全文获取类型
收费全文 | 1434篇 |
免费 | 46篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 25篇 |
综合类 | 1篇 |
化学工业 | 409篇 |
金属工艺 | 16篇 |
机械仪表 | 25篇 |
建筑科学 | 33篇 |
矿业工程 | 7篇 |
能源动力 | 22篇 |
轻工业 | 67篇 |
水利工程 | 10篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 105篇 |
一般工业技术 | 252篇 |
冶金工业 | 240篇 |
原子能技术 | 11篇 |
自动化技术 | 259篇 |
出版年
2023年 | 11篇 |
2022年 | 38篇 |
2021年 | 29篇 |
2020年 | 17篇 |
2019年 | 18篇 |
2018年 | 23篇 |
2017年 | 24篇 |
2016年 | 26篇 |
2015年 | 19篇 |
2014年 | 34篇 |
2013年 | 100篇 |
2012年 | 61篇 |
2011年 | 70篇 |
2010年 | 46篇 |
2009年 | 50篇 |
2008年 | 34篇 |
2007年 | 30篇 |
2006年 | 55篇 |
2005年 | 48篇 |
2004年 | 51篇 |
2003年 | 50篇 |
2002年 | 36篇 |
2001年 | 19篇 |
2000年 | 22篇 |
1999年 | 16篇 |
1998年 | 20篇 |
1997年 | 20篇 |
1996年 | 24篇 |
1995年 | 16篇 |
1994年 | 20篇 |
1993年 | 16篇 |
1992年 | 24篇 |
1991年 | 11篇 |
1990年 | 14篇 |
1989年 | 19篇 |
1988年 | 20篇 |
1987年 | 12篇 |
1986年 | 17篇 |
1985年 | 15篇 |
1982年 | 19篇 |
1981年 | 13篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1978年 | 23篇 |
1977年 | 16篇 |
1976年 | 25篇 |
1975年 | 16篇 |
1974年 | 21篇 |
1973年 | 14篇 |
1970年 | 10篇 |
排序方式: 共有1484条查询结果,搜索用时 0 毫秒
41.
Zhen EY Berna MJ Jin Z Pritt ML Watson DE Ackermann BL Hale JE 《Proteomics. Clinical applications》2007,1(7):661-671
Heart fatty acid binding protein (Fabp3) is a cytosolic protein expressed primarily in heart, and to a lesser extent in skeletal muscle, brain, and kidney. During myocardial injury, the Fabp3 level in serum is elevated rapidly, making it an ideal early marker for myocardial infarction. In this study, an MS‐based selected reaction monitoring method (LC‐SRM) was developed for quantifying Fabp3 in rat serum. Fabp3 was enriched first through an immobilized antibody, and the protein was digested on beads directly. A marker peptide of Fabp3 was quantified using LC‐SRM with a stable isotope‐labeled peptide standard. For six quality control samples with Fabp3 ranging from 0.256 to 25 ng, the average recovery following the procedure was about 73%, and the precision (%CV) between replicates was less than 7%. The Fabp3 concentrations in rat serum peaked 1 h after isoproterenol treatment, and returned to baseline levels 24 h after the dose. Elevated Fabp3 levels were also detected in rats administered with a PPAR α/δ agonist, which has shown to cause skeletal muscle necrosis. Fabp3 can be used as a biomarker for both cardiac and skeletal necroses. The cross‐validation of the LC‐SRM method with an existing ELISA method is described. 相似文献
42.
This paper addresses the problem of aligning multiple sequences of noncoding RNA (ncRNA) genes. We approach this problem with the biologically motivated paradigm that scoring of ncRNA alignments should be based primarily on secondary structure rather than nucleotide conservation. We introduce a novel graph theoretic model (NLG) for analyzing algorithms based on this approach, prove that the RNA multiple alignment problem is NP-Complete in this model, and present a polynomial time algorithm that approximates the optimal structure of size S within a factor of O(log2S). 相似文献
43.
Polychronization: computation with spikes 总被引:10,自引:0,他引:10
Izhikevich EM 《Neural computation》2006,18(2):245-282
We present a minimal spiking network that can polychronize, that is, exhibit reproducible time-locked but not synchronous firing patterns with millisecond precision, as in synfire braids. The network consists of cortical spiking neurons with axonal conduction delays and spike-timing-dependent plasticity (STDP); a ready-to-use MATLAB code is included. It exhibits sleeplike oscillations, gamma (40 Hz) rhythms, conversion of firing rates to spike timings, and other interesting regimes. Due to the interplay between the delays and STDP, the spiking neurons spontaneously self-organize into groups and generate patterns of stereotypical polychronous activity. To our surprise, the number of coexisting polychronous groups far exceeds the number of neurons in the network, resulting in an unprecedented memory capacity of the system. We speculate on the significance of polychrony to the theory of neuronal group selection (TNGS, neural Darwinism), cognitive neural computations, binding and gamma rhythm, mechanisms of attention, and consciousness as "attention to memories." 相似文献
44.
Stochastic neural networks 总被引:2,自引:0,他引:2
Eugene Wong 《Algorithmica》1991,6(1):466-478
The first purpose of this paper is to present a class of algorithms for finding the global minimum of a continuous-variable function defined on a hypercube. These algorithms, based on both diffusion processes and simulated annealing, are implementable as analog integrated circuits. Such circuits can be viewed as generalizations of neural networks of the Hopfield type, and are called diffusion machines.Our second objective is to show that learning in these networks can be achieved by a set of three interconnected diffusion machines: one that learns, one to model the desired behavior, and one to compute the weight changes.This research was supported in part by U.S. Army Research Office Grant DAAL03-89-K-0128. 相似文献
45.
Eugene Santos Deqing Li Eunice E. Santos John Korah 《Expert systems with applications》2012,39(17):12905-12917
Time is ubiquitous. Accounting for time and its interaction with change is crucial to modeling the dynamic world, especially in domains whose study of data is sensitive to time such as in medical diagnosis, financial investment, and natural language processing, to name a few. We present a framework that incorporates both uncertainty and time in its reasoning scheme. It is based on an existing knowledge representation called Bayesian Knowledge Bases. It provides a graphical representation of knowledge, time and uncertainty, and enables probabilistic and temporal inferencing. The reasoning scheme is probabilistically sound and the fusion of temporal fragments is well defined. We will discuss some properties of this framework and introduce algorithms to ensure groundedness during the construction of the model. The framework has been applied to both artificial and real world scenarios. 相似文献
46.
An analytical expression has been obtained for the transient temperature distribution produced when the retina is irradiated by a high-intensity light source. The following factors are included in the analysis: (1) structurally the fundus consists of layers of material which have different physical properties, (2) absorption of energy from the light beam follows the Beer-Lambert law, (3) energy is absorbed in the sclera as well as in the pigment epithelium and choroid, (4) heat is removed from the fundus by blood circulating through the capillaries of the choroid, and (5) intensity of the light source may vary with time. Computed values indicate that absorption of energy in the sclera and removal of heat by convection are both important for longer irradiation times, which agrees with recent experimental observations. The asymptotic response to a train of pulses is presented also. 相似文献
47.
Eugene Kaplounovski 《电子设计技术》2006,13(12):118-118
本设计实例介绍了对某种旧设计的增强措施(参考资料1)。图1中的电路使用常开型单刀单掷按钮开关S1,它代替了原始设计要求的单刀双掷开关。您可以使用膜片开关来大大简化该器件的工业设计并增强它的人机控制特性。另外,该电路消除了流过未动作开关的电流,由此略微减少了工作模式中的泄漏电流。 相似文献
48.
Several classes of regular expressions for timed languages accepted by timed automata have been suggested in the literature. In this article we introduce balanced timed regular expressions with colored parentheses which are equivalent to timed automata, and, differently from existing definitions, do not refer to clock values, and do not use additional operations such as intersection and renaming. 相似文献
49.
During the 1989 Loma Prieta earthquake the Pajaro River levees near Watsonville, Calif., spread laterally at multiple locations. Four of these locations are discussed in this paper. At one location, an industrial facility was also damaged and a dispute arose as to whether lateral spreading of the adjacent levee was the cause. Stability analyses were made of the industrial site for conditions before, during, and after the earthquake. To confirm the findings, analyses were also made of three other nearby locations where the actual deformation was documented and the subsurface conditions are well defined. The calculated levee deformations at the four locations are quite consistent with the observed movements (up to 60 cm). This experience provides increased confidence in the methods of analysis described, for the characterized subsurface conditions, and the range of ground motions experienced. Additional analyses made using the more recently developed multilinear regression lateral-spreading model (e.g., Youd et al. in 1999) yielded inconsistent results. 相似文献
50.
E.Eugene Schultz 《Network Security》2004,2004(1):6-9