全文获取类型
收费全文 | 1574篇 |
免费 | 27篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 20篇 |
综合类 | 9篇 |
化学工业 | 121篇 |
金属工艺 | 16篇 |
机械仪表 | 15篇 |
建筑科学 | 39篇 |
矿业工程 | 4篇 |
能源动力 | 25篇 |
轻工业 | 88篇 |
水利工程 | 4篇 |
武器工业 | 1篇 |
无线电 | 91篇 |
一般工业技术 | 127篇 |
冶金工业 | 927篇 |
原子能技术 | 13篇 |
自动化技术 | 104篇 |
出版年
2022年 | 5篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 9篇 |
2017年 | 16篇 |
2016年 | 13篇 |
2015年 | 8篇 |
2014年 | 11篇 |
2013年 | 24篇 |
2012年 | 20篇 |
2011年 | 29篇 |
2010年 | 11篇 |
2009年 | 20篇 |
2008年 | 39篇 |
2007年 | 28篇 |
2006年 | 19篇 |
2005年 | 38篇 |
2004年 | 32篇 |
2003年 | 19篇 |
2002年 | 25篇 |
2001年 | 21篇 |
2000年 | 22篇 |
1999年 | 48篇 |
1998年 | 275篇 |
1997年 | 132篇 |
1996年 | 99篇 |
1995年 | 77篇 |
1994年 | 57篇 |
1993年 | 66篇 |
1992年 | 12篇 |
1991年 | 17篇 |
1990年 | 23篇 |
1989年 | 22篇 |
1988年 | 30篇 |
1987年 | 29篇 |
1986年 | 28篇 |
1985年 | 22篇 |
1984年 | 19篇 |
1983年 | 11篇 |
1982年 | 14篇 |
1981年 | 14篇 |
1980年 | 8篇 |
1979年 | 9篇 |
1978年 | 13篇 |
1977年 | 35篇 |
1976年 | 59篇 |
1975年 | 5篇 |
1973年 | 7篇 |
1972年 | 7篇 |
1970年 | 6篇 |
排序方式: 共有1604条查询结果,搜索用时 15 毫秒
61.
G. F. Aouad J. A. Kirkhami P. S. Brandon F. E. Brown G. S. Cooper S. Ford 《Construction Management & Economics》2013,31(5):384-397
Modelling of knowledge in the construction industry is a cumbersome task because of the large amount of data involved and the lack of automated information-modelling tools. Adoption of a method and an automated CASE (Computer-Aided Software Engineering) tool could eliminate many problems encountered in the development of information systems in the construction industry. In particular, this approach may help to assess the information requirements and define strategies for such information systems. The Information Engineering Method (IEM) is introduced to illustrate hoar the conceptual models may be improved by using this method. Additionally Texas Instruments' Information Engineering Facility (IEF?) CASE tool is described to illustrate the advantages of automating such a method. The introduction of conceptual modelling in the construction industry using data and process models should lead to a better structuring of information. This should result in the development of well defined and structured, not ad hoc, applications. This conceptual modelling approach using information engineering is currently being used at the University of Salford to study the potential development of an integrated database (design, procurement and management of construction) for the construction industry. The case study describes the information analysis phase of the procurement process included towards the end of this paper. 相似文献
62.
63.
64.
据iSuppli公司,由于全经济和电子市场继续复苏,尽管2011年半导体产业不会再现今年预期中的强劲表现,但将继续增长.
2011年全球半导体销售额将达到3174亿美元,比今年预期的3020亿美元温和增长5.1%. 相似文献
65.
66.
Contact conductivity detection in poly(methyl methacrylate)-based microfluidic devices for analysis of mono- and polyanionic molecules 总被引:1,自引:0,他引:1
Galloway M Stryjewski W Henry A Ford SM Llopis S McCarley RL Soper SA 《Analytical chemistry》2002,74(10):2407-2415
An on-column contact conductivity detector was developed for the analysis of various mono- and polyanionic compounds separated by electrophoresis chips fabricated in poly(methyl methacrylate) (PMMA) using hot embossing techniques from Ni electroforms. The detector consisted of a pair of Pt wires (127 microm diameter) with an end-to-end spacing of approximately 20 microm and situated within the fluidic channel. The waveform applied to the electrode pair was a bipolar pulse with a frequency of 5.0 kHz and was used to reduce the charging current from measurement so that the current recorded at the end of one pulse is more representative of the solution conductivity. Using the detector, separations of amino acids, peptides, proteins, and oligonucleotides were demonstrated. For the amino acids and peptides, free-solution zone electrophoresis was performed. A calibration plot for the amino acid alanine was found to be linear from approximately 10 to 100 nM in a carrier electrolyte consisting of 10 mM triethylamonium acetate. The concentration detection limit was found to be 8.0 nM, with the corresponding mass detection limit equal to 3.4 amol (injection volume = 425 pL). The protein separations with conductivity detection were performed using MEKC, in which the carrier electrolyte contained the anionic surfactant sodium dodecyl sulfate (SDS) above its cmc. Near baseline resolution was achieved in the PMMA microchip for a solution containing 8 different proteins. In the case of the DNA fragments, capillary electrochromatography was used with a C18-modified PMMA chip and a carrier electrolyte containing an ion-pairing agent. 相似文献
67.
Ford MG Hoare NE Hudson BD Nevell TG Banting L 《Journal of molecular graphics & modelling》2002,21(1):29-36
Previous studies of the conformational behaviour of a group of synthetic pyrethroid insecticides have been extended to a more structurally diverse set. This includes compounds with different backbones and differing stereochemistry, with both Types I and II biological activity. These compounds also encompass a large range of biological activities. A parameterisation of the CHARMM force field for these compounds has been performed and the extra parameters are reported. Conformational sampling, using molecular dynamics (MD), has been performed for each of the 41 active structures. The accessible conformations of each have been characterised by the values of the common torsion angles using hierarchichal cluster analysis (HCA). A further CA, based on the centroids derived from the conformational sampling, identified a conformation common to at least 39 of the 41 structures. The critical torsion angles of this conformation lie at the centre of the molecule about the ester linkage and are defining an extended conformation, which differs from the minimum energy conformation of deltamethrin used previously. This may represent a putative pharmacophore for kill. The methods used here improve significantly on those used previously. The CHARMM force field was parameterised for the compounds and an improved method of conformational sampling, based on centroid clustering, has also been used. 相似文献
68.
以两种方法合成了10个取代苯甲酸葡萄糖酯类化合物,一是相转移催化法,二是在三忆胺的存在下,取代苯甲酸与溴代葡萄糖反应,该种合成糖酯的方法未见文献报道,取代苯甲酸葡萄糖酯的结构由IR、MS、^1H NMR和元素分析确认。对化合物的抗病毒活性测试结果发现,其中有两个化合物具有一定的抑制TMV的活性。 相似文献
69.
70.
Butler Stephen F.; Newman Frederick L.; Cacciola John S.; Frank Arlene; Budman Simon H.; McLellan A. Thomas; Ford Sabrina; Blaine Jack; Gastfriend David; Moras Karla; Salloum Ihsan M.; Barber Jacques P. 《Canadian Metallurgical Quarterly》1998,10(4):399
The Addiction Severity Index (ASI) is a reliable and valid measure of problem severity among addicted patients. Concerns have been raised about the reliability of the Interviewer Severity Rating (ISR), a summary score for each of 7 domains. As part of an effort to build a computer-administered ASI, regression equations were developed to predict the ISR. Repeated resampling of a large dataset, consisting of 1,124 ASIs conducted by trained interviewers, permitted derivation of stable regression equations predicting the ISR for each ASI domain from patients' answers to preselected interview items. The resulting 7 Predicted Severity Ratings (PSRs) were tested on 8, standardized vignettes, with "gold standard," expert-generated ISRs. Reliabilities compared well with those of intensively trained interviewers. The PSRs could provide an alternative to potentially unreliable interviewer ratings, enhancing the ASI's role in treatment planning and treatment matching and make possible a computer-administered version of the ASI. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献