全文获取类型
收费全文 | 8504篇 |
免费 | 135篇 |
国内免费 | 20篇 |
专业分类
化学 | 5618篇 |
晶体学 | 66篇 |
力学 | 101篇 |
数学 | 1397篇 |
物理学 | 1477篇 |
出版年
2019年 | 60篇 |
2016年 | 114篇 |
2015年 | 89篇 |
2014年 | 111篇 |
2013年 | 236篇 |
2012年 | 234篇 |
2011年 | 285篇 |
2010年 | 179篇 |
2009年 | 155篇 |
2008年 | 249篇 |
2007年 | 252篇 |
2006年 | 255篇 |
2005年 | 243篇 |
2004年 | 248篇 |
2003年 | 226篇 |
2002年 | 203篇 |
2001年 | 140篇 |
2000年 | 169篇 |
1999年 | 115篇 |
1998年 | 111篇 |
1997年 | 94篇 |
1996年 | 127篇 |
1995年 | 170篇 |
1994年 | 147篇 |
1993年 | 124篇 |
1992年 | 124篇 |
1991年 | 119篇 |
1990年 | 100篇 |
1989年 | 130篇 |
1988年 | 129篇 |
1987年 | 116篇 |
1986年 | 105篇 |
1985年 | 160篇 |
1984年 | 138篇 |
1983年 | 153篇 |
1982年 | 159篇 |
1981年 | 140篇 |
1980年 | 129篇 |
1979年 | 150篇 |
1978年 | 129篇 |
1977年 | 117篇 |
1976年 | 124篇 |
1975年 | 109篇 |
1974年 | 105篇 |
1973年 | 112篇 |
1972年 | 70篇 |
1971年 | 93篇 |
1970年 | 61篇 |
1968年 | 51篇 |
1966年 | 57篇 |
排序方式: 共有8659条查询结果,搜索用时 15 毫秒
1.
Enantiomeric Cyclic Peptides with Different Caco‐2 Permeability Suggest Carrier‐Mediated Transport 下载免费PDF全文
B. Sc. Eduard Puig Prof. Dr. Beat Ernst Prof. Dr. Horst Kessler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8023-8027
Recently, oral absorption of cyclic hexapeptides was improved by N‐methylation of their backbone amides. However, the number and position of N‐methylations or of solvent exposed NHs did not correlate to intestinal permeability, measured in a Caco‐2 model. In this study, we investigate enantiomeric pairs of three polar and two lipophilic peptides to demonstrate the participation of carrier‐mediated transporters. As expected, all the enantiomeric peptides exhibited identical lipophilicity (logD7.4) and passive transcellular permeability determined by the parallel artificial membrane permeability assay (PAMPA). However, the enantiomeric polar peptides exhibited different Caco‐2 permeability (Papp) in both directions a–b and b–a. The same trend was observed for one of the lipophilic peptide, whereas the second lipophilic enantiomer pair showed identical Caco‐2 permeability (within the errors). These findings provide the first evidence for the involvement of carrier‐mediated transport for peptides, especially for those of polar nature. 相似文献
2.
3.
We have recently demonstrated that polarization transfer using an adiabatic passage through the Hartmann-Hahn condition (APHH-CP) by a variation of the radio-frequency amplitude can substantially improve the transfer efficiency over Hartmann-Hahn cross polarization. Here we show that APHH-CP can be combined with fast magic angle sample spinning (MAS). The heteronuclear dipolar order, established in the course of the transfer, can indeed be created and preserved. 相似文献
4.
Werner Leißner 《Results in Mathematics》1991,20(1-2):530-537
5.
We relate the Schramm–Loewner Evolution processes (SLE) to highest-weight representations of the Virasoro Algebra. The restriction properties of SLE that have been recently derived in [19] play a crucial role. In this setup, various considerations from conformal field theory can be interpreted and reformulated via SLE. This enables one to make a concrete link between the two-dimensional discrete critical systems from statistical physics and conformal field theory. To cite this article: R. Friedrich, W. Werner, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 947–952. 相似文献
6.
7.
8.
9.
Ernst Junker 《Colloid and polymer science》1941,95(2):213-250
Ohne ZusammenfassungMeinem verehrten Lehrer, Herrn Prof. Dr. H. Pallmann — auf dessen Anregung diese Arbeit ausgeführt würde — möchte ich für die mir zuteil gewordene Förderung und die wertvollen Ratschläge bestens danken. 相似文献
10.
Viviane Van Hoof Hugo Cluckers Vera Verhaeghe An Hennebel Marleen Truyens Edith Van Loock Pierre Rombouts Dirk Maes Jan Van Elven Katrien Lesage Mark Flothmann Lieve Nijs Filip Colpaert Werner Vercammen Dominique Bolain 《Accreditation and quality assurance》2004,10(1-2):55-59
In response to a change of the Belgian National Directives whereby hospital laboratories became responsible for all point-of-care testing (POCT) performed within hospital walls a standardized and automated POC glucose-testing system was implemented in our hospital. The system consists of 50 AccuCheck Inform instruments (Roche Diagnostics, Vilvoorde, Belgium), 50 docking stations, a DataCare Server, and connections to the medical laboratory information system (MOLIS, Sysmex, Barchon, Belgium) and to the hospital information system. Implementation involved many parties and extensive preparation and communication. Key issues were bar-coded patient and user identification, training, and responsibilities. One year after the hospital wide implementation of this system the quality of POC glucose testing has significantly increased, thereby improving patient safety. This study describes a stepwise change over involving the medical laboratory and with a focus on hands-on quality.Presented at the ninth conference on Quality in the Spotlight, 18–19 March 2004, Antwerp, Belgium. 相似文献