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221.
The discovery of informative itemsets is a fundamental building block in data analytics and information retrieval. While the problem has been widely studied, only few solutions scale. This is particularly the case when (1) the data set is massive, calling for large-scale distribution, and/or (2) the length k of the informative itemset to be discovered is high. In this paper, we address the problem of parallel mining of maximally informative k-itemsets (miki) based on joint entropy. We propose PHIKS (Parallel Highly Informative \(\underline{K}\)-ItemSet), a highly scalable, parallel miki mining algorithm. PHIKS renders the mining process of large-scale databases (up to terabytes of data) succinct and effective. Its mining process is made up of only two efficient parallel jobs. With PHIKS, we provide a set of significant optimizations for calculating the joint entropies of miki having different sizes, which drastically reduces the execution time, the communication cost and the energy consumption, in a distributed computational platform. PHIKS has been extensively evaluated using massive real-world data sets. Our experimental results confirm the effectiveness of our proposal by the significant scale-up obtained with high itemsets length and over very large databases.  相似文献   
222.
The success of the river rehabilitation process depends not only on the intervention project but also on the attention given to the monitoring and evaluation of the implemented measures. In spite of the recent efforts on the quantification and sharing of interventions’ results, there are still very few written records documenting that information. The present work proposes a monitoring methodology for riverbanks’ stabilization interventions by comparing the results obtained by monitoring the implemented technical solutions with the corresponding theoretical time-expected performance. For this purpose, two case studies located in the south of Portugal were analysed. For each of those case studies, the dominant factors that influenced the temporal evolution of the observed outcomes were assessed. It was possible to verify that, depending on the implemented technical solution type and on the specific characteristics of the intervention site, monitoring actions can be fundamental to achieve the expected technical and ecological efficiency, namely when bioengineering technical solutions are involved. This work led to the development of a database structure that will gather information on the application of the proposed methodology over time and that shall be improved with the analysis of the behaviour of other riverbanks’ stabilization interventions. The development of this database will surely contribute to enable choosing and applying the most adequate riverbank protection solutions.  相似文献   
223.
巴西视点     
在有关城市迅速发展的辩论中存在许多说法,特别是对于发展中国家和转型中的国家而言。在这些说法中,有两个在很大程度上是公认的。  相似文献   
224.
A prerequisite of any coordinated research activity is a comparison of the current status of research in the countries in question and a means to monitor the progress in particular sectors. Analysis of indicators of research in different countries allows comparison of the research undertaken. This paper compares input and output indicators of public research in hydrogen and fuel cells (H&FC) both within Europe and between Europe and the US, Japan and China. Overall the combined public H&FC research budget for the EU25 countries, associated states and accession countries was €276M276M in 2005, slightly higher than in the US, but lower than in Japan. An analysis of research outputs indicates that European competitive advantage is being lost to China and the US. Greater and more effective research coordination as well as more targeted allocation of research funds are proposed as potential solutions.  相似文献   
225.
CLEC12A is a myeloid inhibitory receptor that negatively regulates inflammation in mouse models of autoimmune and autoinflammatory arthritis. Reduced CLEC12A expression enhances myeloid cell activation and inflammation in CLEC12A knock-out mice with collagen antibody-induced or gout-like arthritis. Similarly to other C-type lectin receptors, CLEC12A harbours a stalk domain between its ligand binding and transmembrane domains. While it is presumed that the cysteines in the stalk domain have multimerisation properties, their role in CLEC12A expression and/or signaling remain unknown. We thus used site-directed mutagenesis to determine whether the stalk domain cysteines play a role in CLEC12A expression, internalisation, oligomerisation, and/or signaling. Mutation of C118 blocks CLEC12A transport through the secretory pathway diminishing its cell-surface expression. In contrast, mutating C130 does not affect CLEC12A cell-surface expression but increases its oligomerisation, inducing ligand-independent phosphorylation of the receptor. Moreover, we provide evidence that CLEC12A dimerisation is regulated in a redox-dependent manner. We also show that antibody-induced CLEC12A cross-linking induces flotillin oligomerisation in insoluble membrane domains in which CLEC12A signals. Taken together, these data indicate that the stalk cysteines in CLEC12A differentially modulate this inhibitory receptor’s expression, oligomerisation and signaling, suggestive of the regulation of CLEC12A in a redox-dependent manner during inflammation.  相似文献   
226.
Joining shape-memory alloys (SMA) to other materials is strongly required in order to enlarge their fields of application. Fusion welding induces strong compositional and microstructural changes that significantly affect the shape-memory effect and the superelastic behavior of these alloys. The exothermic and in some cases self-propagating character of some nano-multilayer reactions is explored in this study as an alternative for joining SMA. To follow these very fast reactions, high brilliance sources, such as synchrotron radiation, are required. In situ high-resolution x-ray diffraction data, giving the phase evolution sequence with temperature of the Ni/Ti multilayer thin films under study, are presented. A correlation between the multilayer design and the tendency for the sequence of phase formation is established.  相似文献   
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229.
Intermetallic particles, Al3Ti and Al3Zr were formed in Al–5mass%Ti and Al–5mass%Zr alloys, respectively, by centrifugal casting, in order to create functionally graded materials (FGMs). At present, no information is available on the influence of the amount of intermetallics on the electrochemical properties of these alloys.In this paper, the corrosion resistance of Al/Al3Ti and Al/Al3Zr FGMs was investigated by open-circuit measurements, potentiodynamic polarization and electrochemical impedance spectroscopy. Results suggests that the corrosion resistance of the FGMs is affected by galvanic effects between the intermetallic particles and the metallic matrix. Lower centrifugal forces resulted in an improvement of the electrochemical properties.  相似文献   
230.
Comparison of resin beads and resin membranes for extracting soil phosphate   总被引:1,自引:0,他引:1  
Six Portuguese soils of varying P sorption capacity were incubated aerobically at 30° C without and with added P in order to give 0.1.mg P L–1 in the soil solution. Two methods of measuring extractable P were compared: (i) mixed-bed cation-anion-resin beads in bags and (ii) a simpler method with anion-resin membrane only. The bag method extracted about twice and 1.5 times as much as the strip method, respectively, without and with added P. The relationships were much closer after one extraction for 2 hours (r = 0.982, p < 0.01) instead of the cumulative extraction of 24 hours (r = 0.635,p > 0.05.). P recovery after incubation was inversely related to some soil properties as organic matter, buffer capacity, selective dissolution Al forms (Alox and Ald) and P sorption. It is suggested that the simpler resin membrane method is more adequate to assess P for many studies of P reaction with soil. A simpler incubation method was tried, consisting of incubation as a soil suspension in water at a high temperature (50° C). The results suggested that this method gave similar results to aerobic incubation, with the advantage that there was no need to measure the required and final water contents of incubated soil.  相似文献   
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