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   164篇
  免费   7篇
林业   4篇
农学   2篇
  16篇
综合类   5篇
农作物   6篇
水产渔业   19篇
畜牧兽医   107篇
植物保护   12篇
  2022年   5篇
  2021年   9篇
  2020年   3篇
  2019年   7篇
  2017年   8篇
  2016年   5篇
  2015年   5篇
  2014年   7篇
  2013年   13篇
  2012年   10篇
  2011年   12篇
  2010年   3篇
  2009年   7篇
  2008年   11篇
  2007年   8篇
  2006年   8篇
  2005年   11篇
  2004年   13篇
  2003年   9篇
  2002年   7篇
  2001年   1篇
  1999年   2篇
  1992年   3篇
  1988年   1篇
  1987年   2篇
  1960年   1篇
排序方式: 共有171条查询结果,搜索用时 15 毫秒
51.
Somatic cell nuclear transfer (SCNT) has been exploited in efforts to clone and propagate valuable animal lineages. However, in many instances, recipient oocytes are obtained from sources independent of donor cell populations. As such, influences of potential nuclear-cytoplasmic incompatibility, post SCNT, are largely unknown. In the present study, alterations in mitochondrial protein levels were investigated in adult SCNT pigs produced by microinjection of Meishan pig fetus fibroblast cells into enucleated matured oocytes (maternal Landrace genetic background). Mitochondrial fractions were prepared from liver samples by mechanical homogenization and differential centrifugation. Liver mitochondria were then subjected to two-dimensional difference gel electrophoresis (2-D DIGE). Protein expression changes were confirmed with a volume ratio greater than 2 fold (P<0.05). 2-D DIGE analysis further revealed differential expression of three proteins between the Meishan (n=3) and Landrace (n=3) breeds. Differential expression patterns of 16 proteins were detected in SCNT pig liver tissue (n=3) when compared with Meishan control samples. However, none of the 16 proteins correlated with the three differentially expressed Meishan and Landrace liver mitochondrial proteins. In summary, alteration of mitochondrial protein expression levels was observed in adult SCNT pigs that did not reflect the breed difference of the recipient oocytes. Comparative proteomic analysis represents an important tool for further studies on SCNT animals.  相似文献   
52.
A practical method to detect carrot red leaf virus (CtRLV)-RNA in carrot seeds using a multiplex RT-nested PCR was developed. Total RNA was extracted from carrot seeds by the guanidine thiocyanate method. RT-PCR was performed with a one step RT-PCR kit with CtRLV primers and carrot ubiquitin primers for the internal control, and the second PCR was performed with CtRLV nested primers. Ubiquitin were detected by the first PCR in all samples, while distinct CtRLV-RNA was detected by the 2nd PCR. CtRLV-RNA was detected from carrot seeds from three cultivars. The multiplex RT-nested PCR method was able to detect CtRLV-RNA from a single carrot seed.  相似文献   
53.
Six strains of Erysipelothrix rhusiopathiae were isolated from farmed wild boars with acute septicemic erysipelas during the period from 1983 to 1998 in Japan. All isolates belonged to serovar 1a or 2 (predominant serovars in swine). The 50 per cent lethal dose values of those isolates ranged from 10(1.3)to 10(6.2)colony forming units in mice. In swine, all isolates were virulent, capable of inducing localized or generalized urticarial lesions after intradermal inoculation. All of the isolates were resistant to oxytetracycline and/or dihydrostreptomycin. These observations suggest that E. rhusiopathiae strains isolated from wild boars may have aetiological significance in swine erysipelas.  相似文献   
54.
A seven-year-old, spayed female mongrel dog was diagnosed as pemphigus foliaceus (PF) by clinical, histopathological and immunopathological observations. Serum antibodies against the cell surface of keratinocytes in the dog were detected by indirect immunofluorescence (IIF) using cryosectioned bovine esophagus as well as living cultured-canine keratinocytes as the substrates. When we compared the titers of IIF on bovine esophagus with its disease activity, the IIF titers reflected the disease activity throughout the time course. Our findings will suggest that sequential titration of serum antibodies by IIF will be useful for monitoring the serological disease activity in canine PF.  相似文献   
55.
We synthesized the proposed structure of an antifungal compound detected in the culture broth of the edible mushroom Hypsizygus marmoreus. Using the Evans aldol and Abiko–Masamune aldol reactions as the key steps, we synthesized all of the stereoisomers of the compound with high stereoselectivity. The GC retention times and the fragmentation patterns in the mass spectra of the synthesized isomers did not match those of the natural product. Therefore, this result may imply that it is necessary to reisolate the natural product and reconsider its structure. All of the synthesized isomers were found to exhibit antifungal activity against the phytopathogenic fungus Alternaria brassicicola. Due to their simple structures, the obtained isomers could be lead compounds for new pesticides.  相似文献   
56.
2-(l-Menthoxy)ethanol has been frequently employed as a flavoring agent; however, data regarding 2-(l-menthoxy)ethanol toxicity remain limited. We performed a 13-week subchronic toxicity study of 2-(l-menthoxy)ethanol in male and female F344 rats, with doses of 0, 15, 60, or 250 mg/kg body weight (BW)/day orally administered by gavage using corn oil as the vehicle. No significant toxicological changes in general condition, body weight, or food intake were observed in any groups. The hematological assessment showed decreased hemoglobin, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin and increased platelet count in the male 250 mg/kg group. Serum biochemistry revealed elevated total cholesterol in the 250 mg/kg group of male and female rats, reduced triglyceride in the female 250 mg/kg group, and increased total protein in the male 250 mg/kg group, indicating effects on lipid metabolism and protein synthesis. For organ weights, absolute and relative weights of the liver and adrenal glands were increased in the 250 mg/kg group of both sexes and the male 250 mg/kg group, respectively. Histopathological analysis showed chronic nephropathy in the male 15 mg/kg or higher groups, with increased absolute and relative kidney weights, as well as elevated serum creatinine, in the male 60 and 250 mg/kg groups. However, eosinophilic granules containing α2u-globulin were identified in proximal tubules, suggesting α2u-globulin nephropathy specific to male rats and without toxicological significance. These results indicated that the no-observed-adverse-effect level of 2-(l-menthoxy)ethanol was 60 mg/kg BW/day for both sexes.  相似文献   
57.
58.
We investigated the cooking-induced changes in concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) (dioxins) using mackerel and beef. The concentrations of dioxins (29 congeners) were determined by isomer specific analyses and were compared between uncooked and cooked samples. The cooking procedures examined in this study included grilling as a fillet, boiling as a fillet, and boiling as tsumire (small, hand-rolled balls) for mackerel and boiling as a slice, broiling as a slice, and broiling as a hamburger for beef. Three trials were carried out for each cooking method. Generally, concentrations of dioxins were reduced in every cooking trial. When nondetected congener concentrations were assumed to be half the limit of detection for mackerel, the maximum percentage reductions of total concentrations given as 2,3,7,8-tetraCDD equivalents (TEQ) were 31% in grilling as a slice, 14% in boiling as a slice, and 21% in boiling as tsumire under the conditions of this study. In contrast, for beef, the reductions were 42% in boiling as a slice, 42% in broiling as a slice, and 44% in broiling as a hamburger. These results suggest that ordinary cooking processes with heating undoubtedly reduce the dioxin content in animal products, and the reductions estimated should be considered when dioxin intake is evaluated using contamination data for individual food items.  相似文献   
59.
60.
Carcinosarcomas are rare tumors in humans as well as rats and most commonly occur in the uterus. Recently, we observed a case of incidental carcinosarcoma of the uterus in a female Wistar Hannover GALAS [BrlHan:WIST@ Jcl (GALAS)] rat at 2 years of age. Histopathologically, the tumor was characterized by an admixture of malignant epithelial and nonepithelial elements. The carcinomatous components represented a type of endometrial carcinoma, consisting of glandular and solid proliferation of large-sized tumor cells. Prominent mitoses and tumor cell invasion were observed. The sarcomatous components were characterized by multifocal proliferation of severe atypical cells with cartilage matrix and were diagnosed as chondrosarcoma. Transitions between carcinomatous and sarcomatous components were observed, and many tumor cells in the solid lesion showed immunohistochemical reactivity with both cytokeratin and vimentin. Based on these findings, this tumor was diagnosed as a uterine carcinosarcoma. This is the first report of uterine carcinosarcoma in Wistar Hannover GALAS [BrlHan:WIST@Jcl (GALAS)] rats.  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