全文获取类型
收费全文 | 5381篇 |
免费 | 146篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 86篇 |
综合类 | 19篇 |
化学工业 | 944篇 |
金属工艺 | 83篇 |
机械仪表 | 76篇 |
建筑科学 | 469篇 |
矿业工程 | 6篇 |
能源动力 | 139篇 |
轻工业 | 617篇 |
水利工程 | 32篇 |
石油天然气 | 4篇 |
无线电 | 316篇 |
一般工业技术 | 754篇 |
冶金工业 | 1251篇 |
原子能技术 | 63篇 |
自动化技术 | 670篇 |
出版年
2023年 | 32篇 |
2022年 | 51篇 |
2021年 | 100篇 |
2020年 | 65篇 |
2019年 | 71篇 |
2018年 | 95篇 |
2017年 | 62篇 |
2016年 | 101篇 |
2015年 | 79篇 |
2014年 | 138篇 |
2013年 | 180篇 |
2012年 | 203篇 |
2011年 | 310篇 |
2010年 | 205篇 |
2009年 | 184篇 |
2008年 | 204篇 |
2007年 | 347篇 |
2006年 | 154篇 |
2005年 | 131篇 |
2004年 | 129篇 |
2003年 | 123篇 |
2002年 | 127篇 |
2001年 | 88篇 |
2000年 | 94篇 |
1999年 | 118篇 |
1998年 | 418篇 |
1997年 | 260篇 |
1996年 | 154篇 |
1995年 | 133篇 |
1994年 | 100篇 |
1993年 | 95篇 |
1992年 | 52篇 |
1991年 | 51篇 |
1990年 | 54篇 |
1989年 | 52篇 |
1988年 | 37篇 |
1987年 | 35篇 |
1986年 | 29篇 |
1985年 | 38篇 |
1984年 | 33篇 |
1983年 | 25篇 |
1982年 | 27篇 |
1981年 | 38篇 |
1980年 | 35篇 |
1979年 | 41篇 |
1978年 | 22篇 |
1977年 | 40篇 |
1976年 | 61篇 |
1975年 | 23篇 |
1973年 | 27篇 |
排序方式: 共有5529条查询结果,搜索用时 15 毫秒
1.
2.
3.
Test Case Generation as an AI Planning Problem 总被引:6,自引:0,他引:6
Adele E. Howe Anneliese von Mayrhauser Richard T. Mraz 《Automated Software Engineering》1997,4(1):77-106
While Artificial Intelligence techniques have been applied to a variety of software engineering applications, the area of automated software testing remains largely unexplored. Yet, test cases for certain types of systems (e.g., those with command language interfaces and transaction based systems) are similar to plans. We have exploited this similarity by constructing an automated test case generator with an AI planning system at its core. We compared the functionality and output of two systems, one based on Software Engineering techniques and the other on planning, for a real application: the StorageTek robot tape library command language. From this, we showed that AI planning is a viable technique for test case generation and that the two approaches are complementary in their capabilities. 相似文献
4.
Osvath P. Zingales G. Bartnikas R. Salama M.M.A. von Glahn P. Gulski E. Quinlan J. Steiner J.P. Stone G.C. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1995,2(4):685-699
Some of the more salient aspects of the digital processing technology of PD signals are examined. Most of the efforts in this field are concentrated on the application of digital analyzers for pulse height analysis, pattern recognition and identification of the physical phenomena. It is demonstrated that errors in the signal processing unit can lead to dominant mistakes in the interpretation of the test results 相似文献
5.
A system for person-independent classification of hand postures against complex backgrounds in video images is presented. The system employs elastic graph matching, which has already been successfully applied for object and face recognition. We use the bunch graph technique to model variance in hand posture appearance between different subjects and variance in backgrounds. Our system does not need a separate segmentation stage but closely integrates finding the object boundaries with posture classification. 相似文献
6.
Bestehen ausreichende Anhaltspunkte für die Hochwassergef?hrdung, ist die Gemeinde verpflichtet, sich durch Nachforschungen
Gewissheit über das Vorliegen oder Nichtvorliegen eines Hochwasserabflussgebietes gem § 38 Abs 3 WRG zu verschaffen. Liegt
ein solches vor, hat sie gem § 12 Abs 1 Z 2 krnt GplG dieses im Fl?chenwidmungsplan ersichtlich zu machen. Erteilt die Gemeinde
eine Baubewilligung ohne diese von der Erteilung einer wasserrechtlichen Bewilligung abh?ngig zu machen, haftet sie für die
Kosten der Bauführung, die bei gesetzes-konformer Vorgangsweise unterlassen worden w?re. 相似文献
7.
Using boundary element based three dimensional modelling for linear fracture mechanics, we present an analysis of cracking in a homogeneous medium subject to contact load. The proposed iterative solution procedure allows a simultaneous treatment of a reasonable number of partially closed cracks. It is shown that the most probable direction of propagation of a vertical internal crack is strongly dependent on its size compared to the contact radius and its location with respect to the axis of maximum normal load. 相似文献
8.
9.
Dynamic complexity investigates the required effort to maintain knowledge about a property of a structure under changing operations.
This article introduces a refined notion of dynamic problems which takes the initial structure into account. It develops the
basic structural complexity notions accordingly. It also shows that the dynamic version of the LOGCFL-complete problem D2LREACH(acyclic) can be maintained with first-order updates. 相似文献
10.
O Ukkola MJ Savolainen PI Salmela K von Dickhoff T Kiema YA Kes?niemi 《Canadian Metallurgical Quarterly》1995,73(6):307-311
In the search for new risk factors for diabetic macroangiopathy the insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme gene was studied in 237 consecutive patients (125 men and 112 women) with non-insulin-dependent diabetes. The female population showed an excess of ischemic electrocardiographic changes or definite myocardial infarctions in the patients homozygous for the deletion [D/D; odds ratio (OR) 2.8; 95% confidence interval (CI) 1.4-5.3] and in the insertion/deletion heterozygotes (I/D; OR 1.8; CI 1.1-3.1) compared with the patients homozygous for the insertion (I/I). In the total series coronary heart disease, cerebrovascular disease, and claudication were more often observed in the patients with I/D (OR 1.5; CI 1.0-2.2) or the D/D genotype patients (OR 1.7; CI 1.1-2.6) than in those with the genotype I/I. The systolic blood pressure was lower in patients with genotype I/I (138 +/- 19 mmHg) than in those with the genotype I/D (149 +/- 22 mmHg) or D/D (150 +/- 21 mmHg; P < 0.02). The prevalence of hypertension and the median urinary albumin excretion rate also tended to be lowest in the I/I genotype patients. Multiple logistic analysis revealed that in women the angiotensin-converting enzyme D/D genotype is independently associated with coronary heart disease. Our findings suggest that variation at the angiotensin-converting enzyme gene locus is one of the factors involved in the predisposition of diabetic patients to the development of arterial disease and hypertension. 相似文献