全文获取类型
收费全文 | 2120篇 |
免费 | 17篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 17篇 |
综合类 | 1篇 |
化学工业 | 323篇 |
金属工艺 | 41篇 |
机械仪表 | 40篇 |
建筑科学 | 80篇 |
矿业工程 | 15篇 |
能源动力 | 51篇 |
轻工业 | 187篇 |
水利工程 | 31篇 |
石油天然气 | 18篇 |
无线电 | 116篇 |
一般工业技术 | 248篇 |
冶金工业 | 568篇 |
原子能技术 | 12篇 |
自动化技术 | 392篇 |
出版年
2022年 | 12篇 |
2019年 | 14篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 22篇 |
2015年 | 13篇 |
2014年 | 28篇 |
2013年 | 105篇 |
2012年 | 54篇 |
2011年 | 72篇 |
2010年 | 59篇 |
2009年 | 56篇 |
2008年 | 76篇 |
2007年 | 78篇 |
2006年 | 86篇 |
2005年 | 78篇 |
2004年 | 80篇 |
2003年 | 68篇 |
2002年 | 59篇 |
2001年 | 55篇 |
2000年 | 40篇 |
1999年 | 31篇 |
1998年 | 43篇 |
1997年 | 51篇 |
1996年 | 59篇 |
1995年 | 51篇 |
1994年 | 34篇 |
1993年 | 61篇 |
1992年 | 63篇 |
1991年 | 32篇 |
1990年 | 38篇 |
1989年 | 55篇 |
1988年 | 40篇 |
1987年 | 48篇 |
1986年 | 30篇 |
1985年 | 33篇 |
1984年 | 53篇 |
1983年 | 41篇 |
1982年 | 22篇 |
1981年 | 21篇 |
1980年 | 24篇 |
1979年 | 24篇 |
1978年 | 28篇 |
1977年 | 21篇 |
1976年 | 18篇 |
1975年 | 22篇 |
1974年 | 29篇 |
1973年 | 17篇 |
1972年 | 11篇 |
1971年 | 12篇 |
排序方式: 共有2140条查询结果,搜索用时 9 毫秒
151.
Diamond Adele; Zola-Morgan Stuart; Squire Larry R. 《Canadian Metallurgical Quarterly》1989,103(3):526
In this study, (a) what determines success or failure in the AB? and object retrieval tasks and (b) the relation between brain maturation and cognitive development as indexed by these tasks were examined. Intact cynomolgus monkeys and those with bilateral lesions of the hippocampal formation (H+) were tested. Although H+ monkeys exhibited impaired memory by performing poorly on the delayed nonmatching to sample task, they performed well on AB? at delays of 2–25 s. Performance declined as delays increased to 30 s, but H+ monkeys never showed the AB? error pattern. On object retrieval, H+ monkeys succeeded quickly and efficiently, even when required to detour to the box opening. This research demonstrates that memory impairment alone cannot account for deficits on AB? or on object retrieval and strengthens the conclusion (A. Diamond, 1988) that improved performance on AB? and object retrieval during infancy reflects maturation of dorsolateral prefrontal cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
152.
Mohammed Mahmoud Yuqiong Liu Holly Hartmann Steven Stewart Thorsten Wagener Darius Semmens Robert Stewart Hoshin Gupta Damian Dominguez Francina Dominguez David Hulse Rebecca Letcher Brenda Rashleigh Court Smith Roger Street Jenifer Ticehurst Mark Twery Hedwig van Delden Ruth Waldick Denis White Larry Winter 《Environmental Modelling & Software》2009,24(7):798-808
Scenarios are possible future states of the world that represent alternative plausible conditions under different assumptions. Often, scenarios are developed in a context relevant to stakeholders involved in their applications since the evaluation of scenario outcomes and implications can enhance decision-making activities. This paper reviews the state-of-the-art of scenario development and proposes a formal approach to scenario development in environmental decision-making. The discussion of current issues in scenario studies includes advantages and obstacles in utilizing a formal scenario development framework, and the different forms of uncertainty inherent in scenario development, as well as how they should be treated. An appendix for common scenario terminology has been attached for clarity. Major recommendations for future research in this area include proper consideration of uncertainty in scenario studies in particular in relation to stakeholder relevant information, construction of scenarios that are more diverse in nature, and sharing of information and resources among the scenario development research community. 相似文献
153.
The notion that leaders are more effective if they can flex their leadership style to deal with shifting priorities, problems, and situations is receiving an increasing amount of attention from consulting psychologists and applied researchers alike. I discuss how flexible leadership is defined with a variety of concepts in the literature and emphasized in the articles in the special issue of Consulting Psychology Journal: Practice and Research on Developing Flexible and Adaptive Leaders for an Age of Uncertainty (Kaiser, 2010, this issue). By integrating the views of the previous authors, I present flexible leadership as a metacompetency that subsumes multiple, more narrowly defined, components (e.g., a wide behavioral repertoire, a learning orientation to develop it, an ability to remain open to learning in novel situations). A model for applying this conception of flexible leadership is discussed followed by suggestions for further research to help consulting psychologists use these ideas in their practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
154.
Presacco A Forrester LW Contreras-Vidal JL 《IEEE transactions on neural systems and rehabilitation engineering》2012,20(2):212-219
Brain-machine interface (BMI) research has largely been focused on the upper limb. Although restoration of gait function has been a long-standing focus of rehabilitation research, surprisingly very little has been done to decode the cortical neural networks involved in the guidance and control of bipedal locomotion. A notable exception is the work by Nicolelis' group at Duke University that decoded gait kinematics from chronic recordings from ensembles of neurons in primary sensorimotor areas in rhesus monkeys. Recently, we showed that gait kinematics from the ankle, knee, and hip joints during human treadmill walking can be inferred from the electroencephalogram (EEG) with decoding accuracies comparable to those using intracortical recordings. Here we show that both intra- and inter-limb kinematics from human treadmill walking can be achieved with high accuracy from as few as 12 electrodes using scalp EEG. Interestingly, forward and backward predictors from EEG signals lagging or leading the kinematics, respectively, showed different spatial distributions suggesting distinct neural networks for feedforward and feedback control of gait. Of interest is that average decoding accuracy across subjects and decoding modes was ~0.68±0.08, supporting the feasibility of EEG-based BMI systems for restoration of walking in patients with paralysis. 相似文献
155.
Electric vehicles (EVs) are becoming increasingly popular because of their low operating costs. However, the anticipated increase in EV usage presents opportunities as well as challenges for utilities. This paper models EV charging behavior of active consumers who strategize their EV charging schedule to minimize the charging cost. The electric utility employs a temporal and spatially varying real-time pricing scheme that minimizes peak-to-average load ratio by influencing charging behavior of multiple active consumers. These active consumers decide their optimal charging strategy based on real-time electricity prices in order to minimize their EV charging cost. A model predictive control (MPC)-based optimal pricing scheme for electric utility and optimal charging strategy for active consumers is proposed. Effects of the proposed approach on load profile is verified using simulations. 相似文献
156.
Alan P. O. da Silva Cicilia R. M. Leite Larry McMillan Carlos A. Paz de Araujo Marcelo A. C. Fernandes ANA M. G. Guerreiro 《Integrated ferroelectrics》2015,159(1):23-33
In this work we propose the implementation of boolean logic through artificial neurons with Ferroelectric Capacitor (FeCapacitor) as its basic unit on a reconfigurable hardware platform. Two neurons were implemented: the Perceptron and the Spiking Neuron model. Both neurons use the phenomenon of the hysteresis loop as an activation function and were embedded on a Field Gate Programmable Gate Array (FPGA) hardware platform. The implementations were carried out by Simulink models and hardware synthesizable blocks from DSP Builder software and the results are shown in the form of the models and the boolean functions implemented by them. 相似文献
157.
Roles of the Na+/H+ Exchanger Isoform 1 and Urokinase in Prostate Cancer Cell Migration and Invasion
Xiuju Li Benjamin Buckley Konstantin Stoletov Yang Jing Marie Ranson John D. Lewis Mike Kelso Larry Fliegel 《International journal of molecular sciences》2021,22(24)
Prostate cancer is a leading cause of cancer-associated deaths in men over 60 years of age. Most patients are killed by tumor metastasis. Recent evidence has implicated a role of the tumor microenvironment and urokinase plasminogen activator (uPA) in cancer cell migration, invasion, and metastasis. Here, we examine the role of the Na+/H+ exchanger isoform 1 (NHE1) and uPA in DU 145 prostate cancer cell migration and colony formation. Knockout of NHE1 reduced cell migration. The effects of a series of novel NHE1/uPA hexamethylene-amiloride-based inhibitors with varying efficacy towards NHE1 and uPA were examined on prostate cancer cells. Inhibition of NHE1—alone, or with inhibitors combining NHE1 or uPA inhibition—generally did not prevent prostate cancer cell migration. However, uPA inhibition—but not NHE1 inhibition—prevented anchorage-dependent colony formation. Application of inhibitors at concentrations that only saturate uPA inhibition decreased tumor invasion in vivo. The results suggest that while knockout of NHE1 affects cell migration, these effects are not due to NHE1-dependent proton translocation. Additionally, while neither NHE1 nor uPA activity was critical in cell migration, only uPA activity appeared to be critical in anchorage-dependent colony formation of DU 145 prostate cancer cells and invasion in vivo. 相似文献
158.
Effects of allelochemicals on plant respiration and oxygen isotope fractionation by the alternative oxidase 总被引:8,自引:1,他引:8
The goal of this investigation was to determine the effects of allelochemicals on plant respiration that thereby may be responsible for their role in growth inhibition. We have tested the effects of juglone, quercetin, cinnamic acid, and-pinene on respiration rates, and electron partitioning through the cytochrome and alternative respiratory pathways, by measuring on-line oxygen consumption and oxygen isotope fractionation in soybean cotyledon tissue. Cinnamic acid and-pinene decreased the oxygen consumption rate and increased the relative partitioning of electron transport to the alternative pathway. Possible biochemical mechanisms of these effects are discussed. 相似文献
159.
160.
Larry Arnstein Stefan Sigdursson Bob Franza 《Journal of The Association for Laboratory Automation》2001,6(1):66
Our objective is to eliminate the digital divide that persists between the physical and information spaces of wet-lab based enterprises by embedding computational resources into the shared laboratory environment. Our first challenge is to enable individual lab workers to contribute to a fine-grained formal representation of ongoing lab activities - to build the database by doing the work, without having to stop and write things down in a notebook or to enter information into a computer. By eliminating the redundancy of doing the work and then recording it, accuracy and completeness will be improved. And, by capturing information at a finer detail than is practical for manual entry systems, unanticipated applications can be supported. 相似文献