全文获取类型
收费全文 | 15936篇 |
免费 | 1754篇 |
国内免费 | 1099篇 |
专业分类
电工技术 | 841篇 |
技术理论 | 1篇 |
综合类 | 1976篇 |
化学工业 | 2573篇 |
金属工艺 | 477篇 |
机械仪表 | 1085篇 |
建筑科学 | 1261篇 |
矿业工程 | 1014篇 |
能源动力 | 302篇 |
轻工业 | 775篇 |
水利工程 | 430篇 |
石油天然气 | 732篇 |
武器工业 | 124篇 |
无线电 | 1233篇 |
一般工业技术 | 1248篇 |
冶金工业 | 1185篇 |
原子能技术 | 150篇 |
自动化技术 | 3382篇 |
出版年
2024年 | 59篇 |
2023年 | 167篇 |
2022年 | 393篇 |
2021年 | 476篇 |
2020年 | 500篇 |
2019年 | 428篇 |
2018年 | 392篇 |
2017年 | 431篇 |
2016年 | 530篇 |
2015年 | 576篇 |
2014年 | 965篇 |
2013年 | 948篇 |
2012年 | 1175篇 |
2011年 | 1200篇 |
2010年 | 992篇 |
2009年 | 1042篇 |
2008年 | 958篇 |
2007年 | 1131篇 |
2006年 | 1054篇 |
2005年 | 910篇 |
2004年 | 782篇 |
2003年 | 649篇 |
2002年 | 556篇 |
2001年 | 475篇 |
2000年 | 344篇 |
1999年 | 244篇 |
1998年 | 191篇 |
1997年 | 176篇 |
1996年 | 145篇 |
1995年 | 130篇 |
1994年 | 108篇 |
1993年 | 97篇 |
1992年 | 96篇 |
1991年 | 58篇 |
1990年 | 45篇 |
1989年 | 31篇 |
1988年 | 28篇 |
1987年 | 14篇 |
1986年 | 13篇 |
1965年 | 14篇 |
1964年 | 16篇 |
1963年 | 18篇 |
1961年 | 17篇 |
1960年 | 19篇 |
1959年 | 23篇 |
1958年 | 16篇 |
1957年 | 19篇 |
1956年 | 21篇 |
1955年 | 27篇 |
1954年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
钻石型分形晶格上BEG模型的临界行为 总被引:1,自引:0,他引:1
应用实空间重整化群方法研究了分形结构 -钻石型分级晶格上BEG(Blume Emery Griffith)模型的相变和临界现象 ,得到了重整化变换的递推关系 ,确定了重整化变换的不动点 ,并且计算了临界点附近关联长度的临界指数 发现钻石型分级晶格上BEG模型的相变温度为无穷大 ,这表明系统永远处于有序态 相似文献
72.
Leigh M ClemowW.Roy Jackson 《Fuel》2002,81(7):959-961
Non-aqueous potentiometric titration using ethylenediamine as a solvent and sodium aminoethoxide as a titrant has been shown to be reliable for the estimation of total acidity only when the substrate is completely dissolved in the solvent. 相似文献
73.
CIE TC8‐01 has adopted a new color appearance model: CIECAM021 replaces the CIECAM97s.2 The new model consists of a number of refinements and simplifications of the CIECAM97s color appearance model. This article describes further tests to the robustness of the forward and reverse modes. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 99–106, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20087 相似文献
74.
基于模糊匹配的平面连杆机构反求设计研究 总被引:1,自引:0,他引:1
对平面连杆机构曲线进行了分析,提出了用一组特征参数来描述连杆曲线,建立了连杆曲线图谱库,并将模糊论应用于连杆机构的曲线匹配,从而获取所求的机构参数.最后给出了应用实例,证实了该方法的可行性与有效性. 相似文献
75.
Gilbert Baumslag Benjamin Fine Xiaowei Xu 《Applicable Algebra in Engineering, Communication and Computing》2006,17(3-4):205-217
Several suggestions are presented for developing cryptosystems, both classical and public key, using a combination of combinatorial group theory and linear groups. In particular, the Reidemeister-Schreier rewriting process is used as a one way function. These suggestions raise further questions concerning both implementation and security that are being explored in the thesis of Xu [16]. 相似文献
76.
77.
An object design framework for structural engineering 总被引:1,自引:0,他引:1
Object-oriented principles have introduced several useful concepts for developing complex software systems. As a result, several methodologies have been suggested for the overall design of software systems based on these concepts. Methodologies and frameworks for designing objects that are to be part of the software systems are currently lacking. This paper proposes anobject design framework andmethodology, which utilizes the object-oriented concepts, for planning, organizing and designing structural engineering design objects. Design objects in an integrated structural engineering system are complex and often related to each other in various different ways. The paper also identifies several important relationships among structural engineering design objects. These relationships serve as communication channels through wich design objects send messages to and receive responses from each other. Several examples, drawn from reinforced concrete structures, will be presented to demonstrate the object design methodology and to illustrate how the framework is effective in reducing the complexity of design objects in an integrated structural engineering system. 相似文献
78.
瓶组气化站的建筑,结构设计关系到安全,满足使用要求和投资的大小,本文根据多年的实践和最新的有关设计规范的要求,阐述瓶组气化站建筑,结构设计的要点。 相似文献
79.
The toll in death, suffering, and displacement caused by conflicts engaging groups defined by ethnicity, nationality, religion, or other social identities has reached staggering proportions over the past decade. With expertise in research and intervention, psychologists have critical contributions to make to more fully understanding and more effectively confronting this distressing global phenomenon. The authors focus on the parallels between the core beliefs of individuals and the collective worldviews of groups that may operate to trigger or constrain violent struggles. On the basis of a review of relevant literatures, 5 belief domains--superiority, injustice, vulnerability, distrust, and helplessness--are identified as particularly important for further study. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
80.
This paper considers the estimation of both the intercept term and the slope parameter in a linear ultrastructural model using
direct regression and reverse regression methods. Without assuming the errors to be normally distributed, asymptotic expressions
for the bias and the variance of the estimators are derived and analyzed. The effect of departure of the errors from normality
is also studied. 相似文献