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101.
Kumud?B.?MishraEmail author Anamika?Mishra Kate?ina?Novotná Barbora?Rapantová Petra?Hodaňová Otmar?Urban Karel?Klem 《Plant methods》2016,12(1):46
Background
Non-invasive and high-throughput monitoring of drought in plants from its initiation to visible symptoms is essential to quest drought tolerant varieties. Among the existing methods, chlorophyll a fluorescence (ChlF) imaging has the potential to probe systematic changes in photosynthetic reactions; however, prerequisite of dark-adaptation limits its use for high-throughput screening.Results
To improve the throughput monitoring of plants, we have exploited their light-adaptive strategy, and investigated possibilities of measuring ChlF transients under low ambient irradiance. We found that the ChlF transients and associated parameters of two contrasting Arabidopsis thaliana accessions, Rsch and Co, give almost similar information, when measured either after ~20 min dark-adaptation or in the presence of half of the adaptive growth-irradiance. The fluorescence parameters, effective quantum yield of PSII photochemistry (ΦPSII) and fluorescence decrease ratio (R FD) resulting from this approach enabled us to differentiate accessions that is often not possible by well-established dark-adapted fluorescence parameter maximum quantum efficiency of PSII photochemistry (F V/F M). Further, we screened ChlF transients in rosettes of well-watered and drought-stressed six A. thaliana accessions, under half of the adaptive growth-irradiance, without any prior dark-adaptation. Relative water content (RWC) in leaves was also assayed and compared to the ChlF parameters. As expected, the RWC was significantly different in drought-stressed from that in well-watered plants in all the six investigated accessions on day-10 of induced drought; the maximum reduction in the RWC was obtained for Rsch (16%), whereas the minimum reduction was for Co (~7%). Drought induced changes were reflected in several features of ChlF transients; combinatorial images obtained from pattern recognition algorithms, trained on pixels of image sequence, improved the contrast among drought-stressed accessions, and the derived images were well-correlated with their RWC.Conclusions
We demonstrate here that ChlF transients and associated parameters measured even in the presence of low ambient irradiance preserved its features comparable to that of measured after dark-adaptation and discriminated the accessions having differential geographical origin; further, in combination with combinatorial image analysis tools, these data may be readily employed for early sensing and mapping effects of drought on plant’s physiology via easy and fully non-invasive means.102.
Interactions between crops and soil micro- and mesofauna within the root zone were investigated under field conditions on sandy loam on a larger spatial scale and in columns in the laboratory on a smaller spatial scale. During the vegetation period of summer wheat from April to July 1999 soil samples were taken monthly directly from the root zone within plant rows and between plant rows hardly penetrated by roots. Abundances of Enchytraeidae, Collembola, soil flagellates, enzyme activities and contents of total carbon and nitrogen were determined. Additionally, a laboratory experiment was carried out with soil columns. Soil from the field was defaunated and inoculated with soil fauna (Enchytraeidae, Collembola, earthworms) in different combinations. Furthermore, summer wheat was sown. Enzyme activities, soil flagellate abundance and contents of total carbon and nitrogen were measured after 2, 6 and 14 weeks. Our field results revealed considerable interactions between plant roots, sampling date and soil layer affecting Enchytraeidae and Collembola. Within plant rows flagellate numbers correlated higher with Nt and Ct than between plant rows. In the laboratory close relationships between soil fauna as well as enzyme activities and nutrients contents were found within the root zone. 相似文献
103.
The article shows results of an international and interdisciplinary project with the title ‘Rainfall and its Erosivity in Ethiopia’. The article contains information about the traditional soil conservation practices, the reasons for intervention with traditional soil conservation technologies, the historical background of instutionalized soil conservation activities, the institutional frame work for soil conservation activities and their achievements, and the different departments and organisations for soil and water conservation as far as soil erosion in Ethiopia is concerned. As a conclusion and recommendation, the major constraints of the past activities and the current situation including future trends were discussed. 相似文献
104.
Kyle VanderLugt Michael J. Cooney Anna Lechner Petra H. Lenz 《Journal of the World Aquaculture Society》2009,40(5):616-628
First feed production continues to be a major barrier to the cultivation of many fish species. Although copepod nauplii are a suitable food, consistency and high production have been difficult. Temporal changes in production in batch cultures of the calanoid copepod, Bestiolina similis, were investigated to develop management strategies for the use of copepod nauplii as a live food. Population abundances and female egg production rates were measured, and recruitment and mortality rates were calculated. Relative expression levels of a molecular biomarker for stress, heat shock protein hsp70, were determined using real‐time quantitative polymerase chain reaction. The population cycle included a period of rapid increase in abundances, followed by a steep decline and a period of stable but low population densities. Initially, egg production exceeded 25 eggs per female per day and low mortality rates prevailed. The population decline was preceded by upregulation of hsp70 and followed by an 80–90% decline in female fecundity and an increase in mortality rates. Egg production rates remained below four eggs per female per day even after new generations of females reached adulthood. The predictable population cycle provides opportunities to coordinate nauplius production rates with first feed needs of fish larvae. 相似文献
105.
Background
Studies of population genetic structures provide an indication of direction and magnitude of larval transport and hence are an important component in the assessment of the ability of reefs to recover from severe disturbance. This paper reports data on population genetic structures in the coral Pocillopora damicornis from 26 reefs in Kenya and Tanzania. 相似文献106.
Studies of effects of fertilizer treatment on ectomycorrhizal fungal community structure have predominantly been based on large, single additions of nitrogen. Studies involving chronic additions of nutrients in combination with irrigation are much less common. We used morphotyping to study effects of balanced additions of a nutrient solution on ectomycorrhizal fungal community structure in a 36-year-old stand of Picea abies (L.) Karst. Despite high variability among individual samples, principal components analysis revealed a clear shift in community structure in response to fertilization. Irrigated plots receiving only water did not differ significantly from untreated control plots. Mycorrhizal root tips colonized by Cenococcum geophilum Fr. were significantly more common in fertilized plots than in control plots. Possible responses by other ectomycorrhizal species were masked by high variability. Over sixty morphotypes were distinguished, but there was no measurable effect of either fertilizer or irrigation treatment on morphotype richness or total number of root tips. 相似文献
107.
Joyotee Smith Socorro Ferreira Petra van de Kop Célio Palheta Ferreira Cesar Sabogal 《Agroforestry Systems》2003,58(2):125-135
While slash-and burn farmers convert forest to agriculture, they also regenerate significant areas of secondary fallow forests on their farms. Under what conditions does secondary forest cover persist on slash-and-burn farms? Survey data from Pará, Brazil show that secondary forests occupy 20% of farm area even after a century of settlement. In addition to restoring soil fertility, secondary forests contribute over 20% of farmers' income through products such as charcoal, fruit, game animals and firewood for on-farm processing. Econometric analysis shows that slow rates of population growth and increases in agricultural incomes through on-farm processing of agricultural products enable farmers to maintain long fallows and result in diversified systems compatible with secondary forest cover in the study area. On the other hand, declining agricultural productivity, subsidized credit, declines in the growth rate of secondary forests and policies favoring speculative land acquisition threaten secondary forest persistence. In older settlement areas, secondary forests are often the only forest resource available to the rural poor. Fallow areas should therefore be managed not only for agricultural productivity, but also for conserving forest resources. 相似文献
108.
Orfanos P Naska A Trichopoulos D Slimani N Ferrari P van Bakel M Deharveng G Overvad K Tjønneland A Halkjaer J Santucci de Magistris M Tumino R Pala V Sacerdote C Masala G Skeie G Engeset D Lund E Jakszyn P Barricarte A Chirlaque MD Martinez-Garcia C Amiano P Quirós JR Bingham S Welch A Spencer EA Key TJ Rohrmann S Linseisen J Ray J Boeing H Peeters PH Bueno-de-Mesquita HB Ocke M Johansson I Johansson G Berglund G Manjer J Boutron-Ruault MC Touvier M Clavel-Chapelon F Trichopoulou A 《Public health nutrition》2007,10(12):1515-1525
109.
Bamia C Trichopoulos D Ferrari P Overvad K Bjerregaard L Tjønneland A Halkjaer J Clavel-Chapelon F Kesse E Boutron-Ruault MC Boffetta P Nagel G Linseisen J Boeing H Hoffmann K Kasapa C Orfanou A Travezea C Slimani N Norat T Palli D Pala V Panico S Tumino R Sacerdote C Bueno-de-Mesquita HB Waijers PM Peeters PH van der Schouw YT Berenguer A Martinez-Garcia C Navarro C Barricarte A Dorronsoro M Berglund G Wirfält E Johansson I Johansson G Bingham S Khaw KT Spencer EA Key T Riboli E Trichopoulou A 《Public health nutrition》2007,10(6):590-598
110.
Jana Boben Petra Kramberger Nataša Petrovič Katarina Cankar Matjaž Peterka Aleš Štrancar Maja Ravnikar 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(1):59-71
A quantitative RT real-time PCR method was developed for the detection and quantification of Tomato mosaic virus (ToMV) in irrigation waters. These have rarely been monitored for the presence of plant pathogenic viruses, mostly due to the lack of efficient and sensitive detection methods. The newly developed method presented here offers a novel approach in monitoring the health status of environmental waters. ToMV was reliably detected at as low as 12 viral particles per real-time PCR reaction, which corresponds to the initial concentration of approximately 4.2 × 10?10 mg (6,300 viral particles) of ToMV per ml of sample. The sensitivity of the method was further improved by including the Convective Interaction Media® (CIM) monolithic chromatographic columns for quick and efficient concentration of original water samples. Seven out of nine water sources from different locations in Slovenia tested positive for ToMV, after concentrating the sample. Four samples tested ToMV-positive without the concentrating procedure. The presence and integrity of infective ToMV particles in the original sample, as well as in the chromatographic fraction, was confirmed using different methods from test plants, DAS ELISA to electron microscopy and real-time PCR. In this study, we propose a unique and simple diagnostic scheme for rapid, efficient, and sensitive monitoring of irrigation waters that could also be adopted for other plant, human or animal viruses. 相似文献