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141.
Brown capuchin monkeys (Cebus apella apella) in Suriname forage on larvae enclosed within healthy bamboo stalks. We applied the searching versus handling dichotomy of optimal foraging models to highlight developmental processes contributing to foraging on embedded prey. Larvae acquisition begins with search; selecting an appropriate stalk and locating the embedded larvae; followed by handling, ripping the stalk open, and extracting the larvae. Although extraction behaviors were present at low rates in infant capuchins' repertoire, we found that the acquisition of adequate detection techniques was fully completed in subadults, aged around 6. Selecting appropriate foraging substrates, requiring accurate assessment of the physical properties of bamboo stalks, gradually increased with age and experience. We showed that both components of searching required extended practice beyond that required to master the handling components. We conclude that the developmental sequence of skill acquisition goes counter to the preceding logical sequence of foraging process and suggest that searching components present greater challenges than handling components in extractive foraging. Specifying the searching components of foraging more precisely will enhance understanding of species variation in the developmental schedule of foraging skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
142.
The effects of a dam closure (Porto Primavera Dam) on reproduction of the main species that use the floodplain located below a nursery area were determined. Specifically, we examined, before and after the closure of the dam, the spatial distribution of larvae and the differences in density according to life strategy (migratory and non‐migratory species). Fifteen points distributed along the channels of the Paraná, Ivinheima and Paranapanema rivers were sampled, between 1997 and 2001, (October 1997 to December 1998—pre; and between January 1999 to March 2001—post closure), during the spawning period of most fish species found in the region (October to March). Samplings were always conducted at night, using a conical‐cylindrical plankton net (0.5 mm mesh) with a flowmeter attached. There were significant differences in larvae densities between pre and post dam closure for several species. Also, there were significant differences between the pre and post‐closure periods for densities of migratory and non‐migratory species, and between sampling sites. These findings indicate decline in densities and number of taxa caught after the closure of the dam. Larvae of migratory species, formerly common in the entire study area, were registered only in points influenced by the non dammed rivers (such as the Ivinheima River), indicating that the closure of Porto Primavera caused negative impacts on fish reproduction downstream of the dam. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
143.
文章概述了以冷冻干燥的卤虫成虫为主要蛋白源的人工合成饵料和卤虫脱壳卵在鲤鱼 (Cyprinuscarpio)育苗中的应用。实验以新鲜孵化的卤虫无节幼体作为对照饵料 ,测定了幼苗平均个体干重 (DW ) ,湿重 (WW ) ,存活率 ,特殊生长率 (SGR)和饵料系数 (FCR)。孵化后第 2 3天 ,脱壳卵投喂组平均个体湿重达到 45 .9mg ,存活率达到 96 .9%。在人工饵料中 ,Diet2 (含有约 5 0 %卤虫成虫及 5 0 %的酵母和鸡肝 )效果最佳 ,平均个体湿重达到 30 .7mg ,存活率达到 89.1%。  相似文献   
144.
Yellow mealworm larvae (Tenebrio molitor) are being introduced into Western food products. The effect of blanching, followed by either chilled storage or industrial microwave drying, on microbial counts of the larvae was investigated. Whatever time applied (10, 20 or 40 s), considerable log reductions were obtained after blanching (total viable count, Enterobacteriaceae, lactic acid bacteria, yeasts and molds and psychrotrophs), except for aerobic endospores. No major growth was observed during subsequent chilled storage for 6 days. Total viable counts were below 3.5 ± 0.3 log cfu/g for all samples. When blanching for 40 s was followed by industrial microwave drying, drying for 8, 10 or 13 min did not yield larvae with a water activity below 0.60, which is necessary to eliminate all microbial growth. Drying times of 16 or 20 min yielded average water activities of 0.16 and 0.23, respectively. The number of vegetative cells was reduced to a large extent by blanching plus drying, but the number of bacterial endospores only slightly. Total viable counts were maximally 3.4 ± 0.8 log cfu/g for all samples. Bacterial endospores were the most resistant to the processing technologies investigated.  相似文献   
145.
146.
Historically, gilthead seabream (Sparus aurata) has been considered a fish species resistant to nervous necrosis virus (NNV) disease. Nevertheless, mortality in seabream hatcheries, associated with typical clinical signs of the viral encephalopathy and retinopathy (VER) disease has been confirmed to be caused by RGNNV/SJNNV reassortants. Because of this, seabream larvae at 37 and 86 days post-hatching (dph) were infected by immersion with RGNNV/SJNNV and SJNNV/RGNNV reassortants under laboratory conditions, and mortality, viral replication and immunity were evaluated. Our results show that gilthead seabream larvae, mainly those at 37 dph, are susceptible to infection with both NNV reassortant genotypes, with the highest impact from the RGNNV/SJNNV reassortant. In addition, viral replication occurs at both ages (37 and 86 dph) but the recovery of infective particles was only confirmed in 37 dph larvae,; this value was also highest with the RGNNV/SJNNV reassortant. Larvae immunity, including the expression of antiviral, inflammatory and cell-mediated cytotoxicity genes, was affected by NNV infection. Levels of the natural killer lysin (Nkl) peptide were increased in SJNNV/RGNNV-infected larvae of 37 dph, though hepcidin was not. Our results demonstrate that the seabream larvae are susceptible to both NNV reassortants, though mainly to RGNNV/SJNNV, in an age-dependent manner.  相似文献   
147.
通过对家蝇幼虫(蝇蛆)的蛋白质含量及氨基酸组成分析,对其蛋白质营养价值做出初步评价。对家蝇进行养殖,收集蝇蛆,测定蝇蛆的粗蛋白、氨基酸组成及含量,用粮食与农业组织-世界卫生组织(FAO-WHO)提出的参考蛋白模式及氨基酸分析进行评价。蝇蛆粗蛋白含量为62.52%,必需氨基酸含量(色氨酸未测)占总氨基酸(E%)的47.72%,必需氨基酸与非必需氨基酸总量的比值(E/N)为0.91,E%/T为3.18,分别高于参考模式的40%、0.6和3。氨基酸分析第一限制氨基酸为异亮氨酸,AAS为92.45%,CS为68.48%,RCAA为0.69,EAAI、IN值分别为94.75、59.24。蝇蛆粗蛋白含量丰富,蝇蛆蛋白必需氨基酸种类齐全、含量丰富,氨基酸模式高于参考模式,具有较高的营养价值,是种高效优质动物蛋白资源,适用于营养开发利用。  相似文献   
148.
扁谷盗属是一类世界性重要的储藏物害虫。目前由于抗药性、可用技术广谱性和成本较高等问题,使得该类虫害的防治受到严重的挑战。针对杀虫剂抗药性问题,我们积极采取了各种措施包括多样化杀虫剂方式,杀虫剂组合如保幼激素类似物(JHA)与其他药剂复配。保幼激素类似物(JHA),如s-烯虫酯,具有很好的安全性和对多种仓储害虫有效性的特点。了解影响可替代技术效果的关键因素才能进行有效的防治管理。此外,了解害虫所有发育阶段的耐药性表达非常重要,因为药剂应用环境中所有虫态都存在。我们测定了扁谷盗属不同虫态及其F1种群对s-烯虫酯的耐受性。从发育阶段来看,成虫耐受性最高,其次是卵,然后是幼虫,其耐受性与F1代中的蛹大致相同。通过比较不同虫种的结果表明,最敏感的是长角扁谷盗,而耐受性最高的是土耳其扁谷盗。当浓度达到30mg/L及以上,锈赤扁谷盗和长角扁谷盗孵化率均小于50%,而土耳其扁谷盗需达到80mg/L时孵化率才低于50%。在幼虫期,仅需施用5 ppm s-烯虫酯,三个扁谷盗虫种死亡率都超过50%。在试验期间,s-烯虫酯并未完全抑制扁谷盗后代的产生,但即使在0.5 ppm浓度下,也会导致所有扁谷盗属的成虫显著减少。本研究这些结论可以得出,s-烯虫酯对这三个虫种非常有效,可作为储粮害虫综合防治的潜在手段。  相似文献   
149.
The defense strategy of an insect toward natural enemies can include a trait that appears at first sight to contradict its defensive function. We explored phylogeny, chemistry, and defense efficiency of a peculiar group of hymenopteran sawfly larvae where this contradiction is obvious. Pseudodineurini larvae live in leaf mines that protect them from some enemies. Disturbed larvae also emit a clearly perceptible lemon-like odor produced by ventral glands, although the mine hampers the evaporation of the secretion. The mine could also lead to autointoxication of a larva by its own emitted volatiles. Citral was the major component in all Pseudodineurini species, and it efficiently repels ants. We conclude that full-grown larvae that leave their mine to pupate in the soil benefit from citral by avoiding attacks from ground-dwelling arthropods such as ants. In some species, we also detected biosynthetically related compounds, two 8-oxocitral diastereomers (i.e., (2E,6E)- and (2E,6Z)-2,6-dimethylocta-2,6-dienedial). Synthetic 8-oxocitral proved to be a potent fungicide, but not an ant repellent. The discrete distribution of 8-oxocitral was unrelated to species grouping in the phylogenetic tree. In contrast, we discovered that its presence was associated with species from humid and cold zones but absent in species favoring warm and dry environments. The former should be protected by 8-oxocitral when faced with a fungal infestation while crawling into the soil. Our work shows the importance of integrating knowledge about behavior, morphology, and life history stages for understanding the complex evolution of insects and especially their defense strategies.  相似文献   
150.
The harmful effects of excessive ultraviolet (UV) exposure are well known. However, moderate exposure to UV radiation is beneficial and required for active vitamin D synthesis in our body. People living in the coldest regions on the earth are unable to expose their skin to the solar UV radiation and, therefore, additional supplementation of Vitamin D2 is recommended. Mushrooms are one such consumable macrofungi, which has high vitamin content and therefore used in various traditional medicines. Particularly, UVB-irradiated mushrooms are rich in active vitamin D content and that is why recommended to include in the daily diets for the patients suffering from the problems associated with bone mineralization. In the present study, we evaluated the cytotoxic effect of mushroom extract (UVB-ME) (Lentinus edodes) treatment against MG-63 cells, HepG2 cells, and CCD 841 CoN cells. Furthermore, we elucidated the potential of UVB-ME on Ca++ uptake in osteoblast-like MG-63 cells. Next, we validated the response of Ca++ uptake on the growth and development of zebrafish larvae. In addition, the anti-inflammatory and immunomodulatory potential of UVB-ME treatment against lipopolysaccharide-induced inflammatory response was also analyzed in vivo. Collectively, the study suggested that dietary supplementation of UVB-irradiated mushroom is beneficial for bone calcification and could modulate the host immune system.  相似文献   
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