首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1179篇
  免费   49篇
  国内免费   6篇
化学   1009篇
晶体学   5篇
力学   11篇
数学   125篇
物理学   84篇
  2023年   8篇
  2022年   12篇
  2021年   19篇
  2020年   17篇
  2019年   15篇
  2018年   5篇
  2017年   14篇
  2016年   37篇
  2015年   32篇
  2014年   38篇
  2013年   39篇
  2012年   76篇
  2011年   87篇
  2010年   44篇
  2009年   38篇
  2008年   85篇
  2007年   71篇
  2006年   84篇
  2005年   65篇
  2004年   60篇
  2003年   41篇
  2002年   48篇
  2001年   17篇
  2000年   19篇
  1999年   13篇
  1998年   16篇
  1997年   17篇
  1996年   12篇
  1995年   19篇
  1994年   20篇
  1993年   16篇
  1992年   11篇
  1991年   6篇
  1990年   14篇
  1989年   13篇
  1988年   12篇
  1987年   13篇
  1986年   9篇
  1985年   8篇
  1984年   10篇
  1983年   6篇
  1982年   5篇
  1981年   4篇
  1980年   4篇
  1978年   3篇
  1975年   3篇
  1973年   3篇
  1972年   3篇
  1970年   3篇
  1969年   3篇
排序方式: 共有1234条查询结果,搜索用时 578 毫秒
61.
A glucose responsive insulin (GRI) that responds to changes in blood glucose concentrations has remained an elusive goal. Here we describe the development of glucose cleavable linkers based on hydrazone and thiazolidine structures. We developed linkers with low levels of spontaneous hydrolysis but increased level of hydrolysis with rising concentrations of glucose, which demonstrated their glucose responsiveness in vitro. Lipidated hydrazones and thiazolidines were conjugated to the LysB29 side-chain of HI by pH-controlled acylations providing GRIs with glucose responsiveness confirmed in vitro for thiazolidines. Clamp studies showed increased glucose infusion at hyperglycemic conditions for one GRI indicative of a true glucose response. The glucose responsive cleavable linker in these GRIs allow changes in glucose levels to drive the release of active insulin from a circulating depot. We have demonstrated an unprecedented, chemically responsive linker concept for biopharmaceuticals.  相似文献   
62.
63.
64.
We present the software package MO VI PAC for calculations of vibrational spectra, namely infrared, Raman, and Raman Optical Activity (ROA) spectra, in a massively parallelized fashion. MO VI PAC unites the latest versions of the programs SNF and AKIRA alongside with a range of helpful add‐ons to analyze and interpret the data obtained in the calculations. With its efficient parallelization and meta‐program design, MO VI PAC focuses in particular on the calculation of vibrational spectra of very large molecules containing on the order of a hundred atoms. For this purpose, it also offers different subsystem approaches such as Mode‐ and Intensity‐Tracking to selectively calculate specific features of the full spectrum. Furthermore, an approximation to the entire spectrum can be obtained using the Cartesian Tensor Transfer Method. We illustrate these capabilities using the example of a large π‐helix consisting of 20 (S)‐alanine residues. In particular, we investigate the ROA spectrum of this structure and compare it to the spectra of α‐ and 310‐helical analogs. © 2012 Wiley Periodicals, Inc.  相似文献   
65.
66.
67.
Aryl ketones are readily deoxygenated to their corresponding aryl alkanes upon treatment with Raney nickel catalyst in boiling 2-propanol.

Additional information

ACKNOWLEDGMENTS

The authors gratefully acknowledge financial support from the Covenant College Kaleo Center. In addition, we are indebted to the W. R. Grace Company, Chattanooga, for the generous donation of Raney nickel catalyst.  相似文献   
68.
Polyclonal immunoglobulin (Ig) concentrates are important biological medicinal products and the assurance of their quality and safety is crucial. In our present approach we used proteomic methods to check the purity of commercial Ig products of different origin. The experimental setup included nonreducing 2DE or DIGE combined with MALDI‐TOF and the thrombin generation assay, a routine safety test for pharmaceutical Ig preparations, and was complemented by a specific immunoassay. 2DE patterns displayed contaminations with trace amounts of human apolipoprotein H (Apo‐H), transferrin, albumin, and its fragments. In contrast to the latter, Apo‐H is a protein that is active in the coagulation cascade, and thus a potential involvement in thromboembolic events in vivo cannot be excluded. It was found by 2DE and MALDI‐TOF to be a contaminant of several Ig preparations. Spiking experiments of Ig preparations with pure Apo‐H demonstrated an Apo‐H concentration dependent increase in thrombin generation assay values. Traces of Apo‐H are possibly also contributing to unwanted side effects, as already known for factor XIa. The significance of Apo‐H contaminations for these side effects might be verified by detailed analyses of pharmacovigilance data.  相似文献   
69.
The first autosomal sequence-based allele (aka SNP-STR haplotype) frequency database for forensic massively parallel sequencing (MPS) has been published, thereby removing one of the remaining barriers to implementing MPS in casework. The database was developed using a specific set of flank trim sites. If different trim sites or different kits with different primers are used for casework, then SNP-STR haplotypes may be detected that do not have frequencies in the database. We describe a procedure to address calculation of match probabilities when casework samples are generated using an MPS kit with different trim sites than those present in the relevant population frequency database. The procedure provides a framework for comparison of any MPS kit or database combination while also accommodating comparison of MPS and CE profiles.  相似文献   
70.
Arabinogalactan, a microheterogeneous polysaccharide occurring in plants, is known for its allergy-protective activity, which could potentially be used for preventive allergy treatment. New treatment options are highly desirable, especially in a preventive manner, due to the constant rise of atopic diseases worldwide. The structural origin of the allergy-protective activity of arabinogalactan is, however, still unclear and isolation of the polysaccharide is not feasible for pharmaceutical applications due to a variation of the activity of the natural product and contaminations with endotoxins. Therefore, a pentasaccharide partial structure was selected for total synthesis and subsequently coupled to a carrier protein to form a neoglycoconjugate. The allergy-protective activity of arabinogalactan could be reproduced with the partial structure in subsequent in vivo experiments. This is the first example of a successful simplification of arabinogalactan with a single partial structure while retaining its allergy-preventive potential.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号