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   6944篇
  免费   329篇
  国内免费   3篇
林业   524篇
农学   182篇
基础科学   56篇
  1208篇
综合类   1240篇
农作物   382篇
水产渔业   443篇
畜牧兽医   2399篇
园艺   252篇
植物保护   590篇
  2023年   42篇
  2022年   41篇
  2021年   137篇
  2020年   136篇
  2019年   151篇
  2018年   128篇
  2017年   121篇
  2016年   152篇
  2015年   133篇
  2014年   169篇
  2013年   305篇
  2012年   389篇
  2011年   451篇
  2010年   249篇
  2009年   202篇
  2008年   461篇
  2007年   448篇
  2006年   451篇
  2005年   447篇
  2004年   449篇
  2003年   441篇
  2002年   391篇
  2001年   87篇
  2000年   75篇
  1999年   80篇
  1998年   62篇
  1997年   50篇
  1996年   80篇
  1995年   55篇
  1994年   55篇
  1993年   54篇
  1992年   58篇
  1991年   34篇
  1990年   53篇
  1989年   44篇
  1988年   39篇
  1987年   36篇
  1986年   29篇
  1985年   45篇
  1984年   46篇
  1983年   40篇
  1982年   28篇
  1981年   21篇
  1980年   26篇
  1979年   19篇
  1978年   26篇
  1977年   30篇
  1976年   20篇
  1975年   24篇
  1974年   26篇
排序方式: 共有7276条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
56.
57.
58.
59.
OBJECTIVE: To determine ECG and echocardiographic measurements in healthy anesthetized Grevy's zebras (Equus grevyi). ANIMALS: 20 healthy zebras. PROCEDURES: Auscultation, base-apex ECG, and echocardiography were performed on anesthetized zebras. RESULTS: Low-grade systolic murmurs were detected in the left basilar region in 4 of 20 zebras. Evaluation of ECGs from 19 zebras revealed sinus rhythm with a predominantly negative QRS complex and a mean +/- SD heart rate of 67 +/- 10 beats/min. Echocardiograms of sufficient image quality were obtained for 16 zebras. Interventricular septal thickness in diastole, left ventricular chamber in diastole and systole, left atrial diameter, and left ventricular mass were significantly and moderately correlated with estimated body weight (r values ranged from 0.650 to 0.884). Detectable swirling of blood in the right and sometimes the left ventricles was detected in 9 of 16 zebras, whereas physiologic regurgitation of blood was detected for the aortic valve in 3 zebras, pulmonary valve in 2 zebras, mitral valve in 2 zebras, and tricuspid valve in 1 zebra. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study provide reference information for use in the cardiac evaluation of anesthetized Grevy's zebras.  相似文献   
60.
Response of healthy dogs to infusions of human serum albumin   总被引:1,自引:0,他引:1  
OBJECTIVE: To evaluate the clinical and immunologic response in healthy dogs to infusions of human serum albumin (HSA). ANIMALS: 9 healthy purpose-bred mixed-breed dogs. PROCEDURES: Each dog was administered a 25% HSA solution once or twice. Various physical examination and laboratory variables were serially evaluated. Antibody against HSA was assayed before and after infusion by use of an ELISA. Intradermal testing was also conducted. A repeated-measures ANOVA or Friedman repeated-measures ANOVA on ranks was used to compare results for the variables. RESULTS: Adverse clinical reactions were observed after the first or second infusion in 3 dogs. Anaphylactoid reactions were observed in 1 of 9 dogs during the first infusion and in 2 of 2 dogs administered a second infusion. Two dogs developed severe edema and urticaria 6 or 7 days after an initial infusion. All dogs developed anti-HSA antibodies. Positive responses for ID tests were observed in 8 of 9 dogs. Short-term increases were detected in blood protein, total bilirubin, and calcium concentrations after HSA infusion. Serum cholesterol concentrations and platelet counts decreased after HSA infusion. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of HSA resulted in profound reactions in 2 of 9 dogs administered a single infusion and in 2 of 2 dogs administered a second infusion. This indicates that there is risk of life-threatening adverse reactions to HSA infusion in healthy dogs.  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