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   626篇
  免费   19篇
  国内免费   1篇
林业   82篇
农学   29篇
  174篇
综合类   49篇
农作物   31篇
水产渔业   54篇
畜牧兽医   175篇
园艺   5篇
植物保护   47篇
  2023年   3篇
  2022年   9篇
  2021年   7篇
  2020年   7篇
  2019年   8篇
  2018年   10篇
  2017年   7篇
  2016年   14篇
  2015年   12篇
  2014年   13篇
  2013年   89篇
  2012年   29篇
  2011年   45篇
  2010年   19篇
  2009年   28篇
  2008年   34篇
  2007年   30篇
  2006年   37篇
  2005年   36篇
  2004年   30篇
  2003年   19篇
  2002年   17篇
  2001年   21篇
  2000年   18篇
  1999年   16篇
  1998年   10篇
  1997年   4篇
  1995年   2篇
  1994年   2篇
  1993年   3篇
  1992年   3篇
  1991年   8篇
  1990年   3篇
  1989年   3篇
  1988年   3篇
  1987年   4篇
  1986年   10篇
  1985年   7篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1972年   1篇
  1971年   1篇
  1970年   3篇
  1969年   1篇
  1968年   1篇
  1967年   3篇
  1966年   1篇
  1964年   2篇
  1962年   1篇
排序方式: 共有646条查询结果,搜索用时 437 毫秒
21.
22.
23.
24.
25.
Dendritic cells (DCs) are the most potent antigen-presenting cells that are expected to be therapeutic agents for tumor immunotherapy. In this study, we generated DCs of sufficient number for DC-based immunotherapy from peripheral blood mononuclear cells (PBMC) in dogs. PBMC were cultured in the presence of phytohemagglutinin (PHA). On day 6, large adherent cells with dendrite-like projections were seen, and the number of these large cells with projections increased on day 8. These cells were positive for esterase staining. They expressed MHC class II, CD11b, CD8 and weakly CD4 on their surface. They tended to make contact with lymphocytes under culture conditions. We obtained about 2-5 x 10(6) of DCs from 10 ml of peripheral blood. These DCs phagocytosed HEK-293 cells by overnight co-culturing. These cells generated from PBMC are possible canine DCs and are applicable to clinical trials of DC-based whole tumor cell immunotherapy in dogs.  相似文献   
26.
The effects of non-specific immunotherapy with anti-allergic peptides extracted from the urine of human allergic patients (MS-antigen), in two dogs with allergic dermatitis (AD) have been described. Clinically, severe pruritus accompanied by secondary bacterial pyoderma did not respond to conventional therapy with systemic antibiotics. The first clinical change appeared as a significant reduction in pruritus within 3 months, around the time of the 15th injection in both cases. The clinical condition was stabilized after 5 months, allowing the gradual withdrawal of concurrent therapies and an increase of injection intervals. The correlation between the results of intradermal skin tests before and after treatment and the improvement of clinical signs was not obvious.  相似文献   
27.
A number of 689 Streptococcus suis isolates collected nationwide from diseased and healthy pigs from 1987 to 1996 were surveyed for antibiotic susceptibilities to 11 drugs. No isolates resistant to amoxicillin, chloramphenicol, and sulfamethoxazole/trimethoprim were found. Isolates were highly susceptible to penicillins (penicillin G, ampicillin, and amoxicillin) except cloxacillin. They were not susceptible to tetracycline, streptomycin, and kanamaycin (MIC90 50 microg/ml, > or = 100 microg/ml, and > or = 100 microg/ml, respectively). Multiple-resistant isolates (> or = 3 antimicrobial agents) were found in 20.3% of all isolates tested.  相似文献   
28.
Someya  N.  Tsuchiya  K.  Yoshida  T.  Noguchi  M. T.  Akutsu  K.  Sawada  H. 《植物病害和植物保护杂志》2007,114(3):108-112
Journal of Plant Diseases and Protection - The antagonistic rhizobacterium, Pseudomonas fluorescens strain LRB3W1, controls cabbage Fusarium yellows caused by Fusarium oxysporum f. sp. conglutinans...  相似文献   
29.
Relationships between three types of herbicidal activity of N′-substituted phenyl-N-methoxy-N-methylureas and substitution at the benzene ring were analyzed by the Hansch-Fujita method. First, the Hill inhibitory activity was correlated with electronic (σ) as well as hydrophobic (π) substituent constants. The existence of an optimum value of hydrophobicity for substituents was suggested to reach the target site of action. Second, bliaching activity observed for the 3-substituted but not for 4-substituted compounds was correlated with π, σ, and steric substituent constant, Es. Third, the postemergent herbicidal activity was shown to correlate linearly with the Hill inhibitory activity, pI50, and hydrophobic parameter, π.  相似文献   
30.
Sugi (Cryptomeria japonica D. Don) produces secondary metabolite norlignans in xylem. Several norlignans are involved in the coloration of heartwood and defense of sapwood against microbial invasion. Their biosynthetic process should be well understood so that their properties can be exploited to improve the quality and utility of C. japonica wood. Unfortunately, information on the norlignan biosynthesis is limited because norlignans are mainly synthesized in a particular season in the transition zone (TZ) along with the heartwood formation, and is difficult to study. Although the generation of two norlignans of C. japonica, agatharesinol and (E)-hinokiresinol, has been reported, systems for producing other norlignans are not yet known. To establish a novel norlignan generating system, we examined the changes occurring in norlignans in a TZ during the process of drying a C. japonica log. On the day of felling, the TZ contained agatharesinol and (E)-hinokiresinol, which increased until they reached a maximum on day 40 after felling. Sequirin-C appeared on day 40 and increased to day 70. The generation of sequirin-C in the TZ can be used to investigate the biosynthetic process of heartwood norlignans. This study describes for the first time the changes that occur in the composition of norlignan during the drying of the TZ.  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