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101.
Farmers have been slow to adopt decision support system (DSS) models and their outputs, mainly owing to (i) the complexity of the data involved, which most potential users are unable to collect and process; and (ii) inability to integrate these models into real representations of their informational environments. This situation raises questions about the way farm management researchers have modelled information and information management, and especially about the quality of the information assessed by the farmers. We consider that to review advisory procedures we need to understand how farmers select and use farm management-related information, rather than focusing on decisions made in particular situations. The aim of this study was to build a conceptual model of the farmer-targeted farm management-related information system. This model was developed using data collected in commercial beef cattle farms. The design structure and operational procedures are based on (i) data categories representing the diversity of the informational activity; and (ii) selected criteria for supporting decisions. The model is composed of two subsystems, each composed of two units. First, an organizational subsystem organizes, finalizes and monitors informational activity. Second, a processing subsystem builds and exploits the informational resources. This conceptual model makes it possible to describe and understand the diverse range of farmers' informational activity by taking into account both the flow of information and the way farmers make sense of that information. This model could serve as a component of biodecisional DSS models for assigning information in the decision-making process. The next task will be to take into account the broad range of farmers' perceptions of the management situations in DSS models.  相似文献   
102.
The objective of this study was to determine the factors associated with selling price of animals at livestock marts around Ireland. Data consisted of four distinct maturity categories: calves (2 to 84 days of age, n = 53 838); weanlings (6 to 12 months of age, n = 19 972); post-weanlings (12 to 36 months of age, n = 93 081) and cows (>30 months to 12 years of age, n = 94 839); sold through livestock marts between 2000 and 2008. Factors associated with animal price were determined within each maturity category separately using mixed models; random effects were mart, date of sale nested within mart, and herd of origin nested within year of sale. Mean selling price was €157, €580, €655 and €592 for calves, weanlings, post-weanlings and cows, respectively. The greatest prices were paid for singleton crossbred male calves, weanlings and post-weanlings from older dams. With the exception of the Aberdeen Angus, beef breeds and their crosses consistently received higher prices than their dairy counterparts across all four maturity categories; increased proportion of Belgian Blue and Charolais was associated with greater prices compared with other beef breeds. When live-weight was included in the multiple regression models the association between price and all factors regressed toward zero but most factors remained associated with price. The highest price was recorded in the spring months for calves, post-weanlings and cows, and in the autumn months for weanlings. Results from this study may be used to help farmers make more informed management decisions, as well as provide information for bio-economic models for evaluating alternative production systems or estimating economic values.  相似文献   
103.
Intensive livestock production systems are particularly vulnerable to natural or intentional (bioterrorist) infectious disease outbreaks. Large numbers of animals housed within a confined area enables rapid dissemination of most infectious agents throughout a herd. Rapid containment is key to controlling any infectious disease outbreak, thus depopulation is often undertaken to prevent spread of a pathogen to the larger livestock population. In that circumstance, a large number of livestock carcasses and contaminated manure are generated that require rapid disposal.Composting lends itself as a rapid-response disposal method for infected carcasses as well as manure and soil that may harbor infectious agents. We designed a bio-contained mortality composting procedure and tested its efficacy for bovine tissue degradation and microbial deactivation. We used materials available on-farm or purchasable from local farm supply stores in order that the system can be implemented at the site of a disease outbreak. In this study, temperatures exceeded 55°C for more than one month and infectious agents implanted in beef cattle carcasses and manure were inactivated within 14 days of composting. After 147 days, carcasses were almost completely degraded. The few long bones remaining were further degraded with an additional composting cycle in open windrows and the final mature compost was suitable for land application. Duplicate compost structures (final dimensions 25 m x 5 m x 2.4 m; L x W x H) were constructed using barley straw bales and lined with heavy black silage plastic sheeting. Each was loaded with loose straw, carcasses and manure totaling ~95,000 kg. A 40-cm base layer of loose barley straw was placed in each bunker, onto which were placed 16 feedlot cattle mortalities (average weight 343 kg) aligned transversely at a spacing of approximately 0.5 m. For passive aeration, lengths of flexible, perforated plastic drainage tubing (15 cm diameter) were placed between adjacent carcasses, extending vertically along both inside walls, and with the ends passed though the plastic to the exterior. The carcasses were overlaid with moist aerated feedlot manure (~1.6 m deep) to the top of the bunker. Plastic was folded over the top and sealed with tape to establish a containment barrier and eight aeration vents (50 x 50 x 15 cm) were placed on the top of each structure to promote passive aeration. After 147 days, losses of volume and mass of composted materials averaged 39.8% and 23.7%, respectively, in each structure.  相似文献   
104.
From 1980–1985, the Turkana District of Kenya experienced both drought and above average rainfall. The effects of a 2-year drought on the livestock population of the nomadic pastoral Ngisonyoka are discussed. Detailed data on mortality rates and offtake are presented for the animals of four herd owners, and the recovery process is followed for the 5-year period for one herd owner. It is concluded that during the drought, 63% of the cattle, 45% of the camels, and 55% of the small stock left the sample herds. The livestock population of one herd had recovered to pre-drought levels 3 years after the drought.  相似文献   
105.
Grasslands are one of the most endangered and degraded ecosystems globally. Switches in disturbance type can restore grassland function and improve conservation outcomes for fauna, but land-use legacies can limit the capacity of biota to respond positively to shifts in disturbance type, making it difficult to predict ecological outcomes. In semi-arid grasslands of South-Eastern Australia, habitat for grassland birds is managed using livestock grazing, a practice that has continued for >150 years. It is unknown if outcomes for birds can be improved by a switch in disturbance type as alternatives to livestock grazing have not been explored. We compare the effects of status-quo livestock grazing with alternative biomass management tools (no management, ‘crash’ grazing, planned fire) on birds, vegetation structure, and food resources using a BACI design across 3 years (2017–2019). We found crash grazing and fire produced more open, shorter grassy swards, with less exotic grass cover, compared to status-quo grazing or disturbance exclusion. Preferred habitat structure for the critically endangered plains-wanderer (Pedionomus torquatus) was maximized by status-quo grazing. Grassland birds responded in opposing ways to a disturbance switch. Brown songlarks (Megalurus cruralis) and Horsfield's bushlarks (Mirafra javanica) responded positively to disturbance exclusion, while stubble quail (Coturnix pectoralis) responded negatively to crash grazing. Australasian pipits (Anthus novaeseelandiae) were more frequent in response to status-quo grazing. Our findings suggest that multiple disturbance types should be used if the aim is to promote the spectrum of vegetation structures and food sources required to support a diverse grassland bird community in semi-arid grasslands of Australia.  相似文献   
106.
Over the past 10 years, Ghusel VDC, Lalitpur District has moved from primarily subsistence agriculture into the wider cash economy aided by the Small Farmers' Development Program (SFDP), which provides credit to farmers mainly for the purchase of buffalo for milk production, and by the National Dairy Corporation, which supports local dairy cooperatives. Analysis reveals that buffalo-keeping and milk sales are increasing the well-being of many households, while at the same time creating new inequalities in gender roles and responsibilities, greater inequities between Brahmin and Tamang residents in Ghusel, and placing pressures on the ecosystem for increased supplies of fodder and fuelwood. Evidence suggests that there is critical, need for attention to the social, and particularly gender-based, implications of maintaining livestock for milk sales and to the ecological underpinnings of this livelihood system.  相似文献   
107.
何慧芬  张璐  秦爱建  钱琨 《微生物学通报》2022,49(12):5331-5341
cGAS-STING信号通路是一种细胞内DNA感受器,可以识别自身病变或外部进入细胞质中的双链DNA。其不仅与肿瘤、病毒和细菌感染及自身免疫系统疾病密切相关,而且在非特异性免疫系统中发挥重要作用。截至目前,国内外对于cGAS-STING信号通路的研究主要集中在哺乳动物肿瘤相关性疾病及与先天性免疫系统相关的疾病中,而通路对畜禽疾病调控的影响机制非常重要。本文以cGAS-STING信号通路在宿主受到病原感染中发挥的作用为切入点,对其在不同畜禽病原感染中的调控作用进行综合论述,以期为畜禽疾病的防控提供理论依据和参考。  相似文献   
108.
Anopheles arabiensis Patton (Diptera: Culicidae) is the most widespread vector of malaria in the Afrotropical Region. Because An. arabiensis feeds readily on cattle as well as humans, the insecticide-treatment of cattle--as employed to control tsetse (Diptera: Glossinidae) and ticks (Acari: Ixodidae)--might simultaneously affect the malaria vectorial capacity of this mosquito. Therefore, we conducted field experiments in southern Ethiopia to establish whether Zebu cattle (Bos indicus L.) treated with a pour-on pyrethroid formulation of 1% deltamethrin, widely used to control ticks and tsetse, would be effective against An. arabiensis or cause the female mosquitoes to feed more frequently on humans, due to behavioural avoidance of insecticide-treated cattle. Contact bioassays (3 min exposure) showed that the insecticide remained effective for about 1 month (kill rate > 50%) against mosquitoes feeding on the flanks of treated cattle. A novel behavioural assay demonstrated that An. arabiensis readily fed on insecticide-treated cattle and were not deflected to human hosts in the presence of treated cattle. DNA-fingerprinting of bloodmeals revealed that An. arabiensis naturally feeds most frequently on older animals, consistent with the established practice of applying insecticide only to older cattle, while allowing younger untreated animals to gain immunity against infections transmitted by ticks. These encouraging results were tempered by finding that > 90% of An. arabiensis, An. pharoensis and An. tenebrosus females feed on the legs of cattle, farthest from the site of pour-on application along the animal's back and where the treatment may be least residual due to weathering. Observations of mosquitoes feeding naturally on insecticide-treated cattle showed that the majority of wild female anophelines alighted on the host animal for less than 1 min to feed, with significantly shorter mean duration of feeding bouts on insecticide-treated animals, and the effective life of the insecticide was only 1 week. Thus the monthly application of deltamethrin to cattle, typically used to control tsetse and ticks, is unlikely to be effective against An. arabiensis populations or their vectorial capacity. Even so, it seems likely that far greater impact on anopheline mosquitoes could be achieved by applying insecticide selectively to the legs of cattle.  相似文献   
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