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991.
Whilst there have been many studies indicating links between anthropogenic contaminants and reproductive abnormalities in wildlife, very few studies have addressed the effects that might be occurring at the population level. In this study we aimed to assess the mid and long-term population effects of different levels of intersexuality in an amphipod species, Echinogammarus marinus. This aim was achieved by modelling the dynamics of a population of E. marinus with possible contaminant or parasite induced intersexuality over a ten-year period. The model considers five population groups: juveniles, males, immature females, adult normal females and adult intersex females. The costs associated with intersexuality in E. marinus were incorporated into the model using data from previous studies. The basic run of the model considers a population with 50% normal males and 50% normal females, which are prevalent in some field populations of E. marinus. Results of increasing proportions of intersex females were compared with the basic run and suggest that if intersex females occur at the expense of normal females, the population collapses after approximately 6 and 2.3 years when intersex females account for 5 and 10% of the population, respectively. Conversely, the population density increases exponentially if intersex females occur at the expense of males. However, if the number of intersex females reaches approximately (1/2) of the number of normal females, even if the percent of males in the population is as low as 27% (e.g. 27% males, 45% normal females, 28% intersex females), the population will be extinguished within 10 years. These results suggest a selective advantage in female-biased sex ratios in populations with significant levels of intersexuality, up to a certain threshold, where the increase in the total number of females seems to compensate the lower recruitment rates of intersex individuals, namely, intersex females. Furthermore, even in this scenario, if the recruitment rate of normal females is negatively affected, the population survivorship may be compromised. Modelling the effects of intersexuality in this manner should aid both environmental toxicologists and ecologists in predicting the population level effects of endocrine disrupting chemicals and/or parasites. 相似文献
992.
Philippe Moret Walter Binder Alex Villazón Danilo Ansaloni Abbas Heydarnoori 《Software》2010,40(9):825-847
Calling context profiling is an important technique for analyzing the performance of object‐oriented software with complex inter‐procedural control flow. The Calling Context Tree (CCT) is a common data structure that stores dynamic metrics, such as CPU time, separately for each calling context. As CCTs may comprise millions of nodes, there is a need for a condensed visualization that eases the localization of performance bottlenecks. In this article, we discuss Calling Context Ring Charts (CCRCs), a compact visualization for CCTs, where callee methods are represented in ring segments surrounding the caller's ring segment. In order to reveal hot methods, their callers, and callees, the ring segments can be sized according to a chosen dynamic metric. We describe two case studies where CCRCs help us to detect and fix performance problems in applications. A performance evaluation also confirms that our implementation can efficiently handle large CCTs. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
993.
The globally integrated contemporary business environment has prompted new challenges to database architectures in order to enable organizations to improve database applications performance, scalability, reliability and data privacy in adapting to the evolving nature of business. Although a number of distributed database architectures are available for choice, there is a lack of an in‐depth understanding of the performance characteristics of these database architectures in a comparison way. In this paper, we report a performance study of three typical (centralized, partitioned and replicated) database architectures. We used the TPC‐C as the evaluation benchmark to simulate a contemporary business environment, and a commercially available database management system that supports the three architectures. We compared the performance of the partitioned and replicated architectures against the centralized database, which results in some interesting observations and practical experience. The findings and the practice presented in this paper provide useful information and experience for the enterprise architects and database administrators in determining the appropriate database architecture in moving from centralized to distributed environments. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
994.
Performance evaluation of embedded software is essential in an early development phase so as to ensure that the software will run on the embedded device's limited computing resources. The prevailing approaches either require the deployment of the software on the embedded target, which can be tedious and may be impossible in an early development phase, or rely on simulation, which can be very slow. In this article, we introduce a customizable cross‐profiling framework for embedded Java processors, including processors featuring a method cache. The developer profiles the embedded software in the host environment, completely decoupled from the target system, on any standard Java virtual machine, but the generated profiles represent the execution time metric of the target system. Our cross‐profiling framework is based on bytecode instrumentation. We identify several pointcuts in the execution of bytecode that need to be instrumented in order to estimate the CPU cycle consumption on the target system. An evaluation using the JOP embedded Java processor as target confirms that our approach reconciles high profile accuracy with moderate overhead. Our cross‐profiling framework also enables the performance evaluation of new processor architectures before they are implemented. As a case study, we explore the performance impact of various processor design choices and optimizations, such as different cache sizes or pipeline organizations, and come up with an improved processor design that yields speedups of up to 40% on standard Java benchmarks. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
995.
Friman Snchez Felipe Cabarcas Alex Ramirez Mateo Valero 《Concurrency and Computation》2011,23(17):2205-2219
Biological sequence comparison is one of the most important tasks in Bioinformatics. Owing to the fast growth of databases that contain biological information, sequence comparison represents an important challenge for high‐performance computing, especially when very long sequences are compared, i.e. the complete genome of several organisms. The Smith–Waterman (SW) algorithm is an exact method based on dynamic programming to quantify local similarity between sequences. The inherent large parallelism of the algorithm makes it ideal for architectures supporting multiple dimensions of parallelism (TLP, DLP and ILP). Concurrently, there is a paradigm shift towards chip multiprocessors in computer architecture, which offer a huge amount of potential performance that can only be exploited efficiently if applications are effectively mapped and parallelized. In this work, we analyze how large‐scale biology sequence comparison takes advantage of the current and future multicore architectures. Our starting point is the performance analysis of the current multicore IBM Cell B.E. processor; we analyze two different SW implementations on the Cell B.E. Then, using simulation tools, we study the performance scalability when a many‐core architecture is used for performing long DNA sequence comparison. We investigate the efficient memory organization that delivers the maximum bandwidth with the minimum cost. Our results show that a heterogeneous architecture can be an efficient alternative to execute challenging bioinformatic workloads. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
996.
Abstract— With the rise of electrophoretic‐display media from several sources, the world is opening up for new uses of electronic displays. Where “immersive reading” used to be a task strictly reserved for paper, displays can now fulfill that role. Many challenges still remain, such as full‐color photograph‐like performance and video speeds. However, in view of recent accomplishments showing near‐video‐speed switching and potential for full color, after electrophoretic displays obtain a slice of the reading market, application of these developments will take us a significant step towards full‐color animated paper‐like displays. The developments that have led to the presence of electronic paper in the market today will be described, and developments that are about to happen will be discussed. 相似文献
997.
This paper presents an Artificial Immune System (AIS)-based model for cooperative control of multiagent systems. This cooperative control model describes collective behaviors of autonomous agents, known as the AIS agents that are exemplified by the regulated activities performed by individual agents under the computation paradigm of Artificial Immune System. The regulations and emergence of agent behaviors are derived from the immune threshold measures that determine those activities performed by the AIS agents at an individual level. These threshold measures together with the collective behavioral model defined the cooperative control of the AIS-based control framework under which AIS agents behave and act strategically according to the changing environment. The cooperative control model is presented under the three domains, namely exploration, achievement and cooperation domains where AIS agents operate. In this research, we implemented the proposed cooperative control model with a case study of automated material handling with a group of AIS agents that cooperate to achieve the defined tasks. 相似文献
998.
Kentsis A Monigatti F Dorff K Campagne F Bachur R Steen H 《Proteomics. Clinical applications》2009,3(9):1052-1061
Knowledge of the biologically relevant components of human tissues has enabled the invention of numerous clinically useful diagnostic tests, as well as non-invasive ways of monitoring disease and its response to treatment. Recent use of advanced MS-based proteomics revealed that the composition of human urine is more complex than anticipated. Here, we extend the current characterization of the human urinary proteome by extensively fractionating urine using ultra-centrifugation, gel electrophoresis, ion exchange and reverse-phase chromatography, effectively reducing mixture complexity while minimizing loss of material. By using high-accuracy mass measurements of the linear ion trap-Orbitrap mass spectrometer and LC-MS/MS of peptides generated from such extensively fractionated specimens, we identified 2362 proteins in routinely collected individual urine specimens, including more than 1000 proteins not described in previous studies. Many of these are biomedically significant molecules, including glomerularly filtered cytokines and shed cell surface molecules, as well as renally and urogenitally produced transporters and structural proteins. Annotation of the identified proteome reveals distinct patterns of enrichment, consistent with previously described specific physiologic mechanisms, including 336 proteins that appear to be expressed by a variety of distal organs and glomerularly filtered from serum. Comparison of the proteomes identified from 12 individual specimens revealed a subset of generally invariant proteins, as well as individually variable ones, suggesting that our approach may be used to study individual differences in age, physiologic state and clinical condition. Consistent with this, annotation of the identified proteome by using machine learning and text mining exposed possible associations with 27 common and more than 500 rare human diseases, establishing a widely useful resource for the study of human pathophysiology and biomarker discovery. 相似文献
999.
Alex Pavlak 《Systems Engineering》2015,18(3):241-252
Although small emission reductions are easy, large reductions will demand engineered systems. Classical system engineering (SE) development begins with ultimate goals such as big (>90%) reductions in greenhouse gas emissions. The first SE phase, concept development, consists of system tradeoffs to clarify feasible concepts and focus development efforts. These system studies begin with simple concept models and then build complexity in stages to elucidate principles, interfaces, and requirements. The concept definition phase is classically concluded with a critical review followed by a management decision, a value choice. Overall, classical SE starts with the ultimate goals, then works backward to allocate requirements and figure out how to get there from here. Contrast this with today's forward migration approach. Migrating forward without a clear path to an ultimate goal runs the risk of dead end development, stuck with concepts that cannot reach the ultimate goal. This paper illustrates concept development needs for both wind systems and for civilian nuclear power. 相似文献
1000.
This paper reports about our experience in designing and developing Chameleon, a highly portable and adaptable group communication framework for smartphones. Chameleon owes its level of portability to several design choices, including the following: (i) a layered architecture, where the headers of each layer have a standard XML‐based format, enabling automatic, error‐resistant generation of efficient serialization code in any platform; (ii) reliance only on the J2ME library, which serves as least common denominator for Java dialects and facilitates automatic translation to.NET; (iii) having flexible membership models; and (iv) supporting multiple concurrent protocol stacks.Through a single codebase, Chameleon is currently available as an open‐source project for J2ME, J2SE, Android,.NET CF, and.NET. Chameleon is easily extendable and is bundled with tools, configurations, and third‐party code tuned in a way that lifts some of the burden normally associated with multiplatform development for smartphones. Both the header generation from XML and automatic translation to.NET features of Chameleon are readily available to any application that is based on it. Chameleon's threading model separates between execution of internal layers and application's code and by that protects one from the other. As we describe in the paper, it simplifies layers' development and allows the protocol stack to easily block application calls when this is required by internal algorithms. Additionally, this model simplifies testing, and an extensive testing framework is supplied along with Chameleon, which is also usable for testing of application‐specific layers. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献