全文获取类型
收费全文 | 5318篇 |
免费 | 336篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 67篇 |
综合类 | 3篇 |
化学工业 | 1492篇 |
金属工艺 | 59篇 |
机械仪表 | 149篇 |
建筑科学 | 209篇 |
矿业工程 | 9篇 |
能源动力 | 228篇 |
轻工业 | 872篇 |
水利工程 | 67篇 |
石油天然气 | 25篇 |
无线电 | 360篇 |
一般工业技术 | 839篇 |
冶金工业 | 193篇 |
原子能技术 | 27篇 |
自动化技术 | 1064篇 |
出版年
2024年 | 13篇 |
2023年 | 57篇 |
2022年 | 193篇 |
2021年 | 248篇 |
2020年 | 161篇 |
2019年 | 187篇 |
2018年 | 225篇 |
2017年 | 196篇 |
2016年 | 248篇 |
2015年 | 187篇 |
2014年 | 255篇 |
2013年 | 456篇 |
2012年 | 364篇 |
2011年 | 434篇 |
2010年 | 284篇 |
2009年 | 322篇 |
2008年 | 292篇 |
2007年 | 253篇 |
2006年 | 202篇 |
2005年 | 165篇 |
2004年 | 145篇 |
2003年 | 113篇 |
2002年 | 115篇 |
2001年 | 51篇 |
2000年 | 44篇 |
1999年 | 38篇 |
1998年 | 60篇 |
1997年 | 37篇 |
1996年 | 37篇 |
1995年 | 33篇 |
1994年 | 32篇 |
1993年 | 27篇 |
1992年 | 19篇 |
1991年 | 20篇 |
1990年 | 19篇 |
1989年 | 13篇 |
1988年 | 12篇 |
1987年 | 16篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 18篇 |
1983年 | 8篇 |
1982年 | 10篇 |
1980年 | 9篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1974年 | 4篇 |
排序方式: 共有5663条查询结果,搜索用时 15 毫秒
11.
12.
Large diameter slender cylindrical shells used as buoyancy chambers and support legs for compliant marine structures experience a variety of impact loadings which could induce significant levels of dynamic response. By examining the response of a typical range of cylindrical shell geometries to a simulation of the impact loading typical of wave slamming, the paper examines the likely levels and practical significance of the transient dynamic response. It shows that the levels of dynamic response are sufficiently severe to have important implications for the triggering of buckling and fatigue collapse characteristics. It is suggested that this phenomenon requires additional more-detailed consideration, including the provision of reliable predictions of transient slam pressure distributions and the levels and forms of hydrodynamic damping, as well as the effects of more practical shell and stiffening geometries, and ambient stress levels. 相似文献
13.
Ionomeric composites based on sepiolite and hydrogenated poly(styrene butadiene) block copolymer were obtained and characterized from a microstructural and electrical point of view. Before blending, because of the high silanol group concentration in the sepiolite, the latter could be organophilized with suitable coupling agents. The resulting materials were easily processed into thin films or membranes 0.2–0.4 mm thick, their conductivity in some cases approaching 10?1 S/cm. Their suitability for film formation and good electrical properties indicate potential applications as electrolytes in polymer fuel cells. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3512–3519, 2002 相似文献
14.
Proper integration of scheduling and control in Flexible Manufacturing Systems will make available the required level of decision-making capacity to provide a flexibly-automated, efficient, and quality manufacturing process. To achieve this level of integration, the developments in computer technology and sophisticated techniques of artificial intelligence (AI) should be applied to such FMS functions as scheduling. In this paper, we present an Intelligent Scheduling System for FMS under development that makes use of the integration of two AI technologies. These two AI technologies — Neural Networks and Expert Systems — provide the intelligence that the scheduling function requires in order to generate goodschedules within the restrictions imposed by real-time problems. Because the system has the ability to plan ahead and learn, it has a higher probability of success than conventional approaches. The adaptive behavior that will be achieved contribute to the integration of scheduling and control in FMS. 相似文献
15.
Luis Suarez-Villa 《The Annals of Regional Science》1985,19(3):54-108
This article is a contribution to the study of urban and manufacturing evolution that develops and applies the author's concept of the urban-manufacturing life cycle. This concept relates internal characteristics and external impacts of the urban manufacturing base to the process of urban growth by considering the most significant variables and their changes over time. Emphasis is also placed on process-oriented evolution and general relevance rather than outcomes. An application to the general study of border cities with distinct levels of development follows a review of the urban and regional growth literature, as an initial contribution to the development of an evolutionary theory of borders. Empirical analyses with longitudinal data for five major United States and Mexican border urban clusters then evaluate the general assumptions of the concept. Growth trends in urban population, sectoral employment shares, urban industrial structure, employment, and number of manufacturing plants are examined in each of the cities and urban clusters considered. The study concludes that the empirical analyses generally verify the assumptions of the urban-manufacturing life cycle. 相似文献
16.
The aim of this study was to evaluate the effects of paste properties on residence time during drying in a spouted bed dryer with inert bodies. The effect of paste solids content, surface tension, and viscosity on the residence time distribution and the mean residence times were studied using factorial experimental designs. The inert bodies used were glass and polyethylene beads. The mean residence times varied from 13.6 to 16.3 and 12.2 to 17.7 min for drying on glass and polyethylene beads, respectively. The analysis of variance showed that mean residence times significantly depended on solids content and surface tension for glass beads and also on viscosity for polyethylene beads. The residence time distributions for all conditions studied fitted well to the perfect mixing cell when applying the continuous stirred vessels in series model analysis. The powder density, flowability, and particle size depended on paste properties and inert type. 相似文献
17.
Birthe Mller Jose Luis Molina‐Cano Lars Munck 《Journal of the Institute of Brewing》2002,108(3):294-302
In earlier studies concerning vigour, where subsamples are heat‐treated before germination there was found heat‐sensitive as well as heat‐resistant barley samples. The vigour model developed by Ellis and Roberts and further developed at Carlsberg, could only describe the heat‐sensitive barleys. Seventeen samples of the “Alexis” variety grown widely in Europe were collected from the EBC trials in 1994 in order to see if heat resistance in barley was influenced by different growing conditions. We found both heat‐sensitive samples following the vigour model as well as pronounced heat‐resistant samples, but these were not divided according to growing conditions. The germination curves dependent on heat treatment and germination time were evaluated by Principal Component Analysis (PCA). Heat‐resistant barley samples could be differentiated from heat‐sensitive samples already after ½ h of heat treatment at 68°C (12% moisture) and after 3 days of germination. The barley samples were analysed with regard to malting quality. The PCA evaluation of the data divided the samples according to growing location, mainly due to differences in protein and β‐glucan. However, the malting analyses could not describe the differences in heat resistance and sensitivity of the barleys. The biochemical background of the heat resistance found is discussed on the basis of literature. Our findings should give an experimental basis for exploiting a biochemical principle for heat resistance, which is formed during grain filling and consumed during storage and germination. 相似文献
18.
19.
Research on early childhood socialization suggests that Hispanic parents differ from parents of other ethnic groups in their child rearing values and the interpersonal behavior they want their children to display at home and school. In this article, the influence of context and culture on child rearing is shown through a review of conceptual frameworks for understanding child socialization in both minority and nonminority families and research on infant–mother attachment and parental beliefs about young children's behavior. This review indicates that parent and child behaviors are a result of different socialization processes that encompass specific cultural values. Implications for professional practice are drawn for child assessment and psychotherapy, family therapy, and parenting skills programs conducted with Hispanics. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
20.