anticipated internship setting, preferred client population, personal interests, professional goals, and satisfaction with current training. Survey responses showed a clear preference for working directly with children and adolescents following graduation, a high degree of correspondence between training program emphases and student interests and goals, and a moderate degree of student satisfaction with training experiences. Results are interpreted with respect to training trends and standards in school psychology, the relationship between school and clinical psychology, satisfaction of students in clinical and counseling psychology programs, and methodology limitations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
97.
98.
Separation of Triglycerides According to Chain Length and Degree of Saturation by HPLC In routine fat analysis HPLC is efficiently used. For constant work columns with chemically bound C18-groups are especially suitable. There are critical pairs of fatty acid-methylesters which however can be separated by means of elution agents basing on acetonitril. Oleic acid and elaidic acid can be separated by this way, too. By GLC triglycerides can only be separated according to the number ob C-atoms, whereas in HPLC double bounds have a great influence on the retention time, too. This is especially evident if elution agents, basing on nitrils, are used. The separation principle was determined by capillar gas chromatographic analysis of the HPLC fractions. Further on hints are given to avoid technical difficulties in the use of differential refractometers.  相似文献   
99.
100.
The change in hydrogen concentration as a function of applied strain has been studied in commercial titanium alloys that included threeβ-phase, twoα-phase, and an (α + β)-phase Ti-6Al-4V alloy with differingα/β morphologies.Insitu measurements were made using a nondestructive nuclear technique on samples for which uniaxial compressive and tensile stresses were applied by four-point bending. Theβ-phase alloys exhibited hydrogen redistribution under an elastic stress gradient, but no further change was discernible accompanying plastic deformation. The extent of hydrogen concentration change for theβ-phase alloys was of the order of 4 to 6 pct for a 620 MPa stress gradient. This is less than would be predicted based on available data for the partial molal volume of hydrogen. Diffusion coefficients in a stress gradient were also determined and are consistent with those measured inβ-phase titanium at elevated and room temperatures. Within the experimental sensitivities there was no evidence of hydrogen redistribution with applied stress for theα-phase and Ti-6Al-4V alloys.  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