全文获取类型
收费全文 | 2715篇 |
免费 | 344篇 |
国内免费 | 273篇 |
专业分类
化学 | 557篇 |
晶体学 | 17篇 |
力学 | 344篇 |
综合类 | 38篇 |
数学 | 585篇 |
物理学 | 1791篇 |
出版年
2023年 | 8篇 |
2022年 | 30篇 |
2021年 | 44篇 |
2020年 | 72篇 |
2019年 | 64篇 |
2018年 | 44篇 |
2017年 | 77篇 |
2016年 | 87篇 |
2015年 | 75篇 |
2014年 | 134篇 |
2013年 | 200篇 |
2012年 | 156篇 |
2011年 | 192篇 |
2010年 | 149篇 |
2009年 | 182篇 |
2008年 | 217篇 |
2007年 | 161篇 |
2006年 | 162篇 |
2005年 | 151篇 |
2004年 | 133篇 |
2003年 | 112篇 |
2002年 | 114篇 |
2001年 | 104篇 |
2000年 | 67篇 |
1999年 | 67篇 |
1998年 | 70篇 |
1997年 | 61篇 |
1996年 | 61篇 |
1995年 | 40篇 |
1994年 | 37篇 |
1993年 | 30篇 |
1992年 | 36篇 |
1991年 | 24篇 |
1990年 | 16篇 |
1989年 | 25篇 |
1988年 | 25篇 |
1987年 | 18篇 |
1986年 | 20篇 |
1985年 | 13篇 |
1984年 | 13篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 2篇 |
排序方式: 共有3332条查询结果,搜索用时 171 毫秒
91.
92.
We present an off-shell generating function for all cubic interactions of higher spin gauge fields constructed in Manvelyan et al. (2010) [1]. It is a generalization of the on-shell generating function proposed by Sagnotti and Taronna [2], is written in a very compact way, and turns out to have a remarkable structure. 相似文献
93.
The 2-dimensional BF theory is both a gauge theory and a topological Poisson σ-model corresponding to a linear Poisson bracket. In [3], Torossian discovered a connection which governs correlation functions of the BF theory with sources for the B-field. This connection is flat, and it is a close relative of the KZ connection in the WZW model. In this Letter, we show that flatness of the Torossian connection follows from (properly regularized) quantum equations of motion of the BF theory. 相似文献
94.
95.
96.
97.
98.
实验研究了装有Pt覆盖的多孔陶瓷的Swiss-Roll燃烧器的燃烧特性,分别得到了3种不同长度的催化剂基底的熄火极限,并测量3种情况下催化剂壁面及催化剂后部空间的温度。实验结果表明,3种情况中,催化剂基底长4.5mm的燃烧器可燃范围最大,所以此长度较适合此Swiss-Roll燃烧器。从温度数据可以看出来,催化剂后部空间存在反应,且受上游催化剂表面反应强度的影响。 相似文献
99.
Two States Are Not Enough: Quantitative Evaluation of the Valence‐Bond Intramolecular Charge‐Transfer Model and Its Use in Predicting Bond Length Alternation Effects 下载免费PDF全文
Dr. Peter D. Jarowski Prof. Yirong Mo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51):17214-17221
The structural weights of the canonical resonance contributors used in the Two‐state valence‐bond charge‐transfer model, neutral (N, R1) and ionic (VB‐CT, R2), to the ground states and excited states of a series of linear dipolar intramolecular charge‐transfer chromophores containing a buta‐1,3‐dien‐1,4‐diyl bridge have been computed by using the block‐localized wavefunction (BLW) method at the B3LYP/6‐311+G(d) level to provide the first quantitative assessment of this simple model. Ground‐ and excited‐state analysis reveals surprisingly low ground‐state structural weights for the VB‐CT resonance form using either this Two‐state model or an expanded Ten‐state model. The VB‐CT state is found to be more prominent in the excited state. Individual resonance forms were structurally optimized to understand the origins of the bond length alternation (BLA) of the bridging unit. Using a Wheland energy‐based weighting scheme, the weighted average of the optimized bond lengths with the Two‐state model was unable to reproduce the BLA features with values 0.04 to 0.02 Å too large compared to the fully delocalized (FD) structure (BLW: ca. ?0.13 to ?0.07 Å, FD: ca. ?0.09 to ?0.05 Å). Instead, an expanded Ten‐state model fit the BLA values of the FD structure to within only 0.001 Å of FD. 相似文献
100.
Human Y‐chromosome SNP characterization by multiplex amplified product‐length polymorphism analysis 下载免费PDF全文
Laura Smeldy Jurado Medina Marina Muzzio Marisol Schwab María Leticia Bravi Costantino Guillermo Barreto Graciela Bailliet 《Electrophoresis》2014,35(17):2524-2527
We designed an allele‐specific amplification protocol to optimize Y‐chromosome SNP typing, which is an unavoidable step for defining the phylogenetic status of paternal lineages. It allows the simultaneous highly specific definition of up to six mutations in a single reaction by amplification fragment length polymorphism (AFLP) without the need of specialized equipment, at a considerably lower cost than that based on single‐base primer extension (SNaPshot?) technology or PCR‐RFLP systems, requiring as little as 0.5 ng DNA and compatible with the small fragments characteristic of low‐quality DNA. By designation of two primers recognizing the derived and ancestral state for each SNP, which can be differentiated by size by the addition of a noncomplementary nucleotide tail, we could define major Y clades E, F, K, R, Q, and subhaplogroups R1, R1a, R1b, R1b1b, R1b1c, J1, J2, G1, G2, I1, Q1a3, and Q1a3a1 through amplification fragments that ranged between 60 and 158bp. 相似文献