全文获取类型
收费全文 | 10759篇 |
免费 | 930篇 |
国内免费 | 438篇 |
专业分类
电工技术 | 747篇 |
综合类 | 999篇 |
化学工业 | 1381篇 |
金属工艺 | 243篇 |
机械仪表 | 458篇 |
建筑科学 | 1054篇 |
矿业工程 | 473篇 |
能源动力 | 646篇 |
轻工业 | 1558篇 |
水利工程 | 358篇 |
石油天然气 | 584篇 |
武器工业 | 242篇 |
无线电 | 751篇 |
一般工业技术 | 892篇 |
冶金工业 | 478篇 |
原子能技术 | 121篇 |
自动化技术 | 1142篇 |
出版年
2024年 | 58篇 |
2023年 | 152篇 |
2022年 | 260篇 |
2021年 | 327篇 |
2020年 | 386篇 |
2019年 | 319篇 |
2018年 | 284篇 |
2017年 | 359篇 |
2016年 | 431篇 |
2015年 | 429篇 |
2014年 | 663篇 |
2013年 | 765篇 |
2012年 | 783篇 |
2011年 | 886篇 |
2010年 | 613篇 |
2009年 | 576篇 |
2008年 | 569篇 |
2007年 | 651篇 |
2006年 | 556篇 |
2005年 | 519篇 |
2004年 | 395篇 |
2003年 | 360篇 |
2002年 | 315篇 |
2001年 | 229篇 |
2000年 | 213篇 |
1999年 | 166篇 |
1998年 | 148篇 |
1997年 | 106篇 |
1996年 | 100篇 |
1995年 | 72篇 |
1994年 | 81篇 |
1993年 | 52篇 |
1992年 | 42篇 |
1991年 | 31篇 |
1990年 | 40篇 |
1989年 | 24篇 |
1988年 | 27篇 |
1987年 | 18篇 |
1986年 | 16篇 |
1985年 | 15篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1964年 | 9篇 |
1962年 | 8篇 |
1958年 | 4篇 |
1957年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Artificial bee colony (ABC) algorithm has several characteristics that make it more attractive than other bio-inspired methods. Particularly, it is simple, it uses fewer control parameters and its convergence is independent of the initial conditions. In this paper, a novel artificial bee colony based maximum power point tracking algorithm (MPPT) is proposed. The developed algorithm, does not allow only overcoming the common drawback of the conventional MPPT methods, but it gives a simple and a robust MPPT scheme. A co-simulation methodology, combining Matlab/Simulink™ and Cadence/Pspice™, is used to verify the effectiveness of the proposed method and compare its performance, under dynamic weather conditions, with that of the Particle Swarm Optimization (PSO) based MPPT algorithm. Moreover, a laboratory setup has been realized and used to experimentally validate the proposed ABC-based MPPT algorithm. Simulation and experimental results have shown the satisfactory performance of the proposed approach. 相似文献
2.
Seyed Ali Maghami 《热应力杂志》2015,38(2):250-270
Thermal bending analysis of doubly curved laminated shell panels with general boundary conditions and laminations is presented. The equations of equilibrium are derived in the form of two coupled sets of ordinary differential equations based on a general shell theory and solved through the state-space approach in a repeated manner. It is depicted that the results of the present method are in great agreement with analytical solutions. Cylindrical shell panels with general boundary conditions and laminations, where no analytical solution is available, are solved. It is found that the present method exhibits a high convergence rate as well as presenting accurate results in all cases. 相似文献
3.
Kruk Menno R.; Halász József; Meelis Wout; Haller József 《Canadian Metallurgical Quarterly》2004,118(5):1062
Aggressive behavior induces an adrenocortical stress response, and sudden stressors often precipitate violent behavior. Experiments in rats revealed a fast, mutual, positive feedback between the adrenocortical stress response and a brain mechanism controlling aggression. Stimulation of the aggressive area in the hypothalamus rapidly activated the adrenocortical response, even in the absence of an opponent and fighting. Hypothalamic aggression, in turn, was rapidly facilitated by a corticosterone injection in rats in which the natural adrenocortical stress response was prevented by adrenalectomy. The rapidity of both effects points to a fast, mutual, positive feedback of the controlling mechanisms within the time frame of a single conflict. Such a mutual facilitation may contribute to the precipitation and escalation of violent behavior under stressful conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
0.89dtex细旦涤纶短纤维工艺优化探讨 总被引:2,自引:1,他引:1
介绍了纺制 0 89dtex× 3 8mm细旦涤纶短纤维的工艺技术特点 ,着重讨论了熔体温度、纺丝速度、冷却条件等工艺对原丝性能及产品质量的影响 相似文献
5.
对韶钢炼铁厂4号高炉炉况和操作上存在的问题进行了分析,主要原因是原材料质量较差,精料水平低,同时,高炉操作不能完全适应原材料条件.按照上稳下活工艺的原则,采取合理鼓风动能、活跃炉缸工作状态、稳定热制度、合理中部冷却强度、炉顶小高压操作以及使用上部调节手段等一系列措施,使高炉的炉况顺行得到了较大的改善,各项主要技术经济指标取得相应的进步.2001年利用系数达3.024 t/m3·d,焦比达441 kg/t. 相似文献
6.
设计了一种适合在低电源电压下工作的前馈型输入级放大结构,在全摆幅的动态工作范围内,输入级跨导保持不变,采用负载电流补偿以保证增益近似恒定,输出采用前馈型AB类输结构,实现全摆幅输出。 相似文献
7.
In this paper we present some preliminary results about the coupling of shallow water equations for free surface flows and Darcy equation for groundwater flows. A suitable set of interface conditions is discussed: the Beavers and Joseph formula for the bottom stress is used. An iterative algorithm to solve the coupled problem is proposed and some numerical results are presented. 相似文献
8.
A. Yu. Luchka 《Cybernetics and Systems Analysis》2003,39(6):880-888
A modified variational-gradient method is proposed and substantiated for quasilinear operator equations in a Hilbert space. 相似文献
9.
Timo Nurminen 《International Journal of Project Management》1985,3(3):163-168
When dealing with a Soviet client, tendering, scheduling, consideration of available resources, management responsibilities, start-up and hand-over must be approached from a slightly different angle than when dealing with Western clients. Aspects of project management from feasibility analysis to hand-over are described, based on the experience of a Finnish general contractor, Finn Stroi. 相似文献
10.
During the day, there are considerable variations in the climatic factors prevailing in these regions. This is especially so during the 24-hour daily cycle of the long, hot and dry summer (mid-May to midOctober). Such climatic conditions have had a considerable impact on the daily living pattern of family life in the same season, particularly in the urban areas. During the same 24-hour cycle, they have compelled the inhabitants to shift their living activities both vertically in section and horizontally in plan; they do this in pursuit of more acceptable, if not, desirable internal thermal environmental ambience. 相似文献