全文获取类型
收费全文 | 528篇 |
免费 | 25篇 |
国内免费 | 3篇 |
专业分类
化学 | 334篇 |
晶体学 | 3篇 |
力学 | 6篇 |
数学 | 50篇 |
物理学 | 163篇 |
出版年
2024年 | 1篇 |
2023年 | 18篇 |
2022年 | 16篇 |
2021年 | 19篇 |
2020年 | 18篇 |
2019年 | 18篇 |
2018年 | 8篇 |
2017年 | 14篇 |
2016年 | 19篇 |
2015年 | 24篇 |
2014年 | 25篇 |
2013年 | 45篇 |
2012年 | 50篇 |
2011年 | 42篇 |
2010年 | 27篇 |
2009年 | 20篇 |
2008年 | 30篇 |
2007年 | 29篇 |
2006年 | 12篇 |
2005年 | 26篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 1篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1965年 | 1篇 |
1939年 | 2篇 |
1938年 | 1篇 |
排序方式: 共有556条查询结果,搜索用时 15 毫秒
31.
Giri Kumar Tayi Jagdish Gangolly 《The Journal of the Operational Research Society》1985,36(10):951-957
The choice of an audit sample involves integration of diverse goals. Such integration must consider the preferences of the auditor towards costs as well as risks. Traditionally this problem has been formulated to determine minimal sample size and its allocation such that each of the goals is satisfied simultaneously or to the extent possible. However, these formulations do not consider trade-offs between goals, so that the sample may not reflect the auditor's preferences regarding sampling costs and risks. In this paper, we model such trade-offs by utilizing a polynomial goal-programming framework and utilize a practical case problem to illustrate the framework. Computational experience shows the technique to be feasible and inexpensive. 相似文献
32.
33.
The isotropic oscillator on a plane is discussed where the coordinate and momentum space are both considered to be non-commutative.
We also discuss the symmetry properties of the oscillator for three separate cases when the non-commutative parameters Θ and
for x and p-space, respectively, satisfy specific relations. We compare the Landau problem with the isotropic oscillator on non-commutative
space and obtain a relation between the two non-commutative parameters and the magnetic field of the Landau problem. 相似文献
34.
35.
Prof. Dr. Jean Christophe Tremblay Ambre Blanc Dr. Pascal Krause Sucharita Giri Prof. Gopal Dixit 《Chemphyschem》2023,24(2):e202200463
The present work focuses on probing ultrafast charge migration after symmetry-breaking excitation using ultrashort laser pulses. LiCN is chosen as prototypical system because it can be oriented in the laboratory frame and it possesses optically-accessible charge transfer states at low energies. The charge migration is simulated within the hybrid time-dependent density functional theory/configuration interaction framework. Time-resolved electronic current densities and simulated time-resolved x-ray diffraction signals are used to unravel the mechanism of charge migration. Our simulations demonstrate that specific choices of laser polarization lead to a control over the symmetry of the induced charge migration. Moreover, time-resolved x-ray diffraction signals are shown to encode transient symmetry reduction at intermediate times. 相似文献
36.
Kuldeep Sharma Gopal V. Pawar Sanjeev Giri Sriram Rajagopal Ramesh Mullangi 《Biomedical chromatography : BMC》2012,26(12):1589-1595
A highly sensitive, rapid assay method has been developed and validated for the estimation of bicalutamide in mouse plasma using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the negative‐ion mode. The assay procedure involves extraction of bicalutamide and tolbutamide (internal standard, IS) from mouse plasma with a simple protein precipitation method. Chromatographic separation was achieved using an isocratic mobile phase (0.2% formic acid:acetonitrile, 35:65, v/v) at a flow rate of 0.5 mL/min on an Atlantis dC18 column (maintained at 40 ± 1°C) with a total run time of 3.0 min. The MS/MS ion transitions monitored were m/z 428.9 → 254.7 for bicalutamide and m/z 269.0 → 169.6 for IS. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 1.04 ng/mL and the linearity range extended from 1.04 to 1877 ng/mL. The intra‐ and inter‐day precisions were in the ranges of 0.49–4.68 and 2.62–4.15, respectively. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
37.
Venkat R. Donuru Giri K. Vegesna Singaravelu Velayudham Ge Meng Haiying Liu 《Journal of polymer science. Part A, Polymer chemistry》2009,47(20):5354-5366
Novel deep‐red emissive poly(2,6‐BODIPY‐ethynylene)s bearing dodecyl side chains (polymers A , B , and C ) have been prepared by palladium‐catalyzed Sonogashira polymerization of 2,6‐diiodo‐functionalized BODIPY monomers with 2,6‐diethynyl‐functionalized BODIPY monomers. These polymers emit in the deep‐red region with emission maxima at up to 690 nm, and exhibit significant red shifts (up to 166 and 179 nm) of both absorption and emission maxima compared with their parent BODIPY dyes due to significant extension of π‐conjugation. These polymers possess good thermal stability with decomposition temperature between 270 and 360 °C. The polymers exhibit a little larger Stokes shifts and shorter lifetime than their corresponding BODIPY dyes. The solid state thin films of polymers A , B , and C emit in near‐infrared region between 723 and 743 nm, and show significantly red shifts (up to 57 nm) in absorption and emission maxima relative to their polymer solution. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5354–5366, 2009 相似文献
38.
Lalit Giri Arun Kumar Jugran Amit Bahukhandi Praveen Dhyani Indra D. Bhatt Ranbeer Singh Rawal Shyamal Kumar Nandi Uppeandra Dhar 《Applied biochemistry and biotechnology》2017,181(1):267-282
Habenaria edgeworthii Hook. f. ex Collett is an important terrestrial orchid used in different Ayurvedic formulations. In the present study, variations among morphological, phytochemical and molecular markers were assessed. A significant difference was observed among populations using morphological traits. Inter-simple sequence repeat (ISSR) data revealed lower genetic diversity at population level (He = 0.207) as compared to species level (He = 0.334). Analysis of molecular variance (AMOVA) indicates 74 % variation among populations and 26 % within population. Tuber extracts showed significantly (p < 0.05) higher total phenolics and flavonoids among the populations. Antioxidant activity determined by 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assays exhibited considerable antioxidant potential. Furthermore, the associations between molecular and morphological and phytochemical attributes were studied using multiple regression analysis (MRA). Several ISSR fragments were associated with some morphological and phytochemical traits. These ISSR fragments can be useful for breeding programme of the species when no other genetic information, such as linkage maps and quantitative trait loci, is available. 相似文献
39.
40.
Subrata Patra Ivan Mosiagin Rahul Giri Dr. Thomas Nauser Prof. Dr. Dmitry Katayev 《Angewandte Chemie (International ed. in English)》2023,62(28):e202300533
Herein, we introduce an electrochemically assisted generation of nitryl radicals from ferric nitrate under mild reaction conditions using a simple setup with inexpensive graphite and stainless-steel electrodes. The mechanism of the reaction is supported by detailed spectroscopic and experimental studies. Powered by electricity and driven by electrons, the synthetic diversity of this reaction has been demonstrated through the development of highly efficient nitration protocols of various unsaturated hydrocarbons. In addition to a broad application area, these protocols are easy to scale for decagram quantities, and exhibit exceptional substrate generality and functional-group compatibility. 相似文献