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   100篇
  免费   2篇
  国内免费   3篇
林业   7篇
农学   1篇
  9篇
综合类   31篇
农作物   11篇
水产渔业   2篇
畜牧兽医   30篇
园艺   9篇
植物保护   5篇
  2022年   2篇
  2021年   15篇
  2020年   4篇
  2019年   4篇
  2018年   3篇
  2017年   2篇
  2016年   6篇
  2015年   4篇
  2014年   11篇
  2013年   12篇
  2012年   9篇
  2011年   6篇
  2010年   6篇
  2009年   5篇
  2007年   2篇
  2006年   3篇
  2005年   2篇
  2003年   1篇
  2002年   2篇
  2001年   2篇
  1999年   1篇
  1995年   2篇
  1993年   1篇
排序方式: 共有105条查询结果,搜索用时 21 毫秒
1.
The present study was designed to investigate the potential application of native (N) and recombinant (truncated modified [tmFliC] and full-length [flFliC]) flagellin proteins along with inactivated Newcastle disease virus (NDV). Fifty six SPF chickens were immunized twice with PBS (control), inactivated NDV (Ag), inactivated NDV/flFliC (AgF), inactivated NDV/tmFliC (AgT), inactivated NDV/N (AgN), commercial vaccine containing Montanide (Vac) and Vac/N (VacN), with a two-week interval. Blood was collected weekly and spleens were harvested after chickens were sacrificed. Interleukin-6 (IL-6) and tumor necrotic factor-α (TNF-α) gene expression in peripheral blood mononuclear cells were analyzed by Real-Time PCR. Antibody response was assessed by haemagglutination inhibition (HI). Cellular activity was quantified by MTT assay. Results showed that the most IL-6 and TNF-α gene expression was observed in AgF group (P < 0.01). The lowest gene expression among vaccinated groups was observed in Ag group for IL-6 and Ag and Vac group for TNF-α. The highest HI titer was observed in Vac, VacN, AgF and AgT groups. The AgF group showed the highest cellular activity (P < 0.01). In conclusion, flagellin-adjuvanted groups showed a pro-inflammatory effect and acted similarly to or better than the Vac group. Hence, flagellin can be proposed as a potential adjuvant for ND vaccine.  相似文献   
2.
Sexton, Z.S., Hughes, T.J., and Wise, K.A. 20XX. Analyzing isolate variability of Macrophomina phaseolina from a regional perspective. Crop Protection. XX:XXXX. Charcoal rot of soybean (Glycine max L.), caused by Macrophomina phaseolina (Tassi) Goid, has been reported more frequently in the north–central United States in recent years. Growth of isolates collected from the northern and southern U.S. was compared in vitro under various incubation temperatures, and isolate pathogenicity was assessed on cultivars adapted to each region. Results indicate that northern isolates had increased growth at 15 °C compared to isolates from southern states, while southern isolates grew 23% more at 40°C compared to northern isolates. Isolates from both regions were pathogenic on charcoal rot resistant and susceptible cultivars adapted for each region. This is the first research to suggest the importance of screening germplasm under regional environmental conditions and with local or regionally adapted isolates when evaluating cultivar resistance to charcoal rot.  相似文献   
3.
精品课程建设是提高高校教学质量,提高人才培养质量,推进教学改革的重要方式。教学方法的改革是教学改革的关键点和切入点,教学方法的创新促进了精品课程的建设,在教学改革中起着非常重要的作用。经济法作为高校经济管理类专业的一门必修课,在教学过程中,除了要求学生掌握相关的法律知识以外,更重要的是通过学习,学生能将这些理论知识应用在实际工作生活中。但是,在教学实践中,一些传统的教学方法阻碍了课程建设的步伐。文章以经济法省级精品课程为载体,对经济法的教学方法改革进行了反思,分析了经济法教学方法中存在的问题、教学方法改革中应遵循的原则,并对教学方法的改革提出设想。  相似文献   
4.
Burdock roots were stored for six weeks at three temperatures, 0, 15 and 20 °C, and activity of sucrose hydrolase (SH), 1-kestose hydrolase (1-KH), inulin hydrolase (InH), sucrose:sucrose 1-fructosyltransferase (1-SST) and fructan:fructan 1-fructoslytransferase (1-FFT) were assessed. Simultaneously, total fructooligosaccharides (FOS), total inulooligosaccharides (IOS) and inulin were also assessed during storage. During storage, SH showed an irregular variation at 15 and 20 °C, and was significantly higher at 0 °C showing a continuous increase during the storage period. 1-KH decreased progressively at 15 and 20 °C, but showed a sharp increase at 0 °C after two weeks and decreased afterwards. InH showed a different although more regular pattern by decreasing progressively at 0, 15 and 20 °C. However, the decrease was more significant at 15 and 20 °C during the first two weeks, while at 0 °C the decrease was significant after four weeks storage. 1-SST and 1-FFT activities decreased progressively in a pseudo-linear regression during storage, and showed similar patterns. At 15 and 20 °C, total FOS increased during the first three weeks then decreased, while at 0 °C FOS increased progressively during storage. Total IOS increased during storage, however, this increase was much higher at 0 °C than that observed at 15 and 20 °C. Inulin content decreased during storage and final content was lower at 20 °C. The inulin to total FOS plus total IOS ratio decreased sharply during the first two weeks of storage, then progressively during the last four weeks, while the ratio of hydrolyzing to synthesizing activities was quite stable at 15 and 20 °C, but showed a peak at 0 °C after two weeks. The results suggest that carbohydrate metabolism in stored burdock depends partly on temperature and other physiological factors.  相似文献   
5.
AIM: To investigate the effect of a mitochondrial ATP-sensitive potassium channel (mitoKATP) opener diazoxide (DE) on Smac/DIABLO protein expressions in rat heart suffered from different duration of hypothermic preservation. METHODS: The Langendorff model of isolated rat heart was used. After stored in 4 ℃ Celsior solution with or without DE (30 μmol/L) for different time (0, 3, 6, 9 or 12 h). Cell apoptosis was detected by TUNEL technique. The expression of Smac/DIABLO protein in cytoplasm and total caspase-3 protein in myocardia tissue was also analyzed by Western blotting. RESULTS: (1) Compared to the hypothermic preservation groups, DE reduced the percentage of apoptotic cells and the expression of caspase-3 protein in myocardia tissue. (2) The peak of Smac/DIABLO protein expression level appeared at 6 h after hypothermic preservation, and which was postponed to 9 h by DE. (3) The above effects of DE were attenuated by a mitoKATP channel inhibitor 5-hydroxydecanoate (5-HD). CONCLUSION: The findings indicate that in the isolated rat heart, DE protects myocardium against different duration of hypothermic preservation injury via opening of mitoKATP channel and inhibition of Smac/DIABLO protein expression.  相似文献   
6.
Separation anxiety is one of the more prevalent and difficult to treat behavior problems in dogs. The associated behaviors can be undesirable to dog owners and damage the human animal bond, leading to relinquishment or return to an animal shelter. Due to the high prevalence of separation related problems in recently adopted shelter dogs, shelter staff hold a critical role in advising and educating owners on how to prevent separation anxiety post-adoption. The aim of this study was to propose a form of that preventive counseling as a means of preventing the development of separation anxiety in recently adopted shelter dogs. The efficacy of preadoption counseling in the education and prevention of separation anxiety problems was tested in a prospective, randomized, parallel-group study. Participants included 133 new owners of dogs 6 months of age and older. At the time of adoption, sixty-six of these owners were randomly selected to receive five minutes of counseling on the prevention of separation anxiety, while the remaining sixty-seven owners served as the controls. A follow-up survey regarding the signs associated with separation anxiety and other potentially related behaviors was conducted one month post adoption. Results showed that 19 owners reported their dogs as having separation anxiety. There was no significant effect of adoption counseling on the prevention of separation anxiety. Owners in both groups were equally as likely to perform most of the recommendations given during counseling. Dogs that were reported to have separation anxiety were significantly more likely than dogs without reported separation anxiety to show nervous or panicked behavior as the owner prepared to leave (P = 0.0001) and were more likely to be reported as being “needy” (P = 0.031). Having another dog in the home was not protective against the development of separation anxiety. Owners in the counseling group were more likely than those in the control group to put food inside a toy at the time of leaving the dog home alone (P = 0.0001), suggesting the counseling recommendations were indeed followed by the owners. Owner compliance supports the idea that counseling is a useful tool for owners. Separation anxiety is a disorder whose course may be difficult to alter in recently adopted shelter dogs using only basic, interventional information. Brief counseling and a toy do not effectively prevent the occurrence of this complex behavioral condition. Further investigation should be done to find more specific, effective prevention tools for owners to use in the home to minimize the development of separation anxiety and shelter should be prepared to provide interventional resources to owners whose dogs develop separation anxiety despite these efforts.  相似文献   
7.
ABSTRACT:   This study was conducted to determine the effect of dietary vitamin E supplements on non-specific immune responses in juvenile soft-shelled turtles. Turtles were fed diets supplemented with vitamin E at 0 (control), 50, 250, 500, 1000 and 5000 mg/kg, respectively, for 4 weeks. Results showed that blood cell phagocytosis and serum bactericidal activity were significantly improved in turtles from two diets (250 and 500 mg/kg vitamin E supplementation), while had no significant improvement in turtles from the three remaining diets (50, 1000 and 5000 mg/kg vitamin E supplementation) when compared to turtles from the control group. Serum bacteriolytic activity in turtles from diets with 50, 250, 500 and 1000 mg/kg vitamin E supplementation were higher than activity levels quantified for the control group, but no significant difference was observed between the 5000 mg/kg vitamin E supplementation diet and the control diet. The results suggest that vitamin E has an upper and lower threshold for improving non-specific immune function in soft-shelled turtles, and the optimal supplementation may be between 250 and 500 mg/kg.  相似文献   
8.
The chromosomal number variations & structural aberrations of the MDCK cell line, primary feline or canine kidney cell(FKC or CKC) and Hela cell line were investigated and their karyotypes of conventional chromosome bands were analyzed. The carcinogenesis or tumorigenicity testing of these cell lines in about 232 nude mice and for colony formation in soft agarose and for haemagglutination under different concentration of plant lectins of these cells were carried out. Under the prerequisite that the incidence of cancer or tumor in negative-control nude mice inoculated subcutaneously with primary feline or canine kidney cell cultures purified in vitro at passage 3 was 0 (0/22) and 0 (0/10), respectively. The incidence of the progressively-growing malignant tumor(MT) in positive-control nude mice inoculated subcutaneously with Hela cell cultures of KB, X, or NM20/X strain was 10/10, 25/25 and 5/51, respectively. The results showed that the incidence of tumor in nude mice with tetrapioid YA strain of MDCK cell during 20 - 45 passages, with hypodiploid JB strain of MDCK cell on passage 25, with di-and hypoploid JC strain of MDCK cell during 2 - 15passages or with hypoploid M strain of MDCK cell during 9 - 27 passages was 28/58, 1/5, 4/18 and 0/31,respectively. The chromosomal analysis results showed that the ratio of difference in the rate of modal chromosome number between high (mcs + n) and lowest (mcs)passages was not more than 5 % - 15 % and the structure aberrations was generally 0 - 3%. These results proved that the genetic characteristics of chromosomal number of cell lines determines their tumorigenicity, but it is species-specific. MDCK line has tumorigenicity no matter what its chromosome karyotype is, at least it has very low tumorigenicity even when its modal chromosome number is hypoploid. The repeatedly frozen, thawed and split controls of tumorigenicity-positive cell lines(X strain of Hela, M strain of BHK-21, JA strain of Vero, YA strain of MDCK) have much lower tumorigenicity or are even non-carcinogenesis, and the repeatedly frozen, thawed and split controls of very low tumorigenicity cell lines (M or JC strain of MDCK) are certainly non-carcinogenic and never have increased tumorigenicity.It is thus evident that MDCK cell of M, JB or JC strain can be approved as substrate for the preparation of attenuated viral vaccines, but MDCK cell of YA strain can not be approved as substrate for the preparation of comattenuated viral vaccines. In summary, all strains of MDCK cell line have tunorigenicity, at least have low tumorigencity, never have non-cancinogenic MDCK, but very low tumorigenicity MDCK cell strains can certainly be used for the approval production of canine viral vaccines if the DNA content in viral cell cultures was remarkably decreased through conventional means in manufacturing process. Therefore, the master cell stock and working cell bank of MDCK line used for vaccine manufacture were established in China, which are free of infectious agents, and described with respect to cytogenetic characteristics and tumorigenicity. Tests showed that there were correlations among cell line chromosome number variations, anchorage independence in soft agarose, haemagglutination under plant lectins, and tumor-forming ability in nude mice, thus all the in vitro tests are economic, simple and reliable means for monitoring the tumor-forming ability of MDCK line in nude mice.  相似文献   
9.
To produce high-affinity monoclonal antibodies against pesticide carbofuran, and the develop immunochemical assays for people's health and environmental protection, the hapten 4-[[(2,3-dihydro-2,2-dimethyl-7-benzofuranyloxy) carbonyl]- amino]-butanoic acid (BFNB) of carbofuran was synthesized and Balb/c mice were immunized by the hapten-carrier (BFNB-bovine serum albumin, BFNB-BSA) conjugates. The splenocytes of immunized mice were fused with Sp2/0 cells and the cultural supernatants of hybridoma cells were screened by the indirect enzyme-linked immunoabsorbent assay (ELISA), based on BFNB-ovoalbumin conjugates (BFNB-OVA). Purified monoclonal antibody (McAb) was obtained from fluids of ascites, deposited by octanoic acid and ammonium sulfate. The affinity and the specificity of McAb were characterized by ELISA or indirect competitive ELISA. A hybridoma cell line (5D3) secreting anti-carbofuran McAb had been established. The titer of culture medium and ascites was up to 1:2.048 × 10^3 and 1:1.024 × 10^6, respectively, and the subtype of the McAb was IgG1. The affinity constant of the McAb was about 2.54 × 10×9 L mol^-1, with an IC50 value of 1.18 ng mL^-1 and a detection limit of 0.01 ng mL^-1. Cross-reactivity studies showed that the McAb was quiet specific for carbofuran, as among the four analogous compounds, they were all hardly recognized (4.59 × 10^-4% for 2,3-dihydro-2,2- dimethyl-7-benzofuranol and less than 3.0 × 10^4% for others). The prepared McAb had a very high affinity and specificity, and it could be used to develop ELISA for rapid determination of carbofuran.  相似文献   
10.
假设股票价格遵循广义O-U(Ornstein-Uhlenback)过程,执行价格为不确定执行价格并服从几何分数布朗运动,利用拟鞅和测度变换的方法,得到该模型下领子期权定价公式并进行数值分析.该结果推广了常数参数下领子期权的结果,为金融衍生品创新提供了更多的理论依据.  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