全文获取类型
收费全文 | 144篇 |
免费 | 3篇 |
国内免费 | 6篇 |
专业分类
林业 | 8篇 |
农学 | 7篇 |
基础科学 | 2篇 |
12篇 | |
综合类 | 18篇 |
农作物 | 2篇 |
水产渔业 | 5篇 |
畜牧兽医 | 7篇 |
园艺 | 92篇 |
出版年
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 6篇 |
2012年 | 12篇 |
2011年 | 11篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 7篇 |
2007年 | 15篇 |
2006年 | 15篇 |
2005年 | 13篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1998年 | 2篇 |
排序方式: 共有153条查询结果,搜索用时 312 毫秒
1.
CAI Chen-chen YE Li-xia ZHU Jiang-hu BAI Jun-jie ZENG Shan-shan CHEN Shang-qin LIN Zhen-lang 《园艺学报》2019,35(2):311-319
AIM:To investigate whether ellagic acid (EA) attenuates hypoxic-ischemic encephalopathy (HIE) by down-regulating autophagy. METHODS:In vivo, Sprague-Dawley rats (n=17) were randomly divided into 3 groups:5 rats for sham group, 6 rats for HIE group and 6 rats for HIE+EA pretreatment group. The rats in HIE+EA pretreatment group were treated with EA (10 mg/kg, 10 mL/kg, suspended in corn oil, ig). After 24 h of operation, the rats from each group were sacrificed and their brains were collected. TTC staining and HE staining were used to define the infarct areas and brain structure. The autophagy-related proteins beclin-1, P62, LC3-Ⅱ/-I and Atg5 in the cortex in each group were compared by Western blot. In vitro, PC12 cells were divided into 3 groups:control group, CoCl2 group and CoCl2+EA pretreatment group. CoCl2 at 800 μmol/L was added to the PC12 cells to induce an anoxic environment. The PC12 cells were pretreated with EA at 8 μmol/L and the cell viability was measured by CCK-8 assay. The production of reactive oxidative species (ROS) in the cells was detected by flow cytometry with DCFH-DA staining. MDC staining and TMRE staining were applied to reflect the extent of autophagy and the state of apoptosis, respectively. The autophagy-related proteins in PC12 cells were also investigated. RESULTS:In HIE group, 7-day-old rats were given the operations and the their large infarct areas in the hemisphere were observed by TTC staining. HE staining displayed the injured hemispheres which contained few neurons, and exhibited edema status and serious structural damage. EA pretreatment decreased the infarct area and alleviated the damage to hemisphere with more visible neurons, compared with HIE group. Compared with sham group, the levels of autophagy-related proteins Atg5, beclin-1 and LC3-Ⅱ/-I in the cortex were increased (P<0.01), and P62 protein expression was decreased (P<0.01) in HIE group. Compared with HIE group, the protein expression of Atg5, beclin-1 and LC3-Ⅱ/-I was decreased (P<0.01) and P62 protein expression was increased in HIE+EA pretreatment group (P<0.01). In vitro, compared with CoCl2 group, the PC12 cells in CoCl2+EA pretreatment group showed a lower ROS level. Moreover, the cells in CoCl2+EA pretreatment group exhibited higher mitochondrial membrane potential than that in CoCl2 group. MDC staining in CoCl2 group showed high value of fluorescence and increased number of autophagosomes. EA pretreatment reduced the number of autophagosomes and the extent of autophagy to protect PC12 cells. Furthermore, the protein levels of Atg5, beclin-1 and LC3-Ⅱ/-I in CoCl2 group were higher (P<0.01), and the protein expression of P62 was lower (P<0.01) than those in control group. In CoCl2+EA pretreatment group, the protein levels of Atg5, beclin-1 and LC3-Ⅱ/-I were decreased (P<0.01) and the protein expression of P62 was increased as compared with CoCl2 group (P<0.01). CONCLUSION:EA pretreatment attenuates autophagy to protect the neurons against HIE injury. 相似文献
2.
3.
4.
5.
CHEN Wei-qian PENG Yan-ping ZHANG Wei-xi YE Le-ping DONG Liang XIA Xiao-dong 《园艺学报》2017,33(8):1481-1486
AIM: To investigate the effect of hypercapnia on hypoxia-induced pulmonary hypertension and the changes of lysyl oxidase (LOX) and extracellular matrix collagen cross-links in the rat. METHODS: Sprague-Dawley rats were randomly divided into 4 groups:normoxia group, hypoxia group, hypercapnia group and hypoxia+hypercapnia group. LOX activity was detected by fluorescence spectrophotometry. LOX protein expression was detected by immunohistochemistry and Western blot. The mRNA expression of LOX in the pulmonary artery was detected by real-time PCR. RESULTS: The levels of mean pulmonary artery pressure (mPAP), RV/(LV+S) and WA/TA in hypoxia group were significantly higher than those in normoxia group (P<0.01). Moreover, the levels of mPAP and RV/(LV+S) in hypoxia+hypercapnia group were significantly lower than those in hypoxia group (P<0.01). However, no significant difference of mPAP and RV/(LV+S) between hypercapnia group and normoxia group was observed. In hypoxia group, the collagen cross-links in the lung tissue was significantly higher than that in normoxia group and hypercapnia group (P<0.01). Importantly, collagen cross-links in the lung tissue of hypoxia+hypercapnia group was significantly lower than that in hypoxia group (P<0.01). There was no significant difference in collagen cross-links between hypercapnia group and normoxia group. The expression of LOX at mRNA and protein levels and its activity in the pulmonary arteries of hypoxia group were significantly increased as compared with normoxia group (P<0.01). Furthermore, the expression of LOX at mRNA and protein levels and its activity in the pulmonary arteries in hypoxia+hypercapnia group were lower than those in hypoxia group (P<0.01). CONCLUSION: Hypoxia not only up-regulates LOX but also promotes collagen cross-linking in the rat lung, which contributes to the development of pulmonary hypertension. Hypercapnia inhibits hypoxia-induced LOX expression and collagen cross-linking, therefore impairing the progress in hypoxia-induced pulmonary hypertension. 相似文献
6.
采用基于经济效益评价函数和环境效益评价函数的经济与环境协调发展类型定量评判指标——协调发展度D,对1995-2004年芜湖市经济与环境协调发展类型及演化状况进行了研究。结果表明,1995—2004年芜湖市经济与环境协调发展经历了初级协调发展经济滞后型(1995—1996年),初级协调发展经济环境同步型(1997年),中级协调发展经济滞后型(1998和2000年),中级协调发展经济环境同步型(1999和2001年),中级协调发展环境滞后型(2002和2003年)和良好协调发展环境滞后型(2004年)5个阶段。环境发展的不稳定性成为芜湖市实现经济与环境的优质协调发展和经济与环境发展同步的主导制约因子。 相似文献
7.
流域侵蚀强度空间分异及动态变化模拟研究 总被引:8,自引:2,他引:8
流域侵蚀强度空间分异是小流域泥沙来源研究的重要内容之一。该文以小流域模型模拟试验为基础,利用人工模拟降雨、近景摄影测量和GIS技术,对流域模型不同空间部位的侵蚀强度及其随流域所处发育阶段的动态变化进行了研究。研究结果表明:依据次降雨相对侵蚀模数REM将历经25场模拟降雨的小流域模型发育过程划分为初期时段、活跃时段和稳定时段。沟谷侵蚀强度在整个流域模型发育过程中一直大于坡面;在流域发育初期时段至活跃时段前期,主沟侵蚀强度大于支沟,流域下部侵蚀强度大于中部和上部;在流域发育活跃时段后期,主沟侵蚀强度低于支沟,流域中部和下部侵蚀强度快速增长并达到峰值;在稳定期时段,主沟和支沟侵蚀强度变化趋于同步,流域上部的侵蚀强度高于中部和下部。流域侵蚀强度的时空分布特征对于小流域水土流失综合治理具有科学指导意义。 相似文献
8.
9.
大白菜核雄性不育相关基因BrLTP1的克隆及特征分析 总被引:2,自引:0,他引:2
利用cDNA-AFLP技术分析大白菜核雄性不育两用系‘AB02’可育株(msms)和不育株(Msms)花蕾的基因表达谱,在可育株混合花蕾cDNA中扩增出1条特异条带TDF-25,通过RACE和RT-PCR技术克隆了该基因的全长cDNA序列。序列分析表明,该基因编码脂质转移蛋白,命名为BrLTP1。BrLTP1全长cDNA序列为750 bp,推测编码1个包含183个氨基酸残基的前体蛋白。BrLTP1蛋白含有典型的脂质转移蛋白N端信号肽,保守的AAI结构域和半胱氨酸位点。预测BrLTP1蛋白含有多种修饰性位点,包括1个PKC磷酸化位点,2个N–糖基化位点和10个N–端豆蔻酰基化位点。基因表达模式表明,BrLTP1在两用系不育株花蕾中受到强烈抑制,在可育株的大花蕾、成熟花药以及花瓣中高水平表达。 相似文献
10.
岔巴沟流域三维地貌多重分形特征量化 总被引:1,自引:0,他引:1
流域三维地貌形态的科学量化研究是地貌学研究和流域土壤侵蚀模型研究中的热点问题之一。该文针对流域三维地貌所具有的明显各向异性和三维立体特征,根据多重分形理论,构建了基于GIS的流域三维地貌多重分形计算模型及其实现方法;并以此为基础,结合流域数字高程模型(DEM),计算分析了岔巴沟5个研究子流域的三维地貌多重分形谱及其主要参数,探讨了流域三维地貌多重分形特征及其流域地貌表征意义。研究结果表明,该文建立的基于GIS的流域三维地貌多重分形计算模型可实现流域三维地貌多重分形谱及其特征参数的直接量化;岔巴沟5个研究子流域的三维地貌具有显著的多重分形特征;流域三维地貌多重分形谱及其主要参数可以更加敏感、更加全面地对流域三维地貌的总体特征进行描述,能够分层次地刻画流域内部的精细结构,从而更加突出地表现异常局部地貌变化特征。该文研究成果为流域三维地貌复杂形态的科学准确量化研究提供了一种新思路和新方法。 相似文献