全文获取类型
收费全文 | 615篇 |
免费 | 33篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 6篇 |
综合类 | 13篇 |
化学工业 | 115篇 |
金属工艺 | 20篇 |
机械仪表 | 7篇 |
建筑科学 | 63篇 |
矿业工程 | 3篇 |
能源动力 | 16篇 |
轻工业 | 42篇 |
水利工程 | 10篇 |
无线电 | 26篇 |
一般工业技术 | 184篇 |
冶金工业 | 55篇 |
原子能技术 | 1篇 |
自动化技术 | 88篇 |
出版年
2023年 | 7篇 |
2022年 | 4篇 |
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 11篇 |
2018年 | 18篇 |
2017年 | 14篇 |
2016年 | 10篇 |
2015年 | 18篇 |
2014年 | 20篇 |
2013年 | 43篇 |
2012年 | 32篇 |
2011年 | 34篇 |
2010年 | 26篇 |
2009年 | 37篇 |
2008年 | 26篇 |
2007年 | 35篇 |
2006年 | 30篇 |
2005年 | 28篇 |
2004年 | 21篇 |
2003年 | 21篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 16篇 |
1997年 | 12篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 9篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1990年 | 12篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1969年 | 2篇 |
排序方式: 共有649条查询结果,搜索用时 15 毫秒
1.
2.
The relationship between heart failure (HF), sleep-disordered breathing and cardiac arrhythmias is complex and poorly understood. Whereas the frequency of predominantly obstructive sleep apnea in HF patients is low and similar or moderately higher to that observed in the general population, central sleep apnea (CSA) has been observed in approximately 50% of HF patients, depending on the methods used to detect CSA and patient selection. Despite this high prevalence, it is still unclear whether CSA is merely a marker or an independent risk factor for an adverse prognosis in HF patients and whether CSA is associated with an increased risk for supraventricular as well as ventricular arrhythmias in HF patients. The current review focuses on the relationship between CSA and atrial fibrillation as the most common atrial arrhythmia in HF patients, and on the relationship between CSA and ventricular tachycardia and ventricular fibrillation as the most frequent cause of sudden cardiac death in HF patients. 相似文献
3.
Folgen des Globalen Wandels für das Grundwasser in Süddeutschland – Teil 2: Sozioökonomische Aspekte
Dr. Roland Barthel Dr. Tatjana Krimly M. Sc. Michael Elbers Dr. Anja Soboll Dr. Johann Wackerbauer Prof. Dr. Rolf Hennicker Dr. Stephan Janisch Dr. Tim G. Reichenau Prof. Dr. Stephan Dabbert Prof. Dr. Jürgen Schmude Prof. Dr. Andreas Ernst Prof. Dr. Wolfram Mauser 《Grundwasser》2011,16(4):259-268
In order to account for complex interactions between humans climate and the water cycle, the research consortium GLOWA-Danube (www.glowa-danube.de) has developed the simulation system DANUBIA which consists of 17 coupled models. DANUBIA was applied to investigate various impacts of global-change between 2011 and 2060 in the Upper Danube Catchment. This article describes part 2 of an article series with investigations of socio-economic aspects, while part 1 (Barthel et al. in Grundwasser 16(4), doi:10.1007/s007-011-01794, 2011) deals with natural-spatial aspects. The principles of socio-economic actor-modeling and interactions between socio-economic and natural science model components are described here. We present selected simulations that show impacts on groundwater from changes in agriculture, tourism, economy, domestic water users and water supply. Despite decreases in water consumption, the scenario simulations show significant decreases in groundwater quantity. On the other hand, groundwater quality will likely be influenced more severely by land use changes compared to direct climatic causes. However, overall changes will not be dramatic. 相似文献
4.
Sandra Fleischer Stefan C. Weiss Thomas Lucke Wolfram Seitz Wolfgang Schulz Walter H. Weber 《臭氧:科学与工程》2015,37(5):441-449
Although oxamic acid has been identified as an ozone oxidation product from several precursor compounds, concentrations for drinking water have not been published previously. This study shows results from a full-scale drinking water treatment plant, noting that the mean concentrations for oxamic acid reached 21.3 μg/L after ozonation and prior to filtration. Subsequent multiple-layer filtration removed 85% of oxamic acid on average, and mean concentrations in drinking water were 2 μg/L. Up to 5.9% of the oxamic acid found in ozone-treated groundwater may be formed from Chloridazon metabolites. 相似文献
5.
Redistribution of internal forces in the lateral bracing system / Schnittgrößenumlagerungen bei der Gebäudeaussteifung 下载免费PDF全文
Kenan Michel MSc. Prof. Dr.‐Ing. Wolfram Jäger Dr.‐Ing. Frank Steinigen 《Mauerwerk》2015,19(6):441-452
The lateral bracing system of a building should ensure the stability of the building, in terms of the usability and the total load capacity. The governing loads for the lateral bracing system are horizontal loads due to wind and earthquake. The horizontal loads are traditionally distributed to the bracing elements according to the uncracked elastic state dependent on the bending stiffness in the elastic (uncracked) state. This method does not allow consideration of non‐linear effects and load redistribution. Within the framework of the PRB Research Cooperation – Improving the Practical Use of Structural Design Standards through pre‐normative work – Subcontract 5: Masonry Construction, Subproject 3: “Large Shear Walls” [7], the cracked or plastic state can be taken into account through a displacement based approach. A matrix formulation for both the linear and cracked states has been derived and implemented. 相似文献
6.
Computational Economics - We study the functioning of informal value transfer systems through the example of Hawala. By complementing the institutional theory with computational experiments that... 相似文献
7.
8.
Christian Gaber David Jocham Hannes Alois Weiss Ole Böttcher Wolfram Volk 《International Journal of Material Forming》2017,10(3):345-351
The prediction of formability is one of the most important tasks in sheet metal forming process simulation. The common criterion for ductile fracture in industrial applications is the Forming Limit Diagram (FLD). This is only applicable for linear strain paths. However, in most industrial simulation cases non-linear strain paths occur. To resolve this problem, a phenomenological approach is introduced, the so-called Generalized Forming Limit Concept (GFLC). The GFLC enables prediction of localized necking on arbitrary non-linear strain paths. Another possibility is the use of the Time Dependent Evaluation Method (TDEM) within the simulation as a failure criteria. During the Numisheet Benchmark 1 (2014) a two-stage forming process was performed with three typical sheet materials (AA5182, DP600 and TRIP 780) and three different blank shapes. The task was to determinate the point in time and space of local instability. Therefore the strain path for the point of maximum local thinning is evaluated. To predict the start of local necking the Generalized Forming Limit Concept (GFLC), the Time Dependent Evaluation Method (TDEM) and the modified TDEM were applied. The results of the simulation are compared with the results of the Benchmark experiment. 相似文献
9.
The author byline is an indispensable component of a scientific paper. Some journals have added contribution lists for each paper to provide detailed information of each author’s role. Many papers have explored, respectively, the byline and contribution lists. However, the relationship between the two remains unclear. We select three prominent general medical journals: Journal of the American Medical Association (JAMA), Annals of Internal Medicine (Annals), and PLOS Medicine (PLOS). We analyze the relationship between the author byline and contribution lists using four indexes. Four main findings emerged. First, the number, forms, and names of contribution lists significantly differed among the three journals, although they adopted the criteria of the International Committee of Medical Journal Editors. Second, a U-shaped relationship exists between the extent of contribution and author order: the participation levels in contribution lists were highest for first authors, followed by last and second authors, and then middle authors with the lowest levels. Third, regarding the consistency between author order in the contribution list and byline, every contribution category has a high consistency in JAMA and Annals, while PLOS shows a low consistency, in general. Fourth, the three journals have a similar distribution for the first authors in the contribution category; the first author in the byline contributes the highest proportion, followed by the middle and second authors, and then the last author with the lowest proportion. We also develop recommendations to modify academic and writing practice: implement structured cross-contribution lists, unify formats and standards of contribution lists, draft the author contribution criteria in the social sciences and humanities, and consider author contribution lists in scientific evaluation. 相似文献
10.