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   40篇
  免费   0篇
现状及发展   9篇
研究方法   9篇
综合类   22篇
  2018年   1篇
  2013年   1篇
  2012年   2篇
  2011年   2篇
  2010年   1篇
  2009年   1篇
  2008年   5篇
  2007年   3篇
  2006年   4篇
  2005年   2篇
  2004年   2篇
  2003年   1篇
  2002年   4篇
  2001年   1篇
  2000年   1篇
  1999年   3篇
  1994年   1篇
  1981年   1篇
  1980年   1篇
  1975年   1篇
  1963年   1篇
  1962年   1篇
排序方式: 共有40条查询结果,搜索用时 375 毫秒
11.
Zusammenfassung Der 5-Hydroxytryptamingehalt des Igelhirns während der kalten Jahreszeit und besonders während des Winterschlafs war stets höher als mitten im Sommer. Die grösste Zunahme wurde in den Grosshirnhemisphären gefunden. Mechanismus und physiologische Bedeutung der Änderung wurde diskutiert und dabei angenommen, dass diese im Zusammenhang mit einer autonomen Regelung des Hibernationszustandes stehe.  相似文献   
12.
13.
Summary Ethanol was administered i.p. to adult roosters during hormonally induced vitellogenin synthesis. At moderate doses, ethanol had no influence on the synthesis of vitellogenin nor did it cause alterations in the size distribution of liver polyribosomes.This was supported in part by a grant from the Foundation for Alcohol Studies, Finland.  相似文献   
14.
15.
Tests of Einstein's general theory of relativity have mostly been carried out in weak gravitational fields where the space-time curvature effects are first-order deviations from Newton's theory. Binary pulsars provide a means of probing the strong gravitational field around a neutron star, but strong-field effects may be best tested in systems containing black holes. Here we report such a test in a close binary system of two candidate black holes in the quasar OJ 287. This quasar shows quasi-periodic optical outbursts at 12-year intervals, with two outburst peaks per interval. The latest outburst occurred in September 2007, within a day of the time predicted by the binary black-hole model and general relativity. The observations confirm the binary nature of the system and also provide evidence for the loss of orbital energy in agreement (within 10 per cent) with the emission of gravitational waves from the system. In the absence of gravitational wave emission the outburst would have happened 20 days later.  相似文献   
16.
Sillanpää MA  Park JI  Simmonds RW 《Nature》2007,449(7161):438-442
As with classical information processing, a quantum information processor requires bits (qubits) that can be independently addressed and read out, long-term memory elements to store arbitrary quantum states, and the ability to transfer quantum information through a coherent communication bus accessible to a large number of qubits. Superconducting qubits made with scalable microfabrication techniques are a promising candidate for the realization of a large-scale quantum information processor. Although these systems have successfully passed tests of coherent coupling for up to four qubits, communication of individual quantum states between superconducting qubits via a quantum bus has not yet been realized. Here, we perform an experiment demonstrating the ability to coherently transfer quantum states between two superconducting Josephson phase qubits through a quantum bus. This quantum bus is a resonant cavity formed by an open-ended superconducting transmission line of length 7 mm. After preparing an initial quantum state with the first qubit, this quantum information is transferred and stored as a nonclassical photon state of the resonant cavity, then retrieved later by the second qubit connected to the opposite end of the cavity. Beyond simple state transfer, these results suggest that a high-quality-factor superconducting cavity could also function as a useful short-term memory element. The basic architecture presented here can be expanded, offering the possibility for the coherent interaction of a large number of superconducting qubits.  相似文献   
17.
18.
Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequenced the genome of an archaic hominin to about 1.9-fold coverage. This individual is from a group that shares a common origin with Neanderthals. This population was not involved in the putative gene flow from Neanderthals into Eurasians; however, the data suggest that it contributed 4-6% of its genetic material to the genomes of present-day Melanesians. We designate this hominin population 'Denisovans' and suggest that it may have been widespread in Asia during the Late Pleistocene epoch. A tooth found in Denisova Cave carries a mitochondrial genome highly similar to that of the finger bone. This tooth shares no derived morphological features with Neanderthals or modern humans, further indicating that Denisovans have an evolutionary history distinct from Neanderthals and modern humans.  相似文献   
19.
Zusammenfassung Bei ein- bis fünftägiger Verabreichung von 100 mg 2-Aethylisothionicotinamide (TH1314)/kg peroral kommt es bei Ratten nach 2 h zu einer Absenkung des Ascorbinsäuregehalts in den Nebennieren. Nach 14 h ist der Ascorbinsäuregehalt der Nebennieren wieder normal geworden. Nach 2 h wurden keine bedeutenden Veränderungen im Cholesterolgehalt der Nebennieren bemerkt, dagegen stieg der Cholesterolgehalt nach 14 h. stark an. Bei den absoluten Gewichten wurden keine bedeutenden Unterschiede beobachtet. Die Resultate zeigen, dass TH1314 die adrenocorticale Aktivität steigert.

Aided by a grant from the Sigrid Jusélius Foundation.  相似文献   
20.
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