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991.
Brian L. Sullivan Christopher L. Wood Marshall J. Iliff Rick E. Bonney Daniel Fink Steve Kelling 《Biological conservation》2009,142(10):2282-2292
New technologies are rapidly changing the way we collect, archive, analyze, and share scientific data. For example, over the next several years it is estimated that more than one billion autonomous sensors will be deployed over large spatial and temporal scales, and will gather vast quantities of data. Networks of human observers play a major role in gathering scientific data, and whether in astronomy, meteorology, or observations of nature, they continue to contribute significantly. In this paper we present an innovative use of the Internet and information technologies that better enhances the opportunity for citizens to contribute their observations to science and the conservation of bird populations. eBird is building a web-enabled community of bird watchers who collect, manage, and store their observations in a globally accessible unified database. Through its development as a tool that addresses the needs of the birding community, eBird sustains and grows participation. Birders, scientists, and conservationists are using eBird data worldwide to better understand avian biological patterns and the environmental and anthropogenic factors that influence them. Developing and shaping this network over time, eBird has created a near real-time avian data resource producing millions of observations per year. 相似文献
992.
Repeated fire is key to the viability of longleaf pine (Pinus palustris Mill.) ecosystems, but its acceptance as a management tool may depend on satisfactory longleaf pine growth. This is because longleaf pine establishment often has the dual-purpose of ecosystem restoration and stemwood production. Timely recovery of scorched foliage among longleaf pine seedlings and saplings supports maximum juvenile growth. We identified two means of foliage re-establishment in the growing season after prescribed fire regardless of the season of fire application. New foliage growth after spring or fall fire was correlated with un-scorched foliage biomass and the presence of lateral branches. After prescribed fire in spring, foliage biomass recovery also appeared to benefit from the mobilization of starch. The high carbon demand of foliage recovery after fall prescribed fire was associated with interruption of seasonal starch accumulation in the stem and taproot. The implication of low starch accumulation in stem and taproot tissues during the growing season after fall prescribed fire is unknown and warrants further investigation. Our results demonstrate a positive influence of residual foliage, lateral branches, and stored starch on timely foliage recovery of young longleaf pines after fire. Together with knowledge of longleaf pine development and fuel and climate conditions at the time of prescribed fire, this information will aid prescribed fire practitioners charged with maintaining longleaf pine stands of high vigor. 相似文献
993.
994.
Marcelo Braga Bueno Guerra Brian T. Teaney Brianna J. Mount Daniel J. Asunskis Brennan T. Jordan Ryan J. Barker Eliana E. Santos Carlos Ernesto G. R. Schaefer 《Water, air, and soil pollution》2017,228(7):252
On November 5, 2015, after the collapse of the Fundão tailings dam, a massive amount of iron mine waste was released into the Doce River system in southeast Brazil. The aim of our study was to determine the mass fractions of potentially toxic elements in soil affected by the deposition of material by the waste wave. A preliminary screening was performed with portable X-ray fluorescence spectrometry (PXRF) and principal component analysis (PCA). The EPA 3050B method was further applied to digest the samples for quantitative determination of As, Ba, Cr, Cu, Mn, Ni, Pb, V, and Zn by inductively coupled plasma mass spectrometry. PCA was useful to classify the mine waste samples based on the Fe signal from the PXRF spectra, in spite of the heterogeneous nature of the material discharged into the Doce River system. The anomalous levels of As (up to 164 mg kg?1) and Mn (as high as 2410 mg kg?1) found in some mine waste and affected soil samples are within the background ranges typically observed in the soils of the Iron Quadrangle region. The toxicity characteristic leaching procedure shows no evidence of hazards regarding As, but a high natural background level of Mn was found in the mobile fraction. This preliminary environmental assessment highlights the importance of evaluation of long-term effects on soil directly impacted, as well as on the aquatic biota of the Doce River system and adjacent coastal environment given the large affected area, which includes regions with varying background levels of toxic elements. 相似文献
995.
996.
Seasonal floodplain‐tidal slough complex supports size variation for juvenile Chinook salmon (Oncorhynchus tshawytscha)
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Pascale A.L. Goertler Ted R. Sommer William H. Satterthwaite Brian M. Schreier 《Ecology of Freshwater Fish》2018,27(2):580-593
Population diversity is a mechanism for resilience and has been identified as a critical issue for fisheries management, but restoration ecologists lack evidence for specific habitat features or processes that promote phenotypic diversity. Since habitat complexity may affect population diversity, it is important to understand how population diversity is partitioned across landscapes and among populations. In this study, we examined life history diversity based on size distributions of juvenile Central Valley Chinook salmon (Oncorhynchus tshawytscha) within the Yolo Bypass, a remnant transitional habitat from floodplain to tidal sloughs in the upper San Francisco Estuary (SFE). We used a generalized least squares model with an autoregressive (AR1) correlation structure to describe the distribution of variation in fish size from 1998 to 2014, and tested the effect of two possible drivers of the observed variation: (i) environmental/seasonal drivers within the Yolo Bypass, and (ii) the juvenile Chinook source population within the Sacramento River and northern SFE. We found that the duration of floodplain inundation, water temperature variation, season, and sampling effort influenced the observed time‐specific size distribution of juvenile Chinook salmon in the Yolo Bypass. Given the lack of seasonally inundated habitat and low thermal heterogeneity in the adjacent Sacramento River, these drivers of juvenile size diversification are primarily available to salmon utilizing the Yolo Bypass. Therefore, enhancement of river floodplain‐tidal slough complexes and inundation regimes may support the resilience of imperiled Central Valley Chinook salmon. 相似文献
997.
Effects of Season,Strain, and Body Weight on Testes Development and Quality in Three Strains of Blue Catfish,Ictalurus furcatus
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Brian Bosworth Sylvie Quiniou Nagaraj Chatakondi 《Journal of the World Aquaculture Society》2018,49(1):175-182
Production of channel catfish, Ictalurus punctatus, female × blue catfish, Ictalurus furcatus, male hybrids has increased dramatically in the USA. Hybrid production requires surgical removal and maceration of blue catfish testes. Farmers report individual and seasonal variation in blue catfish testes development, and understanding the factors influencing testes development could improve hybrid catfish production. Effects of season (mid‐May vs. mid‐June), strain (D&B, Missouri, and Texas), and body weight on testes development in 5‐yr‐old blue catfish were determined. Males were measured in mid‐May and mid‐June for length, body weight, testes weight, and gonadosomatic index (GSI). Total sperm/g of testes, percent motility, and motile sperm/g of testes were determined. D&B strain males weighed more and had larger testes with more sperm than Missouri or Texas strain males in both months. Mature Texas strain males were larger than immature Texas strain males in both months. Testes were larger and had more sperm in May than in June for all strains; however, there were males from each strain with good quality testes in June. GSI, sperm/g of testes, percent motility, and motile sperm/g of testes were positively correlated. Information from this study provides a better understanding of factors influencing testes development in blue catfish. 相似文献
998.
Georgina Catacora-Vargas Rosa Binimelis Anne I. Myhr Brian Wynne 《Agriculture and Human Values》2018,35(2):489-513
The importance of socio-economic impacts (SEI) from the introduction and use of genetically modified (GM) crops is reflected in increasing efforts to include them in regulatory frameworks. Aiming to identify and understand the present knowledge on SEI of GM crops, we here report the findings from an extensive study of the published international scientific peer-reviewed literature. After applying specified selection criteria, a total of 410 articles are analysed. The main findings include: (i) limited empirical research on SEI of GM crops in the scientific literature; (ii) the main focus of the majority of the published research is on a restricted set of monetary economic parameters; (iii) proportionally, there are very few empirical studies on social and non-monetary economic aspects; (iv) most of the research reports only short-term findings; (v) the variable local contexts and conditions are generally ignored in research methodology and analysis; (vi) conventional agriculture is the commonly used comparator, with minimal consideration of other substantially different agricultural systems; and (vii) there is the overall tendency to frame the research upon not validated theoretical assumptions, and to over-extrapolate small-scale and short-term specific results to generalized conclusions. These findings point to a lack of empirical and comprehensive research on SEI of GM crops for possible use in decision-making. Broader questions and improved methodologies, assisted by more rigorous peer-review, will be required to overcome current research shortcomings. 相似文献
999.
Street sweeping is regularly performed within cities and residential communities to reduce roadway debris and ensure properly functioning storm water management systems. Given removal of plant and soil debris, street sweeping may also reduce nonpoint source pollution through removal of leachate source material. To assess the influence of street sweeping on storm water pollutants, 36 storm water collection devices were installed within six residential communities in Central Florida and subjected to varying municipal sweeping regimes. Additionally, precipitation and storm water retention pond leachate samplers were installed to quantify pollutant sources that may enter and leave selected urban communities. Despite high variability in percentage of impervious surfaces, population density, and volume of road debris among communities, no significant (P?≤?0.05) differences were observed for total Kjeldahl nitrogen (TKN), nitrate + nitrite (NOx), and total phosphorus (TP) concentrations in storm water among communities or between swept and unswept areas of roadways. Similarly, no significant differences were observed for TKN, NOx, and TP concentrations in precipitation and storm water. Significant differences in orthophosphate (ortho-P), however, were observed between communities and precipitation. Additionally, storm water TP concentrations were greater than discharge estimated to originate from communities within the study area. Although street sweeping may be effective at reducing volume of roadway debris, our data did not find it reduced N or P in storm water. 相似文献
1000.
Assessing the value and pest management window provided by neonicotinoid seed treatments for management of soybean aphid (Aphis glycines Matsumura) in the Upper Midwestern United States
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