全文获取类型
收费全文 | 13723篇 |
免费 | 536篇 |
国内免费 | 42篇 |
专业分类
电工技术 | 160篇 |
综合类 | 26篇 |
化学工业 | 3390篇 |
金属工艺 | 333篇 |
机械仪表 | 349篇 |
建筑科学 | 732篇 |
矿业工程 | 43篇 |
能源动力 | 310篇 |
轻工业 | 1218篇 |
水利工程 | 82篇 |
石油天然气 | 28篇 |
武器工业 | 2篇 |
无线电 | 728篇 |
一般工业技术 | 2400篇 |
冶金工业 | 2272篇 |
原子能技术 | 123篇 |
自动化技术 | 2105篇 |
出版年
2023年 | 87篇 |
2022年 | 85篇 |
2021年 | 289篇 |
2020年 | 185篇 |
2019年 | 210篇 |
2018年 | 326篇 |
2017年 | 240篇 |
2016年 | 367篇 |
2015年 | 295篇 |
2014年 | 499篇 |
2013年 | 871篇 |
2012年 | 623篇 |
2011年 | 845篇 |
2010年 | 614篇 |
2009年 | 614篇 |
2008年 | 612篇 |
2007年 | 581篇 |
2006年 | 513篇 |
2005年 | 403篇 |
2004年 | 398篇 |
2003年 | 304篇 |
2002年 | 307篇 |
2001年 | 225篇 |
2000年 | 242篇 |
1999年 | 222篇 |
1998年 | 452篇 |
1997年 | 388篇 |
1996年 | 288篇 |
1995年 | 222篇 |
1994年 | 176篇 |
1993年 | 216篇 |
1992年 | 166篇 |
1991年 | 101篇 |
1990年 | 115篇 |
1989年 | 100篇 |
1988年 | 116篇 |
1987年 | 94篇 |
1986年 | 81篇 |
1985年 | 119篇 |
1984年 | 119篇 |
1983年 | 95篇 |
1982年 | 106篇 |
1981年 | 118篇 |
1980年 | 103篇 |
1979年 | 115篇 |
1978年 | 90篇 |
1977年 | 132篇 |
1976年 | 156篇 |
1975年 | 81篇 |
1973年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 191 毫秒
1.
Prof. Andrea Baier Dr. Anne Kokel Dr. William Horton Ewa Gizińska Dr. Garima Pandey Prof. Ryszard Szyszka Prof. Béla Török Prof. Marianna Török 《ChemMedChem》2021,16(12):1927-1932
A set of novel hydrazone derivatives were synthesized and analyzed for their biological activities. The compounds were tested for their inhibitory effect on the phosphorylating activity of the protein kinase CK2, and their antioxidant activity was also determined in three commonly used assays. The hydrazones were evaluated for their radical scavenging against the DPPH, ABTS and peroxyl radicals. Several compounds have been identified as good antioxidants as well as potent protein kinase CK2 inhibitors. Most hydrazones containing a 4-N(CH3)2 residue or perfluorinated phenyl rings showed high activity in the radical-scavenging assays and possess nanomolar IC50 values in the kinase assays. 相似文献
2.
Marcus Reppich Zdeněk Jegla Jakob Grondinger Yaovi Ouézou Azouma Vojtěch Turek 《化学,工程师,技术》2021,93(10):1581-1589
This study investigates the behavior of fruit and vegetable samples during drying. The experimental data are fitted to several different thin-layer drying models. Regression analysis is used to determine model parameters, while statistical indicators serve to evaluate the goodness of fit. The power function model gives the best fit for all examined samples. Based on this model, different drying and heat storage technologies can be combined to ensure that the required residual moisture content of an agricultural product is reached. It is demonstrated on the case of a specific Togolese processing plant that under favorable conditions, fossil fuel consumption can be decreased by 33 %. 相似文献
3.
Golam Haider Krishna Sampathkumar Tim Verhagen Lukáš Nádvorník Farjana J. Sonia Václav Valeš Jan Sýkora Peter Kapusta Petr Němec Martin Hof Otakar Frank Yang-Fang Chen Jana Vejpravová Martin Kalbáč 《Advanced functional materials》2021,31(29):2102196
Recent advancements in isolation and stacking of layered van der Waals materials have created an unprecedented paradigm for demonstrating varieties of 2D quantum materials. Rationally designed van der Waals heterostructures composed of monolayer transition-metal dichalcogenides (TMDs) and few-layer hBN show several unique optoelectronic features driven by correlations. However, entangled superradiant excitonic species in such systems have not been observed before. In this report, it is demonstrated that strong suppression of phonon population at low temperature results in a formation of a coherent excitonic-dipoles ensemble in the heterostructure, and the collective oscillation of those dipoles stimulates a robust phase synchronized ultra-narrow band superradiant emission even at extremely low pumping intensity. Such emitters are in high demand for a multitude of applications, including fundamental research on many-body correlations and other state-of-the-art technologies. This timely demonstration paves the way for further exploration of ultralow-threshold quantum-emitting devices with unmatched design freedom and spectral tunability. 相似文献
4.
Fabiana D'Isanto Federico Smeacetto Hans-Peter Martin Richard Sedlák Maksym Lisnichuk Andreas Chrysanthou Milena Salvo 《Ceramics International》2021,47(14):19774-19783
A silica-based glass-ceramic, with Y2Ti2O7 as the major crystalline phase, is designed, characterised and tested as an oxidation-protective coating for a titanium suboxide (TiOx) thermoelectric material at temperatures of up to 600 °C. The optimised sinter-crystallisation treatment temperatures are found to be 1300 °C and 855 °C for a duration of 30 min, and this treatment leads to a glass-ceramic with cubic Y2Ti2O7 and CaAl2Si2O8 as crystalline phases. An increase of ~270 °C in the dilatometric softening temperature is observed after devitrification of the parent glass, thus further extending its working temperature range.Excellent adhesion of the glass-ceramic coating to the thermoelectric material is maintained after exposure to a temperature of 600 °C for 120 h under oxidising conditions, thus confirming the effectiveness of the T1 glass-ceramic in protecting the TiOx material. 相似文献
5.
Dr. Sandra Liebscher Dr. Sebastian Mathea Dr. Tobias Aumüller Dr. Andreas Pech Prof. Dr. Frank Bordusa 《Chembiochem : a European journal of chemical biology》2021,22(7):1201-1204
Fluorescent fusion proteins are powerful tools for studying biological processes in living cells, but universal application is limited due to the voluminous size of those tags, which might have an impact on the folding, localization or even the biological function of the target protein. The designed biocatalyst trypsiligase enables site-directed linkage of small-sized fluorescence dyes on the N terminus of integral target proteins located in the outer membrane of living cells through a stable native peptide bond. The function of the approach was tested by using the examples of covalent derivatization of the transmembrane proteins CD147 as well as the EGF receptor, both presented on human HeLa cells. Specific trypsiligase recognition of the site of linkage was mediated by the dipeptide sequence Arg-His added to the proteins’ native N termini, pointing outside the cell membrane. The labeling procedure takes only about 5 minutes, as demonstrated for couplings of the fluorescence dye tetramethyl rhodamine and the affinity label biotin as well. 相似文献
6.
Journal of Low Temperature Physics - This study modeled and investigated the magnetocaloric effect in Ni2MnGa Heusler alloy characterized by its magnetic entropy change (ΔSm) and its... 相似文献
7.
Puneet Parmar Nicolas Lopez-Villalobos John T. Tobin Eoin Murphy Frank Buckley Shane V. Crowley Alan L. Kelly Laurence Shalloo 《International Journal of Food Science & Technology》2021,56(5):2415-2422
The objective of this study was to determine the effect of temperature on whole milk density measured at four different temperatures: 5, 10, 15, and 20 °C. A total of ninety-three individual milk samples were collected from morning milking of thirty-two Holstein Friesian dairy cows, of national average genetic merit, once every two weeks over a period of 4 weeks and were assessed by Fourier transform infrared spectroscopy for milk composition analysis. Density of the milk was evaluated using two different analytical methods: a portable density meter DMA35 and a standard desktop model DMA4500M (Anton Paar GmbH, UK). Milk density was analysed with a linear mixed model with the fixed effects of sampling period, temperature and analysis method; triple interaction of sampling period x analysis method x temperature; and the random effect of cow to account for repeated measures. The effect of temperature on milk density (ρ) was also evaluated including temperature (t) as covariate with linear and quadratic effects within each analytic method. The regression equation describing the curvature and density–temperature relationship for the DMA35 instrument was ρ = 1.0338−0.00017T−0.0000122T2 (R2 = 0.64), while it was ρ = 1.0334 + 0.000057T−0.00001T2 (R2 = 0.61) for DMA4500 instrument. The mean density determined with DMA4500 at 5 °C was 1.0334 g cm−3, with corresponding figures of 1.0330, 1.0320 and 1.0305 g cm−3 at 10, 15 and 20 °C, respectively. The milk density values obtained in this study at specific temperatures will help to address any bias in weight–volume calculations and thus may also improve the financial and operational control for the dairy processors in Ireland and internationally. 相似文献
8.
9.
10.