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101.
在害虫治理中,在消费或贮藏粮食加工产品的建筑设施或场所进行害虫防治需要将杀虫剂施用在各种基质表面上.为了测定不同基质表面上杀虫剂的药效,将四纹豆象Callosobruchus maculatus(F.)成虫接触田间推荐剂量的阿维菌素、溴氰菊酯和毒死蜱.结果表明:施用在玻璃、瓷砖、塑料和纸盘表面上,阿维菌素对四纹豆象成虫的致死率分别为63.33%,22.41%,12.9%和11.9%,而溴氰菊酯在这4种基质表面上对四纹豆象成虫的致死率分别为55%,44.2%,41.3%和37.4%.在所有基质表面上接触毒死蜱,四纹豆象成虫的死亡率均为100%.对数据进行的Probit分析表明,毒死蜱制剂在玻璃、瓷砖、塑料和纸盘上对四纹豆象成虫的LC50值分别为8.66,13.6,29 16和56.5 μg/mL,阿维菌素制剂的相应数值分别为119.4,446.2,774.2和836.4μg/mL,溴氰菊酯制剂的相应数值分别为1008,1131,1210和1336 μg/mL.据此推断,毒死蜱对四纹豆象的毒性最强,且在玻璃、瓷砖、塑料和纸盘表面上的毒性依次降低.  相似文献   
102.
Abstract

Root-knot nematodes (Meloidogyne spp.) are one of the most harmful plant pathogenic nematodes worldwide. Application of some herbal products can safely reduce negative effect of these nematodes. In the present study, the effect of aqueous extracts of Amygdalus scoparia and Arctium lappa on hatching and mortality of second-stage juveniles of M. javanica evaluated under laboratory condition and LC30, LC50, LC70 and LC90 values were determined by probit analysis from March to November 2016. Tomato seeds (cv. Early-Urbana) were sown in 1.5?kg plastic pots and simultaneously were inoculated with 4000 eggs and second stage juveniles (J2s) of M. javanica and soil-drenched (50?ml/pot) with selected concentrations of A. scoparia viz. 0.37, 0.54, 0.8 and 1.39% and A. lappa viz. 0.51, 0.85, 1.4 and 2.91%. The experiments were carried out in completely randomized design tests with four replications. Plant growth parameters as well as nematode population indices were calculated 60?days after inoculation. Results showed that after 120?hours, leaf extracts of A. scoparia at the rate of 7.5 and 10%, and leaf extract of A. lappa at the rate of 10% lead to 100% inhibition of M. javanica egg hatching under laboratory condition. Leaf extracts of both of the tested plants at the rate of 2% caused 100% mortality of J2s. Any increase in concentration of used plant extracts significantly improved the growth indices in both of the inoculated and uninoculated tomato plants. As compared to control, application of A. scoparia leaf extract at the rate of 2%, reduced the number of galls, egg masses and eggs per root system as well as the number of J2s per pot and reproduction factor of nematode by 37, 43, 45, 73 and 46%, and in the case of A. lappa, these indices reduced by15, 26, 27, 74 and 28%, respectively. Our results showed potential of leaf extracts of A. scoparia and A. lappa for management of M. javanica infecting tomato plants.  相似文献   
103.
104.
Redd (nest) surveys for resident brook trout (Salvelinus fontinalis) were conducted annually in a mountain lake in northern New York for 11 years with multiple surveys conducted during the spawning season in eight of those years. Repeated surveys throughout the spawning season allowed us to fit an individually based parametric model and estimate the day of year on which spawning was initiated, reached its midpoint, and ended during each year. Spawning phenology was then assessed relative to (1) mean of maximum daily air temperature and (2) mean of maximum daily water temperature at the lake bottom during summer in each year using a linear model. Elevated temperatures in summer were correlated with a delay in spawning and a reduction in the total number of redds constructed. Increasing the summer mean of maximum daily air temperatures by 1 °C delayed spawning by approximately 1 week and decreased the total number of redds constructed by nearly 65. Lake spawning brook trout select redd sites based on the presence of discharging groundwater that is relatively constant in temperature within and across years, leading to relatively consistent egg incubation times. Therefore, delayed spawning is likely to delay fry emergence, which could influence emergence synchrony with prey items. This work highlights non‐lethal and sub‐lethal effects of elevated summer temperatures on native resident salmonids in aquatic environments with limited thermal refugia.  相似文献   
105.
106.
  • 1 We investigated how modifications in winter and spring temperature conditions may affect the survival of a spring‐hatching Lepidoptera, the oak processionary moth Thaumetopoea processionea.
  • 2 Supercooling and chilling injury experiments indicate that eggs are especially cold hardy at the start of the winter period, although this ability is reduced later in the season. In the spring, young larvae are sufficiently cold hardy to ensure no direct mortality as a result of late frosts.
  • 3 A comparison of phenological models shows that neonate larvae may await the unfolding of new oak leaves for relatively long periods (e.g. 1–30 days). Under both low (4°C after 5 days at 16°C) and high temperature experimental scenarios (constant 16°C), the majority of neonate larvae can survive starvation for more than 2 weeks.
  • 4 Larvae may also suffer from food depletion once their development has been initiated (e.g. during cold springs) if the threshold temperature for feeding is not reached for several consecutive days, or in the case of late frosts affecting foliage availability. When temperature is reduced to 4°C, developing larvae become inactive and do not feed anymore; their starvation survival capability is reduced to approximately 2 weeks (cold spring hypothesis). At 16°C, developing larvae that are deprived of food can only survive for 10 days (late frost hypothesis).
  • 5 We conclude that, in the oak processionary moth, neonate larvae are relatively well adapted to early hatching relative to budburst, ensuring them the highest foliage quality for development. In some years, however, phenological asynchrony or cold spring conditions may affect the persistence of populations at the limits of the species' range.
  相似文献   
107.
Intercommunity aggression in chimpanzees and primitive warfare in humans possess striking similarities, such as the common occurrence of large male coalitions, systematic control of territory boundaries, and lethal attacks on isolated individuals from neighboring groups. However, an important apparent contrast is the absence of recurrent peaceful interactions between neighboring groups of chimpanzees. We observed a remarkable range of behavior in intergroup encounters among three habituated communities of chimpanzees in Taï National Park, Côte d'Ivoire. Lethal attacks are documented in these study groups for the first time, as well as year‐long exchanges of parous adult females and peaceful intergroup visits of mothers with infants. Demographic factors, including group size and number of adult males, are shown to affect the nature of intergroup interactions in ways not considered previously. A reconsideration of the difference in intergroup interactions between eastern and western chimpanzees is proposed including a more important consideration of the female's perspective. The inclusion of the new complexities in intergroup interactions in chimpanzees allows new parallels to be drawn with the evolution of primitive warfare in humans. Am. J. Primatol. 70:519–532, 2008. © 2008 Wiley‐Liss, Inc.  相似文献   
108.
Cooper S 《FEMS yeast research》2008,8(3):345-8; discussion 349-50
The proposal that yeast, and cells in general, contains redundant genes that enable cells to survive mutational change has been supported by experiments and a strong metaphor. The redundant gene proposal is analyzed, and it is noted that there are many problems with the redundant gene model. An alternative metaphor is suggested to explain the genetic composition of a yeast culture.  相似文献   
109.
化学诱变法选育D-核糖高产菌株工艺研究   总被引:4,自引:0,他引:4  
研究了以硫酸二乙酯(DES)为诱变剂,诱变生产D-核糖的转酮醇酶缺陷型枯草芽孢杆菌HG02,考察了不同诱变剂用量对菌体致死率及其生产能力的影响。得出了以DES诱变该菌株的致死率曲线及最佳的诱变条件:诱变剂用量0.8%,诱变时间15min。该诱变条件下对大量的突变株进行筛选,得到D-核糖高产菌HG03,其D核糖产量较出发菌株提高81.69%。达到5.1g/100mL。  相似文献   
110.
The data are presented on genetic and molecular-genetic analysis of a mutant from the collection of morphological insertion mutants of Arabidopsis thaliana we obtained earlier, which belongs to the phenotypic class of recessive lethal germlings. A nucleotide DNA sequence, 147 bp in size, was identified, which adheres to the left border area of T-DNA insertion. The site of localization of the insertion was determined using computer analysis.__________Translated from Ontogenez, Vol. 36, No. 3, 2005, pp. 222–224.Original Russian Text Copyright © 2005 by Ogarkova, Tomilov, Tomilova, Tarasov.  相似文献   
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