全文获取类型
收费全文 | 1093篇 |
免费 | 46篇 |
国内免费 | 6篇 |
专业分类
化学 | 835篇 |
晶体学 | 11篇 |
力学 | 16篇 |
数学 | 77篇 |
物理学 | 206篇 |
出版年
2023年 | 10篇 |
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 11篇 |
2019年 | 20篇 |
2018年 | 19篇 |
2017年 | 15篇 |
2016年 | 22篇 |
2015年 | 34篇 |
2014年 | 32篇 |
2013年 | 56篇 |
2012年 | 89篇 |
2011年 | 100篇 |
2010年 | 40篇 |
2009年 | 40篇 |
2008年 | 80篇 |
2007年 | 63篇 |
2006年 | 63篇 |
2005年 | 70篇 |
2004年 | 58篇 |
2003年 | 46篇 |
2002年 | 55篇 |
2001年 | 10篇 |
2000年 | 13篇 |
1999年 | 8篇 |
1998年 | 5篇 |
1997年 | 13篇 |
1996年 | 16篇 |
1995年 | 9篇 |
1994年 | 11篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 12篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 9篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1974年 | 2篇 |
1971年 | 2篇 |
1968年 | 2篇 |
1961年 | 2篇 |
1960年 | 2篇 |
排序方式: 共有1145条查询结果,搜索用时 31 毫秒
961.
This paper considers a class of stationary batch-arrival, bulk-service queues with generalized vacations. The system consists of a single server and a waiting room of infinite capacity. Arrivals of customers follow a batch Markovian arrival process. The server is unavailable for occasional intervals of time called vacations, and when it is available, customers are served in groups of fixed size B. For this class of queues, we show that the vector probability generating function of the stationary queue length distribution is factored into two terms, one of which is the vector probability generating function of the conditional queue length distribution given that the server is on vacation. The special case of batch Poisson arrivals is carefully examined, and a new stochastic decomposition formula is derived for the stationary queue length distribution.AMS subject classification: 60K25, 90B22, 60K37 相似文献
962.
Modeling of scale-dependent characteristics of mechanical properties of metal polycrystals is studied using both discrete dislocation dynamics and continuum crystal plasticity. The initial movements of dislocation arc emitted from a Frank-Read type dislocation source and bounded by surrounding grain boundaries are examined by dislocation dynamics analyses system and we find the minimum resolved shear stress for the FR source to emit at least one closed loop. When the grain size is large enough compared to the size of FR source, the minimum resolved shear stress levels off to a certain value, but when the grain size is close to the size of the FR source, the minimum resolved shear stress shows a sharp increase. These results are modeled into the expression of the critical resolved shear stress of slip systems and continuum mechanics based crystal plasticity analyses of six-grained polycrystal models are made. Results of the crystal plasticity analyses show a distinct increase of macro- and microscopic yield stress for specimens with smaller mean grain diameter. Scale-dependent characteristics of the yield stress and its relation to some control parameters are discussed. 相似文献
963.
Dr. Ryo Ohtani Dr. Munehiro Inukai Dr. Yuh Hijikata Dr. Tetsuya Ogawa Dr. Mikihito Takenaka Prof. Masaaki Ohba Prof. Susumu Kitagawa 《Angewandte Chemie (International ed. in English)》2015,54(4):1139-1143
Novel organic–inorganic hybrid liposomes, so‐called coordination polymersomes (CPsomes), with artificial domains that exhibit strong lateral cohesion were prepared by a three‐step procedure that formed a coordinative interaction leading to a lipid bilayer. First, the lipophilic complex (dabco‐C18)[Mn(N)(CN)4(dabco‐C18)] ( 1 ; dabco‐C18+=1,4‐diazabicyclo[2,2,2]octane‐(CH2)17? CH3 cation), was synthesized. 1 has a lipophilic alkyl tail part and a tetracyanometallate head group, which can be used for an expansion to two‐dimensional coordination networks. Second, 1 and 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine were mixed to prepare the liposomes. Finally, CPsomes were obtained by the addition of transition‐metal ions ( M ) to form unilamellar faceted liposomes with plain CP raft domains with Mn? CN? M linkages. The concentration of 1 influences the size of the CP raft domains and the shape of the CPsomes. The synthesis of coordination polymers in lipid bilayers is a novel approach for the construction of artificial architectures as raft domains, for example, in cell membranes. 相似文献
964.
Tetsuya Doi Takumi Sakakibara Dr. Hiromu Kashida Dr. Yasuyuki Araki Prof. Dr. Takehiko Wada Prof. Dr. Hiroyuki Asanuma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(45):15974-15980
We report on the characterization of a novel hetero‐selective DNA‐like duplex of pyrene and anthraquinone pseudo base pairs. The pyrene/anthraquinone pairs showed excellent selectivity in hetero‐recognition and even trimers were found to form a hetero‐duplex. Pyrene and anthraquinone moieties were tethered on acyclic D ‐threoninol linkers and linked to adjacent residues by using standard phosphoramidite chemistry. When pyrene and anthraquinone were incorporated at pairing positions in complementary strands of natural DNA oligonucleotides, the duplex was stabilized significantly. Moreover, a pyrene hexamer and an anthraquinone hexamer formed a stable artificial hetero‐duplex without the assistance of natural base pairs. The pyrene/anthraquinone pair was so stable that even trimers formed a hetero‐duplex under conditions in which natural DNA strands of three residues do not. 相似文献
965.
Inside Cover: Environment‐Sensitive Fluorescent Probe: A Benzophosphole Oxide with an Electron‐Donating Substituent (Angew. Chem. Int. Ed. 15/2015)
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
966.
Tetsuya MiyoshiShohei Sato Hiroya TanakaChihiro Hasegawa Masafumi UedaOkiko Miyata 《Tetrahedron letters》2012,53(32):4188-4191
The efficient one-pot umpolung α-phenylation of ketones via N-alkenylisoxazolidine is described. When the various ketones are treated with triphenylaluminum prepared from phenylmagnesium chloride and AlCl3 in the presence of isoxazolidine, the desired products are obtained in good to moderate yield. This method is equivalent to a direct α-arylation reaction of carbonyl groups. 相似文献
967.
968.
Tetsuya Matsuda 《International Journal of Plasticity》2011,27(12):1869-1870
969.
970.
This article examines the accuracy of radiation thermometry in measuring the temperature of silicon wafers in a diffusion furnace. This technique uses optical guides to bring thermal radiation from the wafers to the outside of the furnace. The error due to veiling glare of a rod-type optical guide is 40°C and that of a prism-type is 0.5°C at steady state. 相似文献