全文获取类型
收费全文 | 1107篇 |
免费 | 4篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 89篇 |
金属工艺 | 20篇 |
机械仪表 | 41篇 |
建筑科学 | 3篇 |
矿业工程 | 5篇 |
轻工业 | 2篇 |
水利工程 | 12篇 |
石油天然气 | 72篇 |
无线电 | 33篇 |
一般工业技术 | 104篇 |
冶金工业 | 635篇 |
原子能技术 | 68篇 |
自动化技术 | 20篇 |
出版年
2022年 | 10篇 |
2021年 | 7篇 |
2020年 | 13篇 |
2019年 | 10篇 |
2018年 | 25篇 |
2017年 | 19篇 |
2016年 | 19篇 |
2015年 | 12篇 |
2014年 | 18篇 |
2013年 | 11篇 |
2012年 | 11篇 |
2011年 | 20篇 |
2010年 | 13篇 |
2009年 | 14篇 |
2008年 | 12篇 |
2007年 | 17篇 |
2006年 | 7篇 |
2005年 | 9篇 |
2004年 | 11篇 |
2003年 | 8篇 |
2002年 | 12篇 |
2001年 | 7篇 |
2000年 | 9篇 |
1999年 | 19篇 |
1998年 | 146篇 |
1997年 | 100篇 |
1996年 | 86篇 |
1995年 | 54篇 |
1994年 | 51篇 |
1993年 | 29篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 22篇 |
1988年 | 8篇 |
1987年 | 13篇 |
1986年 | 11篇 |
1985年 | 11篇 |
1983年 | 9篇 |
1982年 | 11篇 |
1981年 | 17篇 |
1980年 | 17篇 |
1978年 | 11篇 |
1977年 | 35篇 |
1976年 | 56篇 |
1975年 | 15篇 |
1973年 | 7篇 |
1972年 | 9篇 |
1971年 | 8篇 |
1969年 | 6篇 |
排序方式: 共有1111条查询结果,搜索用时 15 毫秒
1.
Minds and Machines - An online game of chess against a human opponent appears to be indistinguishable from a game against a machine: both happen on the screen. Yet, people prefer to play chess... 相似文献
2.
Sleptsov V. V. Kukushkin D. Yu. Kulikov S. N. Diteleva A. O. 《Russian Engineering Research》2021,41(5):416-418
Russian Engineering Research - Thin-film vacuum technology permits the creation of new electrode materials on the basis of a flexible carbon matrix with a highly developed surface. Supercapacitor... 相似文献
3.
G. M. Kulikov S. V. Plotnikova 《International journal for numerical methods in engineering》2002,55(10):1167-1183
The precise representation of rigid body motions in the displacement patterns of curved Timoshenko–Mindlin (TM) shell elements is considered. This consideration requires the development of the strain–displacement relationships of the TM shell theory with regard to their consistency with the rigid body motions. For this purpose a refined TM theory of multilayered anisotropic shells is elaborated. The effects of transverse shear deformation and bending‐extension coupling are included. The fundamental unknowns consist of five displacements and eight strains of the face surfaces of the shell, and eight stress resultants. On the basis of this theory the simple and efficient mixed models are developed. The elemental arrays are derived using the Hu–Washizu mixed variational principle. Numerical results are presented to demonstrate the high accuracy and effectiveness of the developed 4‐node shell elements and to compare their performance with other finite elements reported in the literature. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
4.
5.
6.
7.
The clinical presentation, electrocardiographic findings, and technetium-99m sestamibi single-photon emission computed tomography (SPECT) imaging results of 134 consecutive patients who underwent nuclear exercise testing within 14 days of an acute myocardial infarction (AMI) were correlated with cardiac events over a 15 +/- 10-month follow-up. Whereas only 23 patients (17%) had chest pain and 31 (23%) had ischemic ST-segment depression during exercise, 94 (70%) had ischemia on SPECT (p < 0.001). On follow-up, 13 patients experienced a cardiac event: 7 were rehospitalized for unstable angina, 3 had recurrent AMI, and 3 died of cardiac causes. Ischemia on the sestamibi images identified 11 of these patients (85%), whereas chest pain identified only 3 (23%, p = 0.006), and electrocardiographic ischemia identified only 4 (31%, p = 0.017). The presence of either ischemia as seen on SPECT or defects in multiple vascular territories identified 12 patients (92%) with an event, including all who had cardiac death. By Cox regression analysis of clinical, stress, and image parameters, the number of ischemic defects on SPECT was the only significant correlate of a future event (chi-square = 4.62, p = 0.03), and patients with > or = 3 reversible sestamibi defects had an event rate of 38%. The extent of ischemia as seen on nuclear imaging remained a strong correlate (p = 0.008) of an event in the 54 patients (40%) who had received thrombolytic therapy. Thus, exercise technetium-99m sestamibi SPECT after AMI frequently reveals residual ischemia, and is better than clinical data, symptoms, and stress electrocardiographic data in identifying patients who will have a subsequent cardiac event. 相似文献
8.
9.
VA Nikolaev AN Surovaia NIu Sidorova SL Grokhovski? AS Zasedatelev GV Gurski? AL Zhuze 《Canadian Metallurgical Quarterly》1993,27(1):192-210
An analogue of netropsin has been synthesized consisting of two N-propylpyrrolcarboxamide units linked covalently to a copper-chelating tripeptide Gly-Gly-L-His by means of two and three glycine residues. Binding to DNA and synthetic polynucleotides of netropsin analogue containing three glycine residues between Gly-Gly-L-His tripeptide and the N-end of netropsin analogue (His-Nt) has been studied. It is shown that this netropsin analogue chelates a copper ion with 1:1 stoichiometry, similar to a free Gly-Gly-L-His peptide. It is found that this netropsin analogue occupies 3 to 4 base pairs upon binding to poly(dA).poly(dT) and poly[d(AT)].poly[d(AT)] polymers, irrespective of whether it binds in Cu(2+)-ligated or unligated forms. Binding constants and binding site sizes have been calculated for netropsin analogue complexes with DNA, poly(dA).poly(dT) and poly[d(AT)].poly[d(AT)] polymers at the [Cu2+]/[His-Nt] ratio equal to 0 and 1.0. In the three-component system including His-Nt and Cu(2+)-His-Nt, cooperative effects are recognized which can be explained by heterodimer generation on interaction of His-Nt and Cu(2+)-His-Nt at adjacent binding sites. 相似文献
10.