全文获取类型
收费全文 | 88528篇 |
免费 | 1839篇 |
国内免费 | 1061篇 |
专业分类
化学 | 27420篇 |
晶体学 | 843篇 |
力学 | 7006篇 |
综合类 | 35篇 |
数学 | 32456篇 |
物理学 | 17003篇 |
综合类 | 6665篇 |
出版年
2023年 | 137篇 |
2022年 | 172篇 |
2021年 | 219篇 |
2020年 | 225篇 |
2019年 | 166篇 |
2018年 | 10810篇 |
2017年 | 10609篇 |
2016年 | 6495篇 |
2015年 | 1121篇 |
2014年 | 671篇 |
2013年 | 710篇 |
2012年 | 4499篇 |
2011年 | 11618篇 |
2010年 | 6661篇 |
2009年 | 6809篇 |
2008年 | 7356篇 |
2007年 | 9721篇 |
2006年 | 575篇 |
2005年 | 1620篇 |
2004年 | 1872篇 |
2003年 | 2276篇 |
2002年 | 1309篇 |
2001年 | 482篇 |
2000年 | 481篇 |
1999年 | 433篇 |
1998年 | 441篇 |
1997年 | 375篇 |
1996年 | 414篇 |
1995年 | 290篇 |
1994年 | 252篇 |
1993年 | 247篇 |
1992年 | 178篇 |
1991年 | 177篇 |
1990年 | 157篇 |
1989年 | 173篇 |
1988年 | 135篇 |
1987年 | 143篇 |
1986年 | 96篇 |
1985年 | 72篇 |
1984年 | 52篇 |
1983年 | 45篇 |
1982年 | 46篇 |
1981年 | 46篇 |
1980年 | 48篇 |
1979年 | 45篇 |
1914年 | 45篇 |
1913年 | 40篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
LuJian-ke 《武汉大学学报:自然科学英文版》2004,9(1):1-5
The homogeneous quadratic Riemann boundary value problem (1) with Hoelder continuous coefficients for the normal case was considered by the author in 1997. But the solutions obtained there are incomplete. Here its general method of solution is obtained. 相似文献
2.
3.
4.
Static extracting method of software intended behavior based on API functions invoking 总被引:1,自引:0,他引:1
The method of extracting and describing the intended behavior of software precisely has become one of the key points in the fields of software behavior's dynamic and trusted authentication. In this paper, the author proposes a specified measure of extracting SIBDS (software intended behaviors describing sets) statically from the binary executable using the software's API functions invoking, and also introduces the definition of the structure used to store the SIBDS in detail. Experimental results demonstrate that the extracting method and the storage structure definition offers three strong properties: (i) it can describe the software's intended behavior accurately; (ii) it demands a small storage expense; (iii) it provides strong capability to defend against mimicry attack. 相似文献
5.
6.
WANG Xibo ZHOU Benhai YU Gei LI Qian 《武汉大学学报:自然科学英文版》2007,12(5):946-950
μC/OS-Ⅱ is an open source real-time kernel adopting priority preemptive schedule strategy. Aiming at the problem of μC/OS-Ⅱ failing to support homology priority tasks scheduling, an approach for solution is proposed. The basic idea is adding round-robin scheduling strategy in its original scheduler in order to schedule homology priority tasks through time slice roundrobin. Implementation approach is given in detail. Firstly, the Task Control Block (TCB) is extended. And then, a new priority index table is created, in which each index pointer points to a set of homology priority tasks. Eventually, on the basis of reconstructing μC/OS-Ⅱ real-time kernel, task scheduling module is rewritten. Otherwise, schedulability of homology task supported by modified kernel had been analyzed, and deadline formula of created homology tasks is given. By theoretical analysis and experiment verification, the modified kernel can support homology priority tasks scheduling, meanwhile, it also remains preemptive property of original μC/OS-Ⅱ. 相似文献
7.
Christiane Albrecht 《Analytical and bioanalytical chemistry》2008,390(5):1223-1224
8.
9.
Chengzhi Qi Mingyang Wang Qihu Qian Jianjie Chen 《Moscow University Mechanics Bulletin》2008,63(5):113-121
The formation mechanisms for the structural hierarchy in geological media are discussed. It is shown that the formation of such a hierarchy is caused by certain external and internal circumstances. The first ones consist in the fact that, because of external actions, the Earth’s poles continuously execute the translational and rotational motions responsible for a regular structure of rock fracture and for the appearance of the scale factor √2. The second ones consist in the fact that, under the action of many random factors and because of external actions, during the formation of geological media there appear dissipative structures and, hence, some self-similar fractal structures are formed. 相似文献
10.
Howard Robinson 《Acta Analytica》2005,20(3):7-10
Nicholas Nathan tries to resist the current version of the causal argument for sense-data in two ways. First he suggests that,
on what he considers to be the correct re-construction of the argument, it equivocates on the sense of proximate cause. Second
he defends a form of disjunctivism, by claiming that there might be an extra mechanism involved in producing veridical hallucination,
that is not present in perception. I argue that Nathan’s reconstruction of the argument is not the appropriate one, and that,
properly interpreted, the argument does not equivocate on proximate cause. Furthermore, I claim that his postulation of a
modified mechanism for hallucinations is implausibly ad hoc. 相似文献