首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   73篇
  免费   3篇
  国内免费   12篇
  88篇
  2022年   2篇
  2020年   2篇
  2016年   1篇
  2015年   5篇
  2014年   6篇
  2013年   3篇
  2012年   1篇
  2011年   17篇
  2010年   4篇
  2009年   2篇
  2008年   2篇
  2007年   1篇
  2005年   5篇
  2004年   4篇
  2003年   4篇
  2002年   1篇
  2001年   3篇
  2000年   3篇
  1999年   1篇
  1998年   1篇
  1997年   9篇
  1996年   2篇
  1995年   1篇
  1993年   4篇
  1992年   1篇
  1991年   1篇
  1989年   1篇
  1985年   1篇
排序方式: 共有88条查询结果,搜索用时 0 毫秒
61.
柑橘黑斑病是柑橘的重要病害之一。本文通过病原菌的形态特征和致病性,并结合其rDNA-ITS区域序列及柯赫法则,对从福建省福州市闽侯县福橘果上分离的黑斑病病原菌进行了鉴定分析。结果表明:PDA平板上的病原菌菌落生长缓慢,呈圆形凸起;分生孢子器近球形、黑色炭质;分生孢子单孢、无色,呈椭圆形,大小为(7~12)μm×(5~8)μm,分生孢子外包裹一层半透明凝胶状物质。结合序列比对分析结果,最终将分离的福橘果实黑斑病的病原菌鉴定为柑橘球座菌Guig-nardia citricarpa Kiely。本研究为柑橘黑斑病的早期诊断和防治奠定了基础。  相似文献   
62.
蕲蛇酶抗栓作用机理的初步分析   总被引:20,自引:6,他引:14  
王晴川  刘广芬 《蛇志》1997,9(3):9-11
动物实验结果示,蕲蛇酶能裂解纤维蛋白原成为可溶性纤维蛋白,降低血中纤维蛋白原浓度,抑制血小板聚集,对抗在酶诱导的血浆凝块订的血浆凝块回缩,因而发挥防血栓形成作用。对纤维蛋白平板试验无直接溶纤作用,但能增加实验动物血中t-PA活性。可能通过促使血管内皮细胞释放t-PA而发挥溶栓作用。  相似文献   
63.
The exact effect of glycine pre‐treatment on brain ischemic tolerance (IT) remains quite controversial. The objective of this study was to investigate the potential effects of glycine on IT. We used rat models of both in vitro ischemia (oxygen and glucose deprivation) and in vivo ischemia (transient middle cerebral artery occlusion). Low doses of glycine (L‐Gly) significantly decreased hippocampal ischemic LTP (i‐LTP), infarct volume, and neurological deficit scores which were administered before ischemia was induced in rats, whereas high doses of glycine exerted deteriorative effects under the same condition. These findings suggested that exogenous glycine may induce IT in a dose‐dependent manner. Furthermore, L‐Gly‐dependent neuronal protection was inversed by L689, a selective NMDAR glycine site antagonist both in vitro (abolished i‐LTP depression) and in vivo (increased infarct size reduction), but not glycine receptor (GlyR) inhibitor strychnine. Importantly, L‐Gly‐induced IT was achieved by NR2A‐dependent cAMP‐response element binding protein phosphorylation. These data imply that glycine pre‐treatment may represent a novel strategy for inducing IT based on synaptic NMDAR‐dependent neuronal transmission.

  相似文献   

64.
本实验应用离体温育大鼠垂体前叶组织块结合电场刺激及放射免疫测定方法,观察了垂体前叶内的神经纤维兴奋对促肾上腺皮质激素(ACTH)分泌的影响以及其它因素的作用。结果表明,一定参数的电场刺激使温育的大鼠四分之一垂体前叶组织块ACTH分泌增加,能被河豚毒素(TTX)和藜芦碱部分阻断,此效应也可被地塞米松显著抑制,而同一参数的电场刺激与促肾上腺皮质激素释放激素(CRH)诱发的ACTH分泌没有相互作用。经典神经递质受体阻断剂阿托品、心得安、酚妥拉明对电场刺激诱发的ACTH分泌没有显著影响;GAEA_A受体拮抗剂荷包牡丹碱明显促进此效应。该作用不受P物质拮抗剂spantide的影响,而降钙素基因相关肽(CGRP)受体拮抗剂CGRP片段8-37能部分阻断这一作用。上述结果提示电场刺激所诱发的ACTH分泌可能部分由垂体前叶内CGRP能神经纤维介导。  相似文献   
65.
在对福建顺昌半山石灰岩矿区I号地层剖面中的类化石进行系统鉴定和描述的基础上,根据类化石在地层中的分布和垂向变化规律,自下而上划分为5个带:1)Triticites shikhanensis compactus带,2)Pseudoschwa-gerina galatea带,3)Sphaeroschwagerina sphaerica带,4)Eoparafusulina concisa带和5)Staffella moellerana带。通过与华南沉积区同期类生物地层的对比认为,本区类生物地层应归属于晚石炭世的小独山阶和早二叠世的紫松阶和隆林阶。  相似文献   
66.
雌激素受体α在大鼠垂体的表达及其调控的初步探讨   总被引:4,自引:0,他引:4  
目的:观察雌激素受体α(ERα)免疫反应阳性细胞在大鼠垂体的分布,并初步探讨其空因素。方法:应用免疫组织化学和原代细胞培养方法结合图像分析。结果:①正常大鼠垂体前叶和后 有丰富的ERα阳必细胞,ERα在出生3d即有表达,一月龄大鼠已达到成年大鼠水平;②卵巢毁除大鼠ERα表达减少,补充雌激素后其表达有所增高,但仍末达到正常水平;③动情期大鼠垂体前叶ERα表达最高,动情后期逐渐减少,动情间期达最低值;  相似文献   
67.

Background

High mobility group box 1 (HMGB1) plays important roles in a large variety of diseases; glycyrrhizin (GL) is recognized as an HMGB1 inhibitor. However, few studies have focused on whether glycyrrhizin can potentially improve the outcome of traumatic pancreatitis (TP) by inhibiting HMGB1.

Methods

A total of 60 male Wistar rats were randomly divided into three groups (n = 20 in each): Control group, TP group and TP-GL group. Pancreatic trauma was established with a custom-made biological impact machine-III, and GL was administered at 15 minutes after the accomplishment of operation. To determine survival rates during the first 7 days after injury, another 60 rats (n = 20 in each) were grouped and treated as mentioned above. At 24 hours of induction of TP, the histopathological changes in pancreas were evaluated and serum amylase levels were tested. Serum tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and HMGB1 were measured using enzyme linked immunosorbent assay. HMGB1 expressions in pancreas were measured using immunohistochemical staining, Western blot and Real-Time PCR analysis.

Results

Serum levels of HMGB1, TNF-α and IL-6 were increased dramatically in TP group at 24 hours after induction of TP. However, these indicators were reduced significantly by GL administration in TP-GL group comparing with TP group (P<0.05). Meanwhile, survival analysis showed that the seven-day survival rate in TP-GL group was significantly higher than that in TP group (85% versus 65%, P<0.05). GL treatment significantly decreased the pancreatic protein and mRNA expressions of HMGB1 and ameliorated the pancreatic injury in rats with TP.

Conclusions

Glycyrrhizin might play an important role in improving survival rates and ameliorating pancreatic injury of TP by suppression of the expressions of HMGB1 and other proinflammatory cytokine.  相似文献   
68.
Glutathione peroxidase 2 (GPX2) participates in many cancers including pancreatic cancer (PC), and overexpression of GPX2 promotes tumor growth. Herein, we identified the role of GPX2 in epithelial–mesenchymal transformation (EMT), invasion, and metastasis in PC. Bioinformatics prediction was applied to select PC-related genes. The regulatory function of GPX2 in PC was explored by treatment with short hairpin RNA against GPX2 or LiCl (activator of wingless-type MMTV integration site [Wnt] pathway) in PC cells. GPX2 level in PC tissues, the levels of GPX2, β-catenin, Vimentin, Snail, epithelial-cadherin (E-cadherin), matrix metalloproteinase 2 (MMP2), MMP9, and Wnt2 in cells were determined. Subsequently, cell proliferation, invasion, and metastasis were assayed. Bioinformatics analysis revealed that GPX2 was involved in PC development mediated by the Wnt pathway. GPX2 was highly expressed in PC tissues. GPX2 silencing downregulated levels of β-catenin, Vimentin, Snail, MMP2, MMP9, and Wnt2 but upregulated levels of E-cadherin. It was confirmed that GPX2 silencing suppressed PC cell proliferation, metastasis, and invasion. Furthermore, the trend of EMT and invasion and metastasis of PC induced by the LiCl-activated Wnt pathway was reversed when the GPX2 was silenced. GPX2 silencing could inhibit the Wnt pathway, subsequently suppress PC development.  相似文献   
69.
莲草直胸跳甲是恶性入侵杂草喜旱莲子草的有效天敌。为探明莲草直胸跳甲成虫繁育的适宜温度条件和卵的低温冷藏适期,本文研究了莲草直胸跳甲成虫在25、27、30、32、35℃下的存活、取食和产卵特性及卵在15℃下冷藏不同时期的孵化率。结果表明:在25~35℃,莲草直胸跳甲成虫的生存曲线差异显著;随着温度的升高,雌雄成虫寿命呈缩短趋势,表现为25℃>32℃>35℃;但27和30℃的生存曲线与25和32℃差异均不显著。温度对莲草直胸跳甲成虫的取食量和产卵量均有显著影响,在25~35℃,随着温度的升高,跳甲的取食量和产卵量呈下降趋势;成虫期取食量、日均产卵量和世代产卵量表现为25℃>27℃、30℃>32℃>35℃;成虫期取食量和世代产卵量呈显著正相关,相关系数为0.960。将莲草直胸跳甲卵在15℃下冷藏1~10d后转移至25℃,其孵化率均可达100%,但孵化进度则有差异,孵化高峰期随着冷藏时间的延长而提前。与未经冷藏的卵(对照)相比,在15℃下冷藏1d,莲草直胸跳甲卵的始孵化日提前1d,但高峰期不变,均在第5天;在15℃下冷藏4、7和10d后,其孵化高峰期分别较对照提前1、2和3d。可见,在25~35℃时,25℃是莲草直胸...  相似文献   
70.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号