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71.
A great number of complex electronic devices are now part of our everyday lives. While many of us learn to handle these products by trial and error; others, especially older users with little experience in using electronic devices, need support. In order to allow the user maximum flexibility in terms of learning time and location, a training programme is presented which is implemented as part of the software embedded in the product itself. Particular focus is placed on the effect of adaptive training on learning. In this study, the training versions differed in their ability to adjust their complexity to the user's experience (adaptive user interface complexity) and their capability to support the learner by prompting them during the learning process (adaptive training advice). The results show that the adjustment of complexity had a positive effect on users’ experience: elderly users who trained with an adaptive interface were more successful in learning to use a mobile phone. Adaptive training advice, however, was found to have no significant effects on learners’ success and reduced their self-efficacy. This work offers guidelines on how to design integrated training applications for electronic devices that successfully help elderly users with little prior experience.  相似文献   
72.
BerlinMOD: a benchmark for moving object databases   总被引:2,自引:0,他引:2  
This document presents a method to design scalable and representative moving object data (MOD) and two sets of queries for benchmarking spatio-temporal DBMS. Instead of programming a dedicated generator software, we use the existing Secondo DBMS to create benchmark data. The benchmark is based on a simulation scenario, where the positions of a sample of vehicles are observed for an arbitrary period of time within the street network of Berlin. We demonstrate the data generator’s extensibility by showing how to achieve more natural movement generation patterns, and how to disturb the vehicles’ positions to create noisy data. As an application and for reference, we also present first benchmarking results for the Secondo DBMS. Whereas the benchmark focuses on range queries, we demonstrate its ability to incorporate new future classes of queries by presenting a preliminary extension handling various nearest neighbour queries. Such a benchmark is useful in several ways: It provides well-defined data sets and queries for experimental evaluations; it simplifies experimental repeatability; it emphasizes the development of complete systems; it points out weaknesses in existing systems motivating further research. Moreover, the BerlinMOD benchmark allows one to compare different representations of the same moving objects.  相似文献   
73.
Real-time crowd motion planning requires fast, realistic methods for path planning as well as obstacle avoidance. In a previous work (Morini et al. in Cyberworlds International Conference, pp. 144–151, 2007), we introduced a hybrid architecture to handle real-time motion planning of thousands of pedestrians. In this article, we present an extended version of our architecture, introducing two new features: an improved short-term collision avoidance algorithm, and simple efficient group behavior for crowds. Our approach allows the use of several motion planning algorithms of different precision for regions of varied interest. Pedestrian motion continuity is ensured when switching between such algorithms. To assess our architecture, several performance tests have been conducted, as well as a subjective test demonstrating the impact of using groups. Our results show that the architecture can plan motion in real time for several thousands of characters.
Daniel ThalmannEmail:
  相似文献   
74.
    
Zusammenfassung Anaerobe Sporenbildner können Lebensmittelvergiftungen auslösen. In der Mehrzahl der Fälle werden these durchClostridium (Cl.) perfringens Typ A-Stämme verursacht. Neben der Kontamination der Ausgangssubstrate (z. B. Fleisch oder Milch) können Zusätze wie Gewurze und Fleischextrakte die Quelle sein. Meist werden nur geringe Clostridien-Keimzahlen, d. h. his etwa 102 Zellen pro g angetroffen. Die quantitativen Daten sind bisher noch lückenhaft. Deshalb werden 115 handelsübliche Produkte von Gewürzen (n = 70), Fleischextrakten (n = 15) und Instantprodukten (n = 30) untersucht. Die Ermittlung niedriger Keimzahlen (< 103/g) erfolgte mittels der MPN-Technik (Most Probable Number). Zur Erfassung höherer Clostridien-Keimzahlen (> 103/g) wurde ein Plattenkultivierungs-Verfahren entwickelt. Der Anteil mesophiler sulfitreduzierender Clostridien-Sporen wurde mittels der Gußplattentechnik mit Überschichtung ermittelt. Von handelsüblichen Gewürzproben waren Clostridien-positiv 21 von 70, von Instantprodukten 7 von 30 und von Fleischextrakten 12 von 15. Die Keimzahlwerte lagen zwischen 3 × 100 und 103 Zellen pro g, bei der Mehrzahl der Proben (2/3) im Bereich von 101 his 102 pro g. In sechs Fällen konnten über 103 Clostridien ermittelt werden. Es handelte sich bei den Isolaten überwiegend umCl. perfringens (46 von 73). Lediglich bei Fleischextrakten dominierten andere Species. Von 23 überprüftenCl. perfringens-Stämmen waren 3 hitzestabil. Im Rahmen eines quantitativen Modellversuchs (Provokationsversuch) konnte in einem gelösten Fleischextrakt eine Vermehrung eines geringgradigen Befalls (< 101) vonCl. perfringens auf 107/ml bereits nach 24 h nachgewiesen werden. Handelsübliche Gewurze und Fleischextrakte sowie auch Instantnahrungsmittel erfordern bei der küchentechnischen Behandlung der Lebensmittel die notwendige Beachtung, damit nicht Clostridienanreicherungen zu Lebensmittelvergiftungen führen.
Anaerobic spore-formers in commercial spices and ingredients for instant foods
Summary Anaerobic spore-formers can cause food intoxication.Clostridium (Cl.) perfringens type-A strains are mainly involved. In addition to the original contamination of food, e.g., meat or milk, ingredients such as spices or meat extracts are the main source and low numbers of clostridia are present (i.e., up to 102 cells/g). At present, information about the quantitative ecology of clostridia is incomplete; therefore 115 commercial food products were investigated (spices:n=70, meat extracts:n=15, instant foods:n=30). For the detection of low numbers of clostridia (< 103/g), the most probable number (MPN) technique was used. For the detection of higher numbers (> 103/g) a cultivation method in solid media was developed. The mesophilic sulphite-reducing clostridia spores were detected by the pour-plating method with overlayer. Twenty-one of the 70 commercial spices, 7 of the 30 specimen of instant food and 12 of the 15 meat extracts were clostridia-positive. The low counts ranged between 3 × 100 and 103 cells/g, in most cases (2/3) in the range 101/102/g. Only in 6 cases were more than 103 clostridia/g detected. Most of those isolated were identified asCl. perfringens (46 of 73 isolates). Only in meat extracts did clostridia species other thanCl. perfringens strains predominate. Three of the 23Cl. perfringens strains proved to be heat-resistant. A hydrated meat extract originally contaminated with low numbers was tested in a pilot study for the enrichment of clostridia. This extract showed an increase of up to 107 cells/ml after a 24-h incubation period. Commercial spices, meat extracts, and instant food must be handled with care in the kitchen because an increase in the number of clostridia could lead to food intoxication.


Erweiterte and aktualisierte Vortragsfassung anläßlich des XXII. Wissenschaftlichen DGE-Kongresses am 28./29. März 1985 in München  相似文献   
75.
本文提出了一种优化模糊逻辑控制器的新方法。该方法的主要思想是自动地优化误差变化率的隶属度函数,因为这类录属度函数表征了速度的反馈。为此,首先定义了一族参数化的隶属度函数,然后,在系统的运行过程中利用Nelder-Mead单纯算法来优化这类隶属度函数,为了验证所提方法的有效法,报告了控制一非线性被控对象的阶跃与跟踪响应。  相似文献   
76.
We characterize the climatological features of the double inter-tropical convergence zones (DITCZs) over the western Indian Ocean during November–December by a synergistic analysis of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite (HOAPS III) data (1988–2005) and the National Aeronautics and Space Administration's (NASA's) A-Train data (2002–2009). We investigate rainfall, freshwater flux and cloud liquid water, cloud fraction and relative humidity over the DITCZs. In addition, the daily rainfall data from the Global Precipitation Climatology Project (GPCP) are used to document the DITCZs during the El Niño southern oscillation (ENSO) events. An analysis of the GPCP data shows that the DITCZs are clearly discernible during strong ENSO events (1997, 2002 and 2006), in sharp contrast to the DITCZs in the eastern Pacific Ocean, where they are absent during ENSOs. Further, these convergence zones on either side of the equator are of short duration, approximately 3–6 pentads during November and December. All satellite sensor data sets consistently capture the major features of DITCZs. As an accurate simulation of DITCZs in coupled global climate models remains a challenge, the results from the present study would provide a platform for evaluating these models.  相似文献   
77.
Computing surfaces invariant under subdivision   总被引:3,自引:0,他引:3  
In this paper, we propose a general subdivision algorithm for generating surfaces. The algorithm has as motivation our earlier work on the design of free form curves where similar ideas were investigated. Here we describe some properties of uniform refinement algorithms for surface generation. A detail analysis of their properties will be given later by one of us.  相似文献   
78.
We describe a vectorized algorithm for an interval arithmetic Newton-like method for a class of systems of nonlinear equations arising from discretizations of nonlinear elliptic PDE. This method converges to a solution under relatively weak conditions. It is founded on a combination of a Newton-like interval method and interval arithmetic ‘fast’ direct solver. In the present paper we focus our attention on aspects of the vectorization, in particular that of a simulation of an interval arithmetic and that of the direct solver.  相似文献   
79.
80.
The genetic make-up of living systems especially of isolated cells can be altered by a variety of methods including chemical or light-induced mutation. More modern procedures are the in vitro recombination of nucleic acids and the cell-cell fusion. The new methods are especially useful to reprogram microorganisms to produce valuable proteins or other natural products in excess quantties. In the following we will elucidate the importance of the new techniques by describing the bacterial production of glucose dehydrogenase, of the proteinase inhibitor stefin A and by outlining the methods and promisses of substractive cloning. Although the economic value of genetic engineering techniques still awaits justification, the importance of the methodology for basic biological research is well documented.  相似文献   
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