首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   64045篇
  免费   6186篇
  国内免费   2831篇
电工技术   3675篇
技术理论   2篇
综合类   4122篇
化学工业   10736篇
金属工艺   3740篇
机械仪表   4238篇
建筑科学   4706篇
矿业工程   2168篇
能源动力   1709篇
轻工业   4049篇
水利工程   1084篇
石油天然气   3937篇
武器工业   526篇
无线电   7885篇
一般工业技术   7831篇
冶金工业   3068篇
原子能技术   636篇
自动化技术   8950篇
  2024年   586篇
  2023年   1218篇
  2022年   1871篇
  2021年   2632篇
  2020年   2038篇
  2019年   1809篇
  2018年   1976篇
  2017年   2169篇
  2016年   1992篇
  2015年   2522篇
  2014年   3076篇
  2013年   3652篇
  2012年   4066篇
  2011年   4454篇
  2010年   3679篇
  2009年   3520篇
  2008年   3389篇
  2007年   3294篇
  2006年   3663篇
  2005年   3032篇
  2004年   2122篇
  2003年   1799篇
  2002年   1595篇
  2001年   1446篇
  2000年   1559篇
  1999年   1708篇
  1998年   1512篇
  1997年   1267篇
  1996年   1147篇
  1995年   953篇
  1994年   834篇
  1993年   570篇
  1992年   427篇
  1991年   366篇
  1990年   261篇
  1989年   213篇
  1988年   184篇
  1987年   121篇
  1986年   97篇
  1985年   59篇
  1984年   30篇
  1983年   20篇
  1982年   28篇
  1981年   16篇
  1980年   21篇
  1979年   10篇
  1978年   7篇
  1977年   5篇
  1976年   14篇
  1975年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Zan  Wu  Zhang  Qiaochu  Xu  Hu  Liao  Fuyou  Guo  Zhongxun  Deng  Jianan  Wan  Jing  Zhu  Hao  Chen  Lin  Sun  Qingqing  Ding  Shijin  Zhou  Peng  Bao  Wenzhong  Zhang  David Wei 《Nano Research》2018,11(7):3739-3745
Nano Research - A spin-coating method was applied to obtain thinner and smoother PEO/LiClO4 polymer electrolyte films (EFs) with a lower level of crystallization than those obtained using a...  相似文献   
82.
戎真真  虎恩典  刘勇  鲁研青   《计算机测量与控制》2014,22(8):2697-2700,2708
随着电力、电气设备的日益复杂化,对于其安全性能也有了更高的要求,数字兆欧表作为测量绝缘阻值的重要工具,已在工业领域中广泛应用;为了满足测量精度以及兆欧表的可靠性,通过基于S3C2440的嵌入式平台,提出了一种基于数字兆欧表的自动切换档位的实现方案,以达到更加精确的测量;此方案通过判断采集到的电压值选择相应的采样电阻来实现,并结合硬件平台和软件设计,分别介绍了驱动程序和应用程序的编写与测试,并很好地应用到了实际电路中;经测试,能够达到预期的效果,测量精度高,测量误差控制在±2%。  相似文献   
83.
When the Transformer proposed by Google in 2017, it was first used for machine translation tasks and achieved the state of the art at that time. Although the current neural machine translation model can generate high quality translation results, there are still mistranslations and omissions in the translation of key information of long sentences. On the other hand, the most important part in traditional translation tasks is the translation of key information. In the translation results, as long as the key information is translated accurately and completely, even if other parts of the results are translated incorrect, the final translation results’ quality can still be guaranteed. In order to solve the problem of mistranslation and missed translation effectively, and improve the accuracy and completeness of long sentence translation in machine translation, this paper proposes a key information fused neural machine translation model based on Transformer. The model proposed in this paper extracts the keywords of the source language text separately as the input of the encoder. After the same encoding as the source language text, it is fused with the output of the source language text encoded by the encoder, then the key information is processed and input into the decoder. With incorporating keyword information from the source language sentence, the model’s performance in the task of translating long sentences is very reliable. In order to verify the effectiveness of the method of fusion of key information proposed in this paper, a series of experiments were carried out on the verification set. The experimental results show that the Bilingual Evaluation Understudy (BLEU) score of the model proposed in this paper on the Workshop on Machine Translation (WMT) 2017 test dataset is higher than the BLEU score of Transformer proposed by Google on the WMT2017 test dataset. The experimental results show the advantages of the model proposed in this paper.  相似文献   
84.
在目前的原燃料条件下,为保证马钢2500m3高炉炉渣具有良好的流动性和较高的脱硫能力,炉渣的CaO/SiO2应控制在1.05至1.15之间,炉渣温度不低于1450℃.  相似文献   
85.
建立了包括有源电力滤波器(APF)在内的公共连接点(PCC)的数学模型;针对实际控制器计算过程中的时间延迟,提出对负载电流值进行预测的两种算法,对逆变器的开关元件提出一种新型脉宽调制(PWM)控制方案,并采用电力电子仿真软件包进行了仿真验证。  相似文献   
86.
为保证电镀塑料制品的质量,提出了符合电镀要求的塑料制品设计原则,并且指出在注塑成形时,对塑料经过充分干燥,采用较高的注塑温度,较低的注射压力和较慢的注射速度,是使镀层获得良好结合强度的先决条件。  相似文献   
87.
We have used lithographically patterned microchannel arrays with channel widths ranging from 1 to 20 m, fabricated using electron beam lithography and reactive ion etching, in structural studies of DNA–cationic lipid complexes in confinement. Various techniques have been developed for loading these DNA–membrane complexes into the microchannels or to form the complexes in situ by sequentially depositing DNA and lipid solutions into the microchannels. Optical microscopy studies indicate that such complex formation is strongly influenced by the periodic channel structure even at channel widths much larger than the persistent length of the DNA molecules. Preliminary x-ray diffraction experiments conducted at Stanford Synchrotron Radiation Laboratory (SSRL) yielded only a weak signal from the lipid bilayers in the complexes. The use of a microfocused x-ray beam produced by the newly developed Bragg–Fresnel optics at a third-generation synchrotron facility may dramatically increase the signal-to-noise ratio and allow observation of orientational as well as positional ordering of DNA molecules induced by the microchannels. Structural control of the DNA–membrane complexes has a broad range of potential applications in gene probe technology and as mesoscopic biomolecular composites.  相似文献   
88.
In this paper, the dynamic behaviors of a class of neural networks with time-varying delays are investigated. Some less weak sufficient conditions based on p-norm and ∞-norm are obtained to guarantee the existence, uniqueness of the equilibrium point for the addressed neural networks without impulsive control by applying homeomorphism theory. And then, by utilizing inequality technique, Lyapunov functional method and the analysis method, some new and useful criteria of the globally exponential stability with respect to the equilibrium point under impulsive control we assumed are derived based on p-norm and ∞-norm, respectively. Finally, an example with simulation is given to show the effectiveness of the obtained results.  相似文献   
89.
提出一种以词性为参考值的文本挖掘算法,能有效挖掘与种子词有关的关联规则。基于Bootstrapping算法思想,既减少了预处理阶段对于词根还原的依赖,能处理日志中出现的中文词汇。增加了对于日志文本上下的理解,提高了关联规则的有效性,并应用与IDS日志挖掘之中,有效改善挖掘效率,为规则库提供关联规则。  相似文献   
90.
The main theme of this paper is to present a novel evolution, the genetic regulatory network-based symbiotic evolution (GRNSE), to improve the convergent speed and solution accuracy of genetic algorithms. The proposed GRNSE utilizes genetic regulatory network (GRN) reinforcement learning to improve the diversity and symbiotic evolution (SE) initialization to achieve the parallelism. In particular, GRN-based learning increases the global rate by regulating members of genes in symbiotic evolution. To compare the efficiency of the proposed method, we adopt 41 benchmarks that contain many nonlinear and complex optimal problems. The influences of dimension, individual population size, and gene population size are examined. A new control parameter, the population rate is introduced to initiate the ratio between the gene and chromosome. Finally, all the studies of there 41 benchmarks demonstrate that from the statistic point of view, GRNSE give a better convergence speed and a more accurate optimal solution than GA and SE.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号