全文获取类型
收费全文 | 4033篇 |
免费 | 134篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 40篇 |
综合类 | 5篇 |
化学工业 | 809篇 |
金属工艺 | 63篇 |
机械仪表 | 98篇 |
建筑科学 | 151篇 |
矿业工程 | 17篇 |
能源动力 | 63篇 |
轻工业 | 328篇 |
水利工程 | 28篇 |
石油天然气 | 13篇 |
无线电 | 296篇 |
一般工业技术 | 618篇 |
冶金工业 | 1085篇 |
原子能技术 | 21篇 |
自动化技术 | 538篇 |
出版年
2023年 | 23篇 |
2022年 | 45篇 |
2021年 | 74篇 |
2020年 | 63篇 |
2019年 | 47篇 |
2018年 | 69篇 |
2017年 | 65篇 |
2016年 | 96篇 |
2015年 | 65篇 |
2014年 | 102篇 |
2013年 | 239篇 |
2012年 | 187篇 |
2011年 | 228篇 |
2010年 | 149篇 |
2009年 | 151篇 |
2008年 | 152篇 |
2007年 | 161篇 |
2006年 | 118篇 |
2005年 | 85篇 |
2004年 | 92篇 |
2003年 | 98篇 |
2002年 | 91篇 |
2001年 | 58篇 |
2000年 | 42篇 |
1999年 | 72篇 |
1998年 | 211篇 |
1997年 | 120篇 |
1996年 | 87篇 |
1995年 | 70篇 |
1994年 | 71篇 |
1993年 | 72篇 |
1992年 | 31篇 |
1991年 | 30篇 |
1990年 | 55篇 |
1989年 | 47篇 |
1988年 | 31篇 |
1987年 | 36篇 |
1986年 | 28篇 |
1985年 | 47篇 |
1984年 | 27篇 |
1983年 | 36篇 |
1982年 | 30篇 |
1981年 | 36篇 |
1980年 | 38篇 |
1979年 | 33篇 |
1978年 | 37篇 |
1977年 | 59篇 |
1976年 | 70篇 |
1975年 | 46篇 |
1974年 | 24篇 |
排序方式: 共有4173条查询结果,搜索用时 15 毫秒
101.
102.
Albert Culetto 《电子产品世界》2021,28(2):22-23,34
电动汽车和充电基础设施的发展进度取决于众多因素.为了实现可持续发展概念,充分了解各个系统及其之间的关系很重要.其中包括充电概念、行驶范围、财政补贴、资源获取和电池回收. 相似文献
103.
P. Ganesh Kumar T. Aruldoss Albert VictoireP. Renukadevi D. Devaraj 《Expert systems with applications》2012,39(2):1811-1821
Knowledge gained through classification of microarray gene expression data is increasingly important as they are useful for phenotype classification of diseases. Different from black box methods, fuzzy expert system can produce interpretable classifier with knowledge expressed in terms of if-then rules and membership function. This paper proposes a novel Genetic Swarm Algorithm (GSA) for obtaining near optimal rule set and membership function tuning. Advanced and problem specific genetic operators are proposed to improve the convergence of GSA and classification accuracy. The performance of the proposed approach is evaluated using six gene expression data sets. From the simulation study it is found that the proposed approach generated a compact fuzzy system with high classification accuracy for all the data sets when compared with other approaches. 相似文献
104.
Obead Yaseen Maher M. El‐Masri Wasim S. El Nekidy Derrick Soong Mohammed Ibrahim John W. Speirs Albert Kadri 《Hemodialysis international. International Symposium on Home Hemodialysis》2013,17(3):434-440
Hemodialysis catheter (HDC) dysfunction due to thrombosis is common, and dysfunction incidence can reach up to 50% within 1 year of use. Although administration of intraluminal alteplase (tissue plasminogen activator [tPA]) is the standard of practice to pharmacologically restore HDC function, there are no evidence‐based guidelines concerning the optimal tPA dose. The purpose of this study was to compare the efficacy of 1.0‐mg vs. 2.0‐mg tPA dwell protocols in restoring the HDC function in thrombotic dysfunctional catheters. A retrospective, single‐center study was conducted on two independent cohorts of patients; the first (n = 129) received 2.0 mg tPA/catheter lumen, while the second (n = 108) received 1.0 mg tPA/catheter lumen. Kaplan–Meier and Cox regression analyses were performed to compare the catheter survival time between patients who received 1.0 mg tPA and those who received 2.0 mg tPA. Catheter removal occurred in 25 (19.4%) of those catheters treated with 1.0 mg tPA compared with 11 (10.2%) of catheters treated with 2.0 mg tPA (P = 0.05). The hazard ratio (HR) for catheter removal was 2.75 (95% confidence interval [95%CI] = 1.25–6.04) for the 1.0‐mg tPA cohort compared with the 2.0‐mg tPA cohort. Correction added on 3 December 2012, after first online publication: The tPA cohort values were changed. Female gender (HR = 2.51; 95%CI = 1.20–5.27) and age (HR = 0.96; 95%CI = 0.94–0.98) were also associated with catheter survival. Our findings suggest that treatment of dysfunctional HDC with 2.0‐mg tPA dwells is superior to 1.0‐mg tPA dwells. 相似文献
105.
106.
107.
108.
109.
Karla Aguilar Alfonso Garvín Ebner Azuara Albert Ibarz 《Food and Bioprocess Technology》2016,9(8):1399-1407
Rate-controlling mechanisms in the photo-degradation of 5-hydroxymethylfurfural (HMF) were studied applying kinetic and thermodynamic compensations. Aqueous solutions of HMF were prepared at a concentration of 100 mg L?1 and at pH values of 3, 3.4, 4, and 5. The UV irradiation of samples was performed in an installation consisting of a black chamber containing the reactor and a mid-pressure mercury lamp with emission wavelengths between 250 and 740 nm. Every sample was irradiated at 12, 25, 35, and 45 °C for 120 min, analyzing their HMF content each 10 min. The photo-degradation data fitted well to zero-order kinetic model, and the constant values were used to study whether the kinetic and thermodynamic compensation could be applied. The isokinetic temperature was very similar for kinetic compensation (TB?=?278.0 K) and thermodynamic compensation (TB?=?277.8 K). Applying the Leffler’s criterion, the HMF photo-degradation was entropically controlled, probably as a consequence of hydrophobic interactions. In order to check the entropical control, two experiments were repeated at pH 3 but avoiding agitation. As the new obtained kinetic constants were highly different from the values previously obtained using agitation, it can be concluded that the HMF photo-degradation is an entropy-controlled process and can be speeded up by changing non-thermal parameters, like agitation. 相似文献
110.
Dominik Soller Thomas Jaumann Gerd Kilian Jörg Robert Albert Heuberger 《Journal of Signal Processing Systems》2017,89(1):181-190
Development of modern Software Defined Radio (SDR) based communication systems can be accelerated significantly by the use of processing frameworks. The evolution of SDR and the involved departure from digital representations of classical radio architecture towards more abstract software systems raises new requirements of increased flexibility and versatility. The proposed Data Flow Control for C++ (DFC++) processing framework concept addresses those requirements by employing modern programming techniques and flow control mechanisms to allow for variable data rates, dynamic paths, and flexible component designs. Another important trend is the integration of various embedded platforms in the software radio domain. The rapidly increasing performance and efficiency of embedded processors enables the deployment of SDR systems in more space and power constrained environments. Therefore covering a heterogeneous hardware selection becomes increasingly important for processing frameworks. By relying exclusively on C++ and minimizing external dependencies, DFC++ is specifically aiming for excellent portability and adaptability to support a wide range of current and future software radio projects while maintaining high performance and ease of use. This paper introduces the key aspects of the DFC++ concept and implementation with focus on the reference pointer based data transport mechanisms responsible for the propagation of user data between different processing components. 相似文献