全文获取类型
收费全文 | 78391篇 |
免费 | 349篇 |
国内免费 | 377篇 |
专业分类
化学 | 24566篇 |
晶体学 | 789篇 |
力学 | 6724篇 |
数学 | 31963篇 |
物理学 | 15075篇 |
出版年
2018年 | 10432篇 |
2017年 | 10262篇 |
2016年 | 6073篇 |
2015年 | 858篇 |
2014年 | 300篇 |
2013年 | 329篇 |
2012年 | 3809篇 |
2011年 | 10545篇 |
2010年 | 5643篇 |
2009年 | 6042篇 |
2008年 | 6611篇 |
2007年 | 8807篇 |
2006年 | 265篇 |
2005年 | 1351篇 |
2004年 | 1553篇 |
2003年 | 1988篇 |
2002年 | 1025篇 |
2001年 | 248篇 |
2000年 | 287篇 |
1999年 | 154篇 |
1998年 | 197篇 |
1997年 | 145篇 |
1996年 | 200篇 |
1995年 | 115篇 |
1994年 | 77篇 |
1993年 | 95篇 |
1992年 | 53篇 |
1991年 | 65篇 |
1990年 | 51篇 |
1989年 | 58篇 |
1988年 | 58篇 |
1987年 | 58篇 |
1986年 | 57篇 |
1985年 | 51篇 |
1984年 | 48篇 |
1983年 | 36篇 |
1982年 | 43篇 |
1981年 | 45篇 |
1980年 | 51篇 |
1979年 | 51篇 |
1978年 | 35篇 |
1973年 | 26篇 |
1919年 | 24篇 |
1914年 | 45篇 |
1913年 | 40篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
1907年 | 32篇 |
1904年 | 30篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Alison L. Parry 《Journal of polymer science. Part A, Polymer chemistry》2007,45(15):3178-3190
The ring‐opening metathesis polymerizations (ROMP), using RuCl2 (PCy3)2CHPh, of a series of peptide‐functionalized norbornene derivatives have been investigated. Incorporation of a PEG‐monomer was found to prevent premature precipitation of polymer strands during the course of polymerization reactions and yield water compatible polymers in high conversions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3178–3190, 2007 相似文献
5.
Christiane Albrecht 《Analytical and bioanalytical chemistry》2008,390(5):1223-1224
6.
7.
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
8.
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
9.
Rachel L. McSwain Alison R. Markowitz Kenneth R. Shull 《Journal of Polymer Science.Polymer Physics》2004,42(20):3809-3821
To develop a greater understanding of interfacial interactions between a semicrystalline polymer and a glassy polymer, adhesion tests were performed on very thin layers of poly(ethylene oxide) (PEO) sandwiched between two layers of poly(tetramethyl bisphenol A polycarbonate) (TMPC). The tests were designed to provide intimate contact between the surfaces while they were heated above the melting point of the PEO and cooled back to room temperature. A contact mechanics approach, based on the Johnson, Kendall, and Roberts theory, was used to determine values of the energy release rate describing the energetic driving force for crack propagation within the interfacial region. The ability to measure crack propagation at large values of the energy release rate was limited by rupture of the silicone elastomer that was used to provide a sufficiently compliant matrix for the adhesion experiment. By cycling the tensile stress at relatively low loading levels, we were able to measure fatigue crack propagation at values of the energy release rate that did not result in failure of the elastomer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3809–3821, 2004 相似文献
10.