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71.
Low piglet weight at weaning implies a loss of income for the farmer and might influence the welfare of the affected animals negatively. The objective of our cohort study was to identify risk factors in the farrowing section associated with average daily weight gain (ADG) of piglets from birth to weaning. The study was done in 3 Danish farrow-to-finish herds and included 581 sows, 277 pens, 814 farrowings, and 8241 piglets. The data were analysed with a linear mixed model where the response was ADG, and sow and litter were random effects. Piglet treatments for arthritis (-38 g per day), diarrhoea (-8 g per day) and other infections (-21 g per day) were the major infectious contributors to lower ADG. Forelimb-skin abrasions on a piglet (-5 g per day), weak pasterns of sows on concrete slats (-34 g per day), suckling a sow with poor milking 3 weeks after farrowing (-14 g per day), low birth weight (-8.4 g per day per 100 g), male compared to female (-4 g per day) also were associated with lower ADG in the suckling period.  相似文献   
72.
A hereditary skin defect in sheep   总被引:3,自引:0,他引:3  
Some years ago a lamb with abnormal skin was received at the State veterinary research station for small ruminants (SVRS), Stavanger, from a farm in Ryfylke. The lamb had apparently been normal at birth, but by normal activity and contact with its mother, extensive wounds developed, with large, loose skin areas. The lamb’s condition had deteriorated so much that it was killed when it was two days old. Two ewes sired by the same ram had given birth to similar lambs the same year, while some years earlier, lambs with the same defect had been born by other ewes in the flock.  相似文献   
73.
Puroindoline (pin) preparations made from flours of hard and soft wheats contained a mixture of pin‐a, 0.19/0.53 α‐amylase inhibitor, and purothionins. Starch granule preparations from the same cultivars were treated with proteinase to remove surface proteins and incubated with solutions of the pin preparations. Binding of pin‐a and purothionins but not the 0.19/0.53 inhibitor was observed with no apparent differences between the behavior of the pin preparations or starch granule preparations from hard or soft types. No binding was observed when several other proteins (bovine serum albumin, total albumins, a commercial preparation of wheat α‐amylase inhibitors, and barley β‐amylase) were incubated with the starch granules under the same conditions, indicating that in vitro binding can be used to study specific starch granule and protein interactions.  相似文献   
74.
Watersheds constitute a special case of multiple-use common pool resources (CPRs). In a textual sense, watersheds tend to be mosaics of privately owned and managed patches of land. At the same time, however, watersheds are also ecosystems in which multiple resources and people interact through an infinity of bio-physical processes. Through such interaction, new watershed-level qualities emerge that, together with other factors, condition watershed users' continued resource use and access. In this perspective, watersheds become common-pool resources. Hence, watershed users do not only manage their individual plots, crops, forests, etc., knowingly or not, they manage landscape patterns and bio-physical processes that transcend their private property. In this context, drawing on experiences gained through participatory action research in a micro-watershed in the Andean hillsides of southern Colombia, this paper describes a process aimed at fostering collective watershed management. The paper illustrates the importance of platforms as a mechanism for negotiating and coordinating collective action by multiple users and discusses the issues of representation on such platforms as well as the importance of third party facilitation.  相似文献   
75.
Non-treated wastewater is used for irrigation of aquatic food production systems in the peri-urban areas of the major cities in Southeast Asia. This paper complement the knowledge on agricultural soil-based crops irrigated with low quality water, by reviewing the research findings on the wastewater-fed aquatic productions with special focus on heavy metals and other potentially toxic elements (PTEs) in the production systems of Hanoi in Vietnam and Phnom Penh in Cambodia. In Hanoi, sediments in the wastewater exposed rivers of Hanoi were reported to be polluted with PTEs, in particular with Cadmium (Cd). The river sediment had a high retention capacity for PTEs which seems to prevent the transport of PTEs to the wastewater-fed production systems. In Phnom Penh, domestic and industrial wastewater is pumped into the Cheung Ek Lake located south of the city. A major part of the water spinach (Ipomoea aquatica Forssk.) consumed in the city is produced in the lake. The concentrations of some PTEs were elevated at the wastewater inlets to the lake compared to concentrations at the lake outlet and at the control site. Water spinach is by far the major vegetable produced in the wastewater-fed systems in Hanoi and Phnom Penh, but did only contain PTEs in concentrations within or slightly above the concentration range observed for water spinach grown in agricultural soil not exposed to wastewater. PTE concentration in fish grown in wastewater-fed systems in Hanoi and Phnom were low. However, mean PTE concentrations in liver and skin of some fish were high. Consumption of muscle tissue from fish produced in wastewater-fed systems in Hanoi and Phnom Penh resulted in an estimated intake of PTEs amounting to less than 9% of the tolerable intake. It was concluded, that the PTE concentrations in fish and water spinach from Hanoi and Cheung Ek Lake in Phnom Penh constituted low food safety risks for consumers.  相似文献   
76.
We suggest a simple isobole analysis for binary mixture toxicity experiments. The analysis is based on estimated logarithmic effect concentrations and their corresponding standard errors. The suggested model allows for synergism/antagonism and incorporates within-mixture variation as well as between-mixture variation in a random effects model. The likelihood ratio test for the hypothesis of concentration addition (CA) is examined, in particular its small sample properties. We study two datasets on the joint effect of acifluorfen versus diquat and glyphosate versus mechlorprop, respectively, on the growth of the aquatic macrophyte Lemna minor.  相似文献   
77.
78.
Assessment of habitat thresholds is a topical issue in ecology, both from theoretical and applied perspectives. We examined how forest structure influences selection of breeding habitat in the Eurasian treecreeper (Certhia familiaris). It is an old-growth forest passerine, which can be considered an umbrella species. Habitat selection data, covering five breeding seasons, were collected from a study area across three spatial scales: (a) territory core scale (a radius of 30 m), (b) territory scale (a radius of 200 m) and (c) large scale (a radius of 500 m). Logistic regression analyses revealed that the radii of 30 and 200 m from the nest were the most important spatial scales for the forest patch occupancy. A loss of forest habitat and a low circumference of stems within the territory decreased the probability of occupancy. There was a distinct threshold in the amount of forest cover on forest patch occupancy when the volume of timber was taken into account. At low timber volumes (0-151 m3/ha) the amount of forest cover was negatively related to the occupancy rate of forest patches. This negative relationship changed abruptly when the volume of timber exceeded 152 m3/ha, after which forest cover had a positive effect on the occupancy rate of forest patches. This is a new way to examine habitat thresholds in relation to forest cover. Furthermore, as debated in recent literature, treecreepers also tend to respond to habitat loss rather than to changes in habitat configuration, which stresses the need for habitat restoration and conservation. Moreover, our results emphasize the importance of within-territory structure over the characteristics of the habitat matrix in selection of breeding habitat.  相似文献   
79.
A major ecosystem shift in the northern Bering Sea   总被引:5,自引:0,他引:5  
Until recently, northern Bering Sea ecosystems were characterized by extensive seasonal sea ice cover, high water column and sediment carbon production, and tight pelagic-benthic coupling of organic production. Here, we show that these ecosystems are shifting away from these characteristics. Changes in biological communities are contemporaneous with shifts in regional atmospheric and hydrographic forcing. In the past decade, geographic displacement of marine mammal population distributions has coincided with a reduction of benthic prey populations, an increase in pelagic fish, a reduction in sea ice, and an increase in air and ocean temperatures. These changes now observed on the shallow shelf of the northern Bering Sea should be expected to affect a much broader portion of the Pacific-influenced sector of the Arctic Ocean.  相似文献   
80.
Snow samples from 18 sites in Estonia were collected in February and March 1996 after 72–110 days of permanent snow cover. Three snow layers corresponding to different snow accumulation periods were separated in each sampling site. Snow water samples were analysed for sulphate (SO4 2-), nitrate (NO3 -), and chloride (Cl-) ions and elemental composition. Deposition fluxes of 27 chemical species were used for factor, cluster and correlation analysis. The effects of cement dust, oil shale fly ash, sulphur dioxide and chlorine from emissions of thermal power plants were distinguished. A large number of trace metals are strongly correlated with each other (R > 0.8) and with macro-components (except NO3 -), which refers to a common origin, identified as the mineral part of oil shale. Deposition fluxes of Ca, Mg, SO4 2- and a number of mineral components exceed near the power plants 1–2 decimal orders the background value. The deposition fluxes in forested sites are up to 2 times higher than in open land sites. This difference may be caused by more efficient turbulent transfer over rougher surface. It is suggested, that NO3 - and Zn originate mainly and Pb, Cd and Cu partially from non-local or diffuse sources (traffic, domestic heating, far transport). The results of this research could be used to evaluate the air pollution deposition models and for ecological impact estimations.  相似文献   
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