全文获取类型
收费全文 | 4685篇 |
免费 | 284篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 58篇 |
综合类 | 8篇 |
化学工业 | 924篇 |
金属工艺 | 55篇 |
机械仪表 | 74篇 |
建筑科学 | 176篇 |
矿业工程 | 5篇 |
能源动力 | 159篇 |
轻工业 | 326篇 |
水利工程 | 54篇 |
石油天然气 | 35篇 |
无线电 | 391篇 |
一般工业技术 | 1188篇 |
冶金工业 | 586篇 |
原子能技术 | 13篇 |
自动化技术 | 925篇 |
出版年
2024年 | 13篇 |
2023年 | 59篇 |
2022年 | 97篇 |
2021年 | 140篇 |
2020年 | 113篇 |
2019年 | 123篇 |
2018年 | 126篇 |
2017年 | 136篇 |
2016年 | 162篇 |
2015年 | 134篇 |
2014年 | 188篇 |
2013年 | 331篇 |
2012年 | 309篇 |
2011年 | 384篇 |
2010年 | 295篇 |
2009年 | 281篇 |
2008年 | 306篇 |
2007年 | 243篇 |
2006年 | 214篇 |
2005年 | 185篇 |
2004年 | 152篇 |
2003年 | 133篇 |
2002年 | 128篇 |
2001年 | 65篇 |
2000年 | 60篇 |
1999年 | 59篇 |
1998年 | 46篇 |
1997年 | 43篇 |
1996年 | 47篇 |
1995年 | 40篇 |
1994年 | 38篇 |
1993年 | 35篇 |
1992年 | 37篇 |
1991年 | 20篇 |
1990年 | 26篇 |
1989年 | 13篇 |
1988年 | 13篇 |
1987年 | 27篇 |
1986年 | 16篇 |
1985年 | 28篇 |
1984年 | 14篇 |
1983年 | 6篇 |
1982年 | 12篇 |
1981年 | 20篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1975年 | 7篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1964年 | 4篇 |
排序方式: 共有4977条查询结果,搜索用时 10 毫秒
71.
Identifying and integrating patient and caregiver perspectives for clinical practice guidelines on the screening and management of infectious microorganisms in hemodialysis units 下载免费PDF全文
Hilary M. Miller Allison Tong David J. Tunnicliffe Denise Campbell Jule Pinter Robert J. Commons Eugene Athan Jonathan C. Craig Nicole Gilroy Julianne Green Belinda Henderson Martin Howell Rhonda L. Stuart Carolyn van Eps Muh Geot Wong Janak de Zoysa Meg J. Jardine 《Hemodialysis international. International Symposium on Home Hemodialysis》2017,21(2):213-223
72.
Field‐Effect Transistors: Integration of Organic Electrochemical and Field‐Effect Transistors for Ultraflexible,High Temporal Resolution Electrophysiology Arrays (Adv. Mater. 44/2016) 下载免费PDF全文
73.
Huibiao Zhu Jifeng He Jing Li Jonathan P. Bowen 《Innovations in Systems and Software Engineering》2011,7(3):209-224
Web services have become more and more important in these years, and BPEL4WS (BPEL) is a de facto standard for the web service
composition and orchestration. It contains several distinct features, including the scope-based compensation and fault handling
mechanism. We have considered the operational semantics and denotational semantics for BPEL, where a set of algebraic laws
can be achieved via these two models, respectively. In this paper, we consider the inverse work, deriving the operational
semantics and denotational semantics from algebraic semantics for BPEL. In our model, we introduce four types of typical programs,
by which every program can be expressed as the summation of these four types. Based on the algebraic semantics, the strategy
for deriving the operational semantics is provided and a transition system is derived by strict proof. This can be considered
as the soundness exploration for the operational semantics based on the algebraic semantics. Further, the equivalence between
the derivation strategy and the derived transition system is explored, which can be considered as the completeness of the
operational semantics. Finally, the derivation of the denotational semantics from algebraic semantics is explored, which can
support to reason about more program properties easily. 相似文献
74.
Automatic metro map layout using multicriteria optimization 总被引:1,自引:0,他引:1
Stott J Rodgers P Martínez-Ovando JC Walker SG 《IEEE transactions on visualization and computer graphics》2011,17(1):101-114
This paper describes an automatic mechanism for drawing metro maps. We apply multicriteria optimization to find effective placement of stations with a good line layout and to label the map unambiguously. A number of metrics are defined, which are used in a weighted sum to find a fitness value for a layout of the map. A hill climbing optimizer is used to reduce the fitness value, and find improved map layouts. To avoid local minima, we apply clustering techniques to the map-the hill climber moves both stations and clusters when finding improved layouts. We show the method applied to a number of metro maps, and describe an empirical study that provides some quantitative evidence that automatically-drawn metro maps can help users to find routes more efficiently than either published maps or undistorted maps. Moreover, we have found that, in these cases, study subjects indicate a preference for automatically-drawn maps over the alternatives. 相似文献
75.
Livingston MA Decker JW 《IEEE transactions on visualization and computer graphics》2011,17(12):2053-2062
Multi-valued data sets are increasingly common, with the number of dimensions growing. A number of multi-variate visualization techniques have been presented to display such data. However, evaluating the utility of such techniques for general data sets remains difficult. Thus most techniques are studied on only one data set. Another criticism that could be levied against previous evaluations of multi-variate visualizations is that the task doesn't require the presence of multiple variables. At the same time, the taxonomy of tasks that users may perform visually is extensive. We designed a task, trend localization, that required comparison of multiple data values in a multi-variate visualization. We then conducted a user study with this task, evaluating five multivariate visualization techniques from the literature (Brush Strokes, Data-Driven Spots, Oriented Slivers, Color Blending, Dimensional Stacking) and juxtaposed grayscale maps. We report the results and discuss the implications for both the techniques and the task. 相似文献
76.
College students (n = 140) were examined to test whether sensation seeking and perceived stress would predict abuse of the Internet. Previous studies have found that disinhibition, boredom susceptibility, and total sensation seeking scores were related to Internet abuse ( 9 and 30). Because stress has been documented to have a negative effect on students ( Pierceall & Keim, 2007), and may be linked to Internet use ( Lavoie & Pychyl, 2001), it was tested as a possible predictor of Internet abuse. This study also analyzed abuse of the Internet for sexual purposes, because sexuality is prevalent online, and college students are in an age of sexual exploration. Results of stepwise regression analyses revealed that disinhibition and total perceived stress were predictive of Internet abuse for sexual purposes, and perceived hopelessness and boredom susceptibility were predictive of Internet abuse for non-sexual purposes. Implications for students and Internet abuse are discussed. 相似文献
77.
Programmability is an increasingly important barrier to the deployment of multi-robot systems, as no prior approach allows
routine composition and reuse of general aggregate behaviors. The Proto spatial computing language, however, already provides
this sort of aggregate behavior programming for non-mobile systems using an abstraction of the network as a continuous-space-filling
device. We extend this abstraction to mobile systems and show that Proto can be applied to multi-robot systems with an actuator
that turns a vector field into device motion. Proto programs operate on fields of values over an abstract device called the
amorphous medium and can be joined together using functional composition. These programs are then automatically transformed for execution
by individual devices, producing an approximation of the specified continuous-space behavior. We are thus able to build up
a library of simple swarm behaviors, and to compose them together into highly succinct programs that predictably produce the
desired complex swarm behaviors, as demonstrated in simulation and on a group of 40 iRobot SwarmBots. 相似文献
78.
Component software architectures offer an alternative approach for building large, complex hydrologic modeling systems. In contrast to more traditional software paradigms (i.e. procedural or object-oriented approaches), using component-based approaches allows individuals to construct autonomous modeling units that can be linked together through shared boundary conditions during a simulation run. One of the challenges in component-based modeling is designing a simple yet robust means for authoring model components. We address this challenge by presenting an approach for efficiently creating standards-based, process-level hydrologic modeling components. Using this approach, a hydrologic process is implemented as a modeling component by (1) authoring a configuration file that defines the properties of the component and (2) creating a class with three methods that define the pre-run, runtime, and post-run behavior of the modeling component. We present the design and implementation of this approach, which we call the Simple Model Wrapper (SMW), and demonstrate how it can be applied to create an Open Modeling Interface (OpenMI)-compliant modeling component for a basic hydrologic process. 相似文献
79.
Amir Yair Danilov Claudiu Dolev Danny Kirsch Jonathan Lane John Nita-Rotaru Cristina Olsen Josh Zage David 《Dependable and Secure Computing, IEEE Transactions on》2010,7(1):80-93
This paper presents the first hierarchical Byzantine fault-tolerant replication architecture suitable to systems that span multiple wide-area sites. The architecture confines the effects of any malicious replica to its local site, reduces message complexity of wide-area communication, and allows read-only queries to be performed locally within a site for the price of additional standard hardware. We present proofs that our algorithm provides safety and liveness properties. A prototype implementation is evaluated over several network topologies and is compared with a flat Byzantine fault-tolerant approach. The experimental results show considerable improvement over flat Byzantine replication algorithms, bringing the performance of Byzantine replication closer to existing benign fault-tolerant replication techniques over wide area networks. 相似文献
80.
Huibiao Zhu Jifeng He Jing Li Geguang Pu Jonathan P. Bowen 《Innovations in Systems and Software Engineering》2010,6(4):283-298
Web Services have become more and more important in these years, and BPEL4WS (BPEL) is a de facto standard for the web service
composition and orchestration. It contains several distinct features, including the scope-based compensation and fault handling
mechanism. The denotational semantics and operational semantics have been explored for BPEL. The two semantic models should
be consistent. This paper considers the linking of these two semantics. Our approach is to derive the denotational semantics
from operational semantics for BPEL, which aims for the consistency of the two models. Moreover, the derivation can be applied
in exploring the program equivalence easily, especially for parallel programs. 相似文献