全文获取类型
收费全文 | 1624篇 |
免费 | 5篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 45篇 |
金属工艺 | 10篇 |
机械仪表 | 14篇 |
建筑科学 | 11篇 |
能源动力 | 9篇 |
轻工业 | 54篇 |
水利工程 | 2篇 |
无线电 | 30篇 |
一般工业技术 | 77篇 |
冶金工业 | 1343篇 |
原子能技术 | 1篇 |
自动化技术 | 30篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 15篇 |
2012年 | 12篇 |
2011年 | 16篇 |
2010年 | 15篇 |
2009年 | 10篇 |
2008年 | 16篇 |
2007年 | 9篇 |
2006年 | 16篇 |
2005年 | 9篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 12篇 |
2000年 | 6篇 |
1999年 | 41篇 |
1998年 | 436篇 |
1997年 | 217篇 |
1996年 | 136篇 |
1995年 | 95篇 |
1994年 | 73篇 |
1993年 | 85篇 |
1992年 | 14篇 |
1991年 | 19篇 |
1990年 | 18篇 |
1989年 | 29篇 |
1988年 | 18篇 |
1987年 | 27篇 |
1986年 | 22篇 |
1985年 | 16篇 |
1984年 | 7篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 11篇 |
1980年 | 21篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 40篇 |
1976年 | 67篇 |
1975年 | 6篇 |
1974年 | 3篇 |
1972年 | 5篇 |
1971年 | 4篇 |
1970年 | 2篇 |
排序方式: 共有1629条查询结果,搜索用时 15 毫秒
1.
Thomas R. Savage Fernando Almeida-Trasvina Ehecatl A. del-Rio Chanona Robin Smith Dondga Zhang 《American Institute of Chemical Engineers》2021,67(11):e17358
With liquefied natural gas becoming increasingly prevalent as a flexible source of energy, the design and optimization of industrial refrigeration cycles becomes even more important. In this article, we propose an integrated surrogate modeling and optimization framework to model and optimize the complex CryoMan Cascade refrigeration cycle. Dimensionality reduction techniques are used to reduce the large number of process decision variables which are subsequently supplied to an array of Gaussian processes, modeling both the process objective as well as feasibility constraints. Through iterative resampling of the rigorous model, this data-driven surrogate is continually refined and subsequently optimized. This approach was not only able to improve on the results of directly optimizing the process flow sheet but also located the set of optimal operating conditions in only 2 h as opposed to the original 3 weeks, facilitating its use in the operational optimization and enhanced process design of large-scale industrial chemical systems. 相似文献
2.
3.
DD Coelho 《Canadian Metallurgical Quarterly》1997,73(5):397-398
Thoracic infection by anaerobes are uncommon diseases and often presents difficulty in diagnosis. We report a case of thoracic infection due to Fusobacterium Nucleatum. A 60-year old man presented a lesion infiltrating from the lung to the thoracic wall. Fusobacterium Nucleatum was isolated on pus collected. Treatment by penicillin, metronidazole combined with surgical drainage was highly effective. 相似文献
4.
Pantic-Tanner Z. Scott Savage J. Tanner D.R. Peterson A.F. 《Microwave Theory and Techniques》1998,46(2):178-184
The finite-element method (FEM) exhibits a reduced convergence rate when used for the analysis of geometries containing sharp edges where the electromagnetic field is singular. The convergence of the method can be-improved by introducing singular elements that model analytically predicted singular behavior. A number of authors have developed singular elements that are compatible with the scalar FEM. In this paper, we propose a new singular element that is compatible with edge-based vector finite elements and can cope with any order of singularity while preserving the sparsity of the FEM equations. Edge-based singular elements more correctly model singular fields and thus require fewer unknowns, while avoiding the introduction of spurious modes in the numerical solution. Numerical results verify that the convergence of the FEM is significantly improved 相似文献
5.
6.
7.
8.
9.
L Magaudda MR Mondello DD Di Mauro S Pallio M Bottari 《Canadian Metallurgical Quarterly》1996,42(2):61-69
The effects of antiepileptic drugs on cognitive function in 48 healthy volunteers were assessed using event-related potentials (ERP) and the Attention Index included in the Wechsler Memory Scale, revised edition (WMS-R). The study was conducted over 1 week, using a double-blind design. Four drugs, carbamazepine (CBZ), phenytoin (PHT), valproate (VPA) and zonisamide (ZNS) were tested. Using an auditory oddball task, ERP measurements were made under two conditions with different tone intensities: Condition 1 used 70 db SPL; and Condition 2 used 30 db SPL. Results showed that CBZ prolonged target N1 and P3 latencies in Condition 1, and reduced frequent N1 amplitude in Condition 2, which suggests that CBZ may cause a change in sensory memory and prolong stimulus evaluation time. It is suggested that under a low stimulus intensity level, the sensory function itself was affected. Phenytoin was found to prolong target N1 latency in Condition 2, which also indicates a change in the sensory memory function. However, VPA did not significantly affect ERP components, except for the shortened frequent N1 latency, which could not be explained due to the limited information. It was found that ZNS augmented P3 amplitude in Condition 2, and reduced scores on the Attention Index. It is suggested that the augmentation of P3 amplitude was caused by the reduction of processing negativity as a result of the detrimental effect of ZNS on subjects' attention. However, the apparent difference between the ERP and behavioral indices suggests that caution should be exercised in assessing the results obtained only from ERP measurements. 相似文献
10.
JJ Callaghan GS Tooma JP Olejniczak DD Goetz RC Johnston 《Canadian Metallurgical Quarterly》1996,(333):118-125
The senior authors' initial experience with primary hybrid hip replacement in patients with osteoarthritis was studied to evaluate the efficacy of the procedure. Hybrid total hip arthroplasty (uncemented Harris-Galante acetabular component and cemented Iowa precoated femoral component) was performed in 131 consecutive, nonselected hips in 118 patients with the diagnosis of primary osteoarthritis. Followup was performed at 8 to 9 years after the procedure. The average age at the time of the procedure was 68 years (range, 45-87 years). There were 50 men (55 hips) and 68 women (76 hips). At final followup 19 patients (22 hips) had died. The femoral component had been revised for aseptic loosening in 8 hips (6.1%). One additional hip showed definite radiographic loosening. Hence, the prevalence of radiographic femoral failure was 6.9% (9 hips). No acetabular component had been revised for aseptic loosening and no acetabular component had migrated. The senior author continues to perform hybrid total hip arthroplasty in all patients with primary osteoarthritis. However, design modifications have been made in the femoral component that is used. 相似文献