全文获取类型
收费全文 | 881篇 |
免费 | 19篇 |
国内免费 | 2篇 |
专业分类
系统科学 | 33篇 |
理论与方法论 | 17篇 |
现状及发展 | 516篇 |
研究方法 | 53篇 |
综合类 | 220篇 |
自然研究 | 63篇 |
出版年
2020年 | 12篇 |
2019年 | 8篇 |
2018年 | 23篇 |
2017年 | 23篇 |
2016年 | 30篇 |
2015年 | 29篇 |
2014年 | 19篇 |
2013年 | 23篇 |
2012年 | 36篇 |
2011年 | 67篇 |
2010年 | 24篇 |
2009年 | 7篇 |
2008年 | 26篇 |
2007年 | 28篇 |
2006年 | 28篇 |
2005年 | 24篇 |
2004年 | 25篇 |
2003年 | 28篇 |
2002年 | 23篇 |
2001年 | 11篇 |
2000年 | 12篇 |
1999年 | 11篇 |
1993年 | 9篇 |
1992年 | 12篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1979年 | 21篇 |
1978年 | 16篇 |
1977年 | 16篇 |
1976年 | 19篇 |
1975年 | 8篇 |
1974年 | 12篇 |
1973年 | 20篇 |
1972年 | 10篇 |
1971年 | 12篇 |
1970年 | 21篇 |
1969年 | 20篇 |
1968年 | 20篇 |
1967年 | 14篇 |
1966年 | 12篇 |
1965年 | 8篇 |
1964年 | 10篇 |
1963年 | 7篇 |
1962年 | 7篇 |
1961年 | 8篇 |
1959年 | 5篇 |
排序方式: 共有902条查询结果,搜索用时 15 毫秒
51.
Khan ZU Martín-Montañez E Baxter MG 《Cellular and molecular life sciences : CMLS》2011,68(10):1737-1754
Visual perception and memory are the most important components of vision processing in the brain. It was thought that the
perceptual aspect of a visual stimulus occurs in visual cortical areas and that this serves as the substrate for the formation
of visual memory in a distinct part of the brain called the medial temporal lobe. However, current evidence indicates that
there is no functional separation of areas. Entire visual cortical pathways and connecting medial temporal lobe are important
for both perception and visual memory. Though some aspects of this view are debated, evidence from both sides will be explored
here. In this review, we will discuss the anatomical and functional architecture of the entire system and the implications
of these structures in visual perception and memory. 相似文献
52.
Rodríguez-Muñoz M Sánchez-Blázquez P Vicente-Sánchez A Bailón C Martín-Aznar B Garzón J 《Cellular and molecular life sciences : CMLS》2011,68(17):2933-2949
A series of pharmacological and physiological studies have demonstrated the functional cross-regulation between MOR and NMDAR.
These receptors coexist at postsynaptic sites in midbrain periaqueductal grey (PAG) neurons, an area implicated in the analgesic
effects of opioids like morphine. In this study, we found that the MOR-associated histidine triad nucleotide-binding protein
1 (HINT1) is essential for maintaining the connection between the NMDAR and MOR. Morphine-induced analgesic tolerance is prevented
and even rescued by inhibiting PKC or by antagonizing NMDAR. However, in the absence of HINT1, the MOR becomes supersensitive
to morphine before suffering a profound and lasting desensitization that is refractory to PKC inhibition or NMDAR antagonism.
Thus, HINT1 emerges as a key protein that is critical for sustaining NMDAR-mediated regulation of MOR signaling strength.
Thus, HINT1 deficiency may contribute to opioid-intractable pain syndromes by causing long-term MOR desensitization via mechanisms
independent of NMDAR. 相似文献
53.
Lopez-Castejón G Baroja-Mazo A Pelegrín P 《Cellular and molecular life sciences : CMLS》2011,68(18):3095-3107
Plasticity is a well-known property of macrophages that is controlled by different changes in environmental signals. Macrophage
polarization is regarded as a spectrum of activation phenotypes adjusted from one activation extreme, the classic (M1), to
the other, the alternative (M2) activation. Here we show, in vitro and in vivo, that both M1 and M2 macrophage phenotypes
are tightly coupled to specific patterns of gene expression. Novel M2-associated markers were characterized and identified
as genes controlling the extracellular metabolism of ATP to generate pyrophosphates (PPi). Stimulation of M1 macrophages with
PPi dampens both NLR and TLR signaling and thus mediates cytokine production. In this context extracellular PPi enhanced the
resolution phase of a murine peritonitis model via a decrease in pro-inflammatory cytokine production. Therefore, our study
reveals an additional level of plasticity modulating the resolution of inflammation. 相似文献
54.
Two experiments are reported which investigate the factors that influence how persuaded mathematicians are by visual arguments. We demonstrate that if a visual argument is accompanied by a passage of text which describes the image, both research-active mathematicians and successful undergraduate mathematics students perceive it to be significantly more persuasive than if no text is given. We suggest that mathematicians’ epistemological concerns about supporting a claim using visual images are less prominent when the image is described in words. Finally we suggest that empirical studies can make a useful contribution to our understanding of mathematical practice. 相似文献
55.
56.
57.
L Feliubadaló M Font J Purroy F Rousaud X Estivill V Nunes E Golomb M Centola I Aksentijevich Y Kreiss B Goldman M Pras D L Kastner E Pras P Gasparini L Bisceglia E Beccia M Gallucci L de Sanctis A Ponzone G F Rizzoni L Zelante M T Bassi A L George M Manzoni A De Grandi M Riboni J K Endsley A Ballabio G Borsani N Reig E Fernández R Estévez M Pineda D Torrents M Camps J Lloberas A Zorzano M Palacín 《Nature genetics》1999,23(1):52-57
58.
L. A. García-Alonso 《Cellular and molecular life sciences : CMLS》1999,55(11):1386-1398
The peripheral sensory system of the Drosophila adult has been used for the genetic analysis of axon guidance because of its accessibility for experimental manipulation
and mutant screens. Wing, leg, antenna, or eye sensory axons are able to pathfind normally under different perturbations,
indicating that sensory axon guidance is a highly canalized process. Similarly to other model systems, sensory growth cones
seem to use multiple, simultaneous cues for guidance. In addition, sensory axons from peripheral structures seem to be capable
of using alternative substrates for pathfinding. Developmental regulation could account for the high stability of axon guidance
under experimental and natural perturbation conditions. Despite this flexibility, functional characterization of genes involved
in sensory axon guidance is being carried out in situations where there appears to be less system redundancy. 相似文献
59.
60.