全文获取类型
收费全文 | 2382篇 |
免费 | 23篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 4篇 |
综合类 | 3篇 |
化学工业 | 280篇 |
金属工艺 | 16篇 |
机械仪表 | 15篇 |
建筑科学 | 81篇 |
矿业工程 | 28篇 |
能源动力 | 41篇 |
轻工业 | 131篇 |
水利工程 | 13篇 |
石油天然气 | 6篇 |
无线电 | 41篇 |
一般工业技术 | 121篇 |
冶金工业 | 1465篇 |
原子能技术 | 7篇 |
自动化技术 | 155篇 |
出版年
2022年 | 6篇 |
2021年 | 5篇 |
2020年 | 12篇 |
2019年 | 9篇 |
2018年 | 19篇 |
2017年 | 13篇 |
2016年 | 15篇 |
2015年 | 17篇 |
2014年 | 11篇 |
2013年 | 80篇 |
2012年 | 28篇 |
2011年 | 56篇 |
2010年 | 33篇 |
2009年 | 30篇 |
2008年 | 54篇 |
2007年 | 43篇 |
2006年 | 40篇 |
2005年 | 30篇 |
2004年 | 26篇 |
2003年 | 26篇 |
2002年 | 39篇 |
2001年 | 14篇 |
2000年 | 25篇 |
1999年 | 50篇 |
1998年 | 387篇 |
1997年 | 248篇 |
1996年 | 165篇 |
1995年 | 96篇 |
1994年 | 103篇 |
1993年 | 91篇 |
1992年 | 22篇 |
1991年 | 33篇 |
1990年 | 29篇 |
1989年 | 40篇 |
1988年 | 28篇 |
1987年 | 44篇 |
1986年 | 36篇 |
1985年 | 27篇 |
1984年 | 15篇 |
1983年 | 24篇 |
1982年 | 31篇 |
1981年 | 27篇 |
1980年 | 35篇 |
1979年 | 15篇 |
1978年 | 18篇 |
1977年 | 47篇 |
1976年 | 92篇 |
1975年 | 16篇 |
1974年 | 5篇 |
1973年 | 9篇 |
排序方式: 共有2407条查询结果,搜索用时 0 毫秒
1.
Malcolm Southwood 《Rocks & Minerals》2018,93(6):524-527
2.
Malcolm J. Beynon 《国际智能系统杂志》2006,21(2):173-191
The granularity of an information system has an incumbent effect on the efficacy of the analysis from many machine learning algorithms. An information system contains a universe of objects characterized and categorized by condition and decision attributes. To manage the concomitant granularity, a level of continuous value discretization (CVD) is often undertaken. In the case of the rough set theory (RST) methodology for object classification, the granularity contributes to the grouping of objects into condition classes with the same condition attribute values. This article exposits the effect of a level of CVD on the subsequent condition classes constructed, with the introduction of the condition class space—the domain within which the condition classes exist. This domain elucidates the association of the condition classes to the related decision outcomes—reflecting the inexactness incumbent when a level of CVD is undertaken. A series of measures is defined that quantify this association. Throughout this study and without loss of generality, the findings are made through the RST methodology. This further offers a novel exposition of the relationship between all the condition attributes and the RST‐related reducts (subsets of condition attributes). © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 173–191, 2006. 相似文献
3.
4.
Qin‐Tao Liu Malcolm R Clench Judith L Kinderlerer 《Journal of the science of food and agriculture》2002,82(5):553-558
Structural isomers of monoacylglycerols (monoglycerides, MAGs) were identified and compared after degradation of butter oil by two strains of Penicillium roquefortii and a commercial lipase from P roquefortii (EC 3.1.1.3) at pH 7.0 and 10 °C. The conditions were selected as they were comparable with those used in the manufacture of blue mould‐ripened cheese. The commercial lipase was selected to compare with the fungal strains in terms of acyl migration. Results showed that the main isomers formed by lipolysis with the commercial lipase were sn‐2 MAGs (64 mol%), whilst spores and emerging mycelia of P roquefortii produced mainly sn‐1(3) MAGs (83–90 mol%). The work reported here may lead to further assessment of different MAG structural isomers as natural preservatives in foods and dairy products. © 2002 Society of Chemical Industry 相似文献
5.
Zushu Li Kenneth C. Mills Malcolm McLean Kusuhiro Mukai 《Metallurgical and Materials Transactions B》2005,36(2):247-254
The densities of three Ni-based superalloys have been measured in both liquid and mushy states by both a modified sessile
drop method (MSDM) and a modified pycnometric method (MPM) for alloys CMSX-4 and CM186LC, and for CMSX-10 alloy by MSDM only.
The surface tensions of liquid CMSX-4, CM186LC, and CMSX-10 superalloys were measured using the sessile drop method. All measurements
were carried out in a highly purified argon atmosphere with the oxygen partial pressure of less than 10−19 MPa in the gas outlet. The densities of all superalloys in both liquid and mushy states were found to decrease with increasing
temperature. The volume thermal expansion of each superalloy in the mushy state was found to be higher than that in the liquid
state. The densities determined by different methods have been critically assessed and recommended values in both liquid and
mushy states are given as a linear function of temperature for the three Ni-based superalloys. The surface tension of liquid
CMSX-4 superalloy was found to decrease with increasing temperature, while that of liquid CMSX-10 superalloy increases with
increasing temperature. The wetting behavior of liquid CM186LC on the alumina substrate was found (1) to differ significantly
from that of CMSX-4 and CMSX-10 and (2) to vary with time. A HfO2-rich layer was found in the contact area of CM186LC with the alumina substrate, which could lead to some uncertainty in the
value obtained for the surface tension determined for CM186LC. 相似文献
6.
MRI fuzzy segmentation of brain tissue using neighborhood attraction with neural-network optimization. 总被引:11,自引:0,他引:11
Shan Shen William Sandham Malcolm Granat Annette Sterr 《IEEE transactions on information technology in biomedicine》2005,9(3):459-467
Image segmentation is an indispensable process in the visualization of human tissues, particularly during clinical analysis of magnetic resonance (MR) images. Unfortunately, MR images always contain a significant amount of noise caused by operator performance, equipment, and the environment, which can lead to serious inaccuracies with segmentation. A robust segmentation technique based on an extension to the traditional fuzzy c-means (FCM) clustering algorithm is proposed in this paper. A neighborhood attraction, which is dependent on the relative location and features of neighboring pixels, is shown to improve the segmentation performance dramatically. The degree of attraction is optimized by a neural-network model. Simulated and real brain MR images with different noise levels are segmented to demonstrate the superiority of the proposed technique compared to other FCM-based methods. This segmentation method is a key component of an MR image-based classification system for brain tumors, currently being developed. Index Terms-Improved fuzzy c-means clustering (IFCM), magnetic resonance imaging (MRI), neighborhood attraction, segmentation. 相似文献
7.
This paper introduces the quality of sagacity measure in the extended variable precision rough sets model - VPRSl,u. The need for this measure is a direct consequence of the use of the associated l and u values. Moreover, different levels of miss-classification are allowed in the classification of objects to a decision class or its compliment. This measure attempts to take this into account, by acknowledging the classification of an object to the compliment of a decision class, as an appropriate (if not optimum) classification of that object. A consequence of the analysis is a discussion of the notion of open and closed worlds in VPRSl,u. 相似文献
8.
J Tyson L Tranebjaerg S Bellman C Wren JF Taylor J Bathen B Aslaksen SJ S?rland O Lund S Malcolm M Pembrey S Bhattacharya M Bitner-Glindzicz 《Canadian Metallurgical Quarterly》1997,6(12):2179-2185
The Jervell and Lange-Nielsen syndrome (JLNS) comprises profound congenital sensorineural deafness associated with syncopal episodes. These are caused by ventricular arrhythmias secondary to abnormal repolarisation, manifested by a prolonged QT interval on the electrocardiogram. Recently, in families with JLNS, Neyroud et al. reported homozygosity for a single mutation in KVLQT1 , a gene which has previously been shown to be mutated in families with dominantly inherited isolated long QT syndrome [Neyroud et al . (1997) Nature Genet ., 15, 186-189]. We have analysed a group of families with JLNS and shown that the majority are consistent with mutation at this locus: five families of differing ethnic backgrounds were homozygous by descent for markers close to the KVLQT1 gene and a further three families from the same geographical region were shown to be homozygous for a common haplotype and to have the same homozygous mutation of the KVLQT1 gene. However, analysis of a single small consanguineous family excluded linkage to the KVLQT1 gene, establishing genetic heterogeneity in JLNS. The affected children in this family were homozygous by descent for markers on chromosome 21, in a region containing the gene IsK . This codes for a transmembrane protein known to associate with KVLQT1 to form the slow component of the delayed rectifier potassium channel. Sequencing of the affected boys showed a homozygous mutation, demonstrating that mutation in the IsK gene may be a rare cause of JLNS and that an indistinguishable phenotype can arise from mutations in either of the two interacting molecules. 相似文献
9.
Ehrlichia spp. from human and equine sources in the northeastern Unites States were detected by PCR, isolated, and propagated in the HL-60 promyelocytic leukemia cell line. Growth of Ehrlichia from both equine and human sources was enhanced by addition of retinoic acid, which causes granulocytic differentiation of the HL-60 cells. DNA sequencing of a portion of the 16S rDNA gene supported the hypothesis that the same pathogen was responsible for both equine and human granulocytic ehrlichiosis. 相似文献
10.
P Fransen GP Pizzolato P Otten A Reverdin R Lagier N de Tribolet 《Canadian Metallurgical Quarterly》1997,86(6):1027-1030
A case of cystic degeneration of the transverse ligament located posteriorly to the dens and causing compression to the lower medulla and upper cervical spinal cord is reported. The clinical, pathological, and radiological findings are described and compared to the literature to characterize this syndrome more fully. The advantages of a posterolateral surgical approach are stressed. 相似文献