全文获取类型
收费全文 | 1049篇 |
免费 | 26篇 |
国内免费 | 64篇 |
专业分类
化学 | 40篇 |
晶体学 | 1篇 |
力学 | 14篇 |
综合类 | 6篇 |
数学 | 1014篇 |
物理学 | 64篇 |
出版年
2024年 | 2篇 |
2023年 | 17篇 |
2022年 | 18篇 |
2021年 | 22篇 |
2020年 | 18篇 |
2019年 | 26篇 |
2018年 | 21篇 |
2017年 | 17篇 |
2016年 | 16篇 |
2015年 | 13篇 |
2014年 | 39篇 |
2013年 | 98篇 |
2012年 | 35篇 |
2011年 | 49篇 |
2010年 | 46篇 |
2009年 | 71篇 |
2008年 | 81篇 |
2007年 | 76篇 |
2006年 | 56篇 |
2005年 | 50篇 |
2004年 | 38篇 |
2003年 | 40篇 |
2002年 | 41篇 |
2001年 | 31篇 |
2000年 | 24篇 |
1999年 | 28篇 |
1998年 | 28篇 |
1997年 | 23篇 |
1996年 | 19篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 8篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 7篇 |
1984年 | 9篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1139条查询结果,搜索用时 15 毫秒
41.
合班授课教学模式下最大的问题在于难以兼顾各专业实施教学,导致难以激发学员的学习兴趣,定制与专业相关的教学案例恰好能够解决上述问题。本文精选骨质疏松症及新生儿黄疸这两个医学案例,重点探讨了如何贴近护理和生物医学工程专业的需求,定制化设计这两个医学案例,并在医学化学绪论课中实施;实施后通过平时的访谈和期末考试医学应用题的得分统计情况发现,这种定制化的案例教学能够从本质上激发学员的学习热情,也能达到合班教学中兼顾各专业的目的。 相似文献
42.
新高考方案给予学生更多学科选择权,同时也给化学学科带来了新的挑战。以化学教学为视角,在2014级学生实施分类走班教学的基础上,通过调查影响学生化学学考/选考的因素,探究新高考方案对化学教学的影响以及实践相应的教学策略。重点研究教学组织形式的改变、教学内容的重组融合、教学手段的多元互补、教学方式的选择优化、教学观念的更新发展。 相似文献
43.
设V是3-维不定空间,W是V中某个不可约根系的无限Weyl群,本文在仿射群A(V)中共轭的意义下,给出了点群为W的晶体群的分类。 相似文献
44.
It is considered the class of Riemann surfaces with dimT1 = 0, where T1 is a subclass of exact harmonic forms which is one of the factors in the orthogonal decomposition of the spaceΩH of harmonic forms of the surface, namely The surfaces in the class OHD and the class of planar surfaces satisfy dimT1 = 0. A.Pfluger posed the question whether there might exist other surfaces outside those two classes. Here it is shown that in the case of finite genus g, we should look for a surface S with dimT1 = 0 among the surfaces of the form Sg\K , where Sg is a closed surface of genus g and K a compact set of positive harmonic measure with perfect components and very irregular boundary. 相似文献
45.
Zhifu Xie 《Physics letters. A》2011,375(39):3392-3398
This Letter is to provide a new approach to study the phenomena of degeneracy of the number of the collinear central configurations under geometric equivalence. A direct and simple explicit parametric expression of the singular surface H3 is constructed in the mass space (m1,m2,m3)∈3(R+). The construction of H3 is from an inverse respective, that is, by specifying positions for the bodies and then determining the masses that are possible to yield a central configuration. It reveals the relationship between the phenomena of degeneracy and the inverse problem of central configurations. We prove that the number of central configurations is decreased to 3!/2−1=2, m1, m2, and m3 are mutually distinct if m∈H3. Moreover, we know not only the number of central configurations but also what the nonequivalent central configurations are. 相似文献
46.
We study bicriteria problems of minimizing maximum tardiness and total due date assignment cost in various scheduling environments. We assume that each job can be assigned a different due date without any restriction, and that each due date assignment cost is a non-decreasing function of the quoted due date. We settle the complexity of most of the problems studied by either proving that they are NP-hard or finding a polynomial time solution for them. We also include approximation and non-approximability results for several parallel-machine problems. 相似文献
47.
We prove tightness of (r,p)-Sobolev capacities on configuration spaces equipped with Poisson measure. By using this result we construct surface measures on configuration spaces in the spirit of the Malliavin calculus. A related Gauss-Ostrogradskii formula is obtained. 相似文献
48.
We describe a modal sequential calculus some modal rules of which do not contain duplications of the main formula. We also prove its equivalence to the modal calculus S4 and the decidability of some classes of formulas containing only oneplace predicate variables. 相似文献
49.
Let LB be a sequent calculus of the first-order classical temporal logic TB with time gaps. Let, further, LBJ be the intuitionistic counterpart of LB. In this paper, we consider conditions under which a sequent is derivable in the calculus LBJ if and only if it is derivable in the calculus LB. Such conditions are defined for sequents with one formula in the succedent (purely Glivenko -classes) and for sequents with the empty succedent (Glivenko -classes). 相似文献
50.
We show that the Chern character of a variation of polarized Hodge structures of weight one with nilpotent residues at dies up to torsion in the Chow ring, except in codimension 0. 相似文献