全文获取类型
收费全文 | 902篇 |
免费 | 19篇 |
国内免费 | 10篇 |
专业分类
化学 | 562篇 |
晶体学 | 6篇 |
力学 | 7篇 |
数学 | 56篇 |
物理学 | 300篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 4篇 |
2016年 | 11篇 |
2015年 | 15篇 |
2014年 | 15篇 |
2013年 | 29篇 |
2012年 | 50篇 |
2011年 | 44篇 |
2010年 | 29篇 |
2009年 | 39篇 |
2008年 | 39篇 |
2007年 | 40篇 |
2006年 | 43篇 |
2005年 | 43篇 |
2004年 | 37篇 |
2003年 | 33篇 |
2002年 | 42篇 |
2001年 | 30篇 |
2000年 | 32篇 |
1999年 | 10篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 16篇 |
1994年 | 24篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 13篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 7篇 |
1985年 | 20篇 |
1984年 | 6篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1979年 | 12篇 |
1978年 | 9篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1975年 | 9篇 |
1974年 | 7篇 |
1973年 | 9篇 |
1972年 | 13篇 |
排序方式: 共有931条查询结果,搜索用时 15 毫秒
831.
Alastair Hamilton 《Letters in Mathematical Physics》2009,89(2):115-130
In this paper we describe a construction which produces classes in compactifications of the moduli space of curves. This construction
extends a construction of Kontsevich which produces classes in the open moduli space from the initial data of a cyclic A
∞-algebra. The initial data for our construction are what we call a ‘quantum A
∞-algebra’, which arises as a type of deformation of a cyclic A
∞-algebra. The deformation theory for these structures is described explicitly. We construct a family of examples of quantum
A
∞-algebras which extend a family of cyclic A
∞-algebras, introduced by Kontsevich, which are known to produce all the kappa classes using his construction.
相似文献
832.
This paper gives a conceptual formulation of Kontsevich’s ‘dual construction’ producing graph cohomology classes from a differential graded Frobenius algebra with an odd scalar product. Our construction–whilst equivalent to the original one–is combinatorics-free and is based on the Batalin–Vilkovisky formalism, from which its gauge independence is immediate. 相似文献
833.
Zhen Yang Sheng Jiang Feng Li Yatao Qiu Jianhua Gu Roderic I. Pettigrew Mauro Ferrari Dale J. Hamilton Zheng Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(16):5326-5330
Interaction of multiple entities and receptors, or multivalency is widely applied to achieve high affinity ligands for diagnostic and therapeutic purposes. However, lack of knowledge on receptor distribution in living subjects remains a challenge for rational structure design. Herein, we develop a force measurement platform to probe the distribution and separation of the cell surface vascular endothelial growth factor receptors (VEGFR) in live cells, and use this to assess the geometry of appropriate linkers for distinct multivalent binding modes. A tetravalent lead ZD‐4, which was developed from an antitumor drug ZD6474 (Vandetanib) with combined hybrid binding effects, yielded a 2000‐fold improvement in the binding affinity to VEGFR with IC50 value of 25 pm . We confirmed the improved affinity by the associated increase of tumor uptake in the VEGFR‐targeting positron emission tomography (PET) imaging using U87 tumor xenograft mouse model. 相似文献
834.
Crystals of the layered metal organic framework solid Pb[B(Im)4](NO3)(nH2O) can undergo exchange of the nitrate for perrhenate, a model for pertechnetate, forming Pb[B(Im)4](ReO4). We can monitor this reaction by 207Pb solid-state NMR and can isolate single crystals of the resultant material through growth in the presence of an excess of perrhenate. Such a synthetic metal-organic framework solid represents a new candidate for pertechnetate-sequestering materials. 相似文献
835.
836.
Boyd DR Sharma ND Loke PL Malone JF McRoberts WC Hamilton JT 《Chemical communications (Cambridge, England)》2002,(24):3070-3071
A combination method of ozonolysis and chiral stationary phase (CSP)-GC-MS analysis has been developed to determine the enantiopurity values and absolute configurations of a range of alkaloid and coumarin hemiterpenoids derived from C- and O-prenyl epoxides. 相似文献
837.
838.
Surfactant sponges are complex-fluid phases made up of convolutions of bilayer sheets. Although isotropic and free flowing they exhibit transient birefringence when stirred, reminiscent of the birefringence of lamellar phases. Previous attempts to understand this effect have led to confusing and often conflicting results. We have used a novel approach to designing the chemical system that gives us control over the relevant parameters needed to study microstructural and macroscopic responses of these phases to shear. We find a remarkable universal scaling behavior for both sponge and shear-induced lamellar states, which resolves a number of long-standing questions about these systems. 相似文献
839.
To describe multiple interacting fragmentation continua, we develop a method in which the vibrational channel functions obey outgoing wave Siegert boundary conditions. This paper demonstrates the utility of the Siegert approach, which uses channel energy eigenvalues that possess a negative imaginary part. The electron scattering energy in each such channel is rotated upward, giving it an equal and opposite imaginary part. This permits a natural inclusion of vibrational continua without requiring them to appear as explicit channels in the scattering matrix. Calculations illustrate the application of this theory to photoionization, photodissociation, and dissociative recombination. 相似文献
840.
3α-Dihydrocadambine has been synthesized from secologanin. 相似文献