全文获取类型
收费全文 | 21630篇 |
免费 | 796篇 |
国内免费 | 20篇 |
专业分类
电工技术 | 213篇 |
综合类 | 18篇 |
化学工业 | 3685篇 |
金属工艺 | 321篇 |
机械仪表 | 403篇 |
建筑科学 | 1004篇 |
矿业工程 | 49篇 |
能源动力 | 501篇 |
轻工业 | 1677篇 |
水利工程 | 120篇 |
石油天然气 | 58篇 |
武器工业 | 1篇 |
无线电 | 1583篇 |
一般工业技术 | 3056篇 |
冶金工业 | 6724篇 |
原子能技术 | 188篇 |
自动化技术 | 2845篇 |
出版年
2023年 | 140篇 |
2022年 | 226篇 |
2021年 | 458篇 |
2020年 | 341篇 |
2019年 | 366篇 |
2018年 | 424篇 |
2017年 | 388篇 |
2016年 | 493篇 |
2015年 | 424篇 |
2014年 | 520篇 |
2013年 | 1072篇 |
2012年 | 856篇 |
2011年 | 1115篇 |
2010年 | 765篇 |
2009年 | 821篇 |
2008年 | 861篇 |
2007年 | 756篇 |
2006年 | 701篇 |
2005年 | 591篇 |
2004年 | 487篇 |
2003年 | 442篇 |
2002年 | 420篇 |
2001年 | 296篇 |
2000年 | 318篇 |
1999年 | 447篇 |
1998年 | 1777篇 |
1997年 | 1052篇 |
1996年 | 827篇 |
1995年 | 516篇 |
1994年 | 452篇 |
1993年 | 503篇 |
1992年 | 215篇 |
1991年 | 211篇 |
1990年 | 202篇 |
1989年 | 227篇 |
1988年 | 169篇 |
1987年 | 188篇 |
1986年 | 161篇 |
1985年 | 201篇 |
1984年 | 134篇 |
1983年 | 120篇 |
1982年 | 110篇 |
1981年 | 117篇 |
1980年 | 119篇 |
1979年 | 98篇 |
1978年 | 94篇 |
1977年 | 203篇 |
1976年 | 370篇 |
1975年 | 86篇 |
1974年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
161.
162.
Dr. Martin Meints 《Datenschutz und Datensicherheit - DuD》2006,30(1):13-16
Datenschutzmanagement ist eine gesetzlich verankerte Aufgabe, muss sich aber unter Wirtschaftlichkeitsgesichtspunkten in der betrieblichen und zunehmend auch der behördlichen Praxis in andere, bereits etablierte Prozessmanagementstrukturen wie ITIL oder Informationssicherheits-management Systeme (ISMS) einordnen. In diesem Beitrag werden die Möglichkeiten untersucht, die IT-Grundschutz als ein zukünftiges, ISO 27001-kompatibles ISMS bietet. Unter dem Gesichtspunkt der Normierung scheint eine Aktualisierung des Bausteins 3.5 “Datenschutz” dringend. 相似文献
163.
Publications on optimal control of irreversible thermodynamic processes are reviewed. Analogies between irreversible processes in thermodynamics and microeconomics are stated. 相似文献
164.
165.
Outage in digital microwave radio systems during multipath fading is highly correlated with the channel amplitude dispersion. This characteristic is exploited in a new digital microwave radio system measurement technique which yields dispersion signatures. These dispersion signatures can be readily applied to assess the effects of time varying channels on digital radio equipment. Thus, dispersion signatures can be used for in-service monitoring of equipment operation during actual fading. Routine maintenance assessment and laboratory evaluation of digital microwave radio equipment can also be readily carried out. The laboratory evaluation results can be used for system design both with and without diversity. 相似文献
166.
XML hat sich als Sprache zur Definition von Dokumenten für den universellen Datenaustausch etabliert. XML-Schema erm?glicht
ausgefeilte Definitionen für XML-Dokumente und hat beste Chancen, die bisher eingesetzte DTD abzul?sen. Neben einer allgemeinen
Einführung geht dieser Beitrag auch auf verfügbare Produkte und neue M?glichkeiten der objektorientierten Softwareentwicklung
mit XML-Schema ein.
Vorschl?ge an Prof. Dr. Frank Puppe <puppe@informatik.uni-wuerzburg.de> oder Dieter Steinbauer <dieter.steinbauer@schufa.de>
Alle „Aktuellen Schlagw?rter” seit 1988 finden Sie unter: www.ai-wuerzburg.de/as 相似文献
167.
Henry T. Y. Yang Martin Heinstein J.-M. Shih 《International journal for numerical methods in engineering》1989,28(6):1409-1428
The development and integration of available current methods and the development of new methods for an adaptive finite element analysis of metal forming processes are presented. The analysis includes large-strain, elastic–plastic, and thermal effects. Many numerical methods such as mesh generation, simulation of the contact between the workpiece and tool and die, and optimization of the finite element mesh are integrated and incorporated. In addition, an algorithm is developed which can detect certain severely distorted elements where the area of integration is approaching zero. The advantage of correcting these regions of locally distorted elements is demonstrated. These numerical methods are implemented in a finite element program developed for simulating metal forming processes, with the emphasis on automating the analysis. Examples include an axisymmetric stress simulation of a coldheading process, a plane strain simulation of an extrusion process and a plane strain simulation of orthogonal metal cutting, all with noticeable thermal effects. The orthogonal cutting forces and feed forces calculated are compared with two sets of experimental data, with good agreement. 相似文献
168.
Nutrition early in life may influence adult mortality. The fetal-origins hypothesis suggests that nourishment before birth and during the individual's infancy programs the development of risk factors for several important diseases of middle and old age. The present study was designed to evaluate the impact of extreme nutritional deprivation in utero and during infancy and early childhood on mortality in later life. The authors analyzed the survival of the cohorts born in Finland during the severe 1866-1868 famine and during the 5 years immediately preceding and 5 years immediately following the famine. The study included 331,932 individuals born prior to the famine, 161,744 born during the famine, and 323,321 born after the famine. The authors assessed survival by cohorts from birth to age 17 years and from age 17 to 40, 60, and 80 years, as well as average length of life after age 80 years. Survival from birth to age 17 years was significantly lower in cohorts born before and during the famine than in the cohorts born after the famine (males, 0.566 vs. 0.671, a difference of 0.105 (95% confidence interval (CI) 0.102-0.108); females, 0.593 vs. 0.692, a difference of 0.099 (95% CI 0.096-0.102)). At subsequent ages, including old age, mortality was practically identical in the famine-born cohorts and in the five cohorts born before and after the crisis. For both males and females, survival from 17 to 80 years and mean remaining lifetime at age 80 years were very similar across the 13 cohorts studied. These findings suggest that, although cohorts subjected to prolonged and extreme nutritional deprivation in utero and during infancy and early childhood suffer an immediate rise in mortality, after the crisis has passed, they carry no aftereffects that influence their survival in later life. 相似文献
169.
Thomas Stieglitz Martin Schuettler Klaus Peter Koch 《IEEE engineering in medicine and biology magazine》2005,24(5):58-65
In the following article, the technologies to fabricate polyimide-based thin and flexible substrates with monolithically integrated electrode arrays and printed circuit boards (PCB) for hybrid electronic assemblies as well as an assembling technique that connects bare electronic dice with flexible PCBs are presented. The concept of modular, flexible biomedical microsystems as neural prostheses is introduced in general and described in detail in three examples. A cuff electrode with integrated multiplexer circuitry and standard implantable cables represents the combination of microtechnology with precision mechanics; a sieve electrode used as an implant in peripheral nerve regeneration studies demonstrates the next level of integration density but still uses a cable connection; and last, joint effort to fabricate the demonstrator of a vision prosthesis that is completely implantable in the eye with a wireless link for energy supply and data transmission is presented. System design, hybrid assembling technology, and flexible multilayer encapsulation using parylene and silicone rubber are the key components for creating a new generation of neural prostheses for complex and challenging new applications. 相似文献
170.