全文获取类型
收费全文 | 1250篇 |
免费 | 55篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 249篇 |
金属工艺 | 5篇 |
机械仪表 | 13篇 |
建筑科学 | 61篇 |
矿业工程 | 2篇 |
能源动力 | 22篇 |
轻工业 | 165篇 |
水利工程 | 21篇 |
石油天然气 | 3篇 |
无线电 | 55篇 |
一般工业技术 | 188篇 |
冶金工业 | 379篇 |
原子能技术 | 3篇 |
自动化技术 | 131篇 |
出版年
2023年 | 17篇 |
2022年 | 28篇 |
2021年 | 45篇 |
2020年 | 27篇 |
2019年 | 28篇 |
2018年 | 28篇 |
2017年 | 30篇 |
2016年 | 29篇 |
2015年 | 23篇 |
2014年 | 31篇 |
2013年 | 79篇 |
2012年 | 52篇 |
2011年 | 91篇 |
2010年 | 68篇 |
2009年 | 65篇 |
2008年 | 83篇 |
2007年 | 82篇 |
2006年 | 67篇 |
2005年 | 50篇 |
2004年 | 44篇 |
2003年 | 30篇 |
2002年 | 39篇 |
2001年 | 25篇 |
2000年 | 23篇 |
1999年 | 20篇 |
1998年 | 20篇 |
1997年 | 20篇 |
1996年 | 16篇 |
1995年 | 7篇 |
1994年 | 18篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 12篇 |
1983年 | 8篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1973年 | 2篇 |
1958年 | 2篇 |
排序方式: 共有1305条查询结果,搜索用时 31 毫秒
31.
Gary J. Smith C. Robert Bagnell William E. Bakewell Kurt A. Black Thomas W. Bouldin Todd S. Earnhardt Gary E. R. Hook Katherine B. Pryzwansky 《Microscopy research and technique》1991,18(1):38-49
Confocal scanning laser microscopy (CSLM) represents an exciting new tool for scientific disciplines which focus on mechanistic studies such as experimental pathology. Enhanced resolution in the specimen plane and rejection of out-of-focus fluorescence flare allow analysis of specific nucleic acid sequences, enzymes, structural macromolecules, and cellular homeostasis utilizing fluorescent probes. Four different experimental applications are discussed which utilize CSLM to evaluate pathological processes at the subcellular, cellular, and tissue levels. Programmed cell death, or apoptosis, is a natural process of significance both during development and as a response to toxic stimuli. CSLM-imaging of nuclei of human B lymphoblastoid cells following exposure to a monofunctional alkylating agent suggests that the degradation of chromatin characteristic of apoptosis may occur in asymmetric patterns. Surfactant apoprotein-A is the major non-serum protein component of pulmonary surfactant and is essential for the extracellular function of surfactant. CSLM of alveolar type II cells suggests that apoprotein-A is present in both the cytoplasm, predominantly in lamellar bodies, and in the nucleus. The tumor promoter, phorbol myristate acetate, rapidly stimulated the formation of vacuoles in human neutrophils. CSLM using Lucifer Yellow as a probe suggests that cylindrical vacuoles are formed by fluid-phase pinocytosis. The blood-nerve barrier (BNB) in peripheral nerves may be an important target during toxin-induced neuropathies. Ricin-induced permeability of the BNB in the rat was rapidly visualized by CSLM as leakage of fluorescein isothiocynate (FITC)-dextran into the endoneurial compartment. 相似文献
32.
Prior research has shown that people are likely to skim information presented digitally with the resultant deleterious effect on accurate mental models of the text. Teaching monitoring strategies and presenting text with adjunct questions are effective strategies for improving the mental models of readers of scientific text, but the two strategies have not been directly compared for studying text read from a computer screen. In the present study, participants were individually tested in two experiments in which they studied computer-based text on the heart and circulatory system while either reading the text with no interruption, answering adjunct inference questions, answering adjunct factual questions, or answering prompts for global or specific monitoring. Reading time was untimed but looking back was not available. Prompting for global monitoring was most effective for improvement of mental models as measured by scores in diagram drawing, concept map construction, factual memory, and generating inferences. Further, global monitoring did not require more time-on-task than the other methods. 相似文献
33.
Katherine Aschner 《Information Systems Management》2013,30(4):61-66
Facilities—an enterprise's physical work environment—represent a major opportunity for MIS today. Facilities management extends a challenge to support a key strategic resource and a chance to build a solid business case for many technology investments. 相似文献
34.
35.
Municipal infrastructure for water supply and delivery often does not reach populations in rural and peri-urban areas. This article examines rainwater harvesting as a means of increasing water security in such areas, through the case of Guachtuq, a peri-urban community outside San Cristóbal, Alta Verapaz, Guatemala. The project team designed a rainwater harvesting system to improve three dimensions of water security: quantity, quality and access. The design was implemented for 12 households and evaluated for its contribution to water security and for the potential of expanding project coverage to the region and beyond. The system has improved water security. Several concerns remain, however, regarding the potential of expanding the project to other households in the region and beyond, including system cost, water quality and the individualization of public responsibility for water security. 相似文献
36.
Flora W Y Chiu Hakan Bagci Amanda G Fisher Andrew J deMello Katherine S Elvira 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2016,91(1):16-24
Cellular fusion is a key process in many fields ranging from historical gene mapping studies and monoclonal antibody production, through to cell reprogramming. Traditional methodologies for cell fusion rely on the random pairing of different cell types and generally result in low and variable fusion efficiencies. These approaches become particularly limiting where substantial numbers of bespoke one‐to‐one fusions are required, for example, for in‐depth studies of nuclear reprogramming mechanisms. In recent years, microfluidic technologies have proven valuable in creating platforms where the manipulation of single cells is highly efficient, rapid and controllable. These technologies also allow the integration of different experimental steps and characterisation processes into a single platform. Although the application of microfluidic methodologies to cell fusion studies is promising, current technologies that rely on static trapping are limited both in terms of the overall number of fused cells produced and their experimental accessibility. Here we review some of the most exciting breakthroughs in core microfluidic technologies that will allow the creation of integrated platforms for controlled cell fusion at high throughput. © 2015 Society of Chemical Industry 相似文献
37.
Benjamin Letham Cynthia Rudin Katherine A. Heller 《Data mining and knowledge discovery》2013,27(3):372-395
It is easy to find expert knowledge on the Internet on almost any topic, but obtaining a complete overview of a given topic is not always easy: information can be scattered across many sources and must be aggregated to be useful. We introduce a method for intelligently growing a list of relevant items, starting from a small seed of examples. Our algorithm takes advantage of the wisdom of the crowd, in the sense that there are many experts who post lists of things on the Internet. We use a collection of simple machine learning components to find these experts and aggregate their lists to produce a single complete and meaningful list. We use experiments with gold standards and open-ended experiments without gold standards to show that our method significantly outperforms the state of the art. Our method uses the ranking algorithm Bayesian Sets even when its underlying independence assumption is violated, and we provide a theoretical generalization bound to motivate its use. 相似文献
38.
The 1992 Framework Convention on Climate Change created the basic international architecture for addressing climate change. That treaty was negotiated at a time when the research literature examining emissions mitigation and the role of energy technology was relatively limited. In the two subsequent decades a great deal has been learned. The problem of stabilizing the concentration of greenhouse gases in the atmosphere has proved far more difficult than envisioned in 1992 and the role of technology appears even more important when emissions mitigation strategies are co-developed in the context of multiple competing ends. 相似文献
39.
40.
The agglomeration of exporters by destination 总被引:1,自引:0,他引:1
Precise characterization of informational trade barriers is neither well documented nor understood. Using Russian customs data, we document that regional destination-specific export spillovers exist for developing countries, extending a result that was only known for developed countries. This result suggests behavior responding to a destination barrier. To account for this fact, we build on a monopolistic competition model of trade by postulating an externality in the international transaction of goods. We test the model’s prediction on region-level exports using Russian data and find improvement over gravity-type models without agglomeration. This finding has important development implications in that export policy that considers current trade partners may be more effective than policy that focuses only on the exporting country’s industries. Furthermore, our findings can be considered in the burgeoning literature refining transaction costs beyond the traditional iceberg cost. 相似文献