全文获取类型
收费全文 | 20439篇 |
免费 | 2237篇 |
国内免费 | 2066篇 |
专业分类
化学 | 2255篇 |
晶体学 | 30篇 |
力学 | 1752篇 |
综合类 | 523篇 |
数学 | 14037篇 |
物理学 | 6145篇 |
出版年
2024年 | 25篇 |
2023年 | 168篇 |
2022年 | 339篇 |
2021年 | 366篇 |
2020年 | 422篇 |
2019年 | 436篇 |
2018年 | 452篇 |
2017年 | 581篇 |
2016年 | 653篇 |
2015年 | 504篇 |
2014年 | 1019篇 |
2013年 | 1320篇 |
2012年 | 1056篇 |
2011年 | 1285篇 |
2010年 | 1146篇 |
2009年 | 1412篇 |
2008年 | 1390篇 |
2007年 | 1459篇 |
2006年 | 1310篇 |
2005年 | 1255篇 |
2004年 | 1035篇 |
2003年 | 942篇 |
2002年 | 786篇 |
2001年 | 735篇 |
2000年 | 665篇 |
1999年 | 581篇 |
1998年 | 521篇 |
1997年 | 484篇 |
1996年 | 362篇 |
1995年 | 295篇 |
1994年 | 243篇 |
1993年 | 184篇 |
1992年 | 154篇 |
1991年 | 127篇 |
1990年 | 140篇 |
1989年 | 93篇 |
1988年 | 86篇 |
1987年 | 75篇 |
1986年 | 68篇 |
1985年 | 83篇 |
1984年 | 69篇 |
1983年 | 48篇 |
1982年 | 66篇 |
1981年 | 60篇 |
1980年 | 38篇 |
1979年 | 34篇 |
1978年 | 30篇 |
1977年 | 28篇 |
1976年 | 30篇 |
1973年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
J. M. Skowronski 《Annals of Operations Research》1992,37(1):423-437
The Liapunov technique has been introduced in differential games in a sequence of works over the last decade. We discuss application of this technique to the interface between two competitive semi-games, each with different qualitative objective. The feedback information for controllers is provided from designed, analytically integrable state predictors with reduced dynamics, which considerably shortens the computing time. The case is illustrated on the scenario of target reaching before being intercepted, and intercepting before target is reached.Deceased. 相似文献
132.
本工作用x射线衍射技术分析计算了二种天然树脂的局部结构参数,由测得的衍射强度数据求出了它们的结构因子I(r)和径向分布函数RDF(r),并由此得到了分子链内临近原子和次临近原子平均间距、配位数和短程有序畴。 相似文献
133.
An asymptotic formula is obtained for the number of representations of an element of a finite field as a weighted sum of two prescribed powers of primitive elements. This generalises previous work on sums of primitive elements, including that relating to some conjectures of Golomb. 相似文献
134.
In this paper, we give a convergence theorem and error estimates for an iteration method under new Kantorovitch-Ostrowski type condition using the information of higher derivatives at initial points. Compared with the corresponding study in [3],the convergence determination is established under one global condition, instead of two , on the function. 相似文献
135.
Experiments employing photoreflectance spectroscopy have uncovered band bending due to electrically active defects at the Si(1 1 1)–SiO2 interface after sub-keV Ar+ ion bombardment. The band bending of about 0.5 eV resembles that for Si(1 0 0)–SiO2, and both interfaces exhibit two kinetic regimes for the evolution of band bending upon annealing due to defects healing. The healing takes place about an order of magnitude more quickly at the (1 1 1) interface, however, probably because of less fully saturated bonding and higher compressive stress. 相似文献
136.
137.
Using recursive variants of Baire notions of nowhere dense and meagre sets we study the topological size of speedable and infinitely often speedable functions in a machine-independent framework. We show that the set of speedable functions is not “small” whereas the set of infinitely often speedable functions is “large”. In this way we offer partial answers to a question in [4]. 相似文献
138.
灰色Verhulst模型的样条插值函数的残差修正 总被引:4,自引:0,他引:4
本用样条函数对灰色Verhulst模型的残差序列进行插值拟合,然后作用于二阶线性微分方程,并以此修正原模型,得到一种新的预测模型的数值解,提高了拟合的精确度。 相似文献
139.
Cristinel Mortici 《Czechoslovak Mathematical Journal》2005,55(3):709-718
In this paper we give some new results concerning solvability of the 1-dimensional differential equation y′ = f(x, y) with initial conditions. We study the basic theorem due to Picard. First we prove that the existence and uniqueness result
remains true if f is a Lipschitz function with respect to the first argument. In the second part we give a contractive method for the proof
of Picard theorem. These considerations allow us to develop two new methods for finding an approximation sequence for the
solution. Finally, some applications are given. 相似文献
140.