全文获取类型
收费全文 | 609篇 |
免费 | 51篇 |
专业分类
林业 | 40篇 |
农学 | 6篇 |
基础科学 | 2篇 |
90篇 | |
综合类 | 36篇 |
农作物 | 22篇 |
水产渔业 | 38篇 |
畜牧兽医 | 343篇 |
园艺 | 6篇 |
植物保护 | 77篇 |
出版年
2023年 | 6篇 |
2022年 | 5篇 |
2021年 | 24篇 |
2020年 | 24篇 |
2019年 | 20篇 |
2018年 | 16篇 |
2017年 | 18篇 |
2016年 | 20篇 |
2015年 | 26篇 |
2014年 | 29篇 |
2013年 | 34篇 |
2012年 | 31篇 |
2011年 | 36篇 |
2010年 | 20篇 |
2009年 | 36篇 |
2008年 | 55篇 |
2007年 | 35篇 |
2006年 | 19篇 |
2005年 | 17篇 |
2004年 | 27篇 |
2003年 | 32篇 |
2002年 | 17篇 |
2001年 | 17篇 |
2000年 | 19篇 |
1999年 | 3篇 |
1997年 | 4篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 4篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 3篇 |
1968年 | 1篇 |
排序方式: 共有660条查询结果,搜索用时 31 毫秒
91.
Nik G. Wiman Daniel T. Dalton Gianfranco Anfora Antonio Biondi Joanna C. Chiu Kent M. Daane Beverly Gerdeman Angela Gottardello Kelly A. Hamby Rufus Isaacs Alberto Grassi Claudio Ioriatti Jana C. Lee Betsey Miller M. Valerio Rossi Stacconi Peter W. Shearer Lynell Tanigoshi Xingeng Wang Vaughn M. Walton 《Journal of pest science》2016,89(3):653-665
92.
Elisa González-Domínguez Vittorio Rossi Sami Jorge Michereff José García-Jiménez Josep Armengol 《European journal of plant pathology / European Foundation for Plant Pathology》2014,139(4):849-861
Dispersal of conidia of Fusicladium eriobotryae, the causal agent of loquat scab, was investigated in two loquat orchards in Spain from 2010 to 2012. A volumetric spore sampler, horizontally and vertically orientated microscope slides, and rain collectors were placed in loquat fields to trap conidia of F. eriobotryae. No conidia were collected in the volumetric sampler, and highly variable numbers of conidia were collected in the rain gatherers. Large numbers of conidia were collected by microscope slides, particularly by those held in a horizontal orientation compared with those held in a vertical orientation. Approximately 90 % of the F. eriobotryae conidia were collected during rainy periods. Based on ROC and Bayesian analysis, using ≥ 0.2 mm rainfall as a cut-off value resulted in a high probability of correctly predicting actual conidial dispersal, and had a low probability of failing to predict actual conidial dispersal. Based on the index of dispersion and the binary power law, the incidence of loquat scab on fruit was highly aggregated in space between and within trees, and aggregation was influenced by disease incidence. Our results demonstrate, for the first time, that F. eriobotryae is dispersed mainly in rain splash. The results will be integrated into a mechanistic, weather-driven, disease prediction model that should help growers to minimize fungicide application for the management of loquat scab. 相似文献
93.
94.
M Russo M Vignoli G Catone F Rossi G Attanasi GCW England 《Reproduction in domestic animals》2009,44(S2):334-335
Ultrasonography has become the imaging modality of choice for evaluation of the prostate gland in the dog. Unfortunately, despite providing excellent images, it may be difficult to differentiate the common canine prostatic diseases with ultrasound because many have a similar ultrasonographic appearance. Real-time contrast-enhanced ultrasound was used to monitor and characterise the normal perfusion pattern and perfusion dynamics of the canine prostate gland when using a micro bubble contrast agent. In all contrast studies, the prostatic artery, entered the prostate gland on the dorso-lateral surface then tunnelled into the prostatic capsule and branched into many small parenchymal arteries which were directed medially towards the urethra to supply the body of the prostate gland. The flow of the contrast medium into the prostatic parenchyma was visible after 15 s. During the wash-in phase, there was an homogenous enhancement of the prostatic parenchyma. During the wash-out phase, an homogenous decrease of the echogenicity was visible in all cases. 相似文献
95.
The expression pattern of TIR8 is conserved among vertebrates 总被引:1,自引:0,他引:1
Federica Riva Nadia Polentarutti Giulia Tribbioli Alberto Mantovani Cecilia Garlanda Lauretta Turin 《Veterinary immunology and immunopathology》2009,131(1-2):44-49
IL-1R/TLRs play an important role in the inflammatory responses. Their signaling pathway is tightly regulated to keep inflammation under control. The regulation involves both extracellular and intracellular mechanisms. TIR8, also known as SIGIRR (Single Immunoglobulin IL-1R-Related molecule), is an orphan receptor belonging to the IL-1R/TLRs super-family. Recent studies suggest its role in modulating the inflammatory response in the gastrointestinal tract in mice, acting as an IL-1 receptor family antagonist. We identified the sequence and analyzed the expression of TIR8 in a wide panel of organs and tissues in different animals. There was high homology of the cDNA sequence among human, mouse and the domestic species (74–85%). The pattern of expression of this receptor was similar in all the species examined (high levels in kidney and gastrointestinal tract) and similar to the human. These results demonstrate that TIR8 is conserved, in evolutionary terms, both with regard to sequence and pattern of expression, a finding consistent with a key function of this molecule in modulating inflammation in the gastrointestinal tract. 相似文献
96.
Colonisation of native and exotic conifers by indigenous bark beetles (Coleoptera: Scolytinae) in France 总被引:1,自引:0,他引:1
Coralie Bertheau Aurlien Salle Jean-Pierre Rossi Stphanie Bankhead-dronnet Xavier Pineau Graldine Roux-morabito Franois Lieutier 《Forest Ecology and Management》2009,258(7):1619-1628
Planting exotic conifers offers indigenous forest insects an opportunity to extend their host range and eventually to become significant pests. Knowing the ecological and evolutionary modalities driving the colonisation of exotic tree species by indigenous insects is thus of primary importance. We compared the bark beetle communities (Coleoptera: Curculionidae, Scolytinae) associated with both native and introduced conifers in France. The aim of our study was to estimate the influence of both host- and insect-related factors on the beetles’ likelihood to shift onto new hosts. We considered the influence of host origin (i.e. native vs. exotic), host tree species identity, tree bark thickness and tree taxonomic proximity, as well as insects’ host specificity. A field inventory using trap trees was carried out in two regions in France (Limousin and Jura) during two consecutive years (2006 and 2007) on three European native conifer species [Norway spruce (Picea abies); Scots pine (Pinus sylvestris) and European Silver-fir (Abies alba)] and five North American [Sitka spruce (Picea sitchensis); Eastern white pine (Pinus strobus); Grand fir (Abies grandis); Douglas fir (Pseudotsuga menziesii) and Western red cedar (Thuja plicata)]. A total of 18 indigenous and 2 exotic bark beetle species were collected. All exotic conifer species were colonised by indigenous bark beetle species and no significant difference was observed of the cumulated species richness of the latter between native and exotic tree species (13 vs. 14, P < 0.05). The ability of indigenous bark beetles to shift onto exotic conifers appeared to strongly depend on host species (significantly structuring bark beetle assemblages), the presence of phylogenetically related native conifer species and that of similar resources, in combination with insect host specificity. Host tree species status (native or exotic) also seemed to be involved, but its effect did not seem as essential as that of the previous factors. These findings are discussed in terms of adaptation, plasticity and practical aspects of forest management. 相似文献
97.
Federica Menichini Rosa TundisMonica R. Loizzo Marco BonesiMariangela Marrelli Giancarlo A. StattiFrancesco Menichini Filomena Conforti 《Fitoterapia》2009
Ethanolic extract from the fruits of Pimpinella anisoides, an aromatic plant and a spice, exhibited activity against AChE and BChE, with IC50 values of 227.5 and 362.1 μg/ml, respectively. The most abundant constituents of the extract were trans-anethole, (+)-limonene and (+)-sabinene. trans-Anethole exhibited the highest activity against AChE and BChE with IC50 values of 134.7 and 209.6 μg/ml, respectively. The bicyclic monoterpene (+)-sabinene exhibited a promising activity against AChE (IC50 of 176.5 μg/ml) and BChE (IC50 of 218.6 μg/ml). 相似文献
98.
J.-P. Rossi J.-C. Samalens D. Guyon I. van Halder H. Jactel P. Menassieu D. Piou 《Forest Ecology and Management》2009
Bark beetles are notorious pests of natural and planted forests causing extensive damage. These insects depend on dead or weakened trees but can switch to healthy trees during an outbreak as mass-attacks allow the beetle to overwhelm tree defences. Climatic events like windstorms are known to favour bark beetle outbreaks because they create a large number of breeding sites, i.e., weakened trees and for this reason, windthrown timber is generally preventively harvested and removed. In December 1999, the southwest of France was struck by a devastating windstorm that felled more that 27 million m3of timber. This event offered the opportunity to study large-scale spatial pattern of trees attacked by the bark beetle Ips sexdentatus and its relationship with the spatial location of pine logs that were temporally stored in piles along stand edges during the post-storm process of fallen tree removal. The study was undertaken in a pure maritime pine forest of 1300 ha in 2001 and 2002. We developed a landscape approach based on a GIS and a complete inventory of attacked trees. During this study more than 70% of the investigated stands had at least one tree attacked by I. sexdentatus . Spatial aggregation prevailed in stands with n≥15 attacked trees. Patches of attacked trees were identified using a kernel estimation procedure coupled with randomization tests. Attacked trees formed patches of 500–700 m2 on average which displayed a clumped spatial distribution. Log piles stemming from the sanitation removals were mainly distributed along the large access roads and showed an aggregated spatial pattern as well. The spatial relationship between patches of attacked trees and log pile storage areas was analyzed by means of the Ripley’s statistic that revealed a strong association at the scale of the studied forest. Our results indicated that bark beetle attacks were facilitated in the vicinity of areas where pine logs were stored. The spatial extent of this relationship was >1000 m. Similar results were obtained in 2001 and 2002 despite differences in the number and spatial distribution of attacked trees. The presence of a strong “facilitation effect” suggests that log piles should be removed quickly in order to prevent outbreaks of bark beetles. 相似文献
99.
Multi-electrode 3D resistivity imaging of alfalfa root zone 总被引:2,自引:0,他引:2
Mariana Amato Giovanni Bitella Roberta Rossi Jos A. Gmez Stella Lovelli Joo J. Ferreira Gomes 《European Journal of Agronomy》2009,31(4):213-222
Information on the amount and spatial distribution of plant roots is increasingly needed for understanding and managing crop behaviour. Soil electrical resistivity (ρ) tomography has been proposed as a non-destructive method for root biomass quantification and mapping in trees but evidence is needed on the applicability of the technique at low root density and in herbaceous plants.We produced high-resolution 3D DC soil resistivity tomograms in containers with bare soil (B), and alfalfa (Medicago sativa L.) (A1) on a silt loam soil, and alfalfa on a loam (A2). Root biomass (RMD), root length density (RLD), soil electrical conductivity (EC) and water content (θ) were measured destructively.The pattern of soil resistivity matched the spatial distribution of θ in bare soil and of RMD in rooted soil. Univariate linear relations were found between ρ and θ in bare soil and between ρ, RLD and RMD in rooted soil. Across all data RMD and soil texture (P < 0.01) explained a high proportion of variability in soil resistivity.This allows to conclude that soil resistivity is quantitatively related to root biomass in herbaceous plants even at low root density (biomass < 0.001 Mg m−3), providing a basis for the development of resistivity-founded methods for the non-destructive spatial detection of root mass in situ, but the response in ρ is of the same order of magnitude as the effects of grain size and water content. Therefore in field studies reciprocal masking of low-density roots and other soil features is possible, and the effect of variation in other soil properties should be explicitly addressed. 相似文献
100.
Vittorio Rossi Elisabetta Pattori Riccardo Bugiani 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(2):147-159
The dynamics of the production of Stemphylium vesicarium conidia and Pleospora allii ascospores from different inoculum sources on the ground were compared in a model system of a wildflower meadow mainly composed
of yellow foxtail, creeping cinquefoil and white clover. The meadow was either inoculated (each October) or not inoculated
with a virulent strain of S. vesicarium, and either covered or not covered with a litter of inoculated pear leaves. Spore traps positioned a few centimetres above
the ground were exposed for 170 7-day periods between October 2003 and December 2006. Ascospores and conidia were trapped
in 46 and 25% of samples, respectively. Ascospore numbers trapped from the pear leaf litter were about five times higher than
those from the meadow, while conidial numbers were similar from the different inoculum sources. The ascosporic season was
very long, with two main trapping periods: December–April, and August–October; the former was most important for the leaf
litter, the latter for the meadow. The conidial season lasted from April to November, with 92% of conidia caught between July
and September. The fungus persistently colonized the meadow: the meadow inoculated in early October 2003 produced spores until
autumn 2006. The present work demonstrates that orchard ground is an important source of inoculum for brown spot of pear.
Thus, it is important to reduce inoculum by managing the orchard ground all year long. 相似文献