全文获取类型
收费全文 | 78104篇 |
免费 | 332篇 |
国内免费 | 375篇 |
专业分类
化学 | 24281篇 |
晶体学 | 790篇 |
力学 | 6725篇 |
数学 | 31944篇 |
物理学 | 15071篇 |
出版年
2018年 | 10434篇 |
2017年 | 10261篇 |
2016年 | 6061篇 |
2015年 | 840篇 |
2014年 | 289篇 |
2013年 | 319篇 |
2012年 | 3784篇 |
2011年 | 10494篇 |
2010年 | 5637篇 |
2009年 | 6038篇 |
2008年 | 6592篇 |
2007年 | 8764篇 |
2006年 | 238篇 |
2005年 | 1315篇 |
2004年 | 1539篇 |
2003年 | 1975篇 |
2002年 | 1014篇 |
2001年 | 248篇 |
2000年 | 294篇 |
1999年 | 153篇 |
1998年 | 190篇 |
1997年 | 145篇 |
1996年 | 199篇 |
1995年 | 118篇 |
1994年 | 76篇 |
1993年 | 95篇 |
1992年 | 56篇 |
1991年 | 70篇 |
1990年 | 54篇 |
1989年 | 65篇 |
1988年 | 63篇 |
1987年 | 58篇 |
1986年 | 58篇 |
1985年 | 51篇 |
1984年 | 44篇 |
1983年 | 40篇 |
1982年 | 42篇 |
1981年 | 38篇 |
1980年 | 48篇 |
1979年 | 49篇 |
1978年 | 37篇 |
1973年 | 25篇 |
1914年 | 45篇 |
1913年 | 40篇 |
1912年 | 40篇 |
1910年 | 24篇 |
1909年 | 41篇 |
1908年 | 40篇 |
1907年 | 32篇 |
1904年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 42 毫秒
1.
2.
3.
4.
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
5.
Fukuji Higashi Kaori Kira 《Journal of polymer science. Part A, Polymer chemistry》2004,42(11):2725-2733
The solution polyesterification of dicarboxylic acids in pyridine, the activated intermediates of which were difficult to dissolve in tosyl chloride/dimethylformamide/pyridine, was investigated in the presence of lithium chloride. The solubility of the activated dicarboxylic acids was largely improved by the presence of the salt, and the polycondensation with bisphenols was greatly facilitated. The salt was more effectively added to a pyridine solution of dicarboxylic acids than to the activated dicarboxylic acids in pyridine. The favorable additive effect on the improved solubility was attributed to a lowered degree of association of the activated dicarboxylic acids, which led to distributions of the resulting oligomers from bisphenols at an earlier stage closer to the theoretical ones and yielded better polycondensation results. The reaction, which proceeded through favorable distributions of the co‐oligomers, produced copolymers of higher inherent viscosities and slightly block sequence distributions determined by NMR. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2725–2733, 2004 相似文献
6.
7.
8.
9.
James Tanton 《Mathematical Intelligencer》2007,29(3):55-59
This column is a place for those bits of contagious mathematics that travel from person to person in the community, because
they are so elegant, suprising, or appealing that one has an urge to pass them on.
Contributions are most welcome. 相似文献
10.