全文获取类型
收费全文 | 1902篇 |
免费 | 23篇 |
国内免费 | 3篇 |
专业分类
化学 | 1255篇 |
晶体学 | 5篇 |
力学 | 17篇 |
数学 | 189篇 |
物理学 | 462篇 |
出版年
2016年 | 27篇 |
2015年 | 17篇 |
2014年 | 22篇 |
2013年 | 42篇 |
2012年 | 56篇 |
2011年 | 51篇 |
2010年 | 39篇 |
2009年 | 28篇 |
2008年 | 37篇 |
2007年 | 46篇 |
2006年 | 44篇 |
2005年 | 48篇 |
2004年 | 47篇 |
2003年 | 27篇 |
2002年 | 31篇 |
2001年 | 43篇 |
2000年 | 37篇 |
1999年 | 28篇 |
1998年 | 30篇 |
1997年 | 16篇 |
1996年 | 16篇 |
1995年 | 26篇 |
1994年 | 24篇 |
1993年 | 34篇 |
1992年 | 24篇 |
1991年 | 31篇 |
1990年 | 31篇 |
1989年 | 19篇 |
1988年 | 33篇 |
1987年 | 20篇 |
1986年 | 18篇 |
1985年 | 23篇 |
1984年 | 19篇 |
1982年 | 20篇 |
1980年 | 27篇 |
1979年 | 34篇 |
1978年 | 31篇 |
1977年 | 52篇 |
1976年 | 37篇 |
1975年 | 37篇 |
1974年 | 40篇 |
1973年 | 39篇 |
1972年 | 38篇 |
1971年 | 29篇 |
1970年 | 21篇 |
1969年 | 30篇 |
1968年 | 31篇 |
1967年 | 38篇 |
1966年 | 28篇 |
1933年 | 16篇 |
排序方式: 共有1928条查询结果,搜索用时 0 毫秒
151.
From the feeding of young plants of Strychnos nux-vomica with [14C]-1-and [14C]-2-acetate it could be deduced that the C-atoms 22 and 23 were derived from acetate. [14C]-2-mevalonate, [14C]-2-geraniol and [14C]-2-geranyl pyrophosphate were also incorporated into strychnine. The distribution of radioactivity in the «mevalonate-strychnine» was in agreement with the monoterpenoid hypothesis. Feeding experiments especially with [14C]-tryptophane showed that the main production centre of the alkaloid lay in the roots and that only a small part of it was carried to the leaves. Tritium labelled WIELAND GUMLICH aldehyde as well as N(a)-[14C]-1-acetyl WIELAND GUMLICH aldehyde were not converted into strychnine by S. nux-vomica. 相似文献
152.
Viktor Reshetnikov Steffen Daum Dr. Christina Janko Weronika Karawacka Dr. Rainer Tietze Prof. Dr. Christoph Alexiou Dr. Solomiya Paryzhak Dr. Tetiana Dumych Prof. Dr. Rostyslav Bilyy Dr. Philipp Tripal Dr. Benjamin Schmid Dr. Ralf Palmisano Prof. Dr. Andriy Mokhir 《Angewandte Chemie (International ed. in English)》2018,57(37):11943-11946
Mitochondrial membrane potential is more negative in cancer cells than in normal cells, allowing cancer targeting by delocalized lipophilic cations (DLCs). However, as the difference is rather small, these drugs affect also normal cells. Now a concept of pro‐DLCs is proposed based on an N‐alkylaminoferrocene structure. These prodrugs are activated by the reaction with reactive oxygen species (ROS) forming ferrocenium‐based DLCs. Since ROS are overproduced in cancer, the high‐efficiency cancer‐cell‐specific targeting of mitochondria could be achieved as demonstrated by fluorescence microscopy in combination with two fluorogenic pro‐DLCs in vitro and in vivo. We prepared a conjugate of another pro‐DLC with a clinically approved drug carboplatin and confirmed that its accumulation in mitochondria was higher than that of the free drug. This was reflected in the substantially higher anticancer effect of the conjugate. 相似文献
153.
154.
Kochocki JA Allison WW Alner GJ Ambats I Ayres DS Balka LJ Barr GD Barrett WL Benjamin D Border P Brooks CB Cobb JH Cockerill DJ Coover K Courant H Dahlin B DasGupta U Dawson JW Edwards VW Fields TH Kirby-Gallagher LM Garcia-Garcia C Giles RH Goodman MC Heller K Heppelman S Hill N Hoftiezer JH Jankowski DJ Johns K Joyce T Kafka T Litchfield PJ Lopez FV Lowe M Mann WA Marshak ML May EN McMaster L Milburn RH Miller W Napier A Oliver WP Pearce GF Perkins DH Peterson EA Price LE Roback D Rosen DB 《Physical review D: Particles and fields》1990,42(9):2967-2973
155.
Bischoff MM Konvicka C Quinn AJ Schmid M Redinger J Podloucky R Varga P van Kempen H 《Physical review letters》2001,86(11):2396-2399
The first scanning tunneling spectroscopy measurements on V(001) are reported. A strong surface state is detected which is very sensitive to the presence of segregated carbon impurities. The surface state energy shifts from 0.03 eV below the Fermi level at clean areas towards higher energies (up to approximately 0.2 eV) at contaminated areas. Because of the negative dispersion of this state, the upward shift cannot be described in a simple confinement picture. Rather, the surface state energy is governed by vanadium surface s- d interactions which are altered by carbon coverage. 相似文献
156.
157.
The alkaloid lonicerine was isolated from Callichilia barteri (Apocynaceae). By chemical and spectroscopic evidence it could be shown to be 16-epi-aspidodasycarpine ( 1 ). 相似文献
158.
159.
The application of exponential integrators based on Krylov techniques to large‐scale simulations of complex fluid flows with multiple time‐scales demonstrates the efficiency of these schemes in reducing the associated time‐step restrictions due to numerical stiffness. Savings of approximately 50% can be achieved for simulations of the three‐dimensional compressible Navier–Stokes equations while still maintaining a truncation error typical of explicit time‐stepping schemes. Exponential time integration techniques of this type are particularly advantageous for fluid flows with a wide range of temporal scales such as low‐Mach number, reactive or acoustically dominated flows. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
160.