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排序方式: 共有4484条查询结果,搜索用时 15 毫秒
61.
Joris Vaillant Abderrahmane Kheddar Hervé Audren François Keith Stanislas Brossette Adrien Escande Karim Bouyarmane Kenji Kaneko Mitsuharu Morisawa Pierre Gergondet Eiichi Yoshida Suuji Kajita Fumio Kanehiro 《Autonomous Robots》2016,40(3):561-580
We describe the research and the integration methods we developed to make the HRP-2 humanoid robot climb vertical industrial-norm ladders. We use our multi-contact planner and multi-objective closed-loop control formulated as a QP (quadratic program). First, a set of contacts to climb the ladder is planned off-line (automatically or by the user). These contacts are provided as an input for a finite state machine. The latter builds supplementary tasks that account for geometric uncertainties and specific grasps procedures to be added to the QP controller. The latter provides instant desired states in terms of joint accelerations and contact forces to be tracked by the embedded low-level motor controllers. Our trials revealed that hardware changes are necessary, and parts of software must be made more robust. Yet, we confirmed that HRP-2 has the kinematic and power capabilities to climb real industrial ladders, such as those found in nuclear power plants and large scale manufacturing factories (e.g. aircraft, shipyard) and construction sites. 相似文献
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With the advent of intelligent computer aided design systems, companies such as Boeing are embarking on an era in which core competitive engineering knowledge and design rationale is being encoded in software systems. The promise of this technology is that this knowledge can be leveraged across many different designs, product families, and even different uses (e.g., generative process planning for manufacturing). The current state of the practice attempts to achieve this goal through the reuse of software components. A fundamental problem with this approach to knowledge sharing and reuse is that what we are trying to reuse is software—the end artifact in a long and complicated process that goes from requirement specifications, through a process of design, to implementations. Knowledge sharing and reuse can not easily and uniformly occur at the software level. So what can be done as an alternative? This paper describes a theory, methodology, language, and tool for the semi-automatic development and maintenance of engineering software from requirement specifications. In essence, this paradigm for software development and maintenance is one that explicitly captures requirement specifications, designs, implementations, and the refinement processes that lead from requirements all the way down to software. By recording this entire refinement history, we stand a better chance of leveraging knowledge for different uses. 相似文献
64.
The primary aims of this study were to establish a client injury baseline for the New Zealand adventure tourism and adventure sport sector, and to examine patterns and trends in claims for injury during participation in adventure activities. Content analysis of narrative text data for compensated injuries occurring in a place for recreation and sport over a 12-month period produced over 15,000 cases involving adventure tourism and adventure sport. As found in previous studies in New Zealand, highest claim counts were observed for activities that are often undertaken independently, rather than commercially. Horse riding, tramping, surfing and mountain biking were found to have highest claim counts, while hang gliding/paragliding/parasailing and jet boating injuries had highest claim costs, suggesting greatest injury severity. Highest claim incidence was observed for horse riding, with female claimants over-represented for this activity. Younger male claimants comprised the largest proportion of adventure injuries, and falls were the most common injury mechanism. 相似文献
65.
Assessing the quality of use case descriptions 总被引:1,自引:0,他引:1
66.
Modelling and Simulation of Machining Processes 总被引:1,自引:0,他引:1
67.
Toxicoproteomics is the use of proteomic technologies to better understand environmental and genetic factors, toxic mechanisms, and modes of action in response to acute exposure to toxicants and in the long-term development of diseases caused or influenced by these exposures. Use of toxicoproteomic technologies to identify key biochemical pathways, mechanisms, and biomarkers of exposure and toxicity will decrease the uncertainties that are associated with human health risk assessments. This review provides an overview of toxicoproteomics from human health risk assessment perspectives. Key toxicoproteomic technologies such as 2-D gel-based proteomic methods and toxicoproteomic approaches are described, and examples of applications of these technologies and methodologies in the risk assessment context are presented. The discussion includes a focus on challenges and future directions. 相似文献
68.
C. V. Owen D. Cheong O. Buck T. E. Scott 《Metallurgical and Materials Transactions A》1984,15(1):147-153
Mechanical properties of V-Nb alloys were investigated from 78 to about 300 K. The effects of alloying composition on the
yield and flow stress are consistent with a hardening model due to the “misfit”" of one element in the matrix of the other.
Additions of up to about 0.6 at. pct of hydrogen have a moderate strengthening effect on the yield stress of high vanadium
alloys, but relatively little effect on the high niobium alloys. Little or no effect of adding hydrogen to any of the alloys
was observed for the strain hardening coefficient. High Nb alloys were found to be much less embrittled by small additions
of hydrogen than were high V alloys. In addition, the failure of severely embrittled alloys was found to be initiated intergranularly
by impingement of mechanical twins on grain boundaries. It is speculated that the grain boundaries may be enriched hydrogen. 相似文献
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