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311.
An analysis of the regulations of herbicide use for weed control in non-agricultural/urban amenity areas, including actual pesticide use, was carried out as a joint survey of seven European countries: Denmark, Finland, Germany, Latvia, the Netherlands, Sweden and United Kingdom. Herbicides constitute the major part of the pesticides used in urban amenity areas. Herbicide use on hard surfaces is the largest in terms of volume and potential contamination of surface and groundwater. The aim of the study was to investigate the differences in political interest and public debate on the 'use of pesticides in public urban amenity areas', regulations within each country at national, regional and local levels, possible use of alternative weed control methods and the amounts of pesticides used on urban amenity areas. A comparative analysis revealed major differences in political interest, regulations and availability of statistics on pesticide use. Denmark, Sweden, the Netherlands and Germany have, or have had, a strong public and political interest for reducing the use of herbicides to control weeds in urban amenity areas and also have very strict regulations. The UK is currently undergoing a period of increasing awareness and strengthening regulation, while Latvia and Finland do not have specific regulations for weed control in urban amenity areas or on hard surfaces. Statistics on pesticide/herbicide use on urban amenity areas were only available in Denmark and the Netherlands. Developing this kind of information base reveals the differences in herbicide use, regulations and policies in European countries and may enhance the transfer of knowledge on sustainable weed control across countries.  相似文献   
312.
利用FIASCO技术进行波纹巴非蛤微卫星   总被引:1,自引:0,他引:1  
为揭示波纹巴非蛤种质遗传特性、开发种质库,利用FIASCO(Fast Isolation by AFLP of Sequences Containing Repeats)技术开展了其基因组微卫星标记的分离与筛选研究。基因组DNA经限制性内切酶Mse I 酶切后与接头连接,用生物素标记的(CA)15或(AAG)7探针与其杂交,然后用磁珠富集、洗脱获得单链目的片段,经PCR扩增后形成双链,最后进行克隆转化,构建微卫星富集文库。挑选克隆用探针引物(CA)15或(AAG)7和载体引物进行PCR筛选,测序得到含有微卫星DNA的序列,根据序列设计和合成微卫星引物,进行引物适用性分析,并分析了湛江群体的遗传结构。结果表明,8对微卫星引物在湛江群体共检测到108个等位基因,每个位点等位基因数为5~19,期望杂合度为0.666~0.926,观测杂合度为0.400~0.882,4个位点(Pun4,Pun5,Pun6,Pun7)显著偏离哈迪-温伯格平衡(P<0.00625);PIC介于0.62~0.92,所有位点均属于高度多态位点(PIC>0.5)。说明FIASCO技术适合于波纹巴非蛤微卫星标记的分离与筛选,筛选得到的8个微卫星位点能用于波纹巴非蛤遗传多样性分析及野生群体与养殖群体的群体结构分析。  相似文献   
313.
不同处理对西卡柱花草硬实种子发芽的影响   总被引:2,自引:0,他引:2  
采用7种不同方法对西卡柱花草(Siytosanthes scabra CV.Reyan No.14)种子进行处理.结果表明:石英砂磨破两卡柱花草种皮处理效果最好,发芽率达95%;其次是98%浓硫酸浸种20 min,发芽率达60.7%;80℃热水浸种20min,发芽率仅24.7%;高温干燥处理,无水酒精,40%的氢氧化钠,无水纯甘油浸种对西卡柱花草的发芽率没有影响.  相似文献   
314.
Abstract

The objective of this study was to estimate the economic impact on the Florida economy generated by the cultured hard clam industry. Florida certified shellfish wholesalers that handle Florida cultured hard clams were interviewed by telephone survey to determine the number and value of clams that they process, the sources of their clams, prices received, and the marketing channels (wholesale, retail, restaurant, and consumer) where they sell their clams. Of the three regions in the state, northwest Florida handled two-thirds of clams cultured in Florida. Firms obtained their clams from within their own region as well as from the other two regions in Florida. The Florida cultured hard clam wholesale and processing industry had $21.8 million in sales in 1999. Around 43 percent of these sales were within the state and 57 percent of them were to out-of-state locations, including international destinations. Regardless of the geographic destination of the cultured clams sold by clam firms, the majority was sold to other wholesalers. The total economic impact of the clam industry on Florida, after accounting for direct, indirect, and induced impacts, was $33.9 million in output, $9.0 million in labor income, and $12.1 million in value added.  相似文献   
315.
Non‐chemical weed control on pavements needs more frequently repeated treatments than the application of glyphosate and often uses large amounts of fuel. To obtain effective hot water control with minimum energy consumption, an in‐depth study of efficacy‐influencing factors was performed. Three dose–response pot experiments were conducted outdoors to investigate the impact of growth stage (39, 60 and 81 day old), water temperature (78, 88 and 98°C), time of the day (2, 7 and 12 h after sunrise) and treatment interval (2, 3, 4 and 6 week intervals) on hot water sensitivity of seven weed species that are hard to control on pavements. Responses to hot water were quantified by weed coverage and total dry biomass. In general, hot water sensitivity was highest for species with large planophile leaves and lowest for grasses with small erectophile leaves. Most species were twofold to sixfold more sensitive to water at 98°C than at 78 and 88°C, particularly when treated at early growth stages. Among treatment intervals, treating at 3‐week intervals was up to twofold more effective and energy efficient than treating at 6‐week intervals. Sensitivity was about twofold lower in the morning than in the afternoon. For effective control of weeds, while using less fuel, it is recommended to apply hot water in the late afternoon, to operate at high water temperature (98°C) and to treat plants as young as possible at 3‐week intervals.  相似文献   
316.
Abundance, length‐frequencies and distribution of Ruditapes philippinarum (Manila Clams) and Tellina (Quidnipagus) palatum were measured at two beaches in Kāne'ohe Bay, O'ahu, Hawai'i in June, 2010. Abundances had decreased from 866.2 m?2 to 3.4 m?2 for Ruditapes and from 75.5 m?2 to 1.5 m?2 for T. palatum since 1977. Distribution of both species was patchy, but both were most commonly found >40 m from shore. Size frequencies of live clams compared with empty shells suggest that few Ruditapes survive to sexual maturity. A similar trend was not detected for T. palatum. Aquaculture trials of R. philippinarum were conducted at the He'eia and Moli'i traditional Hawaiian fishponds in the same bay. The clams failed to thrive, although triploid and diploid Crassostrea gigas performed well in concurrent trials in the same fishponds. Current lower abundances for wild R. philippinarum could be due to factors related to predation or nutrient limitations. Previously, two large sewage outfalls existed at the surveyed clam bed areas which may have temporarily increased nutrient availability for both wild and cultured clams. Current nutrient levels may inhibit Manila clam growth and recruitment in Kāne'ohe Bay.  相似文献   
317.
以文蛤肉为原料,探讨了胰蛋白酶的加酶量、水解时间、水解温度、pH值及液固比对文蛤肉水解液总氨基氮含量和水解得率的影响规律,确定文蛤肉酶解的最优条件为酶解温度50℃,加酶量4000U/g原料,pH值为(8.00±0.05),水解时间5h,液固比3:1。再以文蛤肉水解液的水解度、水解得率及风味评分值为指标对该酶解优化条件下获得的产品与精制中性蛋白酶水解优化条件下获得的产品进行比较。结果表明,胰蛋白酶为酶法水解文蛤肉最适宜的蛋白酶,其酶解所得文蛤肉水解液的水解度、水解得率及风味评分值分别为42.44%、82.86%及205.92。  相似文献   
318.
为了研究重金属-营养盐-石油烃复合污染下菲律宾蛤仔(Ruditapes philippinarum)的代谢特征及其过氧化物歧化酶(SOD)活性,判断其用于复合污染生态修复的可能性。以海沙模拟菲律宾蛤仔生境,将其暴露于重金属-营养盐-石油烃复合污染,测定其耗氧率、排氨率和SOD活性。结果表明:氨氮和汞对菲律宾蛤仔耗氧有协同增益作用;氨氮促进菲律宾蛤仔氨氮排泄;SOD活性不受重金属、营养盐和石油烃的影响。考虑到菲律宾蛤仔对重金属、营养盐和石油烃的耐受性及富集特性,认为菲律宾蛤仔是修复重金属-营养盐-石油烃复合污染的潜在物种。  相似文献   
319.
温度、盐度对滑顶薄壳鸟蛤面盘幼虫存活和生长的影响   总被引:3,自引:0,他引:3  
就温度和盐度对滑顶薄壳鸟蛤面盘幼虫存活和生长的影响进行了研究。结果表明,在盐度32.2条件下,面盘幼虫存活和生长的最适温度为21.0-24.0℃,存活的温度上限为27.0℃,下限为15.0℃,在21.0℃条件下,面盘幼虫存活和生长的下限盐度为14.0,最适盐度为28.0-32.2,且在此盐度范围内,随盐度升高,面盘幼虫存活率和美元日生长率亦随之增大。  相似文献   
320.
本文对鹰嘴紫云英种子硬实处理措施进行了探讨。结果表明:该草种子硬实率高,造成硬实的主要原因是种皮的障碍作用。采用磨擦浸种、草木灰溶液浸种、硫酸浸种法处理种子,效果很好,硬实率显著下降,发芽势、发芽率、发芽指数明显提高,且平均发芽天数也缩短。  相似文献   
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