全文获取类型
收费全文 | 2647篇 |
免费 | 61篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 46篇 |
综合类 | 24篇 |
化学工业 | 516篇 |
金属工艺 | 40篇 |
机械仪表 | 46篇 |
建筑科学 | 85篇 |
矿业工程 | 21篇 |
能源动力 | 41篇 |
轻工业 | 225篇 |
水利工程 | 38篇 |
石油天然气 | 5篇 |
无线电 | 195篇 |
一般工业技术 | 325篇 |
冶金工业 | 700篇 |
原子能技术 | 37篇 |
自动化技术 | 366篇 |
出版年
2021年 | 31篇 |
2020年 | 28篇 |
2019年 | 35篇 |
2018年 | 23篇 |
2017年 | 29篇 |
2016年 | 53篇 |
2015年 | 41篇 |
2014年 | 40篇 |
2013年 | 135篇 |
2012年 | 76篇 |
2011年 | 99篇 |
2010年 | 94篇 |
2009年 | 83篇 |
2008年 | 101篇 |
2007年 | 101篇 |
2006年 | 89篇 |
2005年 | 98篇 |
2004年 | 66篇 |
2003年 | 51篇 |
2002年 | 68篇 |
2001年 | 41篇 |
2000年 | 32篇 |
1999年 | 36篇 |
1998年 | 72篇 |
1997年 | 57篇 |
1996年 | 56篇 |
1995年 | 40篇 |
1994年 | 42篇 |
1993年 | 45篇 |
1992年 | 42篇 |
1991年 | 25篇 |
1990年 | 39篇 |
1989年 | 39篇 |
1988年 | 28篇 |
1987年 | 24篇 |
1986年 | 44篇 |
1985年 | 51篇 |
1984年 | 56篇 |
1983年 | 43篇 |
1982年 | 55篇 |
1981年 | 25篇 |
1980年 | 38篇 |
1979年 | 32篇 |
1978年 | 30篇 |
1977年 | 41篇 |
1976年 | 41篇 |
1975年 | 38篇 |
1974年 | 30篇 |
1973年 | 27篇 |
1972年 | 24篇 |
排序方式: 共有2710条查询结果,搜索用时 15 毫秒
1.
2.
In executing classical plans in the real world, small discrepancies between a planner's internal representations and the real world are unavoidable. These can conspire to cause real-world failures even though the planner is sound and, therefore, proves that a sequence of actions achieves the goal. Permissive planning, a machine learning extension to classical planning, is one response to this difficulty. This paper describes the permissive planning approach and presents GRASPER, a permissive planning robotic system that learns to robustly pick up novel objects. 相似文献
3.
4.
Abe Schwartz Lili Wang Edward Early Adolfas Gaigalas Yu-zhong Zhang Gerald E. Marti Robert F. Vogt 《Journal of research of the National Institute of Standards and Technology》2002,107(1):83-91
The quantitation of fluorescence radiance may at first suggest the need to obtain the number of fluorophore that are responsible for the measured fluorescence radiance. This goal is beset by many difficulties since the fluorescence radiance depends on three parameters 1) the probability of absorbing a photon (molar extinction), 2) the number of fluorophores, and 3) the probability of radiative decay of the excited state (quantum yield). If we use the same fluorophore in the reference solution and the analyte then, to a good approximation, the molar extinction drops out from the comparison of fluorescence radiance and we are left with the comparison of fluorescence yield which is defined as the product of fluorophore concentration and the molecular quantum yield. The equality of fluorescence yields from two solutions leads to the notion of equivalent number of fluorophores in the two solutions that is the basis for assignment of MESF (Molecules of Equivalent Soluble Fluorophore) values. We discuss how MESF values are assigned to labeled microbeads and by extension to labeled antibodies, and how these assignments can lead to the estimate of the number of bound antibodies in flow cytometer measurements. 相似文献
5.
The functional reanimation of paralyzed limbs has been a longstanding goal of neural prosthetic research, but clinically successful applications have been elusive. Natural voluntary limb movement requires four major elements: actuators (i.e., motor units), sensors (i.e., somatosensory afferents), commands (i.e., cerebral cortical activity), and control (i.e., integration of the previous three elements at various levels of the neuraxis). Prosthetic equivalents of each of these elements are, as yet, primitive and often cumbersome to deploy, but new technologies promise substantial improvements for all. This article focuses on one such technology, bionic neuon (BION) modular microimplants, and its relationship to alternative and complementary technologies. The challenge remains to select and integrate them into systems that can be tailored efficiently to the widely disparate needs of patients with various patterns of weakness and paralysis. 相似文献
6.
Gerald Leach 《Energy Policy》1991,19(10):918-925
The UK differs from may other industrialized nations in that its carbon dioxide (CO2) emissions from energy use have declined in recent years despite relatively rapid economic growth. In all sectors but transport, substantial reductions have already occurred in the level of carbon emissions per unit of GDP output. At the same time, a number of official and unofficial studies have pointed out that the UK has one of the largest remaining potentials amongst comparable industrialized countries for achieving further CO2 reductions through the implementation of cost-effective energy efficiency and fuel switching measures. This paper discusses past and present patterns of energy use and carbons emissions in the UK. The analysis then examines historical trends in UK energy policy and presents policy options for further reducing the UK's energy-use and carbon emissions in the future. 相似文献
7.
Allen Daniel N.; Strauss Gregory P.; Kemtes Karen A.; Goldstein Gerald 《Canadian Metallurgical Quarterly》2007,21(6):713
Hemispheric involvement in reasoning abilities has been debated for some time, and it remains unclear whether the right hemisphere's involvement in problem solving is modality specific or dependent on the type of spatial reasoning required. In the current study, 2 types of nonverbal reasoning abilities were examined, spatial reasoning and proportional reasoning, in 109 patients with cerebrovascular disease that was confined to either the right or the left hemisphere or was diffuse in nature. Results indicated that no lateralizing effects were present based on type of spatial reasoning. Findings are consistent with the suggestion that higher order cognitive processes involved in nonverbal abstraction and problem solving are not strongly lateralized to the right hemisphere but rather are more generally distributed throughout the cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
9.
Sulfate-reducing reactive walls installed in situ in the path of acid mine drainage contaminated groundwater, present a promising passive treatment technology. However, a rigorous and methodical selection of the most appropriate reactive mixture composition still needs to be investigated. The aim of this study was the selection of the most reactive medium using a multiple factor design and the modeling of the sulfate-reduction rate. Reactivity of 17 mixtures was assessed in batch reactors (in duplicates) using a synthetic AMD. Results indicate that within 41 days, sulfate concentrations decreased from initial concentrations of 2,000-3,200 mg/l to final concentrations of <90 mg/l. Metal removal efficiencies ranged between 51-84% for Ni and 73-93% for Zn. Generated sulfate-reduction rate predictive models which had very satisfactory parameters (R2 = 0.86, F = 62.38 (p-level < 10(-13)) and R2 = 0.90. F = 62.30 (p-level < 10(-13))) identified poultry manure and two other carbon sources as the critical variables for sulfate-reduction rate. 相似文献
10.
The effects of age stereotyping on subjects' ratings of interviewee potential were investigated using a simulated auditory interview. Male and female participants (N?=?156) listened to a 12-min interview of a supervisory candidate applying for a temporary position in industry and then rated the interviewee's qualifications for the supervisory position. Participants gave higher overall interview ratings to a younger interviewee even though he had the same qualifications as an older interviewee. Ratings given to the older interviewee, however, were not significantly different from those given to an interviewee whose age was not designated. The findings are discussed in terms of the influence of both positive and negative age stereotypes on ratings of applicant potential. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献