全文获取类型
收费全文 | 8502篇 |
免费 | 352篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 89篇 |
综合类 | 5篇 |
化学工业 | 1701篇 |
金属工艺 | 296篇 |
机械仪表 | 152篇 |
建筑科学 | 337篇 |
矿业工程 | 34篇 |
能源动力 | 226篇 |
轻工业 | 613篇 |
水利工程 | 107篇 |
石油天然气 | 49篇 |
武器工业 | 1篇 |
无线电 | 641篇 |
一般工业技术 | 1328篇 |
冶金工业 | 1960篇 |
原子能技术 | 61篇 |
自动化技术 | 1264篇 |
出版年
2023年 | 51篇 |
2022年 | 80篇 |
2021年 | 151篇 |
2020年 | 112篇 |
2019年 | 129篇 |
2018年 | 142篇 |
2017年 | 140篇 |
2016年 | 188篇 |
2015年 | 175篇 |
2014年 | 230篇 |
2013年 | 483篇 |
2012年 | 389篇 |
2011年 | 521篇 |
2010年 | 371篇 |
2009年 | 405篇 |
2008年 | 458篇 |
2007年 | 436篇 |
2006年 | 341篇 |
2005年 | 289篇 |
2004年 | 287篇 |
2003年 | 264篇 |
2002年 | 223篇 |
2001年 | 168篇 |
2000年 | 159篇 |
1999年 | 161篇 |
1998年 | 194篇 |
1997年 | 160篇 |
1996年 | 159篇 |
1995年 | 137篇 |
1994年 | 130篇 |
1993年 | 150篇 |
1992年 | 106篇 |
1991年 | 84篇 |
1990年 | 110篇 |
1989年 | 108篇 |
1988年 | 101篇 |
1987年 | 93篇 |
1986年 | 78篇 |
1985年 | 91篇 |
1984年 | 98篇 |
1983年 | 77篇 |
1982年 | 70篇 |
1981年 | 77篇 |
1980年 | 65篇 |
1979年 | 63篇 |
1978年 | 68篇 |
1977年 | 44篇 |
1976年 | 53篇 |
1975年 | 43篇 |
1974年 | 36篇 |
排序方式: 共有8864条查询结果,搜索用时 11 毫秒
1.
Using an integrated process of data and modeling in HRA 总被引:1,自引:0,他引:1
John Wreathall Dennis Bley Emilie Roth Jordan Multer Thomas Raslear 《Reliability Engineering & System Safety》2004,83(2):221
The paper describes an approach taken to estimate the probabilities of failure associated with various railroad tasks to prevent accidents (principally collisions and derailments). These probabilities were estimated using an expert elicitation process that used partially relevant data available from a variety of databases and that were filtered and scaled to make them more directly relevant to the analyses being performed. Extensive qualitative studies were performed prior to the elicitation process to identify relevant contexts under which the tasks can be performed. 相似文献
2.
3.
4.
This study, which is based on responses from over 300 individuals in England and Wales, explores how a willingness to use a water-recycling system of specific configuration varies against a number of factors which are linked to system design, system scale, system context, and water-conservation behaviour. Findings show that there is broad willingness to accept in-house water recycling provided that public health is not compromised. 相似文献
5.
6.
Gregory S. Zaric Jeffrey S. Hoch 《International Transactions in Operational Research》2006,13(6):493-513
Interest in medical savings accounts (MSAs) as a potential tool to reduce healthcare costs has been widespread. A small number of countries have either implemented or run pilot programs of MSAs, and vigorous policy debates have taken place in several other countries about the potential merits of introducing MSAs as a method of paying for health care. In this paper we develop a model to assess the cost saving potential of MSAs in a publicly funded healthcare system. We assume that the public healthcare payer may choose between reimbursing healthcare expenditures through an MSA or through a form of third‐party payer insurance. We use the model to identify the conditions under which MSAs may reduce costs. We illustrate using data on healthcare expenditures from Canada. 相似文献
7.
Olivier Merlin Jeffrey P. Walker Abdelghani Chehbouni Yann Kerr 《Remote sensing of environment》2008,112(10):3935-3946
A deterministic approach for downscaling ~ 40 km resolution Soil Moisture and Ocean Salinity (SMOS) observations is developed from 1 km resolution MODerate resolution Imaging Spectroradiometer (MODIS) data. To account for the lower soil moisture sensitivity of MODIS surface temperature compared to that of L-band brightness temperature, the disaggregation scale is fixed to 10 times the spatial resolution of MODIS thermal data (10 km). Four different analytic downscaling relationships are derived from MODIS and physically-based model predictions of soil evaporative efficiency. The four downscaling algorithms differ with regards to i) the assumed relationship (linear or nonlinear) between soil evaporative efficiency and near-surface soil moisture, and ii) the scale at which soil parameters are available (40 km or 10 km). The 1 km resolution airborne L-band brightness temperature from the National Airborne Field Experiment 2006 (NAFE'06) are used to generate a time series of eleven clear sky 40 km by 60 km near-surface soil moisture observations to represent SMOS pixels across the three-week experiment. The overall root mean square difference between downscaled and observed soil moisture varies between 1.4% v/v and 1.8% v/v depending on the downscaling algorithm used, with soil moisture values ranging from 0 to 15% v/v. The accuracy and robustness of the downscaling algorithms are discussed in terms of their assumptions and applicability to SMOS. 相似文献
8.
The role of implicit theories in behavioral judgments continues to be a source of debate. In a study exploring the factorial validity of student ratings of instruction, Cadwell and Jenkins (1985) suggested that students' implicit theories of instructor behavior may account for the robust factor structure underlying student ratings. They argued that students rely on the semantic similarity of the rating items, inflating the observed relations among the items. Marsh and Groves cite methodological and conceptual difficulties with the Cadwell and Jenkins study, but most of these difficulties may arise from Marsh and Groves's misconceptions about the role of implicit theories and semantic similarities and, more generally, the cognitive processes underlying judgment tasks. I review these issues and address various points of Marsh and Groves's critique. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
Amanda Alliband Daniel W. Lenz Laura E. Stevenson Travis Whitmer Rex Cash Dennis Burns Sarah Hall William T.K. Stevenson 《Progress in Organic Coatings》2008
A model has been proposed to explain the failure of the original BMS10-39 epoxy paint on upper vertical surfaces in B-52 fuel tanks. The model involves interaction of the paint with DIEGME, a fuel system ice inhibitor (FSII) in jet fuel, that is distilled from the liquid fuel. In this communication, distillation experiments used to support the model are refined to better match the mass transfer of vapor from fuel in a B-52 fuel tank at close to room temperature. The interaction of these lower temperature distillates with the paint affirms the earlier model. On the basis of these experiments it is proposed that paint failure may be controlled or eliminated by reducing the level of DIEGME in the fuel. Proposed changes in military jet fuel composition are detailed. 相似文献
10.
Penedo Frank J.; Dahn Jason R.; Gonzalez Jeffrey S.; Molton Ivan; Carver Charles S.; Antoni Michael H.; Roos Bernard A.; Schneiderman Neil 《Canadian Metallurgical Quarterly》2003,22(2):220
This study evaluated relations among optimism, perceived stress management skills (PSMS), and positive mood in 46 men who had surgical treatment for localized prostate cancer. The authors found that optimism, PSMS, and positive mood scores were positively correlated. Positive mood was unrelated to demographic and disease-related control variables. In a hierarchical regression model controlling for PSMS, the relationship between optimism and positive mood became nonsignificant, whereas PSMS remained a correlate of positive mood. Results suggest that the relationship between optimism and positive mood may be mediated by belief in being able to use stress management techniques effectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献