全文获取类型
收费全文 | 473篇 |
免费 | 31篇 |
国内免费 | 7篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 19篇 |
2020年 | 8篇 |
2019年 | 11篇 |
2018年 | 8篇 |
2017年 | 10篇 |
2016年 | 19篇 |
2015年 | 21篇 |
2014年 | 27篇 |
2013年 | 33篇 |
2012年 | 35篇 |
2011年 | 28篇 |
2010年 | 23篇 |
2009年 | 19篇 |
2008年 | 19篇 |
2007年 | 23篇 |
2006年 | 23篇 |
2005年 | 18篇 |
2004年 | 18篇 |
2003年 | 16篇 |
2002年 | 23篇 |
2001年 | 15篇 |
2000年 | 11篇 |
1999年 | 7篇 |
1998年 | 12篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1985年 | 2篇 |
1984年 | 6篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有511条查询结果,搜索用时 15 毫秒
31.
Mominul Islam Nahid Frode Fossøy Bård G. Stokke Sajeda Begum Eivin Røskaft 《Bird Study》2019,66(1):141-144
House Crows Corvus splendens lay eggs with bluish-green ground colour and black or brown blotches and only one egg morph was believed to exist. Here, we confirm the existence of an immaculate, spotless blue egg morph that is clearly different from the regular egg morph. 相似文献
32.
Methyl parathion induced alterations in the level of monoamines, viz. norepinephrine, dopamine and serotonin were studied in discrete regions of developing central nervous system of rat pups. A significant decrease in the level of monoamines noticed in methyl parathion toxicosis may be related to the altered neuronal activity and inefficiency, leading to depression and impairment in various behavioural activities. In contrast to AChE inhibition, monoamine oxidase (MAO) activity showed an increasing trend and it could cause deamination of catecholamines and accumulation of its metabolites. This suggests that an increased AChE inhibition may indirectly stimulate MAO activity in developing rat pups exposed to methyl parathion. 相似文献
33.
Moriwaki Y Begum NA Kobayashi M Matsumoto M Toyoshima K Seya T 《The Journal of biological chemistry》2001,276(25):23065-23076
34.
Satow T Ikeda A Yamamoto J Begum T Thuy DH Matsuhashi M Mima T Nagamine T Baba K Mihara T Inoue Y Miyamoto S Hashimoto N Shibasaki H 《American journal of physiology. Gastrointestinal and liver physiology》2004,287(2):G459-G470
We investigated the role of the cerebral cortex, particularly the face/tongue area of the primary sensorimotor (SMI) cortex (face/tongue) and supplementary motor area (SMA), in volitional swallowing by recording movement-related cortical potentials (MRCPs). MRCPs with swallowing and tongue protrusion were recorded from scalp electrodes in eight normal right-handed subjects and from implanted subdural electrodes in six epilepsy patients. The experiment by scalp EEG in normal subjects revealed that premovement Bereitschaftspotentials (BP) activity for swallowing was largest at the vertex and lateralized to either hemisphere in the central area. The experiment by epicortical EEG in patients confirmed that face/tongue SMI and SMA were commonly involved in swallowing and tongue protrusion with overlapping distribution and interindividual variability. BP amplitude showed no difference between swallowing and tongue movements, either at face/tongue SMI or at SMA, whereas postmovement potential (PMP) was significantly larger in tongue protrusion than in swallowing only at face/tongue SMI. BP occurred earlier in swallowing than in tongue protrusion. Comparison between face/tongue SMI and SMA did not show any difference with regard to BP and PMP amplitude or BP onset time in either task. The preparatory role of the cerebral cortex in swallowing was similar to that in tongue movement, except for earlier activation in swallowing. Postmovement processing of swallowing was lesser than that of tongue movement in face/tongue SMI; probably suggesting that the cerebral cortex does not play a significant role in postmovement processing of swallowing. SMA plays a supplementary role to face/tongue SMI both in swallowing and tongue movements. 相似文献
35.
36.
Insulin inhibits PDGF-directed VSMC migration via NO/ cGMP increase of MKP-1 and its inactivation of MAPKs 总被引:9,自引:0,他引:9
Jacob A Molkentin JD Smolenski A Lohmann SM Begum N 《American journal of physiology. Cell physiology》2002,283(3):C704-C713
In this study, we examined the roleof insulin in the control of vascular smooth muscle cell (VSMC)migration in the normal vasculature. Platelet-derived growth factor(PDGF) increased VSMC migration, which was inhibited by pretreatmentwith insulin in a dose-dependent manner. Insulin also caused a 60%decrease in PDGF-stimulated mitogen-activated protein kinase (MAPK)phosphorylation and activation. Insulin inhibition of MAPK wasaccompanied by a rapid induction of MAPK phosphatase (MKP-1), whichinactivates MAPKs by dephosphorylation. Pretreatment with inhibitors ofthe nitric oxide (NO)/cGMP pathway, blocked insulin-induced MKP-1 expression and restored PDGF-stimulated MAPK activation and migration. In contrast, adenoviral infection of VSMCs with MKP-1 or cGMP-dependent protein kinase I (cGK I), the downstream effector of cGMPsignaling, blocked the activation of MAPK and prevented PDGF-directedVSMC migration. Expression of antisense MKP-1 RNA prevented insulin's inhibitory effect and restored PDGF-directed VSMC migration and MAPKphosphorylation. We conclude that insulin inhibition of VSMC migrationmay be mediated in part by NO/cGMP/cGK I induction of MKP-1 andconsequent inactivation of MAPKs. 相似文献
37.
Begum P Hashidoko Y Islam MT Ogawa Y Tahara S 《Zeitschrift für Naturforschung. C, Journal of biosciences》2002,57(9-10):874-882
The EtOAc soluble constituents of the unripe fruits of Ginkgo biloba showed motility inhibition followed by lysis of zoospores of the phytopathogenic Aphanomyces cochlioides. We purified 22:1-omega7-anacardic acid (1), 24:1-omega9-anacardic acid (2) and 22:0-anacardic acid (3), together with other related compounds, 21:1-omega7-cardol (4) and 21:1-omega7-cardanol (5) from the crude extracts of Ginkgo fruits. Amongst them, compound 1 was a major active agent in quality and quantity, and showed potent motility inhibition (98% in 30 min) followed by lysis (55% in 3 h) of the zoospores at 1 x 10(-7) M. The 2-O-methyl derivative (1-c) of 1 displayed antibacterial activity against Bacillus subtilis, but practically inactive to Escherichia coli. A brief study on structure-activity relationships revealed that a carboxyl group on the aromatic ring and an unsaturated side chain in the anacardic acid derivative are important for strong motility inhibitory and lytic activities against the zoospore. 相似文献
38.
WEI MIN NI XIAO YA CHEN ZHI HONG XU HONG WEI XUE. * National Laboratory of Plant Molecular Genetics Institute of Plant Physiology Ecology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Partner Group of Max-Pla 《Cell research》2002,(Z1)
Polar auxin transport plays a divergent role in plant growth and developmental processes including root and embryo development, vascular pattern formation and cell elongation. Recently isolated Arabidopsis pin gene family was believed to encode a component of auxin efflux carrier (G(?)lweiler et al, 1998). Based on the Arabidopsis pin1 sequence we have isolated a Brassica juncea cDNA (designated Bjpin1), which encoded a 70-kDa putative auxin efflux carrier. Deduced BjPIN1 shared 65% identities at protein level with AtPINl and was highly homologous to other putative PIN proteins of Arabidopsis (with highest homology to AtPIN3). Hydrophobic analysis showed similar structures between BjPINl and AtPIN proteins. Presence of 6 exons (varying in size between 65 bp and 1229 bp) and 5 introns (sizes between 89 bp and 463 bp) in the genomic fragment was revealed by comparing the genomic and cDNA sequences. Northern blot analysis indicated that Bjpin1 was expressed in most of the tissues tested, with a relatively h 相似文献
39.
Two new acyl sucroses were isolated from the epigeal parts of Petunia nyctaginiflora Juss. (Solanaceae). Their structures were determined to be 2, 3, 4-tri (5-methylhexanoyl)-alpha-D-glucopyranosyl-beta-D-fructofuranoside (2) and 2, 3, 4-tri (6-methylheptanoyl)-alpha-D-glucopyranosyl-beta-D-fructofuranoside (4) on the basis of chemical and spectroscopic evidence. 相似文献