全文获取类型
收费全文 | 6188篇 |
免费 | 207篇 |
国内免费 | 130篇 |
专业分类
化学 | 1127篇 |
晶体学 | 17篇 |
力学 | 190篇 |
综合类 | 127篇 |
数学 | 4528篇 |
物理学 | 536篇 |
出版年
2023年 | 36篇 |
2022年 | 69篇 |
2021年 | 78篇 |
2020年 | 100篇 |
2019年 | 128篇 |
2018年 | 124篇 |
2017年 | 121篇 |
2016年 | 103篇 |
2015年 | 83篇 |
2014年 | 117篇 |
2013年 | 352篇 |
2012年 | 180篇 |
2011年 | 266篇 |
2010年 | 171篇 |
2009年 | 373篇 |
2008年 | 435篇 |
2007年 | 453篇 |
2006年 | 372篇 |
2005年 | 295篇 |
2004年 | 263篇 |
2003年 | 202篇 |
2002年 | 96篇 |
2001年 | 133篇 |
2000年 | 116篇 |
1999年 | 129篇 |
1998年 | 122篇 |
1997年 | 93篇 |
1996年 | 111篇 |
1995年 | 134篇 |
1994年 | 116篇 |
1993年 | 97篇 |
1992年 | 88篇 |
1991年 | 44篇 |
1990年 | 65篇 |
1989年 | 49篇 |
1988年 | 52篇 |
1987年 | 69篇 |
1986年 | 63篇 |
1985年 | 85篇 |
1984年 | 50篇 |
1983年 | 49篇 |
1982年 | 95篇 |
1981年 | 67篇 |
1980年 | 62篇 |
1979年 | 33篇 |
1978年 | 58篇 |
1977年 | 57篇 |
1976年 | 57篇 |
1975年 | 7篇 |
1974年 | 4篇 |
排序方式: 共有6525条查询结果,搜索用时 15 毫秒
1.
探讨了经济增长及金融发展与城乡收入差距之间互动影响,刻画了三者间的逻辑关系,并基于广西1990-2017年的统计数据,运用状态空间模型及卡尔曼滤波算法对三者间动态关系进行了实证分析.结果显示:经济增长对城乡收入差距呈现倒U型曲线形态,而金融发展则显示出具有不断缩小城乡收入差距的趋势. 相似文献
2.
3.
4.
Jamil Chaker 《Mathematische Nachrichten》2019,292(11):2316-2337
We consider systems of stochastic differential equations of the form for with continuous, bounded and non‐degenerate coefficients. Here are independent one‐dimensional stable processes with . In this article we research on uniqueness of weak solutions to such systems by studying the corresponding martingale problem. We prove the uniqueness of weak solutions in the case of diagonal coefficient matrices. 相似文献
5.
We will focus on the existence of nontrivial solutions to the following Hamiltonian elliptic system where are numbers belonging to the interval [0, 2), V is a continuous potential bounded below on by a positive constant and the functions f and g possess exponential growth range established by Trudinger–Moser inequalities in Lorentz–Sobolev spaces. The proof involves linking theorem and a finite‐dimensional approximation. 相似文献
6.
For a general dyadic grid, we give a Calderón–Zygmund type decomposition, which is the principle fact about the multilinear maximal function on the upper half‐spaces. Using the decomposition, we study the boundedness of . We obtain a natural extension to the multilinear setting of Muckenhoupt's weak‐type characterization. We also partially obtain characterizations of Muckenhoupt's strong‐type inequalities with one weight. Assuming the reverse Hölder's condition, we get a multilinear analogue of Sawyer's two weight theorem. Moreover, we also get Hytönen–Pérez type weighted estimates. 相似文献
7.
Hasliza Hassan Mohd Din Amiruddin Wolfram Weckwerth Umi Salamah Ramli 《Electrophoresis》2019,40(2):254-265
Palm oil is an edible vegetable oil derived from lipid‐rich fleshy mesocarp tissue of oil palm (Elaeis guineensis Jacq.) fruit and is of global economic and nutritional relevance. While the understanding of oil biosynthesis in plants is improving, the fundamentals of oil biosynthesis in oil palm still require further investigations. To gain insight into the systemic mechanisms that govern oil synthesis during oil palm fruit ripening, the proteomics approach combining gel‐based electrophoresis and mass spectrometry was used to profile protein changes and classify the patterns of protein accumulation during these complex physiological processes. Protein profiles from different stages of fruit ripening at 10, 12, 14, 15, 16, 18 and 20 weeks after anthesis (WAA) were analysed by two‐dimensional gel electrophoresis (2DE). The proteome data were then visualised using a multivariate statistical analysis of principal component analysis (PCA) to get an overview of the proteome changes during the development of oil palm mesocarp. A total of 68 differentially expressed protein spots were successfully identified by matrix‐assisted laser desorption/ionisation‐time of flight (MALDI‐TOF/TOF) and functionally classified using ontology analysis. Proteins related to lipid production, energy, secondary metabolites and amino acid metabolism are the most significantly changed proteins during fruit development representing potential candidates for oil yield improvement endeavors. Data are available via ProteomeXchange with identifier PXD009579. This study provides important proteome information for protein regulation during oil palm fruit ripening and oil synthesis. 相似文献
8.
9.
耳蜗感觉毛细胞作为听觉机械感受器,在听觉的发生过程中起着至关重要的作用。 哺乳动物的毛细胞损伤后无法再生,往往会造成听力障碍或永久性听力缺失。因此,阐明内耳感觉毛细胞发育过程中的分子机制对听力损伤的诊断与治疗具有非常重要的意义。Math1 是毛细胞发育与再生过程中的关键基因,本文就Math1 及其相关基因和信号通路在毛细胞的发育与再生过程中的调控作用做简要概述。 相似文献
10.