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   952篇
  免费   42篇
林业   91篇
农学   26篇
  91篇
综合类   51篇
农作物   26篇
水产渔业   34篇
畜牧兽医   629篇
园艺   9篇
植物保护   37篇
  2023年   1篇
  2022年   9篇
  2021年   11篇
  2020年   13篇
  2019年   22篇
  2018年   16篇
  2017年   22篇
  2016年   19篇
  2015年   25篇
  2014年   28篇
  2013年   45篇
  2012年   58篇
  2011年   53篇
  2010年   30篇
  2009年   20篇
  2008年   54篇
  2007年   47篇
  2006年   69篇
  2005年   48篇
  2004年   45篇
  2003年   38篇
  2002年   29篇
  2001年   55篇
  2000年   36篇
  1999年   35篇
  1998年   8篇
  1997年   2篇
  1996年   5篇
  1995年   2篇
  1994年   3篇
  1992年   22篇
  1991年   15篇
  1990年   18篇
  1989年   12篇
  1988年   18篇
  1987年   16篇
  1986年   8篇
  1985年   11篇
  1984年   9篇
  1983年   3篇
  1982年   2篇
  1979年   2篇
  1974年   1篇
  1971年   2篇
  1970年   2篇
  1969年   1篇
  1968年   2篇
  1963年   1篇
  1960年   1篇
排序方式: 共有994条查询结果,搜索用时 31 毫秒
91.
92.
Sera of dogs with gentamicin-induced uremia were analyzed by high performance liquid chromatography system with strongly basic macroreticular anion exchange resin. Satisfactory separation of peaks was achieved with good reproducibility after deproteinization of sera with trichloroacetic acid at a final concentration of 3%, confirming that the system was suitable for qualitative analysis of uremic serum. The chromatograms showed that the number of peaks and the peak area had relation to concentrations of serum urea nitrogen or creatinine and severity of uremia. Four peaks were selected as suspected canine uremic peaks with high correlation to serum creatinine concentrations which were hardly influenced by extrarenal factors. The results suggested that these four fractions might contain uremic toxins.  相似文献   
93.
94.
95.
96.
Total serum creatine kinase (CK) and its isozyme activities were determined in dogs with dirofilariasis. Before heartworm removal, total CK and isozyme activities in dogs of the mild group were not different from those in dogs of the heartworm-free group. BB activity was higher in dogs of the hemoptysis group. Dogs of the ascites group displayed a mild increase in MM activity. In dogs of the caval syndrome (CS) group, total CK and MM activities were highest among the heartworm-free and heartworm-infected dogs, and MM isozyme accounted for most (75%) of total CK activity. MB and BB activities were also higher. However, there were no significant differences in CK activities between the surviving and non-surviving cases. In dogs with pulmonary heartworm disease (mild and ascites groups), MM activity correlated significantly with the number of heartworms (r = 0.45), hematocrit value (Ht, r = -0.40), serum alanine aminotransferase (ALT, r = 0.42) and lactate dehydrogenase (LDH, r = 0.46) activities, mean pulmonary arterial pressure (r = 0.64) and total pulmonary resistance (r = 0.50). In dogs with CS, MM activity did not correlate with any parameter, but BB activity correlated with the number of heartworms at the right atrium (r = 0.61), Ht (r = -0.53), ALT (r = 0.80), LDH (r = 0.73) and serum urea nitrogen (r = 0.47). At 1 week after heartworm removal, BB and MM activity decreased in dogs of the hemoptysis and ascites groups, respectively. In dogs of the CS group, total CK and MM isozyme activities decreased markedly (P less than 0.01) regardless of their prognosis.  相似文献   
97.
Cardiopulmonary values were determined in dogs with an artificial model of heartworm caval syndrome, which was produced by insertion of heartworm-like silicone tubes into the tricuspid valve orifice and right atrium. Fifteen to 25 tubes with some knots were inserted in 6 dogs (knot group), and 7 to 11 tubes (small-number group) or 29 to 37 tubes (large-number group) without a knot in 3 dogs, respectively. After tube insertion, angiographic contrast medium infused into the right ventricle regurgitated to the right atrium in all cases, and the regurgitation was the most severe in the large-number group. On electrocardiographic findings, the atrial and/or ventricular premature beat developed. The height of a- and v-wave of right atrial pressure curves elevated in all groups. The elevation in v-wave was obvious in the large-number group. The pulmonary arterial pressure tended to fall or to elevate slightly, and total pulmonary resistance increased in all groups. The right cardiac output decreased significantly in all cases. The right heart hemodynamics of the model might resemble those in spontaneous cases without disturbed pulmonary circulation.  相似文献   
98.
Changes of body weights and hepatic acetyl-CoA carboxylase activities were measured in voles and mice treated with monosodium-L-aspartate (MSA). MSA was administrated subcutaneously to neonates at 4 mg/g. The MSA-treated mice showed remarkable obesity, associated with the increase in the plasma insulin concentrations and acetyl-CoA carboxylase activities. The activity of acetyl-CoA carboxylase of control voles was very low; under half that of mice. In the MSA-treated voles, although the plasma insulin concentrations also increased, acetyl-CoA carboxylase activities were not elevated and signs of obesity were not observed.  相似文献   
99.
100.
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