全文获取类型
收费全文 | 278篇 |
免费 | 37篇 |
专业分类
化学 | 266篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 30篇 |
物理学 | 15篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 6篇 |
2020年 | 10篇 |
2019年 | 6篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 27篇 |
2015年 | 17篇 |
2014年 | 20篇 |
2013年 | 26篇 |
2012年 | 22篇 |
2011年 | 24篇 |
2010年 | 22篇 |
2009年 | 8篇 |
2008年 | 27篇 |
2007年 | 14篇 |
2006年 | 13篇 |
2005年 | 14篇 |
2004年 | 14篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1985年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1964年 | 1篇 |
排序方式: 共有315条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
Susanne Pahlow Sandra Kloß Dr. Verena Blättel Konstantin Kirsch Dr. Uwe Hübner Dr. Dana Cialla Dr. Petra Rösch Dr. Karina Weber Prof. Dr. Jürgen Popp 《Chemphyschem》2013,14(15):3600-3605
We developed a Raman‐compatible chip for isolating microorganisms from complex media. The isolation of bacteria is achieved by using antibodies as capture molecules. Due to the very specific interaction with the targets, this approach is promising for isolation of bacteria even from complex matrices such as body fluids. Our choice of capture molecules also enabled the investigation of samples containing yet unidentified bacteria, as the antibodies can capture a large variety of bacteria based on their analogue cell wall surface structures. The capability of our system is demonstrated for a broad range of different Gram‐positive and Gram‐negative germs. Subsequent identification is done by recording Raman spectra of the bacteria. Further, it is shown that classification with chemometric methods is possible. 相似文献
105.
Andrew M. Kelly Verena Kaltenhauser Inge Mühlbacher Karl Rametsteiner Harald Kren Christian Slugovc Franz Stelzer Frank Wiesbrock 《Macromolecular bioscience》2013,13(1):116-125
A set of poly(2‐oxazoline)‐derived (co‐)polymers was prepared by microwave‐assisted polymerizations and acid‐mediated hydrolysis and tested for antimicrobial activity in 50 × 50 × 2 mm PP compound plates containing 5 wt% of the polymers. Antimicrobial activity against gram‐negative E. coli and P. aeruginosa as well as C. albicans depended only on the degree of hydrolysis, while antimicrobial activity against gram‐positive S. aureus was only observed for hydrolyzed poly(2‐nonyl‐2‐oxazoline)s. The surface energies of the compound plates compared to pure PP were hardly altered, and the compounds can be considered as alternatives for PP. The presence of the biocide additives at the surface of the PP compound plates could be shown by combined ATR‐IR, zeta potential, and SEM‐EDX measurements. Antimicrobial activity was maintained during double incubation as well as for lowered amounts of the biocide additive of 1% in PP compound plates.
106.
Mira Sundström Anna Pelander Verena Angerer Melanie Hutter Stefan Kneisel Ilkka Ojanperä 《Analytical and bioanalytical chemistry》2013,405(26):8463-8474
The continuing emergence of designer drugs imposes high demands on the scope and sensitivity of toxicological drug screening procedures. An ultra-high performance liquid chromatography/high-resolution time-of-flight mass spectrometry (UHPLC-HR-TOFMS) method was developed for screening and simultaneous confirmation of both designer drugs and other drugs of abuse in urine samples in a single run. The method covered selected synthetic cannabinoids and cathinones, amphetamines, natural cannabinoids, opioids, cocaine and other important drugs of abuse, together with their main urinary metabolites. The database consisted of 277 compounds with molecular formula and exact monoisotopic mass; retention time was included for 192 compounds, and primary and secondary qualifier ion exact mass for 191 and 95 compounds, respectively. Following a solid-phase extraction, separation was performed by UHPLC and mass analysis by HR-TOFMS. MS, and broad-band collision-induced dissociation data were acquired at m/z range 50–700. Compound identification was based on a reverse database search with acceptance criteria for retention time, precursor ion mass accuracy, isotopic pattern and abundance of qualifier ions. Mass resolving power in spiked urine samples was on average FWHM 23,500 and mass accuracy 0.3 mDa. The mean and median cut-off concentrations determined for 75 compounds were 4.2 and 1 ng/mL, respectively. The range of cut-off concentrations for synthetic cannabinoids was 0.2–60 ng/mL and for cathinones 0.7–15 ng/mL. The method proved to combine high sensitivity and a wide scope in a manner not previously reported in drugs of abuse screening. The method’s feasibility was demonstrated with 50 authentic urine samples. Figure
Extracted ion chromatograms of metabolites of synthetic cannabinoids and their fragments, including a new common metabolite: JWH-072-propanoic acid 相似文献
107.
Katrin‐Stephanie Tücking Verena Grützner Ronald E. Unger Holger Schnherr 《Macromolecular rapid communications》2015,36(13):1248-1254
The synthesis of novel amphiphilic hyaluronic acid (HYA) and poly(lactic acid) (PLA) block copolymers is reported as the key element of a strategy to detect the presence of pathogenic bacterial enzymes. In addition to the formation of defined HYA‐block‐PLA assemblies, the encapsulation of fluorescent reporter dyes and the selective enzymatic degradation of the capsules by hyaluronidase and proteinase K are studied. The synthesis of the dual enzyme‐responsive HYA‐b‐PLA is carried out by copper–catalyzed Huisgen 1,3‐dipolar cycloaddition. The resulting copolymers are assembled in water to form vesicular structures, which are characterized by scanning electron microscopy, transmission electron microscopy, dynamic light scattering (DLS), and fluorescence lifetime imaging microscopy (FLIM). DLS measurements show that both enzymes cause a rapid decrease in the hydrodynamic diameter of the nanocapsules. Fluorescence spectroscopy data confirm the liberation of encapsulated dye, which indicates the disintegration of the capsules and validates the concept of enzymatically triggered payload release. Finally, cytotoxicity assays confirm that the HYA‐b‐PLA nanocapsules are biocompatible with primary human dermal microvascular endothelial cells. 相似文献
108.
109.
Dr. Paul S. Campbell Mei Yang Demian Pitz Dr. Joanna Cybinska Prof. Anja‐Verena Mudring 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(16):4704-4712
High quantum yields of up to 40.5 % can be achieved in salicylate‐bearing ionic liquids. A range of these ionic liquids have been synthesized and their photoluminescent properties studied in detail. The differences noted can be related back to the structure of the ionic liquid cation and possible interionic interactions. It is found that shifts of emission, particularly in the pyridinium‐based ionic liquids, can be related to cation–anion pairing interactions. Facile and controlled emission color mixing is demonstrated through combining different ILs, with emission colors ranging from blue to yellow. 相似文献
110.
Verena Pietzner 《Nachrichten aus der Chemie》2003,51(10):1065-1067