全文获取类型
收费全文 | 1824篇 |
免费 | 14篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
综合类 | 2篇 |
化学工业 | 36篇 |
金属工艺 | 12篇 |
机械仪表 | 14篇 |
建筑科学 | 5篇 |
能源动力 | 4篇 |
轻工业 | 125篇 |
无线电 | 32篇 |
一般工业技术 | 80篇 |
冶金工业 | 1451篇 |
原子能技术 | 4篇 |
自动化技术 | 72篇 |
出版年
2023年 | 5篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 18篇 |
2012年 | 11篇 |
2011年 | 15篇 |
2010年 | 32篇 |
2009年 | 17篇 |
2008年 | 17篇 |
2007年 | 16篇 |
2006年 | 16篇 |
2005年 | 13篇 |
2004年 | 14篇 |
2003年 | 15篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 44篇 |
1998年 | 460篇 |
1997年 | 266篇 |
1996年 | 151篇 |
1995年 | 84篇 |
1994年 | 81篇 |
1993年 | 83篇 |
1992年 | 19篇 |
1991年 | 30篇 |
1990年 | 31篇 |
1989年 | 22篇 |
1988年 | 25篇 |
1987年 | 18篇 |
1986年 | 19篇 |
1985年 | 14篇 |
1983年 | 5篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 20篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 34篇 |
1976年 | 98篇 |
1975年 | 5篇 |
1974年 | 9篇 |
1973年 | 3篇 |
1972年 | 4篇 |
排序方式: 共有1839条查询结果,搜索用时 31 毫秒
61.
62.
Mirco Wegener Luckman Muhmood Shouyi Sun Alex V. Deev 《American Institute of Chemical Engineers》2014,60(9):3350-3361
The experiments on the capillary breakup of slag jets at high temperatures are presented in this article. The impact of external excitations on the disintegration process was investigated in a furnace with optical access filmed at frame rates up to 10,000 fps. A synthetic calcia‐alumina slag was used to form jets at different temperatures (1570–1660°C) and jet velocities (0.6–1.4 ms?1). The impact of external vibration on the breakup was evident: for low jet velocities, the jet length decreased, the droplet size increased, satellite droplet formation was hindered, and a distinct “pumping mechanism” was observed. For jets with higher velocity, the jet length decreased by 30%, the droplet generation frequency increased from 20 to 250 droplets per second, the drop sizes were uniform, and satellite formation was also suppressed. In this case, the ideal case in which the volume of one wave instability forms one droplet was achieved. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3350–3361, 2014 相似文献
63.
O. A. Charl G. Czymek B. Giesen M. Sauer L. Scheibl J. Schruff R. Schick A. Panin A. John S. Jung K. Rummel L. Wegener 《Fusion Engineering and Design》2009,84(7-11):1416-1419
Forschungszentrum Jülich has taken over the design, manufacturing and assembly of the superconducting busbar system for the stellarator Wendelstein 7-X. This includes the busbars itself, the support structure consisting of supports and clamps, and the joints for electrical and hydraulic connection of the busbars and coil terminals. Apart from providing the required electrical connection scheme, the busbar system has to be designed for relevant electrical and mechanical loads. Numerous interfaces and geometric boundary conditions define the confined space to accommodate the busbars and their support elements. This article describes how the individual challenges to engineering have been met in the course of the project. This includes design concepts and the method for iterative design of supports with respect to the individual load distribution caused by the supports itself. 相似文献
64.
D. Noack N. Parameswaran G. Seehann E. Plath D. Henrici P. Gresset G. Wegener D. Fengel W. Schweers J. Plath H. Willeitner A. Burmester K. Rügge 《Holz als Roh- und Werkstoff》1974,32(2):72-77
Ohne Zusammenfassung 相似文献
65.
María L Auad Tara Richardson William J Orts Eliton S Medeiros Luiz HC Mattoso Mirna A Mosiewicki Norma E Marcovich Mirta I Aranguren 《Polymer International》2011,60(5):743-750
Segmented polyurethanes exhibiting shape memory properties were modified by the addition of polyaniline (PANI)‐coated cellulose nanofibrils (CNFs). The two‐phase structure of the polymer is responsible for the material's ability to ‘remember’ and autonomously recover its original shape after being deformed in response to an external thermal stimulus. PANI was grown on the surface of the CNFs via in situ polymerization. Modified nanocrystals were added to the segmented polyurethane in concentrations ranging from 0 to 15 wt%. The changes in the material properties associated with the percolation of the coated fibrils appear at higher concentrations than previously observed for non‐modified CNFs, which suggests that fibril agglomeration is occurring due to the PANI coating. The shape memory behavior of the composites is maintained at about the same level as that of the unfilled polyurethane only up to 4 wt% of fibrils. At higher concentrations, the rigidity of the nanofibrils as well as their interaction with the hard‐segment phase and the increasing difficulty of dispersing them in the polymer collaborate to produce early breakage of the specimens when stretched at temperatures above the melting point of the soft segments. Copyright © 2010 Society of Chemical Industry 相似文献
66.
Eduardo Weingärtner Sascha Jaumann Friedrich Kuster Konrad Wegener 《The International Journal of Advanced Manufacturing Technology》2010,48(9-12):1001-1007
Traditional multivariate control charts such as Hotelling’s χ 2 and T 2 control charts are designed to monitor vectors of variable quality characteristics. However, in certain situations, data are expressed in linguistic terms and, under these circumstances, variable or attribute multivariate control charts are not suitable choices for monitoring purposes. Fuzzy multivariate control charts such as fuzzy Hotelling’s T 2 could be considered as efficient tools to overcome the problems of linguistic observations. The purpose of this paper is to develop a fuzzy multivariate exponentially weighted moving average (F-MEWMA) control chart. In this paper, multivariate statistical quality control and fuzzy set theory are combined to develop the proposed method. Fuzzy sets and fuzzy logic are powerful mathematical tools for modeling uncertain systems in industry, nature, and humanity. Through a numerical example, the performance of the proposed control chart was compared to the fuzzy Hotelling’s T 2 control chart. Results indicate uniformly superior performance of the F-MEWMA control chart over Hotelling’s T 2 control chart. 相似文献
67.
68.
Randomized search heuristics like local search, tabu search, simulated
annealing, or all kinds of evolutionary algorithms have many applications. However,
for most problems the best worst-case expected run times are achieved by more
problem-specific algorithms. This raises the question about the limits of general
randomized search heuristics. Here a framework called black-box optimization is developed. The essential
issue is that the problem but not the problem instance is knownto the algorithm which
can collect information about the instance only by asking for the value of points in the
search space. All known randomized search heuristics fit into this scenario. Lower
bounds on the black-box complexity of problems are derived without complexity
theoretical assumptions and are compared with upper bounds in this scenario. 相似文献
69.
Sudden death is a common complication of myocardial infarction, necrotic pancreatitis and other diseases. Physicians usually neglect the possibility of neurological disorders. 59 cases of sudden death among 314 autopsied cases with neurological diseases were analyzed. The most frequent cause of neurological sudden death was cerebrovascular disease (CVD). It was present in 53 (89.9%) cases. 48 of them had hemorrhagic CVD. 37 of these 48 cases were due to hypothalamic lesions. In 37 cases general autopsy was performed; pathological abnormalities of heart, lungs, stomach etc, were found in 28 of them. In conclusion, the size and location of the lesion correlated with the prognosis of the disease. Concomitant multiple organ damage may deteriorate the lesion. Awareness of sudden death resulting from CVD may elevate the rate of correct diagnosis. 相似文献
70.
W Weder RA Schmid H Bruchhaus S Hillinger GK von Schulthess HC Steinert 《Canadian Metallurgical Quarterly》1998,66(3):886-92; discussion 892-3
BACKGROUND: Accurate staging of non-small cell lung cancer is essential for treatment planning. We evaluated in a prospective study the role of whole-body 2-[18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in mediastinal nodal staging with a positive predictive value of 96%. The study was continued to further evaluate the value of whole-body FDG PET in detecting unexpected extrathoracic metastases (ETMs) in patients qualifying for surgical treatment by conventional staging. METHODS: One hundred patients underwent clinical evaluation, chest and upper abdominal computed tomography scan, mediastinoscopy (lymph nodes greater than 1 cm on computed tomography), and routine laboratory tests. In 94 patients with stage IIIa or less and 6 with suspected N3 a whole-body FDG PET was performed. If clinical signs of ETMs were present additional diagnostic methods were applied. All findings in the FDG PET were confirmed histologically or radiologically. RESULTS: Unexpected ETMs were detected in 13 (14%) of 94 patients (stage IIIa or less) at 14 sites. In addition 6 of 94 patients were restaged up to N3 after PET. The suspected N3 disease (stage IIIb) on computed tomography was confirmed by PET in all 6 patients. There was no false positive finding of ETM. Weight loss was correlated with the occurrence of ETM: more than 5 kg, 5 of 13 patients (38%); more than 10 kg, 4 of 6 patients (67%). Pathologic laboratory findings were not predictive for ETM. CONCLUSIONS: Whole-body FDG PET improves detection of ETMs in patients with non-small cell lung cancer otherwise elegible for operation. In 14% of patients (stage IIIa or less), ETMs were detected, and in total, 20% of the patients were understaged. 相似文献