全文获取类型
收费全文 | 2842篇 |
免费 | 144篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 25篇 |
综合类 | 9篇 |
化学工业 | 537篇 |
金属工艺 | 50篇 |
机械仪表 | 47篇 |
建筑科学 | 126篇 |
矿业工程 | 28篇 |
能源动力 | 94篇 |
轻工业 | 353篇 |
水利工程 | 29篇 |
石油天然气 | 7篇 |
无线电 | 242篇 |
一般工业技术 | 408篇 |
冶金工业 | 496篇 |
原子能技术 | 9篇 |
自动化技术 | 533篇 |
出版年
2023年 | 17篇 |
2022年 | 23篇 |
2021年 | 47篇 |
2020年 | 60篇 |
2019年 | 49篇 |
2018年 | 72篇 |
2017年 | 82篇 |
2016年 | 82篇 |
2015年 | 69篇 |
2014年 | 86篇 |
2013年 | 205篇 |
2012年 | 129篇 |
2011年 | 163篇 |
2010年 | 155篇 |
2009年 | 156篇 |
2008年 | 168篇 |
2007年 | 165篇 |
2006年 | 124篇 |
2005年 | 88篇 |
2004年 | 92篇 |
2003年 | 102篇 |
2002年 | 74篇 |
2001年 | 36篇 |
2000年 | 51篇 |
1999年 | 48篇 |
1998年 | 166篇 |
1997年 | 92篇 |
1996年 | 65篇 |
1995年 | 44篇 |
1994年 | 38篇 |
1993年 | 39篇 |
1992年 | 23篇 |
1991年 | 19篇 |
1990年 | 14篇 |
1989年 | 20篇 |
1988年 | 14篇 |
1987年 | 15篇 |
1986年 | 12篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 4篇 |
1981年 | 12篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1973年 | 3篇 |
1971年 | 3篇 |
排序方式: 共有2993条查询结果,搜索用时 0 毫秒
81.
Richard Ashley David Blackwood Nicki Souter Sarah Hendry Jim Moir Judith Dunkerley John Davies David Butler Andrew Cook Jim Conlin Martin Squibbs Andrew Britton Peter Goldie 《Canadian Metallurgical Quarterly》2005,131(2):206-215
The study presented is an example of the assessment of the relative sustainability of either option for disposal of domestic sanitary waste, either via the toilet or via the solid waste route. This required an evaluation of the total (social, economic, environmental, and technical) benefit/cost of implementing and adopting the alternative routes and an assessment of public responsiveness to encouragement to change sanitary waste disposal practices. It illustrates how, even for an apparently straightforward either/or question, the assessment of relative sustainability is complex and the amount of data needed to quantify sustainability indicators is prodigious. The study also provides an appraisal of the effectiveness of public campaigns to reduce waterborne disposal. Important information regarding public attitude and behavior in relation to wastewater systems has been acquired and lessons for ways of encouraging behavioral change to more sustainable ways of living have been gleaned. 相似文献
82.
Golden-Kreutz Deanna M.; Thornton Lisa M.; Wells-Di Gregorio Sharla; Frierson Georita M.; Jim Heather S.; Carpenter Kristen M.; Shelby Rebecca A.; Andersen Barbara L. 《Canadian Metallurgical Quarterly》2005,24(3):288
The authors investigated the relationship between stress at initial cancer diagnosis and treatment and subsequent quality of life (QoL). Women (n = 112) randomized to the assessment-only arm of a clinical trial were initially assessed after breast cancer diagnosis and surgery and then reassessed at 4 months (during adjuvant treatment) and 12 months (postadjuvant treatment). There were 3 types of stress measured: number of stressful life events (K. A. Matthews et al., 1997), cancer-related traumatic stress symptoms (M. J. Horowitz, N. Wilner, & W. Alvarez, 1979), and perceived global stress (S. Cohen, T. Kamarck, & R. Mermelstein, 1983). Using hierarchical multiple regressions, the authors found that stress predicted both psychological and physical QoL (J. E. Ware, K. K. Snow, & M. Kosinski, 2000) at the follow-ups (all ps 相似文献
83.
Neiss Michelle B.; Stevenson Jim; Sedikides Constantine; Kumashiro Madoka; Finkel Eli J.; Rusbult Caryl E. 《Canadian Metallurgical Quarterly》2005,89(4):593
Complementary approaches examined the relations among executive self, self-esteem, and negative affectivity. A cross-sectional (N = 4,242) and a longitudinal (N = 158) study established that self-esteem mediated the relation between executive self and negative affectivity. A 3rd study (N = 878 twin pairs) replicated this pattern and examined genetic and environmental influences underlying all 3 phenotypes. Covariation among the 3 phenotypes reflected largely common genetic influences, although unique genetic effects explained variability in both executive self and negative affectivity. Executive self was influenced by shared environmental influences unique from those affecting self-esteem and negative affectivity. Nonshared environmental influences accounted for the majority of variance in each construct and were primarily unique to each. The unique genetic and nonshared environmental influences support the proposition that the executive self, self-esteem, and negative affectivity capture distinct and important differences between people. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
84.
M. Dolores Jiménez-Gamero Juan Luis Moreno-Rebollo Juan M. Muñoz-Pichardo Ana M. Muñoz-Reyes 《TEST》2005,14(2):515-542
One of the areas of Statistics in which the influence analysis has been widely studied is the multiple linear regression model.
Nevertheless, the influence diagnostics proposed in this context cannot be applied to regression in complex survey, under
randomized inference, since the i.i.d. case does not incorporate any probability weighting or population structure, such as
clustering, stratification or measures of size into the analysis.
In this paper we introduce some influence diagnostics in regression in complex survey. They are built on the conditional bias
concept (Moreno-Rebollo et al., 1999). We emphasize the similarities and differences of the proposed measures with respect
to the existing ones for the i.i.d. case.
Research partly supported by the Spanish MCYT grant BFM2001-3844 and Spanish MEC grant MTM2004-0111433. 相似文献
85.
南宁味精厂废水处理工程剩余污泥脱水实验及工程试运行 总被引:2,自引:1,他引:2
采用加热和絮凝等方法对南宁味精厂废水处理工程剩余污泥进行调理,研究各种方法对其脱水性能的影响。结果表明,絮凝和加温的方法均能提高污泥的脱水性能,其中絮凝方法效果更为明显。水浴加热试验中,温度升到60℃时滤速达到35mL/h;微波加热试验中,只需加热50s滤速就可达到35mL/h。絮凝试验中,聚丙烯酸钠最佳投药量为50mg/L,此时滤速为5.2mL/min。从技术经济角度考虑,在实际工程运行中,采用加温(60℃左右)与投加絮凝剂(聚丙烯酸钠投量为O.2‰)相结合的方法,可使污泥脱水效果得到提高,经压滤后污泥含水率可降至60%~65%。 相似文献
86.
Rodríguez José Ignacio Jiménez José Manuel Funes Francisco Javier García de Jalón Javier 《Multibody System Dynamics》2003,10(2):177-199
In this paper a prototype of a computer program for multi-bodysimulation based on the use of CORBA, Java and XML is presented. Thisprototype makes use of a recursive dynamic formalism which outperformsmany implementations based on global formulations. The prototypepresented has been implemented using distributed Object OrientedProgramming techniques. The definition of the multi-body system is donethrough a data file defined using XML (eXtendible Markup Language). Thisprototype implements a `simulation service' on a network of computers,following a client-server scheme. This `simulation service' can operatein two different ways: offering a remote simulation on the server, orproviding a Java compiled code for local simulation on the client. Thepaper describes the practical implementation of such a service. The useof recursive functions and OOP permits the implementation of ageneral-purpose simulation code, which is compact, clear, clean,re-usable and easy to maintain. Once this Java code is compiled, it isstored in less than 125 Kbytes (including the numerical integrators).The Java programming language is used in order to assure compatibilitybetween different platforms. Finally, practical examples which make useof this approach are shown. 相似文献
87.
J. L. Pons R. Ceres A. R. Jiménez L. Calderón J. M. Martin 《Journal of Intelligent and Robotic Systems》1997,18(3):277-287
The precise control of manipulators depends nonlinearly on the velocity of the motion as well as on manipulator configuration and commanded acceleration requiring complex control strategies. This paper presents a useful tool for identifying and quantifying nonlinear effects appearing during the motion of any manipulator, the Nonlinear Performance Index (npi). The npi takes into account not only the geometrical parameters defining the manipulator but also its structural dynamics through the use of inertial parameters like mass, inertia, centre of mass... The npi can be used in the design stage for analysing and reducing these undesirable nonlinear effects in any general motion or in the trajectory planning looking for paths along which more precise control is expected. The last part of the paper shows how this design optimisation and path planning has been applied to the Agribot, a fruit picking robot designed at the IAI. 相似文献
88.
Multisensor Fusion: An Autonomous Mobile Robot 总被引:7,自引:0,他引:7
A conventional autonomous mobile robot is introduced. The main idea is the integration of many conventional and sophisticated sensor fusion techniques, introduced by several authors in recent years. We show the actual possibility of integrating all these techniques together, rather than analyzing implementation details. The topics of multisensor fusion, observation integration and sensor coordination are widely used throuhout the article. The final goal is to demonstrate the validity of both mathematical and artificial intelligence techniques in guaranteeing vehicle survival in a dynamic environment, while the robot carries out a specific task. We review conventional techniques for the management of uncertainty while we describe an implementation of a mobile robot which combines on-line heterogeneous sensors in its navigation and localisation tasks. 相似文献
89.
90.
A simple method is presented for evaluating wall shear stresses from known flow histories in unsteady pipe flows. The method builds on previous work by Trikha, but has two important differences. One of these enables the method to be used with much larger integration time steps than are acceptable with Trikha’s method. The other, a general procedure for determining approximations to weighting functions, enables it to be used at indefinitely small times (high frequencies). The method is applicable to both laminar and turbulent flows. 相似文献