全文获取类型
收费全文 | 462篇 |
免费 | 40篇 |
国内免费 | 1篇 |
专业分类
化学 | 363篇 |
晶体学 | 4篇 |
力学 | 11篇 |
数学 | 36篇 |
物理学 | 89篇 |
出版年
2023年 | 6篇 |
2022年 | 6篇 |
2021年 | 9篇 |
2020年 | 22篇 |
2019年 | 17篇 |
2018年 | 15篇 |
2017年 | 18篇 |
2016年 | 20篇 |
2015年 | 17篇 |
2014年 | 24篇 |
2013年 | 35篇 |
2012年 | 44篇 |
2011年 | 48篇 |
2010年 | 13篇 |
2009年 | 19篇 |
2008年 | 29篇 |
2007年 | 27篇 |
2006年 | 22篇 |
2005年 | 15篇 |
2004年 | 8篇 |
2003年 | 14篇 |
2002年 | 13篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有503条查询结果,搜索用时 15 毫秒
451.
Dipak Kumar Das Sk Imadul Islam Nirnay Samanta Yogendra Yadav Debabrata Goswami Rajib Kumar Mitra 《Journal of fluorescence》2018,28(3):855-862
Rhodamine group of molecules are widely used dyes for imaging of biological molecules. Application of these dyes however includes a limitation that these molecules absorb in the visible range of the spectrum, which does not fall in the ‘biologically transparent window’ (BTW). Two photon absorption (TPA) process could come up with an alternate solution to this as these dyes could be excited in the near infrared (NIR) window to extract similar information. To validate this we have investigated TPA cross section (TPACS, σ2) of two rhodamine dyes, namely Rhodamine 6G (R6G), Rhodamine B (RhB), site selectively bound with a model protein, bovine serum albumin (BSA), by exciting at 800 nm. Two photon spectroscopy and imaging confirms the binding of the dye to the protein. The decreases in TPACS with increasing temperature at a fixed BSA concentration excellently follows the temperature induced structural transition of BSA as the protein transforms from a molten globule to unfolded conformation beyond 60 °C, which has previously been established through circular dichroism (CD) measurements. The thus established resemblance in TPACS and CD measurement trends thus strongly affirms the suitability of TPA process in protein imaging and as an alternative marker to tracking its conformational transformations using NIR radiation. 相似文献
452.
We report a new source of cw, single-frequency radiation in the blue, offering extended tunability and practical powers in a compact, all-solid-state design. The device is based on a green-pumped, cw, singly resonant optical parametric oscillator using MgO-doped stoichiometric lithium tantalate (MgO:sPPLT) as the nonlinear material. By internal second-harmonic generation of the resonant near-infrared signal radiation in a 5 mm BiB(3)O(6) crystal, we generate nearly 450 mW of cw, single-frequency blue power over a tunable range of 425-489 nm with a linewidth of 8.5 MHz and a Gaussian spatial beam profile. The demonstrated wavelength coverage can be further extended by using alternative gratings for the MgO:sPPLT crystal. 相似文献
453.
454.
Sohini Bhattacharyya Szymon Sobczak Aleksandra Półrolniczak Dr. Syamantak Roy Dr. Debabrata Samanta Prof. Andrzej Katrusiak Prof. Dr. Tapas Kumar Maji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(24):6092-6097
Targeted synthesis of piezoresponsive small molecules and in-depth understanding of their mechanism is of utmost importance for the development of smart devices. This work reports the synthesis, structure and piezosensitivity of a bola-amphiphile 1,4-bis(pentyloxy)-2,5-bis(2-pyridineethynyl)-benzene ( C5-PPB ). Depending on the rate of compression, two different phases in C5-PPB can be generated. The ambient-pressure α-phase is stable up to 0.8 GPa, beyond which it undergoes an isostructural transformation to β-phase, accompanied by a clearly visible elongation of the crystal. This α-to-β phase transition requires the sample to be compressed slowly. When quickly compressed, phase α persists to about 1.5 GPa, beyond which its amorphization starts, accompanied by the appearance of irregular grooves on the largest faces. Mechanical pressure also affects the optical property of C5-PPB , which shows reversible mechanochromism with a green to cyan transformation in the emission, associated with a 15 nm shift in the maxima. The conductivity of C5-PPB as a direct outcome of its crystal packing has also been studied. 相似文献
455.
Suman Kuila Anaranya Ghorai Dr. Pralok K. Samanta Dr. Raja B. K. Siram Prof. Dr. Swapan K. Pati Prof. Dr. K. S. Narayan Prof. Dr. Subi J. George 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(70):16007-16011
Unprecedented ambient triplet-mediated emission in core-substituted naphthalene diimide (cNDI) derivatives is unveiled via delayed fluorescence and room temperature phosphorescence. Carbazole core-substituted cNDIs, with a donor–acceptor design, showed deep-red triplet emission in solution processable films with high quantum yield. This study, with detailed theoretical calculations and time-resolved emission experiments, enables new design insights into the triplet harvesting of cNDIs; an important family of molecules which has been, otherwise, extensively been investigated for its n-type electronic character and tunable singlet fluorescence. 相似文献
456.
Swati Samanta Nayim Sepay Sumitava Mallik Rina Mondal Mosidur Rahaman Molla 《合成通讯》2017,47(23):2195-2201
A facile synthesis of 2,8-dioxabicyclo[3.3.1]nonane derivatives starting from simple molecules, such as 2-hydroxychalcones as one component and dimedone, 4-hydroxycoumarin, 2-hydroxynaphthoquinone, 2-naphthol or 1-naphthol, as the other has been achieved by use of amberlyst-15, a sulfonated polystyrene resin, as a recyclable heterogeneous catalyst. The methodology involves a domino sequence of Michael addition and two-stage cyclisation. 相似文献
457.
Choudhury Binayak S. Samanta Soumen 《International Journal of Theoretical Physics》2017,56(10):3285-3296
International Journal of Theoretical Physics - In this paper we present a protocol to perform the task of a bilateral exchange of entanglements between two parties in the case where one of the... 相似文献
458.
Hydrogen peroxide in high yields can be generated with high efficiency at mild conditions (25 degrees C and atmospheric pressure) with the formation of only environment-friendly by-products (N2 and H2O) by a reduction of O2 by hydrazine from its hydrate/salt with its complete conversion in a short reaction period (相似文献
459.
B. Bagchi K. Samanta A. Lahiri P. K. Roy 《International Journal of Theoretical Physics》1993,32(5):769-774
We suggest a modified factorization scheme within a supersymmetric framework which affords a consistent treatment of a wide class of Schrödinger potentials. A consequence of this is the possibility of deriving a boson-fermion Hamiltonian with linear interaction. 相似文献
460.
Annals of Operations Research - Police patrol is an effective crime prevention tool and boosts public confidence in urban security. Many interesting decision making problems appear in route design,... 相似文献