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   540篇
  免费   43篇
  国内免费   39篇
林业   49篇
农学   48篇
基础科学   72篇
  59篇
综合类   155篇
农作物   11篇
水产渔业   5篇
畜牧兽医   204篇
园艺   11篇
植物保护   8篇
  2024年   2篇
  2023年   9篇
  2022年   33篇
  2021年   35篇
  2020年   34篇
  2019年   24篇
  2018年   23篇
  2017年   31篇
  2016年   21篇
  2015年   20篇
  2014年   29篇
  2013年   28篇
  2012年   33篇
  2011年   25篇
  2010年   29篇
  2009年   23篇
  2008年   20篇
  2007年   25篇
  2006年   26篇
  2005年   19篇
  2004年   14篇
  2003年   9篇
  2002年   12篇
  2001年   13篇
  2000年   10篇
  1999年   13篇
  1998年   13篇
  1997年   11篇
  1996年   5篇
  1995年   2篇
  1994年   5篇
  1993年   6篇
  1992年   11篇
  1991年   4篇
  1990年   1篇
  1989年   1篇
  1986年   1篇
  1980年   1篇
  1962年   1篇
排序方式: 共有622条查询结果,搜索用时 531 毫秒
61.
Colic surgery is one of the most painful procedures carried out in horses. Common strategies to alleviate immediate postsurgical abdominal pain include the administration of potent systemic analgesics; however, these may cause unwanted adverse effects such as cardiovascular depression, ileus, and ataxia. The administration of local anesthetics at the incision site in form of an ultrasound-guided subcostal transversus abdominis plane (TAP) block may therefore be preferred to provide adequate analgesia without significant side effects. To date, no technique for a TAP block in horses undergoing median celiotomy has been described. The objective of the study was to develop a TAP block technique, which will lead to the desensitization of the ventrolateral abdominal wall and adjacent skin area of experimental Shetland Ponies using bupivacaine 0.125%. This is a prospective, blinded, self-controlled trial. A cadaver study was performed to determine the ideal injection points and the volume required to stain the nerves responsible for the sensation of the ventrolateral abdominal wall and skin in Shetland pony cadavers (i.e., T9–L 2). Subsequently, using the ideal injectate volume and the landmarks obtained in the first phase of the study, six Shetland ponies received a bilateral TAP injection, either with a local anesthetic solution (bupivacaine 0.125%) or with saline in a randomized, crossover, blinded fashion. Effectiveness was determined over a 4 hour postinjection time, by using a pinprick technique. Significant differences were found to the responses of the pinprick evaluation between the bupivacaine- and saline-treated sides after 30 minutes of TAP block injection. Reported “learned behavior” could have affected the results of the pinprick testing. The TAP block technique reported in this study using bupivacaine 0.125% appeared effective in desensitizing the lower abdomen of ponies for up to 2 hours. Further research is required to apply this technique in horses undergoing celiotomy. Potentially larger volumes and/or higher concentrations of bupivacaine may be necessary to provide longer duration of action of the block.  相似文献   
62.
The landscape style and features of historical and cultural blocks in Handan show the landscape characteristics of Handan in the specific cultural and historical period.To explore the landscape style and features of historical and cultural blocks in Handan is of great practical significance to maintain the characteristics of historical and cultural blocks,improve city quality,continue city culture and retain cultural characteristics.According to the advantaged natural geography,human geography factors and the current situation of landscape style and features in Handan City,this study discussed the landscape style and features of historical and cultural blocks through practical investigation and scientific research,found out the main problems and put forward corresponding protection and promotion strategies,in order to create a landscape pattern of historical and cultural blocks with cultural connotation,harmony and order,and distinctive characteristics.  相似文献   
63.
目的探讨超声联合神经刺激器引导腋路臂丛神经阻滞的麻醉效果与安全性。方法 60例腋路臂丛神经阻滞患者随机分成两组,一组采用单纯神经刺激器行腋路臂丛神经阻滞(A组),另一组采用高频超声联合神经刺激器引导腋路臂丛神经阻滞(B组)。观察两组病例的操作时间、起效时间、麻醉效果、不良反应情况。结果与A组比较,B组操作时间较短,起效时间较快,麻醉效果较好(P〈0.01或0.05)。A、B组不良反应发生率的差异无统计学意义(P〉0.05)。结论超声联合神经刺激器引导腋路臂丛神经阻滞安全有效。  相似文献   
64.

Objective

To describe a novel ultrasound-guided posterior extraconal block in the dog.

Study design

Prospective experimental cadaveric study.

Animals

A total of 13 Beagle Cross cadaver heads.

Methods

After describing the ultrasound bony landmarks and posterior extraconal local regional technique in one head, 12 heads were used to evaluate the spreading of contrast and evaluate potential complications. A 5–8 MHz microconvex ultrasound probe was positioned caudal to the orbital ligament, with the beam orientated transversely, and then tilted caudally until the orbital fissure was visualized. After identifying the bony structures consistent with the orbital fissure, a needle was advanced using an in-plane technique and 0.5 mL of a 50:50 mixture of iohexol and methylene blue was injected. Computed tomography (CT) and dissection were used to evaluate successful injections and potential complications. The injection was considered successful if radiopaque contrast medium was 5 mm from the orbital fissure. Potential complications were defined as the presence of radiopaque contrast within the globe or the intracalvarial tissues.

Results

The CT images confirmed contrast at the target site in 15/24 (63%) of the injections. Only two injections were found in the temporalis muscle; the rest of the injections were located in the extraconal space. No potential complications such as intracranial spreading of contrast, intravascular or intraocular injection were found.

Conclusions and clinical relevance

The technique can deliver contrast close to the main nerves which provide sensory and motor innervation to the eye. Further studies are needed to evaluate this technique in clinical cases.  相似文献   
65.
66.
67.
This report describes transient trifascicular block in three cats presented with lethargy and inappetence, and elevated cardiac troponin I concentrations.The electrocardiogram (ECG) of cat 1 showed a sinus rhythm with pronounced first-degree atrioventricular (AV) block, right bundle branch block, and left anterior fascicular block. The ECG of cat 2 showed truncular left bundle branch block alternating with left anterior fascicular block coupled with prolonged PR intervals, second-degree heart block, and paroxysmal third-degree AV block. The ECG of cat 3 showed first-degree AV block with concomitant right bundle branch block. The diagnosis of trifascicular block was made when paroxysmal third-degree AV block was documented.All cats recovered with medical management within weeks. Each cat resumed a sinus rhythm. Elevated cardiac troponin I concentrations suggested myocarditis that improved.  相似文献   
68.
A new type of wall materials, a block from desulphogypsum and flyash is prepared with desulph-ogypsum and flyash as solid wastes from power stations.This block presents excellent properties which can meet the requirements for non-loadbearing wall.lts binder proportion,production process,properties and economic benifits are studied and analyzed in thise paper.  相似文献   
69.
为验证复合营养舔砖对山羊的饲用效果,进一步完善其配方,改进产品,促进山羊生产发展,通过饲养试验和屠宰测定等手段,研究了复合营养舔砖对山羊增重速度、胴体性状和经济效益的影响.结果表明:补饲舔砖Ⅰ号和Ⅱ号的试验Ⅰ组和Ⅱ组羊只的平均增重速度分别比对照组提高了43.66%和37.86%;羊只胴体重、肌肉重、屠宰率和胴体瘦肉率也均显著或极显著地高于对照组,尤以试验Ⅰ组为佳;每只羊平均每天比对照组羊只分别净增纯利0.17,0.15元;每吨舔砖产生的直接经济效益分别在2.41,2.06万元以上.  相似文献   
70.
秸秆草块饲料育肥肉牛试验初报   总被引:2,自引:0,他引:2  
开发秸秆饲料发展畜牧业是有效解决黄土高原北部农牧交错区水土保持与生态建设中林牧矛盾的重要措施。以玉米秸秆为原料,用粗饲料压块机生产的草块饲料进行肉牛育肥试验。  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