全文获取类型
收费全文 | 4318篇 |
免费 | 197篇 |
国内免费 | 19篇 |
专业分类
化学 | 2913篇 |
晶体学 | 40篇 |
力学 | 103篇 |
数学 | 426篇 |
物理学 | 1052篇 |
出版年
2023年 | 19篇 |
2022年 | 14篇 |
2021年 | 83篇 |
2020年 | 82篇 |
2019年 | 83篇 |
2018年 | 67篇 |
2017年 | 54篇 |
2016年 | 141篇 |
2015年 | 131篇 |
2014年 | 167篇 |
2013年 | 262篇 |
2012年 | 358篇 |
2011年 | 377篇 |
2010年 | 210篇 |
2009年 | 196篇 |
2008年 | 290篇 |
2007年 | 268篇 |
2006年 | 246篇 |
2005年 | 234篇 |
2004年 | 174篇 |
2003年 | 161篇 |
2002年 | 124篇 |
2001年 | 96篇 |
2000年 | 73篇 |
1999年 | 63篇 |
1998年 | 42篇 |
1997年 | 31篇 |
1996年 | 47篇 |
1995年 | 44篇 |
1994年 | 45篇 |
1993年 | 47篇 |
1992年 | 32篇 |
1991年 | 20篇 |
1990年 | 30篇 |
1989年 | 19篇 |
1987年 | 9篇 |
1986年 | 16篇 |
1985年 | 19篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1982年 | 12篇 |
1980年 | 11篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1974年 | 7篇 |
1973年 | 10篇 |
1943年 | 8篇 |
1942年 | 13篇 |
1941年 | 10篇 |
排序方式: 共有4534条查询结果,搜索用时 31 毫秒
71.
72.
Jae-Hyun Yang Tae-Yang Song Chanhee Jo Jinyoung Park Han-Young Lee Ilang Song Suji Hong Kwan Young Jung Jaehoon Kim Jeung-Whan Han Hong-Duk Youn Eun-Jung Cho 《Experimental & molecular medicine》2016,48(8):e252
Replication-independent incorporation of variant histone H3.3 has a profound impact on chromatin function and numerous cellular processes, including the differentiation of muscle cells. The histone chaperone HIRA and H3.3 have essential roles in MyoD regulation during myoblast differentiation. However, the precise mechanism that determines the onset of H3.3 deposition in response to differentiation signals is unclear. Here we show that HIRA is phosphorylated by Akt kinase, an important signaling modulator in muscle cells. By generating a phosphospecific antibody, we found that a significant amount of HIRA was phosphorylated in myoblasts. The phosphorylation level of HIRA and the occupancy of phosphorylated protein on muscle genes gradually decreased during cellular differentiation. Remarkably, the forced expression of the phosphomimic form of HIRA resulted in reduced H3.3 deposition and suppressed the activation of muscle genes in myotubes. Our data show that HIRA phosphorylation limits the expression of myogenic genes, while the dephosphorylation of HIRA is required for proficient H3.3 deposition and gene activation, demonstrating that the phosphorylation switch is exploited to modulate HIRA/H3.3-mediated muscle gene regulation during myogenesis. 相似文献
73.
74.
An integrated finite element method (FEM) is proposed to simulate incompressible two‐phase flows with surface tension effects, and three different surface tension models are applied to the FEM to investigate spurious currents and temporal stability. A Q2Q1 element is adopted to solve the continuity and Navier–Stokes equations and a Q2‐iso‐Q1 to solve the level set equation. The integrated FEM solves pressure and velocity simultaneously in a strongly coupled manner; the level set function is reinitialized by adopting a direct approach using interfacial geometry information instead of solving a conventional hyperbolic‐type equation. In addition, a consistent continuum surface force (consistent CSF) model is utilized by employing the same basis function for both surface tension and pressure variables to damp out spurious currents and to estimate the accurate pressure distribution. The model is further represented as a semi‐implicit manner to improve temporal stability with an increased time step. In order to verify the accuracy and robustness of the code, the present method is applied to a few benchmark problems of the static bubble and rising bubble with large density and viscosity ratios. The Q2Q1‐integrated FEM coupled with the semi‐implicit consistent CSF demonstrates the significantly reduced spurious currents and improved temporal stability. The numerical results are in good qualitative and quantitative agreements with those of the existing studies. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
75.
Young-Woon Cho Kyung-Seok Kang Chanhyuk Jee Ji-Hyun Kim Dongju Jang 《Molecular Crystals and Liquid Crystals》2016,634(1):73-81
Polyamic acid (PAA) made from 3,3, 4,4-biphenyltetracarboxylic dianhydride and 4,4-diaminodiphenyl ether was synthesized and used as the backbone of nanoporous polyimide. Thermally labile polyethylene glycol (PEG) at 10, 20 or 30 wt% was introduced to the end group of PAA. Self-assembled PAA-b-PEG micelle-like nanoparticles could be formed as a result of amphiphilic characteristics of hydrophobic PAA and hydrophilic PEG. Thermal imidization and degradation of spin-coated amphiphilic PAA-b-PEG film were performed sequentially through one-step heat treatment to obtain polyimide film with nanopores. Pore sizes decreased with increasing amount of PEG block and their dielectric constants decreased from 2.71 ± 0.13 to 2.38 ± 0.11. 相似文献
76.
77.
78.
Nili-Ahmadabadi Mahdi Nematollahi Omid Fatehi Mostafa Cho Dae Seung Kim Kyung Chun 《显形杂志》2020,23(4):591-603
Journal of Visualization - Airfoils are mostly inefficient in their off-design conditions. In order to improve the aerodynamic performance of airfoils in these conditions, using an optimized cavity... 相似文献
79.
Transport in Porous Media - The effective slip length at the interface between pure fluid flow and porous media composed of packed spheres has been accurately characterized. In this study, as the... 相似文献
80.