首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   209篇
  免费   6篇
  国内免费   3篇
林业   13篇
农学   4篇
基础科学   1篇
  37篇
综合类   4篇
农作物   7篇
水产渔业   11篇
畜牧兽医   116篇
园艺   2篇
植物保护   23篇
  2023年   1篇
  2022年   2篇
  2021年   8篇
  2020年   4篇
  2019年   3篇
  2018年   4篇
  2017年   3篇
  2016年   6篇
  2015年   9篇
  2014年   8篇
  2013年   24篇
  2012年   9篇
  2011年   6篇
  2010年   6篇
  2009年   12篇
  2008年   11篇
  2007年   18篇
  2006年   12篇
  2005年   7篇
  2004年   12篇
  2003年   17篇
  2002年   16篇
  2001年   7篇
  2000年   3篇
  1999年   3篇
  1997年   3篇
  1992年   1篇
  1989年   1篇
  1983年   1篇
  1978年   1篇
排序方式: 共有218条查询结果,搜索用时 15 毫秒
51.
This report describes the cases of two Miniature Dachshunds who were suspected to have immune-mediated hemolytic anemia (IMHA) and were treated with immunosuppressive therapy. However, progression of anemia, increases in C-reactive protein (CRP) and total-bilirubin (T-Bil) levels, splenomegaly, transition to nonregenerative anemia, and thrombocytopenia occurred after the treatment. Splenectomy and bone-marrow aspirations were performed subsequently. Both dogs were diagnosed with hemophagocytic syndrome (HPS) associated with IMHA. Unfortunately, they died 9 and 6 days later. These findings indicate that some cases of refractory IMHA have the pathogenicity of HPS. HPS should be included as a differential diagnosis of refractory IMHA concurrent with thrombocytopenia. Continuously elevated CRP and T-Bil levels may be helpful indicators in the detection of HPS associated with IMHA.  相似文献   
52.
Caulogenic calli with a high differentiation potency were induced from mature embryos ofPicea jezoensis seeds stored over a long time, for 29 years, resulting in the active formation of adventitious buds. Embryos began to induce calli within 3 weeks of cultivating on LP medium containing 3 μM BAP and 1 μM 2,4-D. Then, the calli proliferated and transformed into caulogenic calli with bud primordia in 8 weeks. The caulogenic calli increased actively with the addition of 500 mg/l ofl-glutamine in the medium. Furthermore, caulogenic calli, induced on LP medium containingl-glutamine, resulted in the formation of adventitious buds, which elongated after transferring the calli into LP medium with 0.1 μM BAP, but withoutl-glutamine. It appears that the number of adventitious buds and the process of shoot elongation are influenced by the kind of nitrogen contained in the medium for callus induction. A part of this study was presented at the 107th Annual Meeting of the Japanese Forestry Society (1996).  相似文献   
53.
We examined the relationship between the annual escapement of salmon and the δ 15N of willow (Salix spp.) leaves to evaluate the contribution of marine-derived nutrients (MDN) to riparian vegetation around the Pacific Northwest and Northeast regions. Foliar δ 15N values ranged from −3.42‰ to 4.65‰. The value increased with increasing density of carcasses up to 500 fish/km and 1500 fish/km. δ 15N values were variable at carcass densities below 500 fish/km. Possible factors affecting the fluctuation of δ 15N at reference sites are: (1) denitrification; (2) the presence of N2-fixing trees, such as alder; and (3) agricultural runoff. δ 15N values at the sites with carcass densities over 500 fish/km were consistently high, while a value of δ 15N below zero was observed at only one site (Rusha River; δ 15N = −1.87‰). At this site, most adult pink salmon returned to limited locations near the estuary because steeper channel gradients acted as a migration barrier, resulting in the negative δ 15N value. Nevertheless, we concluded that our results showed evidence of the feedback of MDN to terrestrial vegetation, although the use of the δ 15N value as a terrestrial end member at spawning sites is limited. If the relationship between the enrichment index, which is expressed as the values using a mixing model, and salmon abundance was estimated, the availability of MDN in riparian ecosystems could possibly be evaluated and will lead to the establishment of escapement goals. An erratum to this article is available at .  相似文献   
54.
In order to investigate the relationship between vegetation change and fire history in the Siberian boreal forest, fossil pollen and charcoal from two lakes in central Yakutia, eastern Siberia, were analyzed. The vegetation change inferred from the pollen analysis was similar to that found in previous research in the region. Open larch forest covered this region during the late Glacial and early Holocene periods. Later, during the mid-Holocene, Scots pine expanded its range. The low levels of charcoal in the lake deposits represent surface forest fires, suggesting that the present-day surface fire regime has been taking place since at least 6,500 calibrated years before the present (cal yr BP) and that stand-replacing fire has not occurred during the Holocene. Larch and Scots pine forests, which are characterized by surface fire regimes, have been predominant since the early Holocene.  相似文献   
55.
We investigated soil net nitrogen mineralization rate, above- and belowground biomass allocation, and nitrogen use in a Cryptomeria japonica plantation chronosequence. Total biomass accumulation showed an asymptotic accretion pattern, and the peak total biomass accumulation rate occurred approximately 30 years after afforestation. Soil net nitrogen mineralization rate was lowest 30 years after afforestation. Between years 30 and 88, net nitrogen mineralization increased again. These results indicate that an imbalance in soil nitrogen supply and plant nitrogen demand occurred approximately 30 years after afforestation. Furthermore, leaf nitrogen concentration, which was used as an index of plant nitrogen status, was lower in mature forest than in young forest, suggesting that mature stands did not take up nitrogen as successfully. If soil resources such as nitrogen limit plant growth, plants may increase biomass allocation to fine root structure; however, fine root biomass was not higher in 30- and 88-year-old stands than in younger stands, suggesting that changes in biomass allocation may not be effective against nitrogen deficiency in a C. japonica plantation chronosequence.  相似文献   
56.
OBJECTIVE: To investigate the diuretic effects, tolerability, and adverse effects of furosemide and torsemide after short- and long-term administration in healthy dogs. ANIMALS: 8 mixed-breed dogs. PROCEDURES: In a crossover study, furosemide (2 mg/kg), torsemide (0.2 mg/kg), or placebo (bifidobacterium [1 mg/kg]) was administered orally to each dog every 12 hours for 14 days. Blood and urine samples were collected before the study (baseline data) and at intervals on the 1st (short-term administration) and 14th day (long-term administration) of treatment for assessment of urine volume and specific gravity and selected clinicopathologic variables including BUN, creatinine, and aldosterone concentrations, and creatinine clearance. RESULTS: Compared with the baseline value, short-term administration of furosemide or torsemide immediately increased urine volume significantly; after long-term administration of either drug, urine specific gravity decreased significantly. Compared with the effect of placebo, the 24-hour urine volume was significantly increased after short-term administra-tion of furosemide or torsemide. In addition, it was significantly increased after long-term administration of torsemide, compared with that of short-term administration. Long-term administration of furosemide or torsemide increased the BUN and plasma creatinine con-centrations, compared with the baseline value. Compared with the baseline value, plasma aldosterone concentration was significantly increased after long-term administration of either drug and was significantly higher after torsemide treatment than after furosemide treatment. CONCLUSIONS AND CLINICAL RELEVANCE: In dogs, diuretic resistance developed after 14 days of furosemide, but not torsemide, administration; however, both loop diuretics were associated with increased BUN and plasma creatinine concentrations, compared with values before treatment.  相似文献   
57.
Bovine serum contains N-acetyl-D-glucosamine (GlcNAc)-sensitive opsonin inhibitory factors. In the present study, a major component of chitin-binding protein (chitin-binding protein b01, CBPb01) was purified from bovine serum, and identified CBPb01 as bovine IgM by its subunit structure, antigenic properties, and partial sequences. The results of a lectin-binding assay showed that the heavy chain of CBPb01 had a GlcNAc structure, but the commercial IgM did not. It is possible that CBPb01 interconnects through its GlcNAc structure, subsequently forming complexes. We also demonstrated that CBPb01 had opsonin-inhibitory activity, and that this activity was dependent on the binding of CBPb01 to GlcNAc on the zymosan surface. These findings indicate the presence of a kind of IgM that recognizes GlcNAc structure in the regulation of opsonization.  相似文献   
58.
Mitral valve repair is one of the treatment options for mitral regurgitation. Expanded polytetrafluoroethylene (ePTFE) is a polymer that has been widely used in cardiovascular surgery. In this case series, we report the autopsy and histological findings in 6 dogs that underwent cardiopulmonary bypass for mitral annuloplasty using ePTFE sheets and chordoplasty using ePTFE sutures.From May 2005 to October 2009, 3 female and 3 male dogs with severe mitral regurgitation underwent mitral valve repair. This case series included 3 Cavalier King Charles spaniels, 2 Maltese, and 1 Shih Tzu. The survival period after surgery was 19–72 (35 ± 19) months.In all the cases, autopsy revealed that the ePTFE sheets and sutures were not damaged and well integrated into the surrounding highly differentiated, connective tissues. Low-power microscopy revealed that in all cases, the tissues surrounding the ePTFE sheet in the mitral valve annulus had almost completely been covered by granulation tissue. No inflammatory infiltrate or thrombogenesis was observed around the ePTFE in any of the cases.There was no evidence of reactive changes in the region surrounding the ePTFE. These results suggest that ePTFE has excellent tissue compatibility and durability and can be effectively used for canine mitral valve repair.  相似文献   
59.
Feline parvoviruses were isolated from frozen samples of intestines taken from a snow leopard (Uncia uncia) and a serval (Leptailurus serval) that died successively at Sapporo Maruyama Zoo in Hokkaido, Japan. Isolates possessed an antigenic epitope for both the feline panleukopenia virus (FPLV) and mink enteritis virus, identified with a hemagglutination inhibition test. Sequencing analyses of the VP2 region of the isolates revealed that the two isolates were identical and of the FPLV-type. These results suggested that FPLV was introduced from a feral cat which entered the zoo and transmitted the virus inside the zoo.  相似文献   
60.
The objective of this study was to clarify the current status of endangered Kiso horse, population statistics and biological traits, in order to take a step for the conservation by scientific approach. We surveyed 125 Kiso horses (86.2% of the whole breed), analyzed the construction of the population, and calculated the coefficient of inbreeding and effective population size. Moreover, we confirmed coat color variations and the traditional traits of the Kiso horse, and measured their height at the withers and chest circumference to clarify their physical characteristics. The population pyramid of the horses was stationary or contractive, suggesting a reduction of the population in the near future. The effective population size of the horse (47.9) suggested that the diversity was much less than their census size, and the high coefficient of inbreeding, 0.11 ± 0.07 on average, suggested that the horses were surely inbred. The horses had only 4 coat colors; bay, dark bay, buckskin dun, and chestnut, and 116 horses (92.8%) were bayish color, suggesting the fixation in their coat color. Moreover, the majority of them had dorsal stripe (83 horses; 66.4%), and the average heights at withers(131.9 ± 4.4 cm) and chest circumference (167.1 ± 10.1 cm) were not significantly different between males and females.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号