全文获取类型
收费全文 | 22147篇 |
免费 | 2409篇 |
国内免费 | 1527篇 |
专业分类
电工技术 | 2655篇 |
技术理论 | 1篇 |
综合类 | 2698篇 |
化学工业 | 2289篇 |
金属工艺 | 798篇 |
机械仪表 | 1729篇 |
建筑科学 | 1830篇 |
矿业工程 | 631篇 |
能源动力 | 743篇 |
轻工业 | 907篇 |
水利工程 | 463篇 |
石油天然气 | 1497篇 |
武器工业 | 292篇 |
无线电 | 1933篇 |
一般工业技术 | 2201篇 |
冶金工业 | 617篇 |
原子能技术 | 290篇 |
自动化技术 | 4509篇 |
出版年
2024年 | 108篇 |
2023年 | 288篇 |
2022年 | 577篇 |
2021年 | 673篇 |
2020年 | 735篇 |
2019年 | 603篇 |
2018年 | 572篇 |
2017年 | 726篇 |
2016年 | 786篇 |
2015年 | 898篇 |
2014年 | 1372篇 |
2013年 | 1441篇 |
2012年 | 1635篇 |
2011年 | 1727篇 |
2010年 | 1291篇 |
2009年 | 1348篇 |
2008年 | 1266篇 |
2007年 | 1463篇 |
2006年 | 1266篇 |
2005年 | 1118篇 |
2004年 | 929篇 |
2003年 | 813篇 |
2002年 | 736篇 |
2001年 | 576篇 |
2000年 | 528篇 |
1999年 | 424篇 |
1998年 | 346篇 |
1997年 | 313篇 |
1996年 | 268篇 |
1995年 | 238篇 |
1994年 | 220篇 |
1993年 | 178篇 |
1992年 | 146篇 |
1991年 | 97篇 |
1990年 | 81篇 |
1989年 | 79篇 |
1988年 | 49篇 |
1987年 | 24篇 |
1986年 | 27篇 |
1985年 | 23篇 |
1984年 | 19篇 |
1983年 | 23篇 |
1982年 | 12篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1975年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
T. EdagawaAuthor Vitae T. AkaikeAuthor Vitae Y. HigoAuthor Vitae S. HanabusaAuthor Vitae 《Journal of Systems and Software》2011,84(6):976-984
A function point (FP) is a unit of measurement that expresses the degree of functionality that an information system provides to a user. Many software organizations use FPs to estimate the effort required for software development. However, it is essential that the definition of 1 FP be based on the software development experience of the organization. In the present study, we propose a method by which to automatically extract data and transaction functions from Web applications under several conditions using static analysis. The proposed method is based on the International Function Point Users Group (IFPUG) method and has been developed as an FP measurement tool. We applied the proposed method to several Web applications and examined the difference between FP counts obtained by the tool and those obtained by a certified FP specialist (CFPS). The results reveal that the numbers of data and transaction functions extracted by the tool is approximately the same as the numbers of data and transaction functions extracted by the specialist. 相似文献
32.
Jinzhong Yang 《Pattern recognition letters》2011,32(7):910-918
This paper reviews the TPS-RPM algorithm (Chui and Rangarajan, 2003) for robustly registering two sets of points and demonstrates from a theoretical point of view its inherent limited performance when outliers are present in both point sets simultaneously. A double-sided outlier handling approach is proposed to overcome this limitation with a rigorous mathematical proof as the underlying theoretical support. This double-sided outlier handling approach is proved to be equivalent to the original formulation of the point matching problem. For a practical application, we also extend the TPS-RPM algorithms to non-rigid image registration by registering two sets of sparse features extracted from images. The intensity information of the extracted features are incorporated into feature matching in order to reduce the impact from outliers. Our experiments demonstrate the double-sided outlier handling approach and the efficiency of intensity information in assisting outlier detection. 相似文献
33.
V. V. Skobelev 《Cybernetics and Systems Analysis》2008,44(3):362-374
Basic finite-automaton characteristics are established for the class of all linear automata and information-lossless automata
over a ring. The complexities of solving problems of parametric identification and initial-state identification are analyzed.
The sets of fixed points for mappings realized by initial automata are characterized. Canonical forms are proposed for linear
automata over the ring.
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 3, pp. 60–74, May–June 2008. 相似文献
34.
Cheng-Hsing Hsu Po-Chuang Chen Kuang-Yuan Kung Chuan Lai 《The International Journal of Advanced Manufacturing Technology》2007,31(7-8):673-681
The flow field of a long bubble steadily expelling a viscous fluid confined by two closely located parallel plates is examined.
In order to investigate the influence of bubble size on the flow field, a theoretical bubble profile is used to replace the
complicated procedure for computing simultaneously the interface between the gas surface and fluid flows. The present study
showed the two typical flow patterns and also a third flow pattern of the stagnation point moving in the region of the bubble
tip front during transformation of the two typical flow patterns. The vorticity patterns are also drawn for various bubble
profiles and are examined for their effect on the flow. The velocity field is also presented from two different viewpoints
and the phenomena is examined. The stagnation point located on the center line between the bubble tip to the upstream is only
found in the small range of in a channel, where λ is ratio of the bubble width to the distance between two parallel plates. 相似文献
35.
为智能仪表提供一种“十进制浮点数”,其特点是值域宽、值准确,它能代替整、长整型、三字节浮点数、四字节浮点数、BCD码数。用它通信可简化和统一仪表的通信协议,为制定仪表通用通信协议标准创造条件。 相似文献
36.
GPS定位技术日益成熟,在很多领域已得到了广泛应用。文中主要简介说明GPS技术原理与特点,针对工程实践中调查灌区的实际情况存在灌区面积大、渠系长、渠系建筑物多、渠道实际完成不连续的特点,采用传统的测量方法已无法满足快速而准确的调查要求,因此应用GPS定位技术与之比较,同时也验证了新技术的高效性和准确性。 相似文献
37.
The Maximum Likelihood Estimator (MLE) and Extended Quasi-Likelihood (EQL) estimator have commonly been used to estimate the unknown parameters within the joint modeling of mean and dispersion framework. However, these estimators can be very sensitive to outliers in the data. In order to overcome this disadvantage, the usage of the maximum Trimmed Likelihood Estimator (TLE) and the maximum Extended Trimmed Quasi-Likelihood (ETQL) estimator is recommended to estimate the unknown parameters in a robust way. The superiority of these approaches in comparison with the MLE and EQL estimator is illustrated by an example and a simulation study. As a prominent measure of robustness, the finite sample Breakdown Point (BDP) of these estimators is characterized in this setting. 相似文献
38.
研究了一个二阶非线性中立时滞微分方程,给出了关于此方程正解存在的一些充分条件,其优点在于省略了对任意的a〉0,aQ1(t)-Q2(t)都是最终非负的限制条件。最后通过数值例子说明研究结果的优越性。 相似文献
39.
40.
关于第二积分中值定理渐近性的一个注记 总被引:1,自引:0,他引:1
伍建华 《武汉化工学院学报》2006,28(4):73-74,77
对于第二积分中值定理中的搴,本文给出并证明了比文献[3]更一般的结论,文献[3]的有关定理可以看成本文定理的直接推论. 相似文献