首页 | 官方网站   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   362篇
  免费   4篇
农业科学   366篇
  2022年   3篇
  2021年   7篇
  2020年   10篇
  2019年   5篇
  2018年   6篇
  2017年   8篇
  2016年   12篇
  2015年   15篇
  2014年   10篇
  2013年   22篇
  2012年   19篇
  2011年   25篇
  2010年   9篇
  2009年   13篇
  2008年   24篇
  2007年   28篇
  2006年   23篇
  2005年   19篇
  2004年   25篇
  2003年   21篇
  2002年   14篇
  2001年   10篇
  2000年   9篇
  1999年   5篇
  1998年   2篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1992年   2篇
  1990年   1篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   2篇
  1983年   2篇
  1982年   1篇
  1980年   2篇
  1979年   1篇
  1978年   1篇
  1971年   1篇
  1962年   1篇
排序方式: 共有366条查询结果,搜索用时 531 毫秒
51.
'Granular cell' tumor observed in the malar subcutis of a Djungarian hamster was examined to determine its cellular origin. Histologically, the tumor consisted of a solid growth of oval or spindle-shaped large cells with abundant cytoplasm filled with eosinophilic granules that were periodic acid-Schiff-positive and diastase-resistant. Immunohistochemically, the tumor cells were positive to anti-vimentin and anti-desmin antibodies and a few cells showed positivity to anti-actin antibody as well. They did not react to myoglobin, S-100 protein, and glial fibrillary acidic protein (GFAP). Electron microscopic studies revealed that the tumor cells had pinocytotic vesicles, dense plaque and microfilaments. The first granular cell variant of myogenic tumor reported here in Djungarian hamsters was differentiated from granular cell tumor of Schwann cell origin.  相似文献   
52.
We attempted to evaluate the genetic diversity of long-distance transported pollen flowing over fragmented Pinus densiflora populations during a mating season. A P.?densiflora clonal seed orchard, which was located in a rural area where many fragmented populations exist, was selected for pollen capture. Immigrant pollen captured by three clones having different flowering times was regarded as the pollen flowing over fragmented populations during a mating season. The genetic diversity (H e) values of the immigrant pollen captured by the three clones were high (H e?>?0.894). The correlation of paternity (r p) values of the seeds having immigrant parent generated from the three clones were calculated to be negative. From these parameters, the pollen cloud is considered to have maintained high genetic diversity during the mating season. The genetic composition of the pollen cloud showed slight variation. The pollen captured by different trees (i.e., clonal ramets of the three clones) was significantly different based on analysis of molecular variance. Especially, the pollen pools captured by trees planted in the western side of the orchard were significantly different from the gene pool of the surrounding populations. Factors affecting this differentiation could be that the donors of the pollen transported to the orchard vary with time, as well as nonuniform dispersal of the pollen. From these results, the pollen flowing over fragmented P.?densiflora populations is considered to have high genetic diversity, compensating to some extent for fragmentation.  相似文献   
53.
54.
OBJECTIVE: To determine the effects of intestinal ischemia and reperfusion on the expression of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 mRNAs in the jejunum, liver, and lungs of dogs. ANIMALS: 8 healthy adult Beagles. PROCEDURES: In each dog, the cranial mesenteric artery was occluded for 0 (control group; n=4) or 60 (I-R group; 4) minutes, followed by reperfusion for 480 minutes; serum TNF-alpha and IL-6 activities and expression levels of TNF-alpha and IL-6 mRNAs in jejunal, hepatic, and lung tissues were measured before and at the end of the ischemic period and at intervals during reperfusion. For each variable, values were compared between the control and I-R groups at each time point. RESULTS: Compared with the control group, serum IL-6 activity increased significantly after 180 minutes of reperfusion in the I-R group; also, jejunal TNF-alpha mRNA expression increased significantly after 60 (peak) and 180 minutes of reperfusion. In the I-R group, expressions of IL-6 mRNA in the liver and TNF-alpha and IL-6 mRNAs in the lungs increased significantly at 480 minutes of reperfusion, compared with the control group. Serum TNF-alpha activity, expression of IL-6 mRNA in the jejunum, and expression of TNF-alpha mRNA in the liver in the control and I-R groups did not differ. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the liver, lungs, and jejunum contributed to the production of TNF-alpha and IL-6 after intestinal ischemia and reperfusion in dogs, suggesting that intestinal ischemia and reperfusion induce a systemic proinflammatory cytokine response in dogs.  相似文献   
55.
56.
Occurrence of pale potato cyst nematode, Globodera pallida (Stone) Behrens, was first recorded in Japan in 2015. Among several control measures, cultivation of resistant potato (Solanum tuberosum L.) varieties is the most effective in cost and environmental impact. As no G. pallida-resistant varieties have yet been developed in Japan, great emphasis is being placed on screening of germplasm possessing the resistance and development of the resistant varieties. In this study, we first improved previously reported DNA markers linked to the G. pallida resistance loci (GpaIVsadg and Gpa5) and then used these to screen more than 1,000 germplasms to select several candidate germplasms with resistance. We performed inoculation testing on the selected candidates and identified several resistant germplasms to the Japanese G. pallida population. Furthermore, we developed a simultaneous detection method combining three DNA markers linked to G. pallida and Globodera rostochiensis (Wollenweber) Behrens resistance loci. We validated the ability of C237-I marker to select resistant allele of GpaIVsadg and predict the presence of resistance in a Japanese breeding population. Resistant germplasms identified in this study could potentially be used to develop G. pallida-resistant varieties. The marker evaluation methods developed in this study will contribute to the efficient development of resistant varieties.  相似文献   
57.
Fisheries Science - Traditional Japanese koji-fermented tofu (tofuyo) processing was simulated to make fermented seafood. The koji fermentation process at room temperature was applied to steamed...  相似文献   
58.
59.
Setaria faberi and Digitaria ciliaris are summer annual grass weeds that constitute an orchard weed community in Japan. Species dominance in the weed community shifts from S. faberi to D. ciliaris with an emergence delay. The change in species dominance is assumed to be a clue to how weeds dominate or coexist in shaping the community. Population dynamics and seasonal variations in emergence and competitive ability were studied from this viewpoint. Field monitoring and pot experiments exhibited that the emergence period of the two species overlapped extensively from April to June. The emergence of S. faberi began 2 weeks earlier than that of D. ciliaris in April and declined in June as a result of the induction of secondary dormancy. The plant density of D. ciliaris was high during the whole period. The great mortality of the species was replenished with its great natality. The replacement series experiments revealed that S. faberi that had been planted in April was a better competitor than D. ciliaris, but it lost its competitive superiority in the June plantings, when D. ciliaris became a superior competitor to S. faberi. The level of seed output was greater for D. ciliaris, even when it was an inferior competitor. Therefore, the shift in species dominance appeared to be attributed to a change in competitive superiority between the two species. The early emergence of S. faberi and the high plant density of D. ciliaris might accelerate competitive exclusion. The two species coexist when they are equivalent in competitiveness.  相似文献   
60.
The association of the polymorphism of bovine leukocyte antigen ( BoLA-DRB3 ) genes identified by the polymerase chain reaction sequence-based typing (PCR-SBT) method with resistance and susceptibility to mastitis caused by pathogenic bacteria was investigated. Blood samples for DNA extraction were collected from 194 Holstein cows (41 healthy cows and 153 mastitis cows including 24 mixed-infection cows infected with 2 or 3 species of pathogens) from 5 districts of Chiba prefecture, Japan. Sixteen BoLA-DRB3 alleles were detected. The 4 main alleles of DRB3*0101 , *1501 , *1201 , and *1101 constituted 56.8% of the total number of alleles detected. Mastitis cows were divided into 2 groups: group 1 with single-infection cows and group 2 with all mastitis cows including 24 mixed-infection cows. The differences in the frequencies of BoLA-DRB3 alleles and the number of cows homozygous or heterozygous for each BoLA-DRB3 allele between healthy cows and the 2 groups of mastitis cows were evaluated. Furthermore, similar comparisons were performed between healthy cows and the 2 groups of mastitis cows for each mastitis pathogen. It was considered that the 4 alleles, namely, DRB3*0101 , *1501 , *1201 , and *1101 had specific resistance and susceptibility to 4 different mastitis pathogens. Thus, DRB3*0101 might be associated with susceptibility to coagulase-negative Staphylococci and Escherichia coli , and DRB3*1501 might be associated with susceptibility to Escherichia coli . However, DRB3*1101 might be associated with resistance to Streptococci and coagulase-negative Staphylococci , and DRB3*1201 , with resistance to Streptococci , Escherichia coli , and Staphylococcus aureus .  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-23

京公网安备 11010802026262号