全文获取类型
收费全文 | 21404篇 |
免费 | 1447篇 |
国内免费 | 1004篇 |
专业分类
电工技术 | 644篇 |
技术理论 | 14篇 |
综合类 | 2105篇 |
化学工业 | 3787篇 |
金属工艺 | 513篇 |
机械仪表 | 696篇 |
建筑科学 | 2110篇 |
矿业工程 | 1104篇 |
能源动力 | 688篇 |
轻工业 | 5645篇 |
水利工程 | 306篇 |
石油天然气 | 598篇 |
武器工业 | 29篇 |
无线电 | 747篇 |
一般工业技术 | 1239篇 |
冶金工业 | 1729篇 |
原子能技术 | 44篇 |
自动化技术 | 1857篇 |
出版年
2024年 | 103篇 |
2023年 | 266篇 |
2022年 | 646篇 |
2021年 | 764篇 |
2020年 | 760篇 |
2019年 | 541篇 |
2018年 | 422篇 |
2017年 | 488篇 |
2016年 | 623篇 |
2015年 | 587篇 |
2014年 | 1218篇 |
2013年 | 1209篇 |
2012年 | 1405篇 |
2011年 | 1451篇 |
2010年 | 1293篇 |
2009年 | 1135篇 |
2008年 | 948篇 |
2007年 | 1404篇 |
2006年 | 1471篇 |
2005年 | 1259篇 |
2004年 | 1020篇 |
2003年 | 964篇 |
2002年 | 799篇 |
2001年 | 678篇 |
2000年 | 544篇 |
1999年 | 402篇 |
1998年 | 316篇 |
1997年 | 227篇 |
1996年 | 179篇 |
1995年 | 147篇 |
1994年 | 99篇 |
1993年 | 108篇 |
1992年 | 74篇 |
1991年 | 53篇 |
1990年 | 32篇 |
1989年 | 28篇 |
1988年 | 12篇 |
1987年 | 18篇 |
1986年 | 34篇 |
1985年 | 22篇 |
1984年 | 23篇 |
1983年 | 25篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1959年 | 5篇 |
1956年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Corey Andrews Yiting Xu Michael Kirberger Jenny J. Yang 《International journal of molecular sciences》2021,22(1)
Calmodulin (CaM) is an important intracellular protein that binds Ca2+ and functions as a critical second messenger involved in numerous biological activities through extensive interactions with proteins and peptides. CaM’s ability to adapt to binding targets with different structures is related to the flexible central helix separating the N- and C-terminal lobes, which allows for conformational changes between extended and collapsed forms of the protein. CaM-binding targets are most often identified using prediction algorithms that utilize sequence and structural data to predict regions of peptides and proteins that can interact with CaM. In this review, we provide an overview of different CaM-binding proteins, the motifs through which they interact with CaM, and shared properties that make them good binding partners for CaM. Additionally, we discuss the historical and current methods for predicting CaM binding, and the similarities and differences between these methods and their relative success at prediction. As new CaM-binding proteins are identified and classified, we will gain a broader understanding of the biological processes regulated through changes in Ca2+ concentration through interactions with CaM. 相似文献
2.
当前,我国水泥工业在可燃废弃物应用技术方面都还处于一家一户、自制自用、效率极低的初级阶段。发达国家的替代燃料:“垃圾衍生燃料”RDF、“固体回收燃料”SRF、“次煤”Subcoal和“纸塑垃圾衍生燃料”RPF制成的原材料都是可燃废弃物,只是处理工艺技术不同或者由垃圾中分拣出的可燃废弃物不同,制成颗粒状衍生燃料的品质不同,这些都可以替代部分甚或替代全部化石燃料在水泥窑炉中应用。我国大力发展“替代燃料”产业,有助于水泥工业消纳更多的“可燃废弃物”,为改善环境尤其是城镇环境和面貌,为我国的节能减排和绿色高质量发展发挥更大的作用。 相似文献
3.
一场新型冠状病毒肺炎疫情的爆发给染料行业的发展带来了影响,既有负面消极,也有积极影响。疫情将促进染料行业绿色发展,推动染料行业走向信息化、智能化时代,走向高质量发展,指出只要坚持绿色、创新和智能化,就能战胜疫情,推动中国染料行业稳健发展。 相似文献
4.
5.
Gerd J. Hahn 《国际生产研究杂志》2020,58(5):1425-1441
The Fourth Industrial Revolution – also known as Industry 4.0 (i4.0) – comprises the digitalisation of the industrial sector. This paper uses the theoretical lens of supply chain innovation (SCI) to investigate the implications of i4.0 on supply chain management. For these purposes, the method of structured content analysis is applied to more than 200 use cases of i4.0-enabled SCI introduced by both established and startup companies. i4.0-enabled SCI manifests along three dimensions: process, technology, and business architecture. The key findings of this study can be summarised as follows: first, i4.0-enabled SCI extends the initial focus on productivity improvements in SC processes towards scalability and flexibility. Second, extant i4.0 solutions rely mostly on analytics and smart things while omitting smart people technology and the human-centric approach associated with the i4.0 paradigm. Third, established companies adopt i4.0 merely to sustain their existing business architectures while startup companies radically change their operating models, relying heavily on data analytics and the platform economy. Consequently, established companies pursue a problem-driven, engineering-based approach to SCI while startup companies follow an ‘asset-light’, business-driven approach. Lastly, there are two distinct approaches to digitalising operational SC processes: platform-based crowdsourcing of standard processes and on-demand provision of customised services. 相似文献
6.
Hot-dip galvanizing is a standard technology to produce coated steel strips. The primary objective of the galvanizing process is to establish a homogeneous zinc layer with a defined thickness. One condition to achieve this objective is a uniform transverse distance between the strip and the gas wiping dies, which blow off excessive liquid zinc. Therefore, a flat strip profile at the gas wiping dies is required. However, strips processed in such plants often exhibit residual curvatures which entail unknown flatness defects of the strip. Such flatness defects cause non-uniform air gaps and hence an inhomogeneous zinc coating thickness. Modern hot-dip galvanizing lines often use electromagnets to control the transverse strip profile near the gas wiping dies. Typically, the control algorithms ensure a flat strip profile at the electromagnets because the sensors for the transverse strip displacement are also located at this position and it is unfeasible to mount displacement sensors directly at the gas wiping dies. This brings along that in general a flatness defect remains at the gas wiping dies, which in turn entails a suboptimal coating.In this paper, a model-based method for a feedforward control of the strip profile at the position of the gas wiping dies is developed. This method is based on a plate model of the axially moving strip that takes into account the flatness defects in the strip. First, an estimator of the flatness defects is developed and validated for various test strips and settings of the plant. Using the validated mathematical model, a simulation study is performed to compare the state-of-the-art control approach (flat strip profile at the electromagnets) with the optimization-based feedforward controller (flat strip profile at the gas wiping dies) proposed in this paper. Moreover, the influence of the distance between the gas wiping dies and the electromagnets is investigated in detail. 相似文献
7.
8.
Effects of different carbon sources and C/N values on nonvolatile taste components of Pleurotus eryngii
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Wen Li Xiaobei Li Yan Yang Feng Zhou Yanfang Liu Shuai Zhou Hailong Yu 《International Journal of Food Science & Technology》2015,50(11):2360-2366
Pleurotus eryngii, the second largest industrial cultivation mushroom in China, is usually cultivated on substrates mainly consisting of sawdust and corncob. In this study, experiments were performed to determine the effects of different carbon sources and C/N values on nonvolatile taste components of P. eryngii. The effects of different carbon sources on nonvolatile taste components levels revealed that sawdust was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while corncob was beneficial to high contents of carbohydrate, polysaccharides and trehalose. At the similar C/N values, relatively higher sawdust content was beneficial to umami amino acid production, while relatively higher corncob content was beneficial to high contents of carbohydrate, polysaccharides and mannitol. Higher C/N value was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while lower C/N value was beneficial to high contents of carbohydrate, polysaccharides and trehalose. These results provided information for P. eryngii fruit body industrial cultivation to obtain specific nonvolatile taste components with high levels. 相似文献
9.
The development of a sustainable energy system throughout an enterprise is a complex task, which requires an agile holistic approach. Such an approach needs to include a variety of objectives including energy strategy formation and strategic decision-making, which are directly related to the analysis and management of the main areas of sustainable development:The economic, technological, environmental, and social. These multidimensional requirements of sustainability are often difficult to achieve within the enterprise, because these aspects are interrelated and influenced by various internal and external environment factors. This paper first reviews the main challenges for an energy system, and then demonstrates how a strategic agile enterprise architecture driven approach could effectively guide the sustainable energy system development. The study presented in this paper provides a holistic approach that contributes to the advancement and usage of literature dealing with issues of sustainable energy system development and agile enterprise architecture, which has not been discussed before to any great extent. 相似文献
10.
Ensemble pruning deals with the selection of base learners prior to combination in order to improve prediction accuracy and efficiency. In the ensemble literature, it has been pointed out that in order for an ensemble classifier to achieve higher prediction accuracy, it is critical for the ensemble classifier to consist of accurate classifiers which at the same time diverse as much as possible. In this paper, a novel ensemble pruning method, called PL-bagging, is proposed. In order to attain the balance between diversity and accuracy of base learners, PL-bagging employs positive Lasso to assign weights to base learners in the combination step. Simulation studies and theoretical investigation showed that PL-bagging filters out redundant base learners while it assigns higher weights to more accurate base learners. Such improved weighting scheme of PL-bagging further results in higher classification accuracy and the improvement becomes even more significant as the ensemble size increases. The performance of PL-bagging was compared with state-of-the-art ensemble pruning methods for aggregation of bootstrapped base learners using 22 real and 4 synthetic datasets. The results indicate that PL-bagging significantly outperforms state-of-the-art ensemble pruning methods such as Boosting-based pruning and Trimmed bagging. 相似文献