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341.
In an increasingly human-dominated landscape, effective management of disturbance-maintained ecosystems, such as grasslands and savannas, is critical to the conservation of biodiversity. Yet, the response of individual organisms to landscapes created by disturbances and management is rarely studied. In this study, we examined the endangered Karner blue butterfly, Lycaeides melissa samuelis, in a heterogeneous oak savanna. Our objective was to quantify the butterfly’s habitat use and behavior to assess the effects of prescribed burning. The oak savanna management in Ohio, USA divides each Karner blue site (n = 4) into three units. Each one-third unit is then burned, mowed, or unmanaged in an annual rotation within each site, and the result is a fire return interval of ~3 years. Our surveys measured habitat use, while behavior observations quantified reproduction and foraging for the two annual broods. Our habitat use results showed burned treatments were recolonized quickly, but there was not a clear selection for burned treatments. Foraging rates were similar in all treatments; however, females oviposited significantly less in unmanaged treatments (only 5 of 127 ovipositions). This oviposition preference was likely due to habitat degradation and the availability of recently burned, early successional habitat. Since Karner blues avoided reproduction in units unburned for ≥4 years, these units could be burned to create high quality early successional habitat. These results demonstrate how behavioral decisions can be pivotal forces driving spatial population dynamics. Our case study demonstrates how a fine-scale landscape perspective combined with measurements of behavioral processes can assist with management decision-making.  相似文献   
342.
The timing of recurring biological and seasonal environmental events is changing on a global scale relative to temperature and other climate drivers. This study considers the Gulf of Maine ecosystem, a region of high social and ecological importance in the Northwest Atlantic Ocean and synthesizes current knowledge of (a) key seasonal processes, patterns, and events; (b) direct evidence for shifts in timing; (c) implications of phenological responses for linked ecological‐human systems; and (d) potential phenology‐focused adaptation strategies and actions. Twenty studies demonstrated shifts in timing of regional marine organisms and seasonal environmental events. The most common response was earlier timing, observed in spring onset, spring and winter hydrology, zooplankton abundance, occurrence of several larval fishes, and diadromous fish migrations. Later timing was documented for fall onset, reproduction and fledging in Atlantic puffins, spring and fall phytoplankton blooms, and occurrence of additional larval fishes. Changes in event duration generally increased and were detected in zooplankton peak abundance, early life history periods of macro‐invertebrates, and lobster fishery landings. Reduced duration was observed in winter–spring ice‐affected stream flows. Two studies projected phenological changes, both finding diapause duration would decrease in zooplankton under future climate scenarios. Phenological responses were species‐specific and varied depending on the environmental driver, spatial, and temporal scales evaluated. Overall, a wide range of baseline phenology and relevant modeling studies exist, yet surprisingly few document long‐term shifts. Results reveal a need for increased emphasis on phenological shifts in the Gulf of Maine and identify opportunities for future research and consideration of phenological changes in adaptation efforts.  相似文献   
343.
  • 1. Quantitative subtidal surveys of fishes, macro‐invertebrates and sessile organisms at 33 sites within the Lord Howe Island Marine Park revealed a rich fauna and flora, including 164 fishes, 40 mobile invertebrate taxa, 53 coral and other sessile invertebrate taxa, 32 algal taxa, and two seagrasses. The biota in this newly‐zoned marine park was overwhelmingly tropical when species lists were tabulated; however, species with distributions centred on temperate coasts of eastern Australia and New Zealand occurred in disproportionately high densities compared with the tropical species.
  • 2. Lord Howe Island reefs were generally in good condition. Virtually no bleached coral was observed (0.2% of the reef surface; 0.8% of total hard coral cover). Living scleractinian coral comprised the predominant group of organisms growing on reef surfaces, with 25.5% cover overall. Other major taxa observed were brown algae (18.8% cover) and red algae (16.9% cover).
  • 3. Three distinctive community types were identified within the marine park—coral reefs, macroalgal beds and an offshore/open coast community. The distribution of these community types was strongly related to wave exposure, as indicated by an extremely high correlation with the first principal coordinates axis for biotic data (R2=0.80).
  • 4. The close (<3 km) proximity of tropical coral and temperate macroalgal community types off Lord Howe Island is highly unusual, with localized patterns of nutrient enrichment suggested as the primary cause. The macroalgal community type is only known from a small area off the south‐western coast that is not protected from fishing. This community is considered highly susceptible to threats because of potential impacts of global warming and the possibility of expansion of sea urchin barrens. Coral bleaching and ocean acidification associated with global climate change also threaten the coral reef community, which includes relatively high numbers of endemic and near endemic fish species. Copyright © 2009 John Wiley & Sons, Ltd.
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344.
Cooking decreases observed perfluorinated compound concentrations in fish   总被引:1,自引:0,他引:1  
Dietary intake is a major route of exposure to perfluorinated compounds (PFCs). Although fish and seafood contribute significantly to total dietary exposure to these compounds, there is uncertainty with respect to the effect of cooking on PFC concentrations in these foods. Eighteen fish species purchased from markets in Toronto, Mississauga, and Ottawa, Canada were analyzed for perfluorooctanesulfonamide (PFOSAs)-based fluorochemicals and perfluorinated acids (PFAs) in raw and cooked (baked, boiled, fried) samples. Of 17 analytes, perfluorooctanesulfonic acid (PFOS) was detected most frequently; concentrations ranged from 0.21 to 1.68 ng/g ww in raw and cooked samples. PFOSAs were detected only in scallops at concentrations ranging from 0.20 ng/g ww to 0.76 ng/g ww. Total concentrations of PFAs in samples were 0.21 to 9.20 ng/g ww, respectively, consistent with previous studies. All cooking methods reduced PFA concentrations. Baking appeared to be the most effective cooking method; after baking samples for 15 min at 163 C (325 degrees F), PFAs were not detected in any of the samples. The margin of exposures (MOE) between the toxicological points of reference and the dietary intake of perfluorocarboxylates (PFCAs) and PFOS in fish and seafood muscle tissue were greater than 4 orders of magnitude. This indicates that reducing consumption of fish muscle tissue is not warranted on the basis of PFC exposure concerns at the reported levels of contamination, even for high fish consuming populations.  相似文献   
345.
A 7-week-old Appaloosa filly was admitted for persistent urinary incontinence since birth. Vaginal speculum examination revealed urine flowing from an opening in the right vaginal wall. Cystoscopy demonstrated that the ureters did not terminate at the bladder. The endoscope passed easily from the vagina directly into a dilated right ureter. An excretory urogram confirmed the vaginal termination of at least one ureter, based upon extensive filling of the vagina with contrast media in the absence of bladder filling. Bilateral hydroureter and dilated renal pelves were demonstrated both by excretory urography and by ultrasonography. Euthanasia was requested by the owner in lieu of attempted surgical correction. At necropsy, it was confirmed that the right ureter entered the vagina and the left ureter terminated at the urethra. The diagnosis of bilateral ectopic ureter in this foal was suggested by the history and clinical signs, supported by endoscopy and ultrasonography, and confirmed by excretory urography and necropsy. This case establishes the value of diagnostic imaging techniques in the antemortem diagnosis of ectopic ureter.  相似文献   
346.
A retrospective study of 15 dogs and three cats was done to characterize the appearance of meningeal enhancement on magnetic resonance (MR) images of the brain, and to correlate this appearance with its underlying cause. Two patterns of meningeal enhancement (pial and dural) were identified. Enhancement of the pia mater was evident in four dogs and one cat, while enhancement of the dura mater was seen in 11 dogs and 2 cats. A variety of causes of meningeal enhancement were identified, including bacterial and cryptococcal meningitis, plasmacytic meningitis with associated subdural fluid accumulation, granulomatous meningoencephalomyelitis, inflammation secondary to otitis interna, feline infectious peritonitis, and neoplasia. The present study confirms that pial or dural meningeal enhancement may be present on MR images of the brain of dogs or cats in association with a variety of central nervous system diseases. A larger prospective study is required to further establish the incidence of specific patterns of meningeal enhancement seen in association with specific diseases.  相似文献   
347.
A commercially available 1-hour enzyme immunoassay (EIA) for detecting the presence of Clostridium difficile toxins A and B was evaluated for use in diagnosis of C. difficile infections in neonatal swine. This test was compared with a tissue culture cytotoxicity assay, which is considered to be the reference standard for the detection of C. difficile toxins. Twenty-seven samples of colonic contents and 23 fecal samples were collected from freshly euthanized neonatal swine with a history of scours. Of the 50 specimens tested, 20 were positive by the EIA test and tissue culture and 24 were negative by both tests, for an overall correlation of 88%. The sensitivity and specificity of the EIA were 91% and 86%, respectively, and the positive and negative predictive values were 84% and 86%, respectively. The EIA test is considered suitable as an aid for the diagnosis of C. difficile enteritis because of the high correlation between EIA results and those of the tissue culture cytotoxicity assay.  相似文献   
348.
Three Francois' langurs (Trachypithecus francoisi) were found dead, without previous clinical signs, over a 48-hour period at a zoological institution after transfer to a new exhibit. A hybrid yew shrub (Taxus baccata X T. cuspidata) was found in close proximity to the exhibit perimeter fence. Despite clinical suspicion of yew intoxication, thin-layer chromatography performed on gastric contents was negative. However, microscopic examination of gastric contents revealed multiple yew fragments, and taxine alkaloids were detected by gas chromatography and mass spectrometry of the gastric contents to confirm yew intoxication. Acute death of the animals prevented treatment. The fourth langur in the collection survived, most likely because of its low rank in the troop's hierarchy, with a suspected small amount or none of the plant ingested. To the authors' knowledge, this case report is the first yew intoxication documented in a nonhuman primate species. Taxus spp. intoxication is an often fatal condition reported in domestic animals and humans. In comparison with these species, mortality appeared delayed in the Francois' langurs, most likely because of their unique gastrointestinal anatomy, with both foregut and colonic fermentation. Plant intoxication should be a differential diagnosis when multiple acute deaths are observed after recent introduction to a new enclosure.  相似文献   
349.
In urban environments, raccoons (Procyon lotor) may act as reservoirs for an array of pathogenic organisms, presenting spillover risks for human, domestic animal, and captive (zoo) animal populations. Over 5 yr, 159 raccoons from a high-density raccoon population in St. Louis, Missouri (USA), were surveyed for exposure to canine distemper virus (CDV), canine adenovirus 1 (CAV-1); feline parvovirus (FPV; =feline panleukopenia), and several serovars of Leptospira interrogans. Exposure to each of the viruses and two Leptospira serovars (grippotyphosa and icterohemorrhagiae) was detected (prevalence of CDV = 54.1%; FPV = 49.7%; CAV-1 = 6.9%; L. interrogans icterohemorrhagiae = 8.9%; L. interrogans grippotyphosa = 6.3%). Eighty percent of raccoons showed evidence of exposure to at least one of the five primary pathogens, and 39% were positive for multiple species. Among the viruses, there was a significant co-occurrence of CDV and CAV-1. Longitudinal data on a subset of animals revealed that among individuals who were diagnosed as seropositive on first capture, 33-100% became seronegative for the pathogen of interest when reexamined at a later date. Thus, free-ranging urban raccoons have been exposed to multiple infectious agents, some of which may pose risks to humans and to nonvaccinated domestic and captive animal populations.  相似文献   
350.
Mycobacterium szulgai was associated with mortality in two captive African elephants (Loxodonta africana) housed at Lincoln Park Zoo. The first elephant presented with severe, acute lameness of the left rear limb. Despite extensive treatments, the animal collapsed and died 13 mo after initial presentation. Necropsy revealed osteomyelitis with loss of the femoral head and acetabulum and pulmonary granulomas with intralesional M. szulgai. The second elephant collapsed during transport to another institution with no premonitory clinical signs. This animal was euthanized because of prolonged recumbency. Granulomatous pneumonia with intralesional M. szulgai was found at necropsy. Two novel immunoassays performed on banked serum samples detected antibody responses to mycobacterial antigens in both infected elephants. It was not possible to determine when the infection was established or how the elephants were infected. When reviewing the epidemiology of this organism in humans, however, transmission between elephants seemed unlikely because human-to-human transmission of this organism has never been reported and a third elephant in the herd was not affected. In addition to Mycobacterium bovis and Mycobacterium tuberculosis, atypical mycobacterial organisms need to be considered potentially pathogenic in elephants.  相似文献   
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