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991.
In this work, the Nb-rich ternary eutectic in the Nb-Si-Cr system has been experimentally determined to be Nb-10.9Si-28.4Cr (in at. pct). The eutectic is composed of three main phases: Nb solid solution (Nbss), β-Cr2Nb, and Nb9(Si,Cr)5. The ternary eutectic microstructure remains stable for several hundred hours at a temperature up to 1473 K (1200 °C). At 1573 K (1300 °C) and above, the silicide phase Nb9(Si,Cr)5 decomposes into α-Nb5Si3, Nbss, and β-Cr2Nb. Under creep conditions at 1473 K (1200 °C), the alloy deforms by dislocation creep while the major creep resistance is provided by the silicide matrix. If the silicide phase is fragmented and, thus, its matrix character is destroyed by prior heat treatment [e.g., at 1773 K (1500 °C) for 100 hours], creep is mainly controlled by the Laves phase β-Cr2Nb, resulting in increased minimum strain rates. Compared to state of the art Ni-based superalloys, the creep resistance of this three-phase eutectic alloy is significantly higher.  相似文献   
992.
The authors investigated mechanisms involved in transformation of spatially extended targets into saccadic eye-movement vectors. Human subjects performed horizontal saccades to targets of varying diameter, which contained no conspicuous elements within the target shape. With increasing target size, express saccades and saccades with fast regular latencies decreased in frequency, whereas frequency of saccades with slow regular latencies increased. For all targets, saccade amplitude distributions showed a peak close to the geometric center of the targets. However, with large targets, increased scatter of saccade amplitudes and increased undershoot of the target center was observed. These effects may reflect distinct subprocesses involved in sensorimotor transformation to spatially extended targets, and may result from modulation of neuronal activity in the superior colliculus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
993.
994.
OBJECTIVES: To evaluate and to compare the bleeding patterns obtained with two regimens of hormone replacement therapy given to early postmenopausal women with asymptomatic uterine leiomyomas. METHODS: In this randomised prospective 1-year study 50 early postmenopausal women with one to four asymptomatic uterine leiomyomas were enrolled into two study-groups to take two regimens of hormone replacement therapy for 12 28-day cycles: (A) Tibolone, 2.5 mg/day; (B) conjugated equine estrogens (CEE), 0.625 mg/day plus medroxyprogesterone acetate (MPA), 5 mg/day. The bleeding patterns and the changes in uterine volume of the 47 outpatients who completed the study were evaluated and compared. RESULTS: Amenorrhea incidence was higher in group A (75.0% of the cycles) than in group B (65.6% of the cycles), while irregular bleeding and irregular spotting incidences were higher in group B (29.7 and 4.7% of the cycles, respectively) compared to group A (22.6 and 2.4% of the cycles, respectively). The mean bleeding and spotting lengths were not statistically different between patients in group A and those in group B. Finally, at the end of the study period transvaginal ultrasonography showed no significant change in leiomyoma size. CONCLUSIONS: The results demonstrate that, in early postmenopausal patients with asymptomatic uterine leiomyomas, Tibolone treatment seems to be preferable compared to CEE-MPA continuous combined treatment in relation to the lesser occurrence of irregular bleeding. Furthermore, neither Tibolone nor CEE-MPA therapy, at the doses used here, promote fibroid growth.  相似文献   
995.
We charted daily variations in intrusive thoughts to gain access to adult age differences in affective reactivity to daily stressors. On 100 days, 101 younger and 103 older adults reported stressors, intrusive thoughts, and negative affect. Although increments in intrusive thoughts were similar in both age groups on days with stressors, older adults' negative affect increased less than younger adults' on such days. In addition, (a) levels of intrusive thoughts and negative affect across study time were positively associated; (b) days with increased thoughts were days with increased negative affect; and (c) experiencing above-average intrusive thoughts about stressors strengthened affective reactions to stress. Relative to younger adults, all three associations were reduced in older adults. We tentatively conclude that normal aging dampens the stress-induced link between intrusive thoughts and affect. This dampening may contribute to preserved affective well-being and reduced affective reactivity to daily stress in old age. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
996.
Objective: To examine whether death anxiety underlies emotional reactions toward people with disabilities (PWDs). Study Design: In Study 1, participants were primed with thoughts of death, read a vignette describing a PWD, and completed a compassion scale. Study 2 replicated the design of Study 1 and also examined the impact of target ethnicity. Studies 3 and 4 assessed the impact of physical disability on death-related cognitions and on fear of personal death. Results: Men reacted to death primes by emotionally withdrawing from a PWD and reporting less compassion, whereas women exhibited more compassionate responses. These differences in compassion were reflected in the death-related cognitions and fears sparked by physical disability. Conclusions: The human need to manage the terror of death shapes emotional reactions toward PWDs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
997.
Subsurface two-phase flow in porous media often takes place in reservoirs with a high ratio between the associated lateral and vertical extent and the lateral and vertical flow time scales. This allows for a two-scale approach with effective quantities for two-dimensional horizontal flow equations obtained from reconstructed hydrostatic vertical pressure and saturation distributions. Here, we derive explicit expressions for the two dimensional constitutive relationships for a play-type hysteretic Brooks–Corey capillary pressure function with a pore-size distribution index of 2 and quadratic relative permeabilities. We obtain an explicit hysteretic parametrization for the upscaled capillary pressure function and the upscaled relative permeabilities. The size of the hysteresis loop depends on the ratio between buoyancy and the entry pressure, i.e. it scales with the reservoir height and the ratio between drainage and imbibition capillary pressure. We find that the scaling for the relative permeability is non-monotonic and hysteresis vanishes for both small and large reservoirs.  相似文献   
998.
Named entity recognition (NER) denotes the task to detect entities and their corresponding classes, such as person or location, in unstructured text data. For most applications, state of the art NER software is producing reasonable results. However, as a consequence of the methodological limitations and the well‐known pitfalls when analyzing natural language data, the NER results are likely to contain ambiguities. In this paper, we present an interactive NER ambiguity resolution technique, which enables users to create (post‐processing) rules for named entity recognition data based on the content and entity context of the analyzed documents. We specifically address the problem that in use‐cases where ambiguities are problematic, such as the attribution of fictional characters with traits, it is often unfeasible to train models on custom data to improve state of the art NER software. We derive an iterative process model for improving NER results, show an interactive NER ambiguity resolution prototype, illustrate our approach with contemporary literature, and discuss our work and future research.  相似文献   
999.
Complex technical systems, such as mechatronic systems, can exploit networking as well as the computational power available today to achieve an automatic improvement of the technical system performance at run-time through self-optimization. To realize this vision, appropriate means for the design of such self-optimizing mechatronic systems are required. Well-established techniques and tools for the modeling of cognitive behavior, reflective behavior, and control behavior exist. However, to really enable self-optimization and its full potential, these different aspects have to be safely integrated in a manner that remains comprehensible to the designer. In this article, we present how this required integration has been realized at the semantic level by extending the unified modeling language (UML), and at the tool level by integrating the CAE tool CAMeL and the CASE tool Fujaba real-time tool suite. The presented Mechatronic UML approach supports the design of verifiable, complex, reconfigurable mechatronic systems using the multi-agent system metaphor. This work was developed in the course of the Special Research Initiative 614—self-optimizing concepts and structures in mechanical engineering—University of Paderborn, and was published on its behalf and funded by the Deutsche Forschungsgemeinschaft. Sven Burmester, Oliver Oberschelp, Florian Klein and Peter Scheideler are members of the respective research group which left after the paper was submitted.  相似文献   
1000.
In this paper, we describe the application of the interactive theorem prover Coq to the security analysis of bytecode as used in Java. We provide a generic specification and proof of non-interference for bytecode languages using the Coq module system. We illustrate the use of this formalization by applying it to a small subset of Java bytecode. The emphasis of the paper is on modularity of a language formalization and its analysis in a machine proof. C. B. Jones  相似文献   
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