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   156篇
  免费   4篇
林业   19篇
农学   4篇
  21篇
综合类   12篇
农作物   4篇
水产渔业   21篇
畜牧兽医   71篇
园艺   1篇
植物保护   7篇
  2023年   1篇
  2022年   2篇
  2021年   2篇
  2020年   1篇
  2019年   3篇
  2018年   4篇
  2017年   3篇
  2016年   4篇
  2015年   8篇
  2014年   6篇
  2013年   9篇
  2012年   13篇
  2011年   10篇
  2010年   3篇
  2009年   12篇
  2008年   13篇
  2007年   13篇
  2006年   11篇
  2005年   13篇
  2004年   5篇
  2003年   6篇
  2002年   6篇
  2001年   4篇
  2000年   1篇
  1999年   1篇
  1998年   2篇
  1997年   1篇
  1989年   1篇
  1987年   2篇
排序方式: 共有160条查询结果,搜索用时 31 毫秒
91.
Lactoferrin purified from canine seminal plasma by a three-step chromatography procedure had a molecular mass of 75.2 kDa and cross-reacted with antiserum to equine seminal plasma lactoferrin. Seminal plasma lactoferrin concentrations were determined by a competitive enzyme-linked immunosorbent assay (ELISA) by using rabbit anti-equine lactoferrin antibody and alkaline phosphatase-labeled goat anti-rabbit IgG antibody in 14 normal dogs and found to range from 12 to 197 micro g/ml, with a mean value of 77 +/- 59 micro g/ml (the mean +/- SD). Seminal plasma transferrin concentrations were determined by a sandwich ELISA with goat antibody to canine serum transferrin and alkaline phosphatase-conjugated goat anti-canine transferrin antibody and found to range from 0.32 to 12.6 micro g/m l, with a mean value of 2.44 +/- 3.25 micro g/m l. The lactoferrin concentration significantly correlated with the sperm concentration (r=0.7025, P<0.01), but there was no significant correlation between the seminal plasma transferrin concentration and sperm density. These results indicate that seminal plasma lactoferrin, but not transferrin, reflects gonadal function.  相似文献   
92.
Cellular activation and functional cell surface markers were evaluated during experimentally-induced endotoxemia in healthy horses. Eight healthy adult horses were infused a low dose of endotoxin (lipopolysaccharide from Escherichia coli O26: B6, 30 ng/kg of body weight, IV) and five control horses were given an equivalent volume of sterile saline solution. Venous blood samples were collected for flow cytometric analysis of peripheral blood mononuclear cells (PBMCs) and to measure plasma endotoxin concentrations. Clinical signs of endotoxemia were recorded at 10, 20, 30, 40, 50 min, 1, 2, 3, 4, 8, 16, 24 and 48 hr after endotoxin or saline solution administration. Clinical findings characteristic of endotoxemia (tachycardia, tachypnea, increased rectal temperature, and leukopenia) occurred transiently in all horses administered endotoxin; however, plasma endotoxin concentrations were detectable in only 50% (4/8) of the endotoxin-infused horses. The percentage of CD4(+), CD5(+), and CD8(+) cells decreased while the percentage of CD14(+), IgM(+), and MHC class II(+) cells increased significantly after endotoxin infusion. Alterations in the immunophenotype of PBMCs from horses with experimentally-induced endotoxemia were associated with changes in vital signs, indicating that endotoxin altered the immuno balance.  相似文献   
93.
A case of pulmonary acariasis in lung of Japanese macaque   总被引:3,自引:0,他引:3  
A 20-year-old female Japanese macaque, weighing 8.7 kg, developed severe pulmonary acariasis. Numerous whitish nodules, 2-4 mm, were scattered throughout the lungs. Histologically multifocal granulomatous lesions consisting of a large number of eosinophils, epithelioid cells, foreign body type giant cells, and collagen fibers were aggregated around the mait bodies. Numerous mast cells were also detected in the lesions by toluidine blue staining, and tested positive for tryptase by immunohistochemistry. This may be the first reported case of severe pulmonary acariasis in a Japanese macaque.  相似文献   
94.
Various dog breeds are remarkably different from each other not only in their sizes and shapes but also in behavioral traits, suggesting that some of these characteristics are under genetic control. However, little is known about genes related to behavioral traits in canine species. In humans, it has been reported that the dopamine receptor D4 gene (DRD4) includes polymorphism at several regions that relate to personality or psychiatric disorders. In an earlier study by the authors of the present study, the polymorphisms in canine DRD4 exon III and exon I regions were reported. In the present study, a novel polymorphism in canine DRD4 intron II was found based on a 17 base pair insertion/deletion, and the two alleles detected were named P (shorter allele) and Q (longer allele). The allelic distribution in 28 breeds of dog, including a total of 1114 unrelated individuals, were then investigated. Both P and Q alleles were detected in most of the breeds investigated; however, the frequencies of P and Q differed greatly between breeds. With respect to classification based on breed origin, P and Q alleles were frequent in Occidental and Oriental breeds, respectively. Furthermore, two subspecies of wolves, the ancestors of dogs, were analyzed for the comparison of allele frequencies with dogs, and the P allele was predominant in both European and Chinese wolves.  相似文献   
95.
The present study deals with the effects of gibberellins (GA3 GA4) and uniconazole-P, an inhibitor of gibberellin biosynthesis, on negative gravitropism and xylem formation in the stems of horizontally positioned, 2-year-oldFraxinus mandshurica Rupr. var.japonica Maxim. seedlings. Each growth regulator (100 g) dissolved in 5 l acetone (50%) was applied to the basal node of the current shoot on May 24, 1995. The same treatment was repeated five times weekly until June 28. Five seedlings were used for each treatment. The seedlings were positioned horizontally 24h after the first application on May 25. Within 5 weeks the horizontal stem of control and GA-treated seedlings exhibited negative gravitropism. In contrast, the application of uniconazole-P inhibited negative gravitropic stem bending. The application of GAs increased the number of gelatinous fibers having thickened cell walls on the upper side of stems. The uniconazole-P application decreased xylem cell formation but did not inhibit the formation of gelatinous fibers. These results indicate that not only the differentiation of gelatinous fibers but also xylem increment is important in the negative gravitropism of horizontally positionedF. mandshurica seedlings. These results also suggest that GAs may be involved in xylem cell :formation rather than the differentiation of gelatinous fibers in this species.Part of this research was reported at the 23rd annual meeting of the Plant Growth Regulation Society of America, Calgary, Canada, July 1996  相似文献   
96.
Hepatitis E virus (HEV) is known as a causative agent of zoonosis and food poisoning. Pigs and some species of wild animals, including wild boar, are known to be a reservoir of HEV. In this study, we investigated the situation regarding HEV infection in wild boars in Ibaraki Prefecture, Japan. Serum, liver and feces samples from 68 animals were collected, and the presence or absence of HEV genomic RNA and HEV antibodies were analyzed. The viral genome was detected in samples from 7 (10.3%) animals, with all HEVs classified as genotype 3, subtype 3b. HEV antibodies were detected in samples from 28 (41%) animals. This report demonstrates for the first time the high prevalence of HEV infection in wild boars in Ibaraki Prefecture.  相似文献   
97.
Ticks removed from 1136 dogs and 134 cats all over Japan were examined for Borrelia infection by PCR and sequencing. The 5S-23S rDNA intergenic spacer of Borrelia was detected from two Ixodes persulcatus ticks from two dogs and two unidentified Ixodes spp. from another two dogs in Hokkaido, and two Ixodes granulatus ticks from two cats in Okinawa. Additional 2 I. granulatus from the same cats also showed positive. Sequence analysis of the PCR products revealed that the one from Hokkaido was similar to B. garinii, the three from Hokkaido to B. tanukii, and the four from Okinawa to a novel Borrelia sp. closely related to B. valaisiana. The data was confirmed by analysis of the flagellin gene sequence. Infected ticks carried by companion animals can be introduced into the human environment.  相似文献   
98.
The development of human civilization has caused many problems, among them increases in atmospheric CO2 and shortage of fossil fuel resources. Fast-growing tree species can help solve these problems. Short rotations cause concern that fast-growing species contain a high proportion of juvenile wood, thus limiting their use. To use fast-growing species for timber, this concern must be addressed.  相似文献   
99.
Physical, chemical, and biological properties of wood depend largely on the properties of cellulose, noncellulosic polysaccharides, and lignin, and their assembly mode in the cell wall. Information on the assembly mode in the main part of the ginkgo tracheid wall (middle layer of secondary wall, S2) was drawn from the combined results obtained by physical and chemical analyses of the mechanically isolated S2 and by observation under scanning electron microscopy. A schematic model was tentatively proposed as a basic assembly mode of cell wall polymers in the softwood tracheid as follows: a bundle of cellulose microfibrils (CMFs) consisting of about 430 cellulose chains is surrounded by bead-like tubular hemicellulose-lignin modules (HLM), which keep the CMF bundles equidistant from each other. The length of one tubular module along the CMF bundle is about 16 ± 2 nm, and the thickness at its side is about 3–4 nm. In S2, hemicelluloses are distributed in a longitudinal direction along the CMF bundle and in tangential and radial directions perpendicular to the CMF bundle so that they are aligned in the lamellae of tangential and radial directions with regard to the cell wall. One HLM contains about 7000 C6-C3 units of lignin, and 4000 hexose and 2000 pentose units of hemicellulose.  相似文献   
100.
Studies of the impact of traditional agroforestry practices on soil nutrient status in the Amazon Basin have largely been limited to upland sites, many of which are oligotrophic. However, rural population density in Amazonia is highest on the floodplains of the major rivers and shifting cultivation has been practiced on the floodplains for millennia. We established a slash-and-burn cultivation plot and an untreated forest plot in tidal floodplain successional forest in the Islands of Abaetetuba, Pará, Brazil, and sampled soils (0–10 cm) during four phases of the agroforest cycle (n = 9 in each plot for each sampling period): (1) prior to clearing, (2) following burning, (3) harvest one (rice at four months), and (4) harvest two (sugar cane at 15 months). During the course of this pilot experiment, background temporal variability in SOC, total N and available mineral nutrient pools (P, K, Ca, Mg) exceeded treatment effects, suggesting that soil nutrient pools in this environment are well-buffered against the effects of shifting cultivation. These results contrast markedly with those reported for Amazonian upland sites where nutrient pulses and declines associated with the agroforest cycle have been demonstrated and may restrict the potential for low-input, continuous cultivation. Physical limitations imposed by flooding and fluvial erosion, rather than nutrient constraints, restrict the potential of agricultural intensification in the tidal floodplains. This revised version was published online in June 2006 with corrections to the Cover Date.  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