全文获取类型
收费全文 | 1586篇 |
免费 | 56篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 14篇 |
综合类 | 2篇 |
化学工业 | 248篇 |
金属工艺 | 11篇 |
机械仪表 | 27篇 |
建筑科学 | 45篇 |
矿业工程 | 1篇 |
能源动力 | 19篇 |
轻工业 | 114篇 |
水利工程 | 5篇 |
石油天然气 | 3篇 |
无线电 | 208篇 |
一般工业技术 | 218篇 |
冶金工业 | 571篇 |
原子能技术 | 22篇 |
自动化技术 | 135篇 |
出版年
2021年 | 27篇 |
2020年 | 11篇 |
2019年 | 16篇 |
2018年 | 18篇 |
2017年 | 29篇 |
2016年 | 24篇 |
2015年 | 16篇 |
2014年 | 20篇 |
2013年 | 48篇 |
2012年 | 42篇 |
2011年 | 61篇 |
2010年 | 36篇 |
2009年 | 58篇 |
2008年 | 52篇 |
2007年 | 45篇 |
2006年 | 37篇 |
2005年 | 40篇 |
2004年 | 45篇 |
2003年 | 27篇 |
2002年 | 32篇 |
2001年 | 29篇 |
2000年 | 27篇 |
1999年 | 33篇 |
1998年 | 116篇 |
1997年 | 79篇 |
1996年 | 55篇 |
1995年 | 54篇 |
1994年 | 38篇 |
1993年 | 42篇 |
1992年 | 23篇 |
1991年 | 25篇 |
1990年 | 27篇 |
1989年 | 26篇 |
1988年 | 16篇 |
1987年 | 29篇 |
1986年 | 21篇 |
1985年 | 32篇 |
1984年 | 13篇 |
1983年 | 18篇 |
1982年 | 13篇 |
1981年 | 24篇 |
1980年 | 13篇 |
1979年 | 18篇 |
1978年 | 23篇 |
1977年 | 28篇 |
1976年 | 32篇 |
1975年 | 12篇 |
1974年 | 11篇 |
1973年 | 12篇 |
1971年 | 8篇 |
排序方式: 共有1643条查询结果,搜索用时 46 毫秒
1.
Wen Cao Zhonghua Zhou Chenyu Li Qun Wang Yue Huang Shirley Shen 《Ceramics International》2021,47(2):1807-1818
Sodalime float (SF) glass is widely used in our societies and industries. Hydrothermal corrosion method is one of the effective ways to prepare a superhydrophobic glass, but there is still lack of knowledge about hydrothermal corrosion behavior and mechanism of SF glass. We have hydrothermally treated SF glass at 180 °C for different time, and tried to reveal the aqueous corrosion process of SF glass. We have characterized the morphologies and chemical compositions of samples, and found that (1) the two sides of SF glass have different corrosion resistances, and (2) a multilayer structural coating with a nanoflake layer (Mg-rich gel layer), a nanowire layer (Ca-rich gel layer), and a porous layer (etched layer) is formed on the air-side of SF glass. Based on the experimental results, we have proposed an aqueous corrosion mechanism of SF glass. The insights of the hydrothermal corrosion behaviors and mechanism provide helpful guidelines to glass surface structural control and functionalization. 相似文献
2.
3.
Intraseptal scopolamine has differential effects on Pavlovian eye blink and heart rate conditioning.
Evaluated the effects of intraseptal scopolamine hydrobromide (40 μg) injections on Pavlovian (classical) conditioning, with tones used as the CS and a periorbital electric shock train as the UCS, using New Zealand albino rabbits. Eyeblink (EB) and heart rate (HTR) CRs were concomitantly recorded. Although injections of scopolamine into the medial septum impaired the acquisition of the Pavlovian conditioned eyelid reflex, these injections enhanced the magnitude of accompanying Pavlovian conditioned HTR decelerations. However, scopolamine applied to the lateral septal area had no effect on EB conditioning, relative to the vehicle; like medial injections, scopolamine also enhanced the magnitude of the accompanying HTR decelerations. Results are compatible with those of previous investigations indicating that medial septal dysfunction impairs somatomotor conditioning but leaves autonomic conditioning intact and that septal dysfunction produces a parasympathetic bias of the cardiovascular system. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
Lasers containing a nanopatterned active layer demonstrating excellent threshold characteristics are presented. The nanopatterned active layer is fabricated using high-resolution electron beam lithography and selective-area metal organic chemical vapour deposition crystal growth. Results demonstrating an order of magnitude improvement over previous results are reported. 相似文献
5.
In this work, we have created a new type of structure, the nanopore active layer, for achieving quantization of carrier states in a semiconductor. The nanopore structure consists of a periodic two-dimensional array of localized energy barriers perturbing an otherwise conventional quantum well. This perturbation leads to the formation of intraband forbidden energy gaps which are observed experimentally. 相似文献
6.
Geoffrey Rowden Shirley Dean James Campbell Philip Belitsky 《Microscopy research and technique》1985,2(6):547-555
Aspiration biopsy of tumors and transplanted organs is a popular atraumatic method for diagnosis and also for the management of patients. Apart from the cytological analyses, it is clear that large aggregates of cells are obtained and these may be examined by electron microscopy. A study was carried out with dogs to assess the yield of intact glomeruli and tubules, resulting from a standard fine-needle aspiration procedure. Employing a 20-gauge needle, yields of approximately ten intact glomeruli were obtained with a tissue processing protocol that utilized filtration through a nylon mesh and backwashing, to resuspend the trapped aggregates. Processing for electron microscopy was carried out in microcentrifuge tubes. The ultrastructural preservation was excellent and the extension of these studies to investigations of not only renal transplantation, but also for diagnosis in human renal diseases of a broad spectrum, is suggested. 相似文献
7.
8.
The visual sector of the reticular thalamic nucleus has come under some intense scrutiny over recent years, principally because of the key role that the nucleus plays in the processing of visual information. Despite this scrutiny, we know very little of how the connections between the reticular nucleus and the different areas of visual cortex and the different visual dorsal thalamic nuclei are organized. This study examines the patterns of reticular connections with the visual cortex and the dorsal thalamus in the rat, a species where the visual pathways have been well documented. Biotinylated dextran, an anterograde and retrograde tracer, was injected into different visual cortical areas [17; rostral 18a: presumed area AL: (anterolateral); caudal 18a: presumed area LM (lateromedial); rostral 18b: presumed area AM (anteromedial); caudal 18b: presumed area PM (posteromedial)] and into different visual dorsal thalamic nuclei (posterior thalamic, lateral geniculate nuclei), and the patterns of anterograde and retrograde labelling in the reticular nucleus were examined. From the cortical injections, we find that the visual sector of the reticular nucleus is divided into subsectors that each receive an input from a distinct visual cortical area, with little or no overlap. Further, the resulting pattern of cortical terminations in the reticular nucleus reflects largely the patterns of termination in the dorsal thalamus. That is, each cortical area projects to a largely distinct subsector of the reticular nucleus, as it does to a largely distinct dorsal thalamic nucleus. As with each of the visual cortical areas, each of the visual dorsal thalamic (lateral geniculate, lateral posterior, posterior thalamic) nuclei relate to a separate territory of the reticular nucleus, with little or no overlap. Each of these dorsal thalamic territories within the reticular nucleus receives inputs from one or more of the visual cortical areas. For instance, the region to the reticular nucleus that is labelled after an injection into the lateral geniculate nucleus encompasses the reticular regions which receive afferents from cortical areas 17, rostral 18b and caudal 18b. These results suggest that individual cortical areas may influence the activity of different dorsal thalamic nuclei through their reticular connections. 相似文献
9.
Kerlavage A.R. FitzHugh W. Gladek A. Kelley J. Scott J. Shirley R. Sutton G. Man Wai-Chiu White O. Adams D. 《IEEE engineering in medicine and biology magazine》1995,14(6):710-717
The rapid advances in molecular biology have begun to shift many of the bottlenecks in genome research from the laboratory to the data analysis facility. The pace at which this has occurred creates a situation in which software development always has to catch up with the flow of data. Since such large-scale processes were not anticipated, the analysis infrastructure has not been fully established. Furthermore, most systems that have been built were designed by the biologists who collected the data. More recently, computer scientists, mathematicians, and engineers have taken an interest in this problem. This has had a positive effect, since it has created a tight synergy between the informatics and the biology. Several principles affected the design of the system developed at TIGR. Each of the sample preparation, sequencing, and analysis steps had to be managed, scheduled, and tracked. This information had to be made readily available to those who needed it for carrying out their tasks. Different skill levels of the users had to be taken into account. The degree of human intervention at each step had to be evaluated and built into the design. A mixed processing environment of Macintosh and Unix platforms had to be integrated. Most importantly, the system had to save time, reduce error, and ensure uniformity of the analysis and quality of the results. In the authors' experience, the tools they have built work well because of their early decisions as to which systems to use for development. The authors settled on a robust relational database management system (Sybase) and a portable development environment (C, C++) 相似文献
10.
Describes methods and techniques of play therapy for use with multicultural and diverse populations. Barriers to counseling multicultural children and Eurocentric play therapy techniques with multicultural populations are highlighted. Specific guidelines and examples for play therapy with multicultural children are provided. Recommendations and implications for mental health professionals are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献