全文获取类型
收费全文 | 200篇 |
免费 | 30篇 |
专业分类
林业 | 40篇 |
农学 | 11篇 |
基础科学 | 1篇 |
36篇 | |
综合类 | 15篇 |
农作物 | 4篇 |
水产渔业 | 17篇 |
畜牧兽医 | 80篇 |
园艺 | 4篇 |
植物保护 | 22篇 |
出版年
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 5篇 |
2013年 | 1篇 |
2012年 | 11篇 |
2011年 | 17篇 |
2010年 | 16篇 |
2009年 | 9篇 |
2008年 | 12篇 |
2007年 | 14篇 |
2006年 | 16篇 |
2005年 | 13篇 |
2004年 | 12篇 |
2003年 | 8篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1981年 | 2篇 |
1978年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有230条查询结果,搜索用时 13 毫秒
61.
Myeloperoxidase concentration in bronchoalveolar lavage fluid from healthy horses and those with recurrent airway obstruction 下载免费PDF全文
Tatiana Art Thierry Franck Pierre Lekeux Brieuc de Moffarts Laurent Couëtil Martine Becker Serge Kohnen Ginette Deby-Dupont Didier Serteyn 《Canadian journal of veterinary research》2006,70(4):291-296
The aim of this work was to measure the myeloperoxidase (MPO) concentration in bronchoalveolar lavage (BAL) fluid collected from horses with recurrent airway obstruction (RAO), both in crisis and in remission, as well as from healthy horses. Seven horses with RAO were exposed to moldy hay until the maximum change in pleural pressure was greater than 1.5 kPa. At that point, BAL was performed, and the total cell counts and percentages in the fluid were immediately determined. To measure the MPO concentration in BAL-fluid supernatant, we used a specific enzyme-linked immunosorbent assay with polyclonal antibodies against equine MPO. The tests were repeated on the horses with RAO after they had spent 2 mo on pasture. Six healthy horses serving as controls underwent the same tests. The absolute and relative neutrophil counts and the MPO concentration in the BAL fluid were significantly greater in the horses with an RAO crisis than in the control horses. After 2 mo on pasture, the horses that had been in RAO crisis were clinically normal, and their neutrophil counts and MPO levels in BAL fluid had significantly decreased; during remission their neutrophil counts were not significantly different from those in the healthy horses, but their MPO concentration remained significantly higher. This study showed that determining the MPO concentration in a horse's BAL fluid is technically possible and that during remission from RAO the concentration remains higher than normal. Thus, MPO may be a marker of neutrophil presence and activation in the lower airways. 相似文献
62.
Delphine?Allorent Serge?SavaryEmail author 《European journal of plant pathology / European Foundation for Plant Pathology》2005,113(4):329-341
In this review, available knowledge on angular leaf spot (ALS) of bean, caused by Phaeoisariopsis griseola, is analysed and synthesised. This is done through a systems-analytical approach, and successive flowcharts of the system,
in order to identify knowledge gaps and guide further research. Six connected sub-models of the ALS monocycle are used as
a framework: lesion establishment, lesion extension, defoliation, sporulation, spore liberation, and spore deposition. Each
of the sub-models enables the linking of processes to various effects of environmental (physical and host) factors. Disease-induced
defoliation is one feature of the pathosystem, leading to a depletion of infectious tissues from the canopy, which are transferred
to the ground. Consequences of defoliation may include: strong reductions of the amount of inoculum and of vacant sites in
the canopy, limited maximum disease severity, and progressive accumulation of inoculum below the canopy, which may become
important a later stage of disease epidemics. These elements are hypothesised to explain the typical behaviour of ALS epidemics
in the field, especially late onset, high apparent rate of disease increase, and low level of terminal disease severity in
the standing canopy. Epidemiological consequences of lesion expansion, sporulation, and survival of spores deposited onto
the canopy are other knowledge gaps in this pathosystem. 相似文献
63.
Delphine?Allorent Laetitia?Willocquet Aloisio?Sartorato Serge?SavaryEmail author 《European journal of plant pathology / European Foundation for Plant Pathology》2005,113(4):377-394
Daily multiplication factor (number of daughter lesions per mother lesion per day) values were experimentally measured in
four replications of a monocyclic experiment on angular leaf spot (ALS) of bean, where sources of inoculum were artificially
established within a bean canopy, on the ground (defoliated infected leaves), or both. Daily multiplication factor of lesions
in the canopy (DMFRc) was higher than that of infectious, defoliated tissues (DMFRd) in all replications. Both DMFRc and DMFRd
were strongly reduced under dry compared to rainy conditions. Under rainy conditions for spore dispersal DMFRd was about two
to three times smaller than DMFRc. Defoliated leaves may nevertheless represent a significant source of infection, depending
on the amount of infectious tissues. Mother lesions within the canopy generated more daughter lesions in the medium (or lower)
layers of the canopy than at its upper level (DMFRc higher at the medium and lower layers of a canopy), whereas DMFRd values
seemed to decrease with height in the canopy. A mechanistic simulation model that combines host growth and disease-induced
defoliation was designed to simulate the respective contributions of the two components of the dual inoculum source of a diseased
canopy (infected foliage and defoliated infectious tissues), and varying infectious periods in both sources. Simulations suggest
that higher DMFRc values have a large polycyclic effect on epidemics whereas that of DMFRd is small, and that large effects
of the infectious period of lesions in the canopy are found when DMFRc is high. Simulations using experimentally measured
DMFRc and DMFRd values indicated much stronger epidemics in rainy compared to dry conditions for spore dispersal, but disease
persistence in the latter. The implications of considering a dual source of inoculum in the course of a polycyclic process
are discussed with respect to epidemic thresholds. 相似文献
64.
Vertical root separation and light interception in a temperate tree-based intercropping system of Eastern Canada 总被引:1,自引:0,他引:1
Léa Bouttier Alain Paquette Christian Messier David Rivest Alain Olivier Alain Cogliastro 《Agroforestry Systems》2014,88(4):693-706
We analysed the spatial distribution of fine roots and light availability in a tree-based intercrop system (TBI) composed of Quercus rubra L. (QUR), hybrid poplar (Populus deltoides × Populus nigra—HYP) and hay (CROP) in southern Québec (Canada) to evaluate interactions between trees and crop. Trees in the 8-year-old TBI system had superficial fine root profiles, which is common in tree species grown in conventional plantations and natural forests. More than 95 % of fine roots were found within the first 25 and 45 cm for QUR and HYP, respectively, and 35 cm for CROP. However, vertical separation between the fine root systems of QUR and CROP was evident, as QUR allocated less fine roots to the top 10 cm of soil, and more to depths between 10 and 30 cm, as opposed to CROP which had a greater proportion of fine roots in the top 10 cm. HYP fine roots showed no adaption when intercropped with hay. High tree fine root length density (FRLD) in the top soil layer was observed near the tree stems while hay FRLD was reduced by 45 %, suggesting strong competition for resources. Hay yield analysis revealed significant reduction near trees, particularly HYP. However, light did seem to be the main driver of intercrop yield, as it not only accounted for the effect of competition by roots (being correlated), but also had a singular effect. 相似文献
65.
Ahmed SH 《Science (New York, N.Y.)》2004,306(5703):1901-1902
66.
Moïse Nola Thomas Njiné Norbert Kemka Serge H. Zébazé Togouet Samuel Foto Menbohan Adolphe Monkiedje Pierre Servais Mohamed Messouli Claude Boutin 《Water, air, and soil pollution》2006,171(1-4):253-271
Groundwater protection from pollutants depends mostly on retention potentials of soil above groundwater table. Soil separating soil surface from groundwater table is made up of several layers and can be divided into different columns along its vertical transect. Wastewater percolation tests were carried out through one soil column CA, in contact with soil surface and through another CB, closely above groundwater table. The aim of the study was to assess the importance of soil columns CA and CB, in total coliforms and staphylococci retention during wastewater infiltration or groundwater recharge, in equatorial soils in Central African region. The results showed that, the fraction of total coliforms retained through soil column CA varied with respect to wastewater loads applied on top of soil column, from 69.22% to 99.95%, relative to the total coliforms concentration deposited on top. The fraction of total coliforms retained through CB varied with respect to wastewater loads applied, from 96.98 to 99.89% relative to the total coliforms deposited on top. Through both soil columns, fractions of staphylococci retained was in the order of 99.99% relative to the total staphylococci concentration deposited on top. For the whole bacteriological analysis, the fractions of total coliforms retained seems to be greater through deeper soil column than that of upper soil column. The bacterial contaminants retained relative to their concentrations in wastewater poured on soil column surfaces, varied from 6.17 log units to 9.73 log units. An applied load of 100 ml seemed to lead to the bacterial pollutants transported through both soil columns studied. NH4 + was retained by fractions varying from 97.37 to 98.74%. Concentrations of various contaminants found in groundwater would be a tiny part, relative to quantities deposited on soil surface. Bacterial retention potentials of soil column separating soil surface from groundwater table during wastewater percolation, varies along its transect. It would be due to numerous and variable physical, chemical and structural properties of soil layers and bacteria on the one hand, and to results of various interactions between soil layer particles and cell bacteria, on the other hand. 相似文献
67.
László Sági Serge Remy Bert Verelst Bart Panis Bruno P. A. Cammue Guido Volckaert Rony Swennen 《Euphytica》1955,85(1-3):89-95
Summary In order to introduce currently-available genes with agronomical value into banana, two genetic transformation protocols have been optimized.Firstly, regenerable protoplasts isolated from embryogenic cell suspensions of the cultivar Bluggoe have been used for the introduction of several chimaeric uidA gene constructs by electroporation. With the inclusion of polyethylene glycol and heat shock, the frequency of transiently expressing protoplasts reached 1.8% as shown by an in situ -glucuronidase assay. A duplicated 35S promoter with an alfalfa mosaic virus leader sequence (pBI-426) induced the highest expression rate among the constructs tested.Embryogenic cell suspensions of cv. Bluggoe have also been bombarded with accelerated particles coated with a high expression uidA gene construct (pEmuGN) using a biolistic gun. After a partial optimization of the procedure, transient GUS assays reproducibly demonstrated the presence of 400 blue foci in 30 l of settled cell volume (approximately 25 mg cells). Selection and characterization of antibiotic-resistant transformed cultures is in progress.Abbreviations AMV
alfalfa mosaic virus
- GUS
-glucuronidase
- TGE
transient GUS expression
-
uidA
gene for -glucuronidase 相似文献
68.
Summary Deterioration of cotton, Gossypium hirsutum L., seed can adversely affect stands, seedling vigor, and subsequent performance of plants, but deterioration can be lessened by improved genetic resistance. This study was conducted to evaluate the relationship of physical and germination characteristics of cotton seed and to determine the inheritance of resistance to seed deterioration. Physical (weight, volume, density, and imbibition rate) and germination (germination of non-deteriorated seed and deteriorated seed) characteristics were determined for eight cotton genotypes. In addition, imbibition rate and the germination characteristics were determined for all possible F1, including reciprocals, combinations of the eight genotypes. Variation among the parents for germination of deteriorated seed and imbibition rate were significantly, highly correlated (r=–0.97) and intrinsically related. Resistance to seed deterioration tended to increase as seed weight and volume decreased. Significant genetic effects were found for imbibition rate and germination of both non-deteriorated and deteriorated seed. However, general combining ability (GCA) accounted for only 21% of the variation in crosses sums of squares for germination of non-deteriorated seed. In contrast, GCA accounted for 90% of the variation for germination of deteriorated seed and imbibition rate. A breeding approach involving selection of early generation seed for ability to survive hot water treatment, then evaluating later generations for imbibition rate is suggested as a means to improve resistance to seed deterioration in cotton. 相似文献
69.
Seaman Dave J. I. Voigt Maria Bocedi Greta Travis Justin M. J. Palmer Stephen C. F. Ancrenaz Marc Wich Serge Meijaard Erik Bernard Henry Deere Nicolas J. Humle Tatyana Struebig Matthew J. 《Landscape Ecology》2021,36(10):2957-2975
Landscape Ecology - Agricultural expansion is a leading cause of deforestation and habitat fragmentation globally. Policies that support biodiversity and facilitate species movement across farmland... 相似文献
70.
Christopher L. Brown Serge I. Doroshov Michael D. Cochran Howard A. Bern 《Fish physiology and biochemistry》1989,7(1-6):295-299
Elevation of the triiodothyronine (T3) content of striped bass (Morone saxatilis) eggs by maternal T3 injection confirms the uptake of T3 by oocytes. The resulting offspring were influenced favorably by the T3, as seen in quantitative indices of development. As reported previously, larvae from T3-supplemented eggs raised under laboratory conditions exhibited increased body area, length, dry weight, and rates of swimbladder
inflation and survival, compared to controls. Also, the T3 content of unfertilized oocytes correlated positively and highly significantly with survival to two weeks of age within individual
cohorts (Brownet al., 1988). In the present study, the survival of experimental and control striped bass was monitored through the fingerling
stage, under hatchery production conditions. The rate of recovery of maternally T3-treated cohorts from pond-culture was approximately fourfold that of controls. The striking effects of T3 enrichment of eggs on offspring indicate the potential contribution of maternal hormones in striped bass development, and
suggest possible applications in aquaculture. 相似文献