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   1753篇
  免费   112篇
林业   98篇
农学   29篇
基础科学   11篇
  257篇
综合类   367篇
农作物   59篇
水产渔业   107篇
畜牧兽医   835篇
园艺   36篇
植物保护   66篇
  2023年   16篇
  2022年   22篇
  2021年   41篇
  2020年   50篇
  2019年   52篇
  2018年   39篇
  2017年   35篇
  2016年   47篇
  2015年   25篇
  2014年   45篇
  2013年   67篇
  2012年   108篇
  2011年   123篇
  2010年   69篇
  2009年   54篇
  2008年   119篇
  2007年   95篇
  2006年   101篇
  2005年   73篇
  2004年   61篇
  2003年   74篇
  2002年   75篇
  2001年   21篇
  2000年   14篇
  1999年   18篇
  1996年   13篇
  1994年   12篇
  1993年   8篇
  1992年   17篇
  1991年   16篇
  1990年   15篇
  1989年   11篇
  1988年   8篇
  1987年   11篇
  1986年   18篇
  1985年   15篇
  1984年   10篇
  1983年   11篇
  1980年   8篇
  1979年   11篇
  1978年   12篇
  1977年   10篇
  1976年   10篇
  1975年   10篇
  1974年   10篇
  1973年   12篇
  1971年   13篇
  1969年   13篇
  1968年   7篇
  1967年   13篇
排序方式: 共有1865条查询结果,搜索用时 578 毫秒
41.
42.
43.
44.
Dacryocystorhinography in the dog   总被引:1,自引:0,他引:1  
  相似文献   
45.
46.
A preliminary field experiment was undertaken to evaluate the efficacy of alum precipitated toxoids of Sphaerophorus necrophorus prepared from sonicated whole cells and cell fractions to reduce the incidence of bovine abscesses. A total of 108 calves were divided into five groups and treated as follows: I. uninoculated control, II. adjuvant inoculated control, III. 15.5 mg protein of sonicated (fragmented cells) toxoid, IV. 10.5 mg protein of cytoplasmic toxoid. V. 15.5 mg protein of cytoplasmic toxoid. All animals were maintained under similar conditions to those prevailing in feedlots in Alberta. Livers were examined at slaughter. The most promising result was achieved with the injection of 15.5 mg protein of cytoplasmic toxoid. In this treatment group, no scars (healed lesions) were found in the liver and the incidence of liver abscesses was reduced to 10% from the average 35% liver abscesses and scars found in the uninoculated and adjuvant inoculated groups. The toxoid from sonicated whole cells did not reduce liver abscess incidence. These data suggest that the incidence of liver abscesses in cattle fattened in feedlots may be reduced by immunization.  相似文献   
47.
A bacteriological survey of meat pies, frozen prepared dinners and entrees indicated that their bacterial populations were related to the components, the environment and handling in manufacture. Results were correlated with microbiological examinations of ingredients, line samples and plant environmental samples. Total bacterial counts, coliform counts and Staphylococcus counts of the finished product were low. Coliform organisms found were primarily Aerobacter spp. originating with the frozen vegetables. Enterococci were also found in the frozen vegetables and finished product. Both enterococci and Aerobacter organisms were recovered from the plant environment where they appeared to multiply. Many of the plant personnel carried coagulase-positive staphylococci in the throat or nasal cavity, and this was indicated as a possible source for these organisms found in low numbers in the finished product. Cooking of the products produced sterility except for the survival of some spore forming Bacillus spp. The presence of a poultry slaughtering operation adjacent to the manufacturing area was considered to contribute to microbial contamination of the air in the plant.  相似文献   
48.
A double-DNA approach was developed to discriminate the three Trachurus species that abide in European waters: T. trachurus, T. mediterraneus, and T. picturatus. The analysis aimed at both mitochondrial and nuclear loci. Polymerase Chain Reaction (PCR) amplification of the cytochrome b gene of mtDNA was followed by restriction analysis with three species-specific enzymes: NlaIII, NciI, and BsmAI. Digestion with these endonucleases yielded species-specific electrophoretic profiles. The universality of the results was verified by screening a large number of individuals from 12 geographical regions covering most of the distribution of the species. Additionally, the nuclear multicopy 5S rRNA gene was selected as an alternative candidate for the discrimination of the three Trachurusspecies. A simple agarose gel electrophoretic analysis of the amplicons proved to be capable of leading to unambiguous identification of the three Trachurus species. Thus, the double-DNA methodology presented here allows the accurate discrimination of Trachurus fish species and the detection of commercial fraud.  相似文献   
49.
Spray mixtures consisting of the plant activator BABA (DL-3-aminobutyric acid) and the protectant fungicide mancozeb were significantly more effective than BABA or mancozeb alone in controlling late blight (Phytophthora infestans) in potato and tomato and downy mildew (Pseudoperonospora cubensis) in cucumber. A mixture composed of 5 parts BABA and 1 part mancozeb (w/w, a.i.) exhibited a higher synergy factor than the 1+1 or the 1+5 (BABA + mancozeb) mixtures. No synergistic interaction was detected between BABA plus mancozeb in controlling sporangial or cystospore germination, nor mycelial growth ofP. infestans in vitro. The results showed enhanced effect of mancozeb in BABA-induced plants, suggesting, therefore, that lower dosages of this fungicide may be sufficient to control late blight or downy mildew under field conditions. http://www.phytoparasitica.org posting July 15, 2003.  相似文献   
50.
Cyclosporine has been reported to be effective for the treatment of various cutaneous autoimmune disorders in dogs. Adverse reactions have generally been limited to gastrointestinal tract disturbances and cutaneous eruptions. The article describes antimicrobial-responsive cutaneous reactions in 3 dogs being treated with microemulsified cyclosporine A because of various dermatologic conditions. Cutaneous reactions in these dogs were similar to psoriasiform-lichenoid dermatitis and may represent an atypical staphylococcal infection.  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