全文获取类型
收费全文 | 604篇 |
免费 | 53篇 |
国内免费 | 2篇 |
专业分类
化学 | 452篇 |
晶体学 | 2篇 |
力学 | 19篇 |
数学 | 56篇 |
物理学 | 87篇 |
无线电 | 43篇 |
出版年
2023年 | 15篇 |
2022年 | 12篇 |
2021年 | 16篇 |
2020年 | 23篇 |
2019年 | 24篇 |
2018年 | 23篇 |
2017年 | 13篇 |
2016年 | 34篇 |
2015年 | 28篇 |
2014年 | 23篇 |
2013年 | 27篇 |
2012年 | 63篇 |
2011年 | 53篇 |
2010年 | 36篇 |
2009年 | 23篇 |
2008年 | 46篇 |
2007年 | 33篇 |
2006年 | 21篇 |
2005年 | 29篇 |
2004年 | 19篇 |
2003年 | 19篇 |
2002年 | 20篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1967年 | 1篇 |
1928年 | 1篇 |
1921年 | 1篇 |
1913年 | 1篇 |
排序方式: 共有659条查询结果,搜索用时 734 毫秒
41.
Chin‐Yi Liu Zachary C. Holman Uwe R. Kortshagen 《Advanced functional materials》2010,20(13):2157-2164
Silicon nanocrystals (Si NCs) are shown to be an electron acceptor in hybrid solar cells combining Si NCs with poly(3‐hexylthiophene) (P3HT). The effects of annealing and different metal electrodes on Si NC/P3HT hybrid solar cells are studied in this paper. After annealing at 150 °C, Si NC/P3HT solar cells exhibit power conversion efficiencies as high as 1.47%. The hole mobility in the P3HT phase extracted from space‐charge‐limited current measurements of hole‐only devices increases from 2.48 × 10?10 to 1.11 × 10?9 m2 V?1 s?1 after annealing, resulting in better transport in the solar cells. A quenching of the open‐circuit voltage and short‐circuit current is observed when high work function metals are deposited as the cathode on Si NC/P3HT hybrid devices. 相似文献
42.
Max M. Abrahams Gregory W. Cushing Zachary N. Pickett William A. Howard Kraig A. Wheeler 《Journal of chemical crystallography》2010,40(7):583-590
Abstract
Mer-RhBr3(Me2pzH)3 (Me2pzH = 3,5-dimethylpyrazole) (monoclinic, P21/n, a = 8.3300 (5) Å, b = 16.2889 (9) Å, c = 15.9299 (11) Å, α = 90°, β = 100.217 (5)°, γ = 90°; V = 2,127.2 (2) Å3; Z = 4) has been characterized by X-ray diffraction, 1H and 13C nuclear magnetic resonance spectroscopy, infrared spectroscopy, and electronic absorption spectroscopy, and modeled by density functional theory (DFT) and time-dependent density functional theory (TDDFT). Mer-RhBr3(Me2pzH)3 is an octahedral complex with a HOMO → LUMO transition at 486 nm. The DFT and TDDFT calculations predicted mer-RhBr3(Me2pzH)3 to be an octahedral complex with a HOMO → LUMO transition at 540 nm. 相似文献43.
We study the transmission of an optical field through a rotating coupled resonator optical waveguide (CROW) in which the size of the ring resonators changes from one ring to the next. We focus on symmetric integer wavelength chirps of the circumference of the rings relative to the central ring in the array. The transfer matrix method is used to obtain the transmission as a function of the inertial rotation rate Ω resulting from the Sagnac effect. Chirping increases the slope of the oscillations in the transmission as a function of Ω, which can be exploited to further enhance the rotation sensitivity beyond that of a CROW with uniform resonators. 相似文献
44.
Noah J. Tremblay Alon A. Gorodetsky Dr. Marshall P. Cox Theanne Schiros Dr. Bumjung Kim Rachel Steiner Zachary Bullard Aaron Sattler Woo‐Young So Dr. Yoshimitsu Itoh Dr. Michael F. Toney Dr. Hirohito Ogasawara Dr. Arthur P. Ramirez Prof. Ioannis Kymissis Dr. Michael L. Steigerwald Dr. Colin Nuckolls Prof. 《Chemphyschem》2010,11(4):742-742
45.
Background
The mammalian taste bud, a complex collection of taste sensory cells, supporting cells, and immature basal cells, is the structural unit for detecting taste stimuli in the oral cavity. Even though the cells of the taste bud undergo constant turnover, the structural homeostasis of the bud is maintained by balancing cell proliferation and cell death. Compared with nongustatory lingual epithelial cells, taste cells express higher levels of several inflammatory receptors and signalling proteins. Whether inflammation, an underlying condition in some diseases associated with taste disorders, interferes with taste cell renewal and turnover is unknown. Here we report the effects of lipopolysaccharide (LPS)-induced inflammation on taste progenitor cell proliferation and taste bud cell turnover in mouse taste tissues. 相似文献46.
Alexander N. Zaykov Brian V. Popp Dr. Zachary T. Ball Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(22):6651-6659
The use of carboxylate side chains to induce peptide helicity upon binding to dirhodium centers is examined through experimental and computational approaches. Dirhodium binding efficiently stabilizes α helicity or induces α helicity in otherwise unstructured peptides for peptides that contain carboxylate side chains with i, i+4 spacing. Helix induction is furthermore possible for sequences with i, i+3 carboxylate spacing, though in this case the length of the side chains is crucial: ligating to longer glutamate side chains is strongly helix inducing, whereas ligating the shorter aspartate side chains destabilizes the helical structure. Further studies demonstrate that a dirhodium metallopeptide complex persists for hours in cellular media and exhibits low toxicity toward mammalian cells, enabling exploitation of these metallopeptides for biological applications. 相似文献
47.
48.
49.
50.
Trust management in a networked environment consists of authentication and integrity checking. In a mobile computing environment, both remote hosts and mobile code are suspect. We present a model that addresses trust negotiation between the remote host and the mobile code simultaneously. Our model uses tamper resistant hardware, public key cryptography, and one-way hash functions. 相似文献