全文获取类型
收费全文 | 120篇 |
免费 | 5篇 |
专业分类
化学 | 77篇 |
晶体学 | 3篇 |
力学 | 1篇 |
数学 | 6篇 |
物理学 | 38篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 4篇 |
2012年 | 9篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 2篇 |
2008年 | 7篇 |
2007年 | 15篇 |
2006年 | 9篇 |
2005年 | 4篇 |
2004年 | 5篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有125条查询结果,搜索用时 15 毫秒
101.
Dr. Stephan M. Rummelt Dr. Gui‐Juan Cheng Dr. Puneet Gupta Prof. Walter Thiel Prof. Alois Fürstner 《Angewandte Chemie (International ed. in English)》2017,56(13):3599-3604
The recognition of the dual binding mode of propargyl and allyl alcohols to [Cp*Ru] fragments fostered the development of a highly regioselective intermolecular Alder‐ene‐type reaction of alkynes with 1,2‐disubstituted alkenes. The increased substrate scope opens new perspectives in stereochemical terms. As the loaded catalyst is chiral‐at‐metal, stereochemical information is efficiently relayed from the propargylic site to the emerging C−C bond. This interpretation is based on the X‐ray structure of the first Cp*Ru complex carrying an intact enyne ligand, and provides valuable insights into bonding and activation of the substrates. Computational data draw a clear picture of the principles governing regio‐ and stereocontrol. 相似文献
102.
We highlight the structural diversity of strategically designed two short peptide amphiphiles (sPAs) and describe their structure–function relationship studies. The shuffling of two key amino acids, that is, tyrosine and phenylalanine, in a designed sPA lead to a pair of constitutional isomers. Such small and strategic alteration can bring a substantial change in the self‐assembling pattern. Inspired from the naturally occurring metallopeptides, bioactive transition‐metal ions were used for constructing the unusual nanostructures. Use of appropriate metal ions created bigger differences between the properties of these isomers and hence the self‐assembly. Coordination of appropriate transition metal ions modifies the internal nanoscale structures of sPA, thus leading to the formation of vertically stacked terraced layers with decreasing size, which possess a high degree of dimensional regularity. We propose that such metal‐induced terraced nanodome‐like hierarchical self‐assembly may have relevance for specific biotechnology applications. 相似文献
103.
Abhisek Kar Jamsad Mannuthodikayil Sameer Singh Anamika Biswas Puneet Dubey Amit Das Kalyaneswar Mandal 《Angewandte Chemie (International ed. in English)》2020,59(35):14796-14801
We report an operationally simple method to facilitate chemical protein synthesis by fully convergent and one‐pot native chemical ligations utilizing the fluorenylmethyloxycarbonyl (Fmoc) moiety as an N‐masking group of the N‐terminal cysteine of the middle peptide thioester segment(s). The Fmoc group is stable to the harsh oxidative conditions frequently used to generate peptide thioesters from peptide hydrazide or o‐aminoanilide. The ready availability of Fmoc‐Cys(Trt)‐OH, which is routinely used in Fmoc solid‐phase peptide synthesis, where the Fmoc group is pre‐installed on cysteine residue, minimizes additional steps required for the temporary protection of the N‐terminal cysteinyl peptides. The Fmoc group is readily removed after ligation by short exposure (<7 min) to 20 % piperidine at pH 11 in aqueous conditions at room temperature. Subsequent native chemical ligation reactions can be performed in presence of piperidine in the same solution at pH 7. 相似文献
104.
Puneet Sharma R. A. Rocha S. N. de Medeiros A. Paesano Jr B. Hallouche 《Hyperfine Interactions》2007,175(1-3):77-84
In the present study, BaFe12?X Mn X O19 hexaferrites were prepared by high-energy ball milling and subsequent thermal annealing. The structural and magnetic characterizations were carried out by X-ray diffraction, Mössbauer spectroscopy and magnetization measurements. The analyses showed that manganese occupies all iron sites, decreasing the magnetization and increasing the coercivity. 相似文献
105.
Three-component one pot silica gel promoted synthesis of 2,3-disubstituted 4-thiazolidinones is described. The method provides rapid and easy access to thiazolidinone compounds in good to excellent yields. 相似文献
106.
Palladium‐Catalyzed Synthesis of Phenanthridine/Benzoxazine‐Fused Quinazolinones by Intramolecular CH Bond Activation
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Puneet K. Gupta Nisha Yadav Subodh Jaiswal Mohd. Asad Dr. Ruchir Kant Dr. Kanchan Hajela 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(38):13210-13215
A highly efficient synthesis of phenanthridine/benzoxazine‐fused quinazolinones by ligand‐free palladium‐catalyzed intramolecular C?H bond activation under mild conditions has been developed. The C?C coupling provides the corresponding N‐fused polycyclic heterocycles in good to excellent yields and with wide functional group tolerance. 相似文献
107.
Christopher M. Ryan Puneet Souda Frederic Halgand David T. Wong Joseph A. Loo Kym F. Faull Julian P. Whitelegge 《Journal of the American Society for Mass Spectrometry》2010,21(6):908-917
A hybrid linear ion-trap Fourier-transform ion cyclotron resonance mass spectrometer was used for top-down characterization
of the abundant human salivary cystatins, including S, S1, S2, SA, SN, C, and D, using collisionally activated dissociation
(CAD) after chromatographic purification of the native, disulfide intact proteins. Post-translational modifications and protein
sequence polymorphisms arising from single nucleotide polymorphisms (SNPs) were assigned from precursor and product ion masses
at a tolerance of 10 ppm, allowing confident identification of individual intact mass tags. Cystatins S, S1, S2, SA, and SN
were cleaved of a N-terminal 20 amino acid signal peptide and cystatin C a 26-residue peptide, to yield a generally conserved
N-terminus. In contrast, cystatin D isoforms with 24 and 28 amino acid residue N-terminal truncations were found such that
their N-termini were not conserved. Cystatin S1 was phosphorylated at Ser3, while S2 was phosphorylated at Ser1 and Ser3,
in agreement with previous work. Both cystatin D isoforms carried the polymorphism C46R (SNP: rs1799841). The 14,328 Da isoform
of cystatin SN previously assigned with polymorphism P31L due to a SNP (rs2070856) was found only in whole saliva. Parotid
secretions contained no detectable cystatins while whole saliva largely mirrored the contents of submandibular/sublingual
(SMSL) secretions. With fully characterized cystatin intact mass tags it will now be possible to examine the correlation between
the abundance of these molecules and human health and disease. 相似文献
108.
109.
110.
A general picture on the mechanism of electron exchange between low energy He+ ions and solid surfaces is proposed on the basis of experiments on three-dimensional angle resolving ion scattering spectroscopy in which not only He+ but neutral He is used as a projectile. 相似文献