全文获取类型
收费全文 | 76篇 |
免费 | 6篇 |
国内免费 | 23篇 |
出版年
2024年 | 1篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 1篇 |
2011年 | 4篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 7篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
排序方式: 共有105条查询结果,搜索用时 15 毫秒
61.
FA-JUN CHEN GANG WU JUN LUE FENG GE 《Insect Science》2005,12(5):359-365
Effects of elevated CO2 on the foraging behavior of cotton bollworm Helicoverpa arrnigera Hübner reared on milky grains of spring wheat grown in ambient, 550μL/L and 750μL/L CO2 concentration atmospheres in open-top chambers (OTC) were studied. The results indicated that: (i) elevated CO2 significantly affected both the type and amount of food eaten by H.arrnigera reared on milky grains of ambient CO2-grown wheat were significant higher than those for bollworm larvae reared on wheat grains grown in 550 and 750μL/L CO2 atmospheres; (ii) when bollworm larvae were reared on mixed milky grains from different CO2-grown wheat (food-choice condition), larval duration increased significantly-pupal weight, adult longevity, and fecundity decreased significantly, comparing with those reared on milky grains of ambient CO2-grown wheat, 550μL/L CO2-grown wheat and 750μL/L CO2-grown wheat respectively; (iii) significant decreases in the contents of fructose and gross protein (GP) and significant increases in the contents of glucose, amylose, total saccharides (TSC), TSC: GP ratio, free amino acids and soluble protein in the wheat grains with CO2 rising; (iv) and selected-foraging amount/food-choice index of cotton bollworm H.armigera were significantly positive correlated with the contents of fructose and GP of wheat grains, but they had significantly negative relationships with the contents of glucose, amylose, TSC and TSC: GP ratio of wheat grains. 相似文献
62.
LIANXIN YANG YULONG WANG KAZUHIKO KOBAYASHI† JIANGUO ZHU‡ JIANYE HUANG HONGJIE YANG YUNXIA WANG GUICHUN DONG GANG LIU‡ YONG HAN‡ YUHUA SHAN JIAN HU JUAN ZHOU 《Global Change Biology》2008,14(8):1844-1853
Over time, the relative effects of elevated [CO2] on the aboveground photosynthesis, growth and development of rice (Oryza sativa L.) are likely to be changed with increasing duration of CO2 exposure, but the resultant effects on rice belowground responses remain to be evaluated. To investigate the impacts of elevated [CO2] on seasonal changes in root growth, morphology and physiology of rice, a free‐air CO2 enrichment (FACE) experiment was performed at Wuxi, Jiangsu, China, in 2002–2003. A japonica cultivar with large panicle was exposed to two [CO2] (ambient [CO2], 370 μmol mol−1; elevated [CO2], 570 μmol mol−1) at three levels of nitrogen (N): low (LN, 15 g N m−2), medium (MN, 25 g N m−2) and high N (HN, 35 g N m−2). Elevated [CO2] increased cumulative root volume, root dry weight, adventitious root length and adventitious root number at all developmental stages by 25–71%, which was mainly associated with increased root growth rate during early growth period (EGP) and lower rate of root senescence during late growth period (LGP), while a slight inhibition of root growth rate occurred during middle growth period (MGP). For individual adventitious roots, elevated [CO2] increased average length, volume, diameter and dry weight early in the season, but the effects gradually disappeared in subsequent stages. Total surface area and active adsorption area per unit root dry weight reached their maxima 10 days earlier in FACE vs. ambient plants, but both of them together with root oxidation ability per unit root dry weight declined with elevated [CO2] during MGP and LGP, the decline being larger during MGP than LGP. The CO2‐induced decreases in specific root activities during MGP and LGP were associated with a larger amount of root accumulation during EGP and lower N concentration and higher C/N ratio in roots during MGP and LGP in FACE vs. ambient plants. The results suggest that most of the CO2‐induced increases in shoot growth of rice are similarly associated with increased root growth. 相似文献
63.
结合甲型H1N1流感特点,建立了基于元胞自动机的异质个体甲型H1N1流感传播模型,并给出了该模型的动态仿真过程.异质即考虑到不同个体在传染性、对疾病抵抗能力等方面的差异.进而,从网络动力学的角度考虑了个体相互作用之间的关系,包括感染甲型H1N1流感死亡者占总数的比例随时间的变化以及甲型H1N1流感消失所需要的时间.本文计算出的病死率为0.0037,与中华人民共和国卫生部官网提供的甲型H1N1流感病毒的病死率0.004接近,说明了模型的合理性和有效性.模型及计算结果,可为疫情发展趋势的预测、以及政府制定干预疫情的有效措施提供可靠的依据. 相似文献
64.
65.
转PaGLK基因银中杨抑制表达株系叶绿素含量显著降低,叶片呈现黄色(命名为金叶银中杨),以转PaGLK基因的银中杨为材料,测定其叶色参数和叶绿素含量的时序变化规律、分析生长特性。结果显示,转PaGLK基因的银中杨使叶片颜色发生改变,抑制表达株系整个生长期叶绿素含量显著低于WT(P<0.05),叶色亮度显著高于WT(P<0.05),并且在生长发育期叶片一直呈现深黄绿色。抑制表达株系中的Y2速生期内苗高日生长量(GD)高于对照株系,苗期株高不受影响。而过表达转基因银中杨的当年高生长都显著低于对照株系 (P<0.05),其速生期内苗高日生长量均值(GD)也低于对照株系,其均值为对照株系的22.19%。PaGLK抑制表达株系在城市园林绿化具有潜在的应用价值。 相似文献
66.
JON FLANDERS§ GARETH JONES§ PETR BENDA‡ CHRISTIAN DIETZ† SHUYI ZHANG¶ GANG LI¶ MOZAFAR SHARIFI STEPHEN J. ROSSITER 《Molecular ecology》2009,18(2):306-318
Phylogeographical studies are typically based on haplotype data, occasionally on nuclear markers such as microsatellites, but rarely combine both. This is unfortunate because the use of markers with contrasting modes of inheritance and rates of evolution might provide a more accurate and comprehensive understanding of a species' history. Here we present a detailed study of the phylogeography of the greater horseshoe bat, Rhinolophus ferrumequinum , using 1098 bp of the mitochondrial ND2 gene from 45 localities from across its Palaearctic range to infer population history. In addition, we re-analysed a large microsatellite data set available for this species and compared the results of both markers to infer population relationships and the historical processes influencing them. We show that mtDNA, the most popular marker in phylogeography studies, yielded a misleading result, and would have led us to conclude erroneously that a single expansion had taken place in Europe. Only by combining the mitochondrial and microsatellite data sets are we able to reconstruct the species' history and show two colonization events in Europe, one before the Last Glacial Maximum (LGM) and one after it. Combining markers also revealed the importance of Asia Minor as an ancient refugium for this species and a source population for the expansion of the greater horseshoe bat into Europe before the LGM. 相似文献
67.
68.
69.
昆虫血细胞形态多样,变异复杂,不仅给血细胞的分类带来困难,而且还影响对其生理功能的研究(傅贻玲,1982a、1982b)。为了从细胞和分子水平研究各类血细胞的特性和功能,必须制备一定数量的、形态一致的血细胞样品。因此对昆虫各类血细胞分离技术的研究十分重要,但这方面的研究报道还很少(Cook等,1985;Mead等,1986)。 相似文献
70.
Human rhodopsin kinase (RK) and a carboxyl terminus-truncated mutant RK lacking the last 59 amino acids (RKC) were expressed in human embryonic kidney 293 cells to investigate the role of the carboxyl terminus of RK in recognition and phosphorylation of rhodopsin.RKC,like the wild-type RK,was detected in both plasma membranes and cytosolic fractions.The Cterminal truncated rhodopsin kinase was unable to phosphorylate photo-activated rhodopsin,but possesses kinase activity similar to the wild-type RK in phosphorylation of small peptide substrate.It suggests that the truncation did not disturb the gross structures of RK catalytic domain.Our results also show that RKC failed to translocate to photo-activated rod out segments.Taken together,our study demonstrate the carboxyl terminus of RK is required for phosphorylation of photo-activated rhodopsin and strongly indicate that carboxyl-terminus of RK may be involved in interaction with photo-activated rhodopsin. 相似文献