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红脂大小蠹高效引诱剂林间引诱试验结果初报   总被引:1,自引:0,他引:1  
红脂大小蠹是原产北美近年传入我国的一种危险性森林害虫 ,生活隐蔽 ,防治难度很大。为筛选出对我国油松林中红脂大小蠹种群有高效引诱作用的药剂 ,为今后控制红脂大小蠹的危害提供经济、实用、高效的监测方法和防治技术提供技术和物质依据 ,作者于 2 0 0 2年 5~ 7月在石家庄井陉和邢台内丘两地 ,先后进行了连续 2次的引诱试验。试验以加拿大生产的商品和松节油分别作为对照 ,共对 2 7种不同药剂的林间引诱效果进行了测定。试验结果表明 ,2B -7号引诱剂引诱效果显著好于加拿大对照 (a=0 .0 1 4) ,每个诱捕器平均诱虫数量比加拿大引诱剂多 96.3 9%。初步测算其成本比购买加拿大产品低 3 0 %~ 5 0 %以上。  相似文献   
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Given the choice of waiting for an adverse outcome or getting it over with quickly, many people choose the latter. Theoretical models of decision-making have assumed that this occurs because there is a cost to waiting-i.e., dread. Using functional magnetic resonance imaging, we measured the neural responses to waiting for a cutaneous electric shock. Some individuals dreaded the outcome so much that, when given a choice, they preferred to receive more voltage rather than wait. Even when no decision was required, these extreme dreaders were distinguishable from those who dreaded mildly by the rate of increase of neural activity in the posterior elements of the cortical pain matrix. This suggests that dread derives, in part, from the attention devoted to the expected physical response and not simply from fear or anxiety. Although these differences were observed during a passive waiting procedure, they correlated with individual behavior in a subsequent choice paradigm, providing evidence for a neurobiological link between the experienced disutility of dread and subsequent decisions about unpleasant outcomes.  相似文献   
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This study was conducted to investigate whether agmatine (AGM) provides protection against oxidative stress induced by treatment with chlorpromazine (CPZ) in Wistar rats. In addition, the role of reactive oxygen species and efficiency of antioxidant protection in the brain homogenates of forebrain cortexes prepared 48 h after treatment were investigated. Chlorpromazine was applied intraperitoneally (i.p.) in single dose of 38.7 mg/kg body weight (BW) The second group was treated with both CPZ and AGM (75 mg/kg BW). The control group was treated with 0.9% saline solution in the same manner. All tested compounds were administered i.p. in a single dose. Rats were sacrificed by decapitation 48 h after treatment Treatment with AGM significantly attenuated the oxidative stress parameters and restored antioxidant capacity in the forebrain cortex. The data indicated that i.p. administered AGM exerted antioxidant action in CPZ-treated animals. Moreover, reactive astrocytes and microglia may contribute to secondary nerve-cell damage and participate in the balance of destructive vs. protective actions involved in the pathogenesis after poisoning.  相似文献   
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Ips duplicatus (Coleoptera: Curculionidae) was reported in the Euro-Siberian taiga from Sweden to Sakhalin and in the Alps at the beginning of the 20th Century. It has been recorded in spruce stands in the north-eastern part of the Czech Republic since the beginning of the 1970s; monitoring of I. duplicatus was conducted in the Czech Republic in 9 years between 1997 and 2009. Beetles of the overwintering generation were captured in Theysohn pheromone traps baited with a lure of ipsdienol and E-myrcenol, and after 2005 in ID Ecolure lures. Surprisingly, I. duplicatus was found throughout the Czech Republic already in 1997. In 2002, there was a nationwide decrease in their numbers. Particularly since 2005, there has been a spread from the main center of occurrence in the eastern areas to the south and west into the central part of Bohemia where, until that time, its population densities had been lower and had not caused economically significant damage. Moreover, it was observed that in the north-eastern parts of the Czech Republic up to 80% of spruce trees from sanitary felling had been infested by this pest in recent years. The recorded amount of spruce trees infested by I. duplicatus is correlated significantly with the amount of spruce trees recorded as damaged by Ips typographus, Ips amitinus and Pityogenes chalcographus infestation as well as with the numbers of individuals of I. duplicatus captured during the aforementioned monitoring.  相似文献   
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In general, magnetic resonance imaging (MRI) is used to obtain a spatial representation of the water distribution in an object. Water in soft materials (living matter) often shows a high degree of translational mobility, giving rise to relatively long magnetic relaxation times. This allows the use of conventional MRI techniques such as the spin-echo, to acquire an image. However, when hydration levels become low, water becomes less mobile, resulting in much shorter magnetic relaxation times and a corresponding signal loss. To avoid problems arising from rapid decaying signals, we investigated the use of single point imaging (SPI) in the study of seeds. We were able to obtain SPI images of nonimbibed and imbibed seeds. Using SPI with shaped gradients significantly reduced the acoustic noise level.  相似文献   
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Temperatures in Jupiter's atmosphere derived from Galileo Probe deceleration data increase from 109 kelvin at the 175-millibar level to 900 ± 40 kelvin at 1 nanobar, consistent with Voyager remote sensing data. Wavelike oscillations are present at all levels. Vertical wavelengths are 10 to 25 kilometers in the deep isothermal layer, which extends from 12 to 0.003 millibars. Above the 0.003-millibar level, only 90- to 270- kilometer vertical wavelengths survive, suggesting dissipation of wave energy as the probable source of upper atmosphere heating.  相似文献   
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Polyspermy is the most commonly observed cause of embryonic abnormalities in fertilization, often resulting in death. In sterlet (Acipenser ruthenus), however, polyspermic embryos have high survival (similar to a control group) and morphological development is similar to monospermic larvae. Ploidy of these individuals is n/2n mosaic (whereas the normal state for A. ruthenus is a functional diploid). This study was undertaken to test whether sturgeon eggs can be fertilized by several spermatozoa from different species to produce viable offspring from three interspecific parents: A. ruthenus (2n), A. gueldenstaedtii (4n), and A. baerii (4n). Four trials were performed: (1) and (2) A. baerii eggs were fertilized with a mixture of A. ruthenus and A. gueldenstaedtii sperm; (3) A. gueldenstaedtii eggs were fertilized with a mixture of A. baerii and A. ruthenus sperm; and (4) A. gueldenstaedtii eggs were fertilized with a mixture of A. gueldenstaedtii and A. ruthenus sperm. Fertilized embryos with abnormal cleavage (3, 5, 6, 7, 9, and 10 cells) were collected and kept separately until 14 days post-fertilization. Ploidy level of 25 larvae (hatched from abnormal cleaved embryos) was evaluated by flow cytometry. Forty-four percent of observed hybrids had a mosaic 2n/3n ploidy. Five larva were processed further with microsatellite analysis and demonstrated that three specimens were heterospecific polyspermic larvae, containing alleles from three parents, and two specimens were conspesific polyspermic larvae from two parents. This astonishing phenomenon was emphasized by the fact that it was generated without any significant intervention.  相似文献   
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