全文获取类型
收费全文 | 5837篇 |
免费 | 127篇 |
国内免费 | 34篇 |
专业分类
化学 | 4049篇 |
晶体学 | 88篇 |
力学 | 134篇 |
数学 | 985篇 |
物理学 | 742篇 |
出版年
2022年 | 36篇 |
2021年 | 42篇 |
2020年 | 41篇 |
2019年 | 62篇 |
2018年 | 58篇 |
2017年 | 47篇 |
2016年 | 113篇 |
2015年 | 113篇 |
2014年 | 113篇 |
2013年 | 314篇 |
2012年 | 262篇 |
2011年 | 320篇 |
2010年 | 148篇 |
2009年 | 145篇 |
2008年 | 287篇 |
2007年 | 313篇 |
2006年 | 264篇 |
2005年 | 301篇 |
2004年 | 250篇 |
2003年 | 281篇 |
2002年 | 234篇 |
2001年 | 102篇 |
2000年 | 87篇 |
1999年 | 84篇 |
1998年 | 63篇 |
1997年 | 86篇 |
1996年 | 94篇 |
1995年 | 92篇 |
1994年 | 84篇 |
1993年 | 64篇 |
1992年 | 54篇 |
1991年 | 60篇 |
1990年 | 49篇 |
1989年 | 63篇 |
1988年 | 72篇 |
1987年 | 55篇 |
1986年 | 52篇 |
1985年 | 78篇 |
1984年 | 99篇 |
1983年 | 67篇 |
1982年 | 90篇 |
1981年 | 95篇 |
1980年 | 90篇 |
1979年 | 74篇 |
1978年 | 77篇 |
1977年 | 72篇 |
1976年 | 67篇 |
1975年 | 58篇 |
1974年 | 48篇 |
1973年 | 36篇 |
排序方式: 共有5998条查询结果,搜索用时 15 毫秒
81.
Alan D. Sokal 《Probability Theory and Related Fields》1981,56(4):537-548
Summary Let (, , ) be a perfect probability space with countably generated, and let IB be a family of sub--fields of . Under a countability condition on the family IB, I show that there exists a family {}IB of regular conditional probabilities which are everywhere compatible. Under a more stringent condition on IB, I show that the
can furthermore be chosen to be everywhere proper. It follows that in the Dobrushin-Lanford-Ruelle formulation of the statistical mechanics of classical lattice systems, every (perfect) probability measure is a Gibbs measure for some specification.Research supported in part by NSF PHY-78-23952NSF Predoctoral Fellow (1976–79) and Danforth Fellow (1979–81). 相似文献
82.
Goren AC Hrovat DA Seefelder M Quast H Borden WT 《Journal of the American Chemical Society》2002,124(13):3469-3472
Time-dependent B3LYP/6-31G calculations have been performed at the optimized C(2) or C(2v) geometries of several substituted semibullvalenes (1(deloc)) and barbaralanes (2(deloc)), to compare the computed vertical electronic excitation energies with the temperature-dependent, long-wavelength absorptions that have been observed in the UV/vis spectra of some of these compounds by Quast and co-workers. The excellent agreement between the calculated vertical excitation energies and the observed values of lambda(max) provides strong support for the identification of the bishomoaromatic species 1(deloc) and 2(deloc) as the source of these absorptions. Furthermore, the CN stretching frequencies, computed for the C(2) geometry of 1,5-dimethyl-2,6-dicyano-4,8-diphenylsemibullvalene (1f(deloc)), fit the low-frequency absorptions seen in the IR spectrum of 1f, thus furnishing independent evidence that bishomoaromatic geometries of semibullvalenes have, in fact, been observed spectroscopically. B3LYP/6-31G calculations predict that 2,6-dicyano-4,8-diphenylsemibullvalene 1c has a C(2) equilibrium geometry (1c(deloc)) and that the long-wavelength UV/vis absorption (lambda(max) = 585 nm) and CN stretching frequencies (2192 and 2194 cm(-1)) computed for 1c(deloc) should serve to identify this bishomoaromatic semibullvalene when it is synthesized. 相似文献
83.
Lawan Ly Xiaoqian Cheng Saravana R. K. Murthy Olivia Z. Jones Taisen Zhuang Steven Gitelis Alan T. Blank Aviram Nissan Mohammad Adileh Matthew Colman Michael Keidar Giacomo Basadonna Jerome Canady 《Molecules (Basel, Switzerland)》2022,27(13)
Soft tissue sarcomas (STS) are a rare and highly heterogeneous group of solid tumors, originating from various types of connective tissue. Complete removal of STS by surgery is challenging due to the anatomical location of the tumor, which results in tumor recurrence. Additionally, current polychemotherapeutic regimens are highly toxic with no rational survival benefit. Cold atmospheric plasma (CAP) is a novel technology that has demonstrated immense cancer therapeutic potential. Canady Cold Helios Plasma (CHCP) is a device that sprays CAP along the surgical margins to eradicate residual cancer cells after tumor resection. This preliminary study was conducted in vitro prior to in vivo testing in a humanitarian compassionate use case study and an FDA-approved phase 1 clinical trial (IDE G190165). In this study, the authors evaluate the efficacy of CHCP across multiple STS cell lines. CHCP treatment reduced the viability of four different STS cell lines (i.e., fibrosarcoma, synovial sarcoma, rhabdomyosarcoma, and liposarcoma) in a dose-dependent manner by inhibiting proliferation, disrupting cell cycle, and inducing apoptosis-like cell death. 相似文献
84.
Direct measurements of the in-plane London penetration depth λ L have recently been performed on high-temperature superconducting copper oxides by a new low-energy muon spin rotation technique. The results show that λ L is isotope dependent, evidencing unconventional electron–phonon interactions as its source. The data are interpreted here in terms of polaronic effects on the single-particle energies, which leads to level shifts and exponential band narrowing. Good agreement with the experimental data is obtained. 相似文献
85.
86.
87.
R. Alan Aitken Bernd Fodi Michael H. Palmer Alexandra M.Z. Slawin Jing Yang 《Tetrahedron》2012,68(29):5845-5851
The structures of pyridazine N-oxide, pyrimidine N-oxide and pyrazine N-oxide have been determined by X-ray diffraction for the first time. Comparison with theoretical predictions of the equilibrium structures using the B3LYP method together with a cc-pVTZ basis set, show close agreement with the structural parameters observed, and experimental dipole moments, which suggests that the charge distribution is realistic. An ‘atoms in molecules’ (AIM) analysis of the computed wave-functions shows total electron densities rather different from the classical picture of a dative bond, whereas the same wave-functions subjected to Mulliken analysis show a more conventional view of the electron distribution. This latter procedure allows a bond dipole analysis of the N-oxide charge distribution. 相似文献
88.
We discuss the length of the longest directed cycle in the sparse random digraph , constant. We show that for large there exists a function such that a.s. The function where is a polynomial in . We are only able to explicitly give the values , although we could in principle compute any . 相似文献
89.
90.