全文获取类型
收费全文 | 68篇 |
免费 | 5篇 |
专业分类
73篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2006年 | 6篇 |
2005年 | 7篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有73条查询结果,搜索用时 15 毫秒
1.
Springer MS Meredith RW Janecka JE Murphy WJ 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2011,366(1577):2478-2502
Palaeobiogeographic reconstructions are underpinned by phylogenies, divergence times and ancestral area reconstructions, which together yield ancestral area chronograms that provide a basis for proposing and testing hypotheses of dispersal and vicariance. Methods for area coding include multi-state coding with a single character, binary coding with multiple characters and string coding. Ancestral reconstruction methods are divided into parsimony versus Bayesian/likelihood approaches. We compared nine methods for reconstructing ancestral areas for placental mammals. Ambiguous reconstructions were a problem for all methods. Important differences resulted from coding areas based on the geographical ranges of extant species versus the geographical provenance of the oldest fossil for each lineage. Africa and South America were reconstructed as the ancestral areas for Afrotheria and Xenarthra, respectively. Most methods reconstructed Eurasia as the ancestral area for Boreoeutheria, Euarchontoglires and Laurasiatheria. The coincidence of molecular dates for the separation of Afrotheria and Xenarthra at approximately 100 Ma with the plate tectonic sundering of Africa and South America hints at the importance of vicariance in the early history of Placentalia. Dispersal has also been important including the origins of Madagascar's endemic mammal fauna. Further studies will benefit from increased taxon sampling and the application of new ancestral area reconstruction methods. 相似文献
2.
Matrix metalloproteinases (MMPs) and urokinase plasminogen activator (uPA) regulate proteolysis of the extracellular matrix (ECM) and as a consequence are involved in a number of physiological and pathological states, including cancer. A crucial feature of cancer progression and metastasis is the disruption of the ECM and spreading of proliferating cancer cells. Over-expression of MMPs and uPA is common for most types of cancers and correlates well with the adverse prognosis. Compounds able to modulate the activity of these proteolytic enzymes may become important agents in cancer therapy. In the present study, we examined the effect of the ??-opioid receptor selective peptide, morphiceptin, and its two synthetic analogs on mRNA and protein levels of MMP-9 and uPA in three human cancer cell lines: MCF-7, HT-29, and SHSY5Y. Our findings indicate that in all three cell lines morphiceptin and its analogs attenuated MMP-9 expression and secretion and that this effect is not mediated by opioid receptors but is under control of the nitric oxide system. On the other hand, tested opioids up-regulated uPA levels through a mechanism that involved opioid-receptors. Different pathways by which opioid peptides exert their action in cancer cells can explain their contradictory influence on the level of cancer markers. 相似文献
3.
Anna Adamska‐Bartłomiejczyk Attila Borics Csaba Tömböly Szabolcs Dvorácskó Marek Lisowski Alicja Kluczyk Grzegorz Wołczański Justyna Piekielna‐Ciesielska Anna Janecka 《Journal of peptide science》2017,23(12):864-870
Three novel morphiceptin analogs, in which Pro in position 2 and/or 4 was replaced by cis‐4‐aminoproline connected with the preceding amino acid through the primary amino group, were synthesized. The opioid receptor affinities, functional assay results, enzymatic degradation studies and experimental and in silico structural analysis of such analogs are presented. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
4.
Katarzyna Gach Janusz Szemraj Anna Wyrębska Anna Janecka 《Molecular biology reports》2011,38(2):1231-1236
Matrix metalloproteinases (MMPs) are proteolytic enzymes involved in degradation of extracellular matrix, a process that initiates
uncontrolled spread of proliferating cancer cells and therefore plays a crucial role in cancer invasion and metastasis. Compounds
able to modulate MMP activity may become important tools in cancer research. In the present study we examined the effect of
two μ-selective opioids, morphine and endomorphin-2 (EM-2) on the production of MMP-2 and MMP-9 in MCF-7 cells. We report
that both opioids time- and concentration-dependently inhibited the expression and secretion of these MMPs. The observed effect
was not reversed by naloxone (Nal). Further experiments showed that morphine and EM-2 decreased endothelial nitric oxide synthase
(eNOS) mRNA level and nitric oxide (NO) secretion in MCF-7 cells. These findings indicate that attenuation of MMP secretion
by opioids was not mediated by opioid receptors but was under the control of nitric oxide system. 相似文献
5.
Nociceptin receptor (NOP) belongs to the family of opioid receptors but was discovered and characterized much later than the so called classical opioid receptors, μ, δ and κ (or MOP, DOP and KOP, resp.). Nociceptin/orphanin FQ (N/OFQ) is the endogenous ligand of this receptor and it controls numerous important functions in the central nervous system and in the periphery, so its analogs may be developed as innovative drugs for the treatment of a variety of conditions and pathological states. Availability of potent and selective ligands with high affinity to NOP receptor is essential to fully understand the role of NOP-N/OFQ system in the body, which in turn may lead to designing novel therapeutics. Here, we have focused on reviewing the structure of potent peptide-based agonists, antagonists, biased analogs and bivalent ligands that target NOP receptor. 相似文献
6.
A series of 30 primary facial nerve tumors is reviewed. Most of them were benign (n = 26); there were four malignant tumors. Neoplasms originating within the temporal bone were found to have preoperative facial paralysis in 84 percent of cases; the extracranial tumors had a 35 percent incidence of preoperative facial paralysis. All tumors in this series were treated surgically--by means of a middle fossa or transmastoid approach for the intratemporal group of tumors; the extracranial tumors were removed by the technique of parotid tumor surgery with complete facial nerve dissection. All the patients with preoperative facial weakness required facial nerve transection. Facial paralysis was rehabilitated with nerve grafts, hypoglossal crossover, or muscle transfers. Because "normal" facial expression is still not attainable following repair of complete facial nerve transection, an early diagnosis, hopefully prior to total neurotmesis, is essential. All patients with unexplained facial weakness, especially that which is progressive and persistent, should have the entire course of the facial nerve investigated for the possibility of treatable etiology. 相似文献
7.
8.
Mark J. Statham James Murdoch Jan Janecka Keith B. Aubry Ceiridwen J. Edwards Carl D. Soulsbury Oliver Berry Zhenghuan Wang David Harrison Malcolm Pearch Louise Tomsett Judith Chupasko Benjamin N. Sacks 《Molecular ecology》2014,23(19):4813-4830
Widely distributed taxa provide an opportunity to compare biogeographic responses to climatic fluctuations on multiple continents and to investigate speciation. We conducted the most geographically and genomically comprehensive study to date of the red fox (Vulpes vulpes), the world's most widely distributed wild terrestrial carnivore. Analyses of 697 bp of mitochondrial sequence in ~1000 individuals suggested an ancient Middle Eastern origin for all extant red foxes and a 400 kya (SD = 139 kya) origin of the primary North American (Nearctic) clade. Demographic analyses indicated a major expansion in Eurasia during the last glaciation (~50 kya), coinciding with a previously described secondary transfer of a single matriline (Holarctic) to North America. In contrast, North American matrilines (including the transferred portion of Holarctic clade) exhibited no signatures of expansion until the end of the Pleistocene (~12 kya). Analyses of 11 autosomal loci from a subset of foxes supported the colonization time frame suggested by mtDNA (and the fossil record) but, in contrast, reflected no detectable secondary transfer, resulting in the most fundamental genomic division of red foxes at the Bering Strait. Endemic continental Y‐chromosome clades further supported this pattern. Thus, intercontinental genomic exchange was overall very limited, consistent with long‐term reproductive isolation since the initial colonization of North America. Based on continental divergence times in other carnivoran species pairs, our findings support a model of peripatric speciation and are consistent with the previous classification of the North American red fox as a distinct species, V. fulva. 相似文献
9.
Substance P (SP), vasoactive intestinal polypeptide (VIP) and galanin (GAL), present in primary sensory neurons, are involved in transmission of nociceptive signaling from the peripheral to central nervous system. In this study we investigated the effect of GAL on SP-induced or VIP-induced evoked tongue jerks (ETJ) in response to noxious tooth pulp stimulation during perfusion of the cerebral ventricles with SP or VIP solutions. The experiments were carried out on rats under chloralose anesthesia. It was shown that both, SP and VIP, perfused through the cerebral ventricles enhanced the ETJ amplitude as compared with control, but the effect produced by SP was stronger. The intracerebroventricular perfusion of GAL 5 minutes before SP caused a dose-dependent inhibition of SP-induced ETJ, whereas GAL perfused through the cerebral ventricles 5 minutes before VIP did not reduce the excitatory effect of VIP on ETJ. These results indicate that the antinociceptive effect of GAL perfused through the cerebral ventricles, tested on the trigemino-hypoglossal reflex in rats, is specifically mediated by the SP-ergic system. 相似文献
10.
Kruszynski R Fichna J do-Rego JC Janecki T Kosson P Pakulska W Costentin J Janecka A 《Bioorganic & medicinal chemistry》2005,13(24):6713-6717
In this paper, we describe the synthesis of a series of endomorphin-2 analogs containing N-methylated amino acids, consecutively in each position. The μ-opioid receptor binding affinities of the new analogs were determined in the displacement experiments. Their in vivo antinociceptive activity was assessed in the hot-plate test in mice after central (icv) and peripheral (ip) administration. [Sar2]endomorphin-2, which had the highest μ-receptor affinity, also showed the strongest analgesic effect when administered centrally and was the only analog that retained activity after peripheral injection. 相似文献