全文获取类型
收费全文 | 3720篇 |
免费 | 308篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 102篇 |
综合类 | 21篇 |
化学工业 | 743篇 |
金属工艺 | 131篇 |
机械仪表 | 46篇 |
建筑科学 | 182篇 |
矿业工程 | 24篇 |
能源动力 | 73篇 |
轻工业 | 827篇 |
水利工程 | 11篇 |
石油天然气 | 3篇 |
无线电 | 240篇 |
一般工业技术 | 696篇 |
冶金工业 | 138篇 |
原子能技术 | 22篇 |
自动化技术 | 776篇 |
出版年
2023年 | 70篇 |
2022年 | 62篇 |
2021年 | 134篇 |
2020年 | 118篇 |
2019年 | 110篇 |
2018年 | 153篇 |
2017年 | 132篇 |
2016年 | 179篇 |
2015年 | 156篇 |
2014年 | 193篇 |
2013年 | 238篇 |
2012年 | 223篇 |
2011年 | 206篇 |
2010年 | 218篇 |
2009年 | 176篇 |
2008年 | 159篇 |
2007年 | 157篇 |
2006年 | 107篇 |
2005年 | 67篇 |
2004年 | 50篇 |
2003年 | 35篇 |
2002年 | 37篇 |
2001年 | 35篇 |
2000年 | 27篇 |
1999年 | 29篇 |
1998年 | 60篇 |
1997年 | 36篇 |
1996年 | 15篇 |
1995年 | 19篇 |
1994年 | 22篇 |
1991年 | 16篇 |
1943年 | 18篇 |
1942年 | 14篇 |
1936年 | 18篇 |
1935年 | 13篇 |
1934年 | 16篇 |
1932年 | 13篇 |
1931年 | 13篇 |
1930年 | 15篇 |
1929年 | 13篇 |
1928年 | 15篇 |
1925年 | 19篇 |
1924年 | 26篇 |
1923年 | 19篇 |
1918年 | 28篇 |
1917年 | 30篇 |
1916年 | 26篇 |
1915年 | 34篇 |
1911年 | 14篇 |
1910年 | 15篇 |
排序方式: 共有4035条查询结果,搜索用时 15 毫秒
1.
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
2.
3.
A contact layer element for large deformations 总被引:1,自引:0,他引:1
4.
Dr. Raysa Khan Tareque Dr. Storm Hassell-Hart Dr. Tobias Krojer Dr. Anthony Bradley Dr. Srikannathasan Velupillai Dr. Romain Talon Dr. Michael Fairhead Dr. Iain J. Day Kamlesh Bala Dr. Robert Felix Dr. Paul D. Kemmitt Prof. Paul Brennan Prof. Frank von Delft Dr. Laura Díaz Sáez Prof. Kilian Huber Prof. John Spencer 《ChemMedChem》2020,15(24):2513-2520
Combined photochemical arylation, “nuisance effect” (SNAr) reaction sequences have been employed in the design of small arrays for immediate deployment in medium-throughput X-ray protein–ligand structure determination. Reactions were deliberately allowed to run “out of control” in terms of selectivity; for example the ortho-arylation of 2-phenylpyridine gave five products resulting from mono- and bisarylations combined with SNAr processes. As a result, a number of crystallographic hits against NUDT7, a key peroxisomal CoA ester hydrolase, have been identified. 相似文献
5.
6.
Semi‐Markovian processes (SMP) serve as a versatile means to model various traffic types generated by sources or superposed
from links in ATM networks. An efficient discrete time analysis method is proposed for SMP/G/1 queueing systems to evaluate
ATM switches with non‐renewal input. Some basic results are derived for the autocorrelation function of semi‐Markovian processes
and for the effect of state space reduction on autocorrelation, which show how to represent correlated traffic with given
characteristic by an adequate SMP model of limited size.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
7.
Larissa Canilha Walter Carvalho Marco Giulietti Maria Das Graças Almeida Felipe João Batista Almeida E Silva 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(5):715-721
BACKGROUND: Xylitol bioproduction from lignocellulosic residues comprises hydrolysis of the hemicellulose, detoxification of the hydrolysate, bioconversion of the xylose, and recovery of xylitol from the fermented hydrolysate. There are relatively few reports on xylitol recovery from fermented media. In the present study, ion‐exchange resins were used to clarify a fermented wheat straw hemicellulosic hydrolysate, which was then vacuum‐concentrated and submitted to cooling in the presence of ethanol for xylitol crystallization. RESULTS: Sequential adsorption into two anion‐exchange resins (A‐860S and A‐500PS) promoted considerable reductions in the content of soluble by‐products (up to 97.5%) and in medium coloration (99.5%). Vacuum concentration led to a dark‐colored viscous solution that inhibited xylitol crystallization. This inhibition could be overcome by mixing the concentrated medium with a commercial xylitol solution. Such a strategy led to xylitol crystals with up to 95.9% purity. The crystallization yield (43.5%) was close to that observed when using commercial xylitol solution (51.4%). CONCLUSION: The experimental data demonstrate the feasibility of using ion‐exchange resins followed by cooling in the presence of ethanol as a strategy to promote the fast recovery and purification of xylitol from hemicellulose‐derived fermentation media. Copyright © 2008 Society of Chemical Industry 相似文献
8.
9.
Alpidem, an imidazopyridine that acts at the gamma-aminobutyric acid/benzodiazepine receptor complex, has been reported to be an effective anxiolytic with a more favorable side effect profile than benzodiazepines. The effect of alpidem was investigated in an 8-week, open, clinical trial in 13 patients with panic disorder, with or without agoraphobia. Three patients were responders (much improved or very much improved), five patients were nonresponders, and five patients dropped out after less than 6 weeks of treatment. Significant improvement was seen in the sample as a whole for spontaneous panic attacks, phobic avoidance, and anticipatory anxiety. Most improvement occurred during the first 4 weeks of treatment, and responders had milder panic disorder at baseline. Adverse effects were generally mild. After 8 weeks of treatment, taper of medication over 2 weeks occurred without significant worsening of panic disorder symptoms. The efficacy of alpidem in the treatment of panic disorder remains uncertain and requires assessment in a controlled trial. 相似文献
10.