全文获取类型
收费全文 | 8719篇 |
免费 | 512篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 47篇 |
综合类 | 3篇 |
化学工业 | 2406篇 |
金属工艺 | 133篇 |
机械仪表 | 142篇 |
建筑科学 | 237篇 |
矿业工程 | 13篇 |
能源动力 | 167篇 |
轻工业 | 1604篇 |
水利工程 | 79篇 |
石油天然气 | 30篇 |
无线电 | 360篇 |
一般工业技术 | 1307篇 |
冶金工业 | 1550篇 |
原子能技术 | 25篇 |
自动化技术 | 1133篇 |
出版年
2024年 | 12篇 |
2023年 | 111篇 |
2022年 | 438篇 |
2021年 | 446篇 |
2020年 | 212篇 |
2019年 | 231篇 |
2018年 | 315篇 |
2017年 | 329篇 |
2016年 | 340篇 |
2015年 | 271篇 |
2014年 | 371篇 |
2013年 | 630篇 |
2012年 | 540篇 |
2011年 | 539篇 |
2010年 | 396篇 |
2009年 | 408篇 |
2008年 | 393篇 |
2007年 | 361篇 |
2006年 | 226篇 |
2005年 | 195篇 |
2004年 | 187篇 |
2003年 | 154篇 |
2002年 | 161篇 |
2001年 | 109篇 |
2000年 | 92篇 |
1999年 | 113篇 |
1998年 | 570篇 |
1997年 | 320篇 |
1996年 | 216篇 |
1995年 | 115篇 |
1994年 | 87篇 |
1993年 | 86篇 |
1992年 | 17篇 |
1991年 | 18篇 |
1990年 | 13篇 |
1989年 | 14篇 |
1988年 | 23篇 |
1987年 | 15篇 |
1986年 | 15篇 |
1985年 | 21篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1977年 | 20篇 |
1976年 | 29篇 |
1975年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有9236条查询结果,搜索用时 0 毫秒
1.
2.
3.
M Tuena de Gómez-Puyou F Sandoval JJ García A Gómez-Puyou 《Canadian Metallurgical Quarterly》1998,255(1):303-308
Soluble mitochondrial F1 and F1 in complex with the natural ATPase inhibitor protein (F1-IP) catalyze the spontaneous synthesis of [gamma-32P]ATP from medium [32P]phosphate and enzyme-bound ADP when incubated in media with dimethylsulfoxide (Me2SO); under these conditions, the synthesized [gamma-32P]ATP is not released into the media, it remains tightly bound to the enzymes [Gómez-Puyou, A., Tuena de Gómez-Puyou, M. & de Meis, L. (1986) Eur. J. Biochem. 159, 133-140]. Some of the characteristics of the synthesized [gamma-32P]ATP were studied in F1 and F1-IP (ATPase activities of 70 and 1-3 micromol x min(-1) x mg(-1), respectively). In Me2SO media, gamma-phosphate of synthesized ATP in F1 or F1-IP exchanges with medium phosphate. From the rates of the exchange reaction, the half-times for hydrolysis of the synthesized ATP in F1 and F1-IP were calculated: 45 min and 58 min for F1 and F1-IP, respectively. The course that synthesized [gamma-32P]ATP follows after dilution of the Me2SO synthetic mixture with aqueous buffer was determined. After dilution, the half-life of synthesized ATP in F1 was less than 1 min. In F1-IP, ATP was also hydrolyzed, but at significantly lower rates. In F1-IP, dilution also produced release of the synthesized [gamma-32P]ATP. This was assayed by the accessibility of [gamma-32P]ATP to hexokinase. About 25% of [gamma-32P]ATP synthesized in F1-IP, but not in F1, was released into the media after dilution with aqueous buffer that contained 20 mM phosphate. Release of tightly bound ATP required the binding energy of phosphate and solvation of F1-IP, however, the particular kinetics of F1-IP were also central for medium ATP synthesis in the absence of electrochemical H+ gradients. 相似文献
4.
P Sánchez García 《Canadian Metallurgical Quarterly》1997,114(1):157-63; discussion 164-7
5.
Elena Crespi Antonio Capolongo Davide Fissore Antonello A. Barresi 《Drying Technology》2008,26(3):349-356
The aim of this article is to develop an experiment and a procedure to investigate the restoration of water-damaged paper and archival materials using freeze drying in order to allow a reproducible test and comparison of the influence of different operating conditions on drying time and restored paper quality. Firstly, a reproducible method for the preparation of soaked samples simulating water-damaged paper has been developed. Then, the samples have been freeze-dried in a laboratory-scale apparatus that allowed monitoring the temperature as well as the weight of the samples. The technique of evaporative freezing, which reduces the drying time required, has been used in this case. An innovative procedure for the visualization of the progress of the drying process has been validated, thus allowing the validation of a simple phenomenological model of the time evolution of the ice core volume; in addition, data on the residual moisture of the dried paper sheets in different zones have been given. Finally, optimization of this particular drying process by using simple or more sophisticated approaches has been discussed. 相似文献
6.
Imperfection in information can be considered a crosscutting concern that manifests itself in diverse kinds of imprecision, uncertainty, or inconsistency in the data models of a software system. The extension of existing programming and querying interfaces for the different aspects of information imperfection requires a proper modularization of the different concerns of numerical imprecision handling, so that the extensions do not interfere with existing programming practices and do not obscure the original design. Aspect‐oriented design (AOD) enables such a form of nonintrusive extensions to be added to existing software libraries, clearly separating fuzziness or other imperfections in data as a differentiated concern that can be considered from the early phases of development. In this article, a general framework for aspect‐based extension of data models and fuzzy databases is described, and some design and implementation issues of such AOD‐based extensions on OJB database libraries are described as a case study. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 1199–1216, 2006. 相似文献
7.
8.
Moutafis Panagiotis García-García Francisco Mavrommatis George Vassilakopoulos Michael Corral Antonio Iribarne Luis 《Distributed and Parallel Databases》2021,39(3):733-784
Distributed and Parallel Databases - Given two datasets of points (called Query and Training), the Group (K) Nearest-Neighbor (GKNN) query retrieves (K) points of the Training with the smallest sum... 相似文献
9.
Software Quality Journal - Energy consumption of software has been becoming increasingly significant, since it can vary according to how the software has been developed. In recent years, developers... 相似文献
10.
C García Barroso R Cela Torrijos J A Pérez-Bustamante 《Zeitschrift für Lebensmittel-Untersuchung und -Forschung》1987,185(4):307-314
The different groups and/or classes among phenolic acids and aldehydes identified during the elaboration process of "fino" sherry wine have been studied. The study was carried out using different processes during the elaboration of the wine and we have attempted to establish whether the different treatments of the grape affect these groupings. The study was undertaken by means of cluster and multifactorial analysis on the data obtained by the quantitative determination of phenolic acids and aldehydes during vinification and in experiments carried out on the grape under different mechanical treatments. The analysis of phenolic acids and aldehydes was done with HPLC, using a C-18 mu-Bondapak and a stepwise composite gradient. The samples were previously extracted with ethylic ether. 相似文献