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971.
972.
973.
Schäberle TF Goralski E Neu E Erol O Hölzl G Dörmann P Bierbaum G König GM 《Marine drugs》2010,8(9):2466-2479
Three myxobacterial strains, designated SWB004, SWB005 and SWB006, were obtained from beach sand samples from the Pacific Ocean and the North Sea. The strains were cultivated in salt water containing media and subjected to studies to determine their taxonomic status, the presence of genes for the biosynthesis of polyketides and antibiotic production. 16S rDNA sequence analysis revealed the type strain Enhygromyxa salina SHK-1(T) as their closest homolog, displaying between 98% (SWB005) and 99% (SWB004 and SWB006) sequence similarity. All isolates were rod-shaped cells showing gliding motility and fruiting body formation as is known for myxobacteria. They required NaCl for growth, with an optimum concentration of around 2% [w/v]. The G + C-content of genomic DNA ranged from 63.0 to 67.3 mol%. Further, the strains were analyzed for their potential to produce polyketide-type structures. PCR amplified ketosynthase-like gene fragments from all three isolates enhances the assumption that these bacteria produce polyketides. SWB005 was shown to produce metabolites with prominent antibacterial activity, including activity towards methicillin resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE). 相似文献
974.
Eve Runno-Paurson Triinu Remmel Ann Ojarand Alice Aav Marika Mänd 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(3):373-383
The characteristics of populations of Phytophthora infestans from organic farms, small conventional farms and large conventional farms were determined from isolates collected in northern
Estonia in 2004 and 2005. For the population as a whole 41% were A2; all virulence factors to the 11 R genes from Solanum demissum were found; and more than 70% had high or intermediate resistance to metalaxyl. Isolates from organic farms tended to have
more complex pathotypes than isolates from either large or small conventional farms, but there was a higher proportion of
metalaxyl resistant isolates from large conventional farms than from small conventional farms or from organic farms. 相似文献
975.
976.
977.
Alan L Knight 《Pest management science》2010,66(8):865-874
BACKGROUND: Codling moth, Cydia pomonella (L.), has been intensely managed with the organophosphate insecticide azinphos‐methyl for 50 years, and populations have developed resistance. New management programs have been developed and implemented that rely more heavily on other classes of insecticides. A prerequisite for developing effective resistance management strategies for these compounds is to establish their current levels of effectiveness. Adult and neonate larval assays were conducted to assess the response of field‐collected codling moth populations from apple in Washington State. RESULTS: Male codling moth populations exhibited a range of responses to a discriminating concentration of azinphos‐methyl in a survey of 20 populations. Populations from certified organic orchards were more susceptible than those from conventional orchards. Mean fecundity was inversely related to azinphos‐methyl tolerance. Male responses to azinphos‐methyl and acetamiprid varied significantly among populations and were correlated. The residual effectiveness of field applications of both insecticides varied significantly against neonate larvae. Neonate bioassays with insecticide‐dipped fruit found significant differences among populations with azinphos‐methyl, acetamiprid, methoxyfenozide and spinosad, but not with esfenvalerate. CONCLUSION: These results support a concern that alternation of insecticides with different modes of action may not be a sufficient strategy to avoid the evolution of broad‐spectrum insecticide resistance by codling moth. Published 2010 by John Wiley & Sons, Ltd. 相似文献
978.
Martin Kohler Julia Sohn Gregor Nägele Jürgen Bauhus 《European Journal of Forest Research》2010,129(6):1109-1118
To investigate whether drought tolerance of individual trees can be increased through the provision of more growing space,
trees from a thinning experiment were analysed for reductions in radial growth during drought years and their subsequent recovery.
Tree-ring widths were quantified on increment cores as well as stem discs of 32 trees from stands of a thinning trial established
in 1974 in 27-year-old spruce stands in the Alpine Foreland of Southwest Germany. Three different thinning regimes of the
trial were selected for this study: unthinned control (8 trees), moderate (13 trees) and heavy thinning (11 trees) intensities.
All trees sampled were of a co-dominant to dominant canopy status. The standardisation of growth data was carried out using
the software program ARSTAN (University of Arizona). For the year 1976—a widespread and severe drought year in Germany—we
found year ring widths were not reduced compared to those of the pre-drought years for all treatments. However, we observed
the formation of false year rings and resin ducts for this year in all trees investigated. The drought events in 1992 and
2003 led to severe growth depressions in the year of the drought event in all trees, regardless of previous thinning regimes.
However, the resilience—the recovery of basal area growth in subsequent years—was significantly more rapid in trees from heavily
thinned stands, even if the drought event occurred more than 10 years after the last thinning intervention. This indicates
a shorter stress period for trees with more growing space, which may reduce the susceptibility to secondary pathogens or pest
species such as bark beetles. 相似文献
979.
980.
Markus Holopainen Antti Mäkinen Jussi Rasinmäki Juha Hyyppä Hannu Hyyppä Harri Kaartinen Risto Viitala Mikko Vastaranta Annika Kangas 《European Journal of Forest Research》2010,129(5):899-907
The objective was to compare tree-level airborne laser-scanning (ALS) data accuracy with standwise estimation data accuracy
as input data for forest planning, using tree- and stand-level simulators. The influence of the input data accuracy was studied
with respect to (1) timing of the next thinning or clear-cutting and (2) the relative variation in the predicted income of
the next logging expressed as the net present value (NPV). The timing and predicted NPV of thinning and clear-cutting operations
were considered separately. The research was based on Monte Carlo simulations carried out with the tree- and stand-level simulators
using a simulation and optimisation (SIMO) framework. The simulations used treewise measurements taken on 270 circular plots
measured at the Evo Field Station, Finland, as input data. Deviations in the tree data measured were generated according to
the mean standard errors found in standwise field estimation and tree-level ALS. The accuracy factors of ALS individual tree
detection were based on the EUROSDR/ISPRS Tree Extraction Project. The results show that input data accuracy significantly
affects both the timing and relative NPV of loggings. Tree-level ALS produces more accurate simulation results than standwise
estimation with the error levels assumed. Diameter-based characteristics are the most important input data in all simulations.
Accurate tree height estimates cannot be fully utilised in current simulators. 相似文献