全文获取类型
收费全文 | 2224篇 |
免费 | 136篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 55篇 |
综合类 | 15篇 |
化学工业 | 567篇 |
金属工艺 | 39篇 |
机械仪表 | 35篇 |
建筑科学 | 66篇 |
矿业工程 | 8篇 |
能源动力 | 31篇 |
轻工业 | 246篇 |
水利工程 | 18篇 |
石油天然气 | 16篇 |
武器工业 | 4篇 |
无线电 | 292篇 |
一般工业技术 | 311篇 |
冶金工业 | 376篇 |
原子能技术 | 7篇 |
自动化技术 | 283篇 |
出版年
2023年 | 18篇 |
2022年 | 84篇 |
2021年 | 78篇 |
2020年 | 56篇 |
2019年 | 40篇 |
2018年 | 47篇 |
2017年 | 50篇 |
2016年 | 66篇 |
2015年 | 61篇 |
2014年 | 66篇 |
2013年 | 101篇 |
2012年 | 119篇 |
2011年 | 110篇 |
2010年 | 72篇 |
2009年 | 92篇 |
2008年 | 82篇 |
2007年 | 90篇 |
2006年 | 67篇 |
2005年 | 74篇 |
2004年 | 54篇 |
2003年 | 67篇 |
2002年 | 57篇 |
2001年 | 59篇 |
2000年 | 37篇 |
1999年 | 47篇 |
1998年 | 129篇 |
1997年 | 77篇 |
1996年 | 55篇 |
1995年 | 46篇 |
1994年 | 40篇 |
1993年 | 47篇 |
1992年 | 32篇 |
1991年 | 15篇 |
1990年 | 16篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 14篇 |
1986年 | 12篇 |
1985年 | 19篇 |
1984年 | 13篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 16篇 |
1979年 | 6篇 |
1977年 | 13篇 |
1976年 | 18篇 |
1975年 | 8篇 |
1974年 | 9篇 |
1973年 | 7篇 |
排序方式: 共有2369条查询结果,搜索用时 15 毫秒
21.
The initial stages of the deposition of nickel on vitreous carbon from aqueous NiCl2 (10–2M adjusted to 1 M in chloride) has been studied using voltammetric and potentiostatic methods. The morphology of the deposits was observed by scanning electron and optical microscopy. A discussion of the relation between the deposition mechanism and the morphology is presented. 相似文献
22.
Examines ritual as a tool for psychotherapeutic application with clients experiencing grief, trauma, anxiety, and family dysfunction. Case vignettes are provided to illustrate the therapeutic properties and creative power of rituals as interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
23.
D. Eckert A. Junod A. Bezinge T. Graf J. Muller 《Journal of Low Temperature Physics》1988,73(3-4):241-254
We have measured the low-temperature specific heat (1.3T20 K) and the dc magnetic susceptibility (100T250 K) of eight samples of the high-T
c
superconductor Y
x
Ba3–x
Cu3O7– (x=0.9, 1.0, 1.1) and of two samples of nonsuperconducting YBa2Cu3O6+. We have also performed specific heat measurements on the possible impurity phases: YBa3Cu2O7, Y2BaCuO5, CuO, and BaCuO2+x
. The superconducting samples all have a nonzero, sample-dependent linear term * and an upturn inC/T at very low temperature. We show that this anomalous behavior is at least partly due to the presence of a small amount (1%) of BaCuO2+x
impurity phase in the measured samples. This is evidenced by the correlation between * and the Curie component of the susceptibility, which is proportional to the amount of paramagnetic impurities. 相似文献
24.
Galina M. Viryasova Ekaterina A. Golenkina Tibor Hianik Nataliya V. Soshnikova Nina G. Dolinnaya Tatjana V. Gaponova Yulia M. Romanova Galina F. Sudina 《International journal of molecular sciences》2021,22(5)
Neutrophil-mediated innate host defense mechanisms include pathogen elimination through bacterial phagocytosis, which activates the 5-lipoxygenase (5-LOX) product synthesis. Here, we studied the effect of synthetic oligodeoxyribonucleotides (ODNs), which mimic the receptor-recognized sites of bacterial (CpG-ODNs) and genomic (G-rich ODNs) DNAs released from the inflammatory area, on the neutrophil functions after cell stimulation with Salmonella typhimurium. A possible mechanism for ODN recognition by Toll-like receptor 9 (TLR9) and RAGE receptor has been proposed. We found for the first time that the combination of the magic peptide LRR11 from the leucine-rich repeat (LRR) of TLR9 with the CpG-ODNs modulates the uptake and signaling from ODNs, in particular, dramatically stimulates 5-LOX pathway. Using thickness shear mode acoustic method, we confirmed the specific binding of CpG-ODNs, but not G-rich ODN, to LRR11. The RAGE receptor has been shown to play an important role in promoting ODN uptake. Thus, FPS-ZM1, a high-affinity RAGE inhibitor, suppresses the synthesis of 5-LOX products and reduces the uptake of ODNs by neutrophils; the inhibitor effect being abolished by the addition of LRR11. The results obtained revealed that the studied peptide-ODN complexes possess high biological activity and can be promising for the development of effective vaccine adjuvants and antimicrobial therapeutics. 相似文献
25.
Dawid Polak Marcin Talar Nina Wolska Dagmara W. Wojkowska Kamil Karolczak Karol Kramkowski Tomasz A. Bonda Cezary Watala Tomasz Przygodzki 《International journal of molecular sciences》2021,22(6)
Blood platelets’ adenosine receptors (AR) are considered to be a new target for the anti-platelet therapy. This idea is based on in vitro studies which show that signaling mediated by these receptors leads to a decreased platelet response to activating stimuli. In vivo evidence for the antithrombotic activity of AR agonists published to date were limited, however, to the usage of relatively high doses given in bolus. The present study was aimed at verifying if these substances used in lower doses in combination with inhibitors of P2Y12 could serve as components of dual anti-platelet therapy. We have found that a selective A2A agonist 2-hexynyl-5’-N-ethylcarboxamidoadenosine (HE-NECA) improved the anti-thrombotic properties of either cangrelor or prasugrel in the model of ferric chloride-induced experimental thrombosis in mice. Importantly, HE-NECA was effective not only when applied in bolus as other AR agonists in the up-to-date published studies, but also when given chronically. In vitro thrombus formation under flow conditions revealed that HE-NECA enhanced the ability of P2Y12 inhibitors to decrease fibrinogen content in thrombi, possibly resulting in their lower stability. Adenosine receptor agonists possess a certain hypotensive effect and an ability to increase the blood–brain barrier permeability. Therefore, the effects of anti-thrombotic doses of HE-NECA on blood pressure and the blood–brain barrier permeability in mice were tested. HE-NECA applied in bolus caused a significant hypotension in mice, but the effect was much lower when the substance was given in doses corresponding to that obtained by chronic administration. At the same time, no significant effect of HE-NECA was observed on the blood–brain barrier. We conclude that chronic administration of the A2A agonist can be considered a potential component of a dual antithrombotic therapy. However, due to the hypotensive effect of the substances, dosage and administration must be elaborated to minimize the side-effects. The total number of animals used in the experiments was 146. 相似文献
26.
The influence of demineralisation and ammoxidation on the adsorption properties of an activated carbon prepared from a Polish lignite 总被引:1,自引:0,他引:1
Julien Starck Sebastien Muller Guy Furdin Cathie Vix_Guterl Pierre Faure 《Carbon》2006,44(12):2549-2557
The preparation of cheap nitrogen-enriched materials with large adsorptive capacities and selectivity towards volatile organic compounds remains a challenge. Ammoxidation has been used to prepare nitrogen-enriched activated carbons using a demineralised Polish lignite. The lignite samples were demineralised by two different methods before nitrogen-enrichment by ammoxidation and physical activation in steam. The surface chemistry was investigated by elemental analysis, Boehm titration, infrared and XPS spectroscopies and adsorptive properties by a linear solvation energy relationship approach. Results show a quasi-total demineralisation and a higher reactivity towards nitrogen for the demineralised samples. The BET surface is also higher than for the non-demineralised lignite. Active carbons previously ammoxidated and demineralised are more interesting in terms of selective removal of gaseous pollutants. 相似文献
27.
E. Stamatakis C. Chatzichristos A.K. Stubos J. Muller 《Chemical engineering science》2006,61(21):7057-7067
The applicability of a newly developed radiotracer technique as a reliable laboratory procedure for the evaluation of scale inhibitors performance to prevent mineral precipitation is demonstrated. The performance of two new environmentally friendly inhibitors to prevent calcite and barite scale was evaluated experimentally in connection with a standard phosphonate-type scale inhibitor using the radioactive tracer technology. The radiotracers 47Ca and 131Ba were employed in order to monitor at real-time calcite and barite scale formation, respectively. The results show that the developed radiotracer technique can be established as a novel method for the determination of the minimum inhibitor concentration (MIC) under dynamic, reservoir conditions. In addition, the radioactive tritiated water (HTO) was used as a reference water tracer to identify the inhibitors’ properties, such as adsorption/desorption characteristics, in sandpack-flooding tests. Further issues regarding the implementation of the radiotracer technology for the laboratory evaluation of scale inhibitors performance are also discussed. 相似文献
28.
Kerstin A. Kessel Christian Bohn Uwe Engelmann Dieter Oetzel Nina Bougatf Rolf Bendl Jürgen Debus Stephanie E. Combs 《Computer methods and programs in biomedicine》2014
In radiation oncology, where treatment concepts are elaborated in interdisciplinary collaborations, handling distributed, large heterogeneous amounts of data efficiently is very important, yet challenging, for an optimal treatment of the patient as well as for research itself. This becomes a strong focus, as we step into the era of modern personalized medicine, relying on various quantitative data information, thus involving the active contribution of multiple medical specialties. Hence, combining patient data from all involved information systems is inevitable for analyses. Therefore, we introduced a documentation and data management system integrated in the clinical environment for electronic data capture. We discuss our concept and five-year experience of a precise electronic documentation system, with special focus on the challenges we encountered. We specify how such a system can be designed and implemented to plan, tailor and conduct (multicenter) clinical trials, ultimately reaching the best clinical performance, and enhancing interdisciplinary and clinical research. 相似文献
29.
Interactions between the antioxidant Santonox (4,4′-thiobis(6-tert-butyl-m-cresol)) and the LCST polymer blend of polystyrene (PS) and polyvinylmethylether (PVME) were examined. The presence of the antioxidant caused inhomogeneities in blend films cast from toluene solutions at antioxidant compositions greater than 0.25 wt% of the PVME. Also, the cloud-point of the blend decreased linearly with antioxidant content with a slope of 21 °C/wt%. As expected, the ability of the antioxidant to prevent degradation of the PVME within the blend was found to increase with increasing Santonox composition. Based on these results, an antioxidant composition of no more than 0.10 wt% is recommended in the studies of PS/PVME blends. 相似文献
30.
低雾化低挥发性汽车用新型聚氨酯泡沫塑料助剂 总被引:1,自引:1,他引:1
康普顿公司开发了一系列适用于消除或减少汽车内饰件中胺扩散或雾化的添加剂,其中包括快速、有效的生产用零扩散催化剂和低雾化表面活性剂。该系列添加剂能大大降低泡沫制品中的胺扩散,与异氰酸酯和多元醇原料能组成最佳组合,以保持良好的泡沫物理性能。 相似文献