全文获取类型
收费全文 | 5729篇 |
免费 | 324篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 51篇 |
综合类 | 34篇 |
化学工业 | 1410篇 |
金属工艺 | 182篇 |
机械仪表 | 135篇 |
建筑科学 | 238篇 |
矿业工程 | 13篇 |
能源动力 | 244篇 |
轻工业 | 804篇 |
水利工程 | 36篇 |
石油天然气 | 28篇 |
武器工业 | 2篇 |
无线电 | 311篇 |
一般工业技术 | 935篇 |
冶金工业 | 678篇 |
原子能技术 | 62篇 |
自动化技术 | 899篇 |
出版年
2023年 | 50篇 |
2022年 | 66篇 |
2021年 | 199篇 |
2020年 | 145篇 |
2019年 | 151篇 |
2018年 | 213篇 |
2017年 | 206篇 |
2016年 | 228篇 |
2015年 | 172篇 |
2014年 | 242篇 |
2013年 | 423篇 |
2012年 | 376篇 |
2011年 | 452篇 |
2010年 | 326篇 |
2009年 | 308篇 |
2008年 | 293篇 |
2007年 | 220篇 |
2006年 | 213篇 |
2005年 | 186篇 |
2004年 | 137篇 |
2003年 | 141篇 |
2002年 | 130篇 |
2001年 | 79篇 |
2000年 | 66篇 |
1999年 | 44篇 |
1998年 | 183篇 |
1997年 | 138篇 |
1996年 | 77篇 |
1995年 | 66篇 |
1994年 | 61篇 |
1993年 | 66篇 |
1992年 | 24篇 |
1991年 | 21篇 |
1990年 | 18篇 |
1989年 | 22篇 |
1988年 | 20篇 |
1987年 | 22篇 |
1986年 | 19篇 |
1985年 | 23篇 |
1984年 | 13篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1981年 | 21篇 |
1980年 | 14篇 |
1979年 | 17篇 |
1978年 | 14篇 |
1977年 | 13篇 |
1976年 | 31篇 |
1972年 | 9篇 |
1971年 | 9篇 |
排序方式: 共有6062条查询结果,搜索用时 23 毫秒
1.
2.
Dr. Thomas Le Bihan Dr. Cathryn H. S. Driver Dr. Thomas Ebenhan Dr. Nathalie Le Bris Dr. Jan Rijn Zeevaart Prof. Dr. Raphaël Tripier 《ChemMedChem》2021,16(5):809-821
An improved glucose-chelator-albumin bioconjugate (GluCAB) derivative, GluCAB-2Mal, has been synthesized and studied for in vivo 64Cu-PET/CT imaging in breast cancer mice models together with its first-generation analogue GluCAB-1Mal. The radioligand works on the principle of tumor targeting through the enhanced permeability and retention (EPR) effect with a supportive role played by glucose metabolism. [64Cu]Cu-GluCAB-2Mal (99 % RCP) exhibited high serum stability with immediate binding to serum proteins. In vivo experiments for comparison between tumor targeting of [64Cu]Cu-GluCAB-2Mal and previous-generation [64Cu]Cu-GluCAB-1Mal encompassed microPET/CT imaging and biodistribution analysis in an allograft E0771 breast cancer mouse model. Tumor uptake of [64Cu]Cu-GluCAB-2Mal was clearly evident with twice as much accumulation as compared to its predecessor and a tumor/muscle ratio of up to 5 after 24 h. Further comparison indicated a decrease in liver accumulation for [64Cu]Cu-Glu-CAB-2Mal. 相似文献
3.
Dr. Jelena Melesina Conrad V. Simoben Lucas Praetorius Emre F. Bülbül Dr. Dina Robaa Prof. Dr. Wolfgang Sippl 《ChemMedChem》2021,16(9):1336-1359
This review classifies drug-design strategies successfully implemented in the development of histone deacetylase (HDAC) inhibitors, which have many applications including cancer treatment. Our focus is on especially demanded selective HDAC inhibitors and their structure-activity relationships in relation to corresponding protein structures. The main part of the paper is divided into six subsections each narrating how optimization of one of six structural features can influence inhibitor selectivity. It starts with the impact of the zinc binding group on selectivity, continues with the optimization of the linker placed in the substrate binding tunnel as well as the adjustment of the cap group interacting with the surface of the protein, and ends with the addition of groups targeting class-specific sub-pockets: the side-pocket-, lower-pocket- and foot-pocket-targeting groups. The review is rounded off with a conclusion and an outlook on the future of HDAC inhibitor design. 相似文献
4.
5.
This paper reports an investigation into new connection types and their behaviors determined using full-scale experiments. T-shaped connections were created using the IPE standard profile. The aim of this study was to analyze the influence of T connections based on the IPE standard profile, height of beam to height of T-stub joint (H) of T-stub joints, and lengths (X) of T-stub joints on the behavior of steel connections, in order to provide the necessary data for improving Eurocode 3 and enable efficient use of residue IPE standard profiles and back to the consumption cycle. While the moment resistance values increased with an increase in H from Hmin to Hmax in model groups with X of 126 mm, and the energy dissipation increased with an increase in H from Hmin to Hmax and also with an increase in the lengths (X) of T-stub joints from 54 to 126 mm. 相似文献
6.
In solution, amphoteric compounds exist in anionic, uncharged, zwitterionic and cationic forms. The importance of zwitterionic drugs is currently under-represented in the literature. Herein, the acid-base parameters, lipophilicity and solubility of such compounds are discussed to deepen the molecular-level understanding of their pharmacokinetic and pharmacodynamic behaviour. Our recent studies show there are many drug molecules, including thyroid hormones and 5-hydroxytryptophan, the precursor of the neurotransmitter serotonin, for which the contribution of the zwitterionic microspecies to the overall lipophilicity exceeds that of the uncharged one, which is of higher individual lipophilicity, but occurs in much lower concentration. The second part of the minireview highlights the most important zwitterionic compounds in therapy, grouped into therapeutic classes. The importance of the charge of the molecules is emphasized in their binding to the target molecules. 相似文献
7.
Tolga Taner Mecit Sivrioğlu Hüseyin Topal Ahmet Selim Dalkılıç Somchai Wongwises 《Sadhana》2018,43(3):42
This study presents a case study of energy management in a sugar factory in Turkey. The main idea of the study is to analyse energy consumption, the quantity of material production, and figure out a suitable energy efficiency for the case study of a sugar factory subsequently. Firstly, a material production and energy consumption audit were performed for the sugar factory. Secondly, energy efficiency was calculated from the energy data. The SPSS (Statistical Package for the Social Sciences) statistical software was used to ensure the accuracy of the data. The factory’s energy consumption was calculated as 43,590.25 toe (tons of oil equivalent) over the last year. These results were used for CUSUM (Cumulative Sum Deviation Method) graphics. This research poses the consumption of energy, cost of energy and the relationship between energy usage and material production of sugar. The unit of energy cost was 688.22 [$/toe] for the last year. This result showed that the factory decreased the unit of energy by optimisation. The results indicated that the investigated sugar factory should pay attention to the energy management issue in order to comply with the Energy Efficiency of Turkish Law and Directives. 相似文献
8.
Concentration of Gamma‐Linolenic and Stearidonic Acids as Free Fatty Acids and Ethyl Esters from Viper's Bugloss Seed Oil by Urea Complexation 下载免费PDF全文
9.
Adrien N. Djomo J. Andrew Grant Celestine Fonyikeh-Bomboh Lucha Julie Tchoko Gagoe Noël H. Fonton Neal Scott 《The International journal of environmental studies》2018,75(2):251-266
Forests play a significant role in the global carbon budget, and can help to mitigate climate change impacts. Tropical forests which experience high rates of deforestation and forest degradation are particularly important, as they are the most active in winter. Based on academic research into global environmental policies in Central Africa, this study finds that REDD+ policies can succeed when there is a carbon market mechanism that increases participation by developing countries, with better integration of forest management and community forestry. Incentives should be based on an appropriate baseline, accurate carbon stocks and fluxes estimation, a suitable silvicultural system and regular monitoring. 相似文献
10.
Chunliang Li Theo Veldhuis Bart Reuvers Rafaël J Sablong Cor E Koning 《Polymer International》2020,69(1):24-30
Limonene‐derived polycarbonate‐based alkyd resins (ARs) have been prepared by copolymerization of limonene dioxide with CO2, catalysed by a β‐diiminate zinc–bis(trimethylsilyl)amido complex, and subsequent chemical modification with soybean oil fatty acids using triphenylethylphosphonium bromide as the catalyst. This quantitative partial modification was realized via epoxy–carboxylic acid chemistry, affording ARs with higher oil lengths, lower polydispersities and higher glass transition temperatures (Tg) in comparison to a conventional polyester AR based on phthalic acid, multifunctional polyol pentaerythritol and soybean fatty acid. The novel limonene polycarbonate AR and the conventional polyester AR were evaluated as coatings and both the physical drying (without the presence of the oxidative drying accelerator Borchi® Oxy Coat) and chemical curing (with Borchi® Oxy Coat) processes of these coatings were monitored by measuring the König hardness and complex modulus development with time. A better performance was obtained for the alkyd paint containing polycarbonates modified with fatty acids (FA‐PCs), which showed a faster chemical drying, a higher König hardness and a higher Tg in coating evaluation, demonstrating that the fully renewable FA‐PCs are promising resins for alkyd paint applications. © 2019 Society of Chemical Industry 相似文献