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   297篇
  免费   24篇
  国内免费   4篇
林业   4篇
农学   3篇
  2篇
综合类   82篇
农作物   36篇
畜牧兽医   177篇
园艺   21篇
  2023年   3篇
  2022年   7篇
  2021年   17篇
  2020年   9篇
  2019年   11篇
  2018年   9篇
  2017年   19篇
  2016年   13篇
  2015年   23篇
  2014年   27篇
  2013年   21篇
  2012年   28篇
  2011年   19篇
  2010年   27篇
  2009年   14篇
  2008年   7篇
  2007年   11篇
  2006年   12篇
  2005年   6篇
  2004年   5篇
  2003年   5篇
  2002年   3篇
  2001年   2篇
  2000年   3篇
  1999年   3篇
  1998年   4篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1993年   4篇
  1992年   3篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1983年   1篇
  1981年   1篇
排序方式: 共有325条查询结果,搜索用时 0 毫秒
71.
72.
Vanadium has potential for use in diabetes therapy. Many investigators have reported toxic effects of inorganic vanadium salts; however, there are few reports on toxic effects of oxovanadium(VO2+) complexes. Therefore, we studied VO2+ toxicity by examining histological changes and measuring the vanadium concentration in the testis after repeated oral administration of bis(1-oxy-2-pyridine-thiolato)oxovanadium(VO2+) (VO(opt)2) for 2 or 4 weeks in KK-Ay mice. Severe mineralization and degeneration/necrosis of the seminiferous tubules were detected after either 2 or 4 weeks of administration. Vacuolar changes in Sertoli cells and the seminiferous epithelia, and hyperplasia of Leydig cells were observed in the testes of some animals. Vanadium concentrations in the mineralized testis were much higher than those in the testis of untreated KK-Ay mice. These results represent the first report of the possibility for seminiferous tubules mineralization induced by VO(opt)2 administration. Therefore, our research provides important information about the potentially toxic effects of VO2+ complexes.  相似文献   
73.
74.

Objective

To determine the infusion rates that maintain the train-of-four (TOF) ratio within 20–70% in dogs and compare the infusion rates between diabetic and nondiabetic dogs.

Study design

Prospective clinical study.

Animals

In total, 47 dogs scheduled for phacoemulsification were included with a median (80% central range) bodyweight of 10.6 (5.7–35.5) kg and age of 7 (1–11) years. Diabetes mellitus was previously diagnosed in nine dogs.

Methods

After premedication using acepromazine and methadone, anaesthesia was induced by intravenous (IV) propofol and maintained by isoflurane and fentanyl or remifentanil. The TOF ratio was monitored by stimulating the peroneal nerve and the response quantified by accelerometry. Rocuronium 0.5 mg kg?1 was administered IV, and further infused to maintain the TOF ratio between 20% and 70%. The infusion rates of rocuronium were compared by the Mann–Whitney test between diabetic and nondiabetic dogs, and the influence of age, sex, bodyweight, body temperature, end-tidal carbon dioxide, end-tidal isoflurane concentration, mean arterial blood pressure, pulse rate and time from induction and time from rocuronium bolus to stable rocuronium infusion rate were investigated in a stepwise, forward regression model.

Results

A stable infusion rate was found in 42 dogs. A higher median (80% central range) infusion rate was found in diabetic [0.43 (0.35–0.50) mg kg?1 hour?1] compared with nondiabetic dogs [0.30 (0.20–0.50) mg kg?1 hour?1] (p = 0.013). None of the other variables investigated were found to significantly influence the infusion rate.

Conclusions and clinical relevance

There is a quite large individual variation in the infusion rates of rocuronium needed to maintain a stable neuromuscular block in a varied population of dogs. Of the variables investigated, diabetes mellitus was the only one found to significantly influence the infusion rate of rocuronium.  相似文献   
75.
以大波斯菊种子水提物为基础,研究其对糖尿病小鼠肝脏组织形态学变化的影响,进而探讨其在治疗糖尿病模型小鼠方面的药用价值。将60只8周龄雄性昆明小鼠随机分为5组,每组12只;第1组为正常对照组,第2组~第5组采用四氧嘧啶尾静脉注射造成Ⅰ型糖尿病模型。5组小鼠按基础日粮饲喂的同时,其中第2组为模型组,每日每只小鼠分别灌服生理盐水0.2mL;第3组~第5组为大波斯菊水提物低、中、高浓度组,每日分别灌服不同浓度(0.5、1.0、2.0g/mL)的大波斯菊种子水提物0.2mL,连续给药30d。期间每日测量各组小鼠体重,在饲喂30d后,处死小鼠,记录肝脏重量,计算肝脏指数,并进行组织学观察。肝脏病理学显示,高剂量试验组小鼠肝脏指数低于模型组和低浓度组,差异显著(P0.05);糖尿病模型组小鼠的肝脏有不同程度的颗粒变性,组织结构改变。不同浓度大波斯菊种子水提物可使Ⅰ型糖尿病模型小鼠肝脏指数降低,能抑制糖尿病小鼠肝脏肿大,并可减轻肝脏组织病理变化,进而起到调节糖尿病肝脏糖代谢的作用。  相似文献   
76.
OBJECTIVE: To evaluate duration of action of an insulin zinc suspension (Caninsulin, Intervet) in spontaneously occurring cases of canine diabetes mellitus and suitability of its use as a once daily administered insulin for treatment of this disease. DESIGN: Eight client-owned canine diabetics were included in a prospective pilot study. All dogs had been treated with Caninsulin for a minimum of 2 months and were considered on clinical grounds to be adequately stabilised. PROCEDURE: Dogs were hospitalised for 24 h and blood collected every 2 h via indwelling venous catheters for blood glucose determination. RESULTS: Once daily Caninsulin administration failed to maintain glycaemic control for greater than 13 h in five of eight dogs, but acceptable blood glucose concentrations were maintained for 22 h and greater than 24 h in two others. One dog became distressed during hospitalisation and the blood glucose curve did not show an identifiable response to the insulin. CONCLUSION: Most diabetic dogs may require twice daily administration of Caninsulin for satisfactory glycaemic control, but once daily administration may be adequate in some animals. More comprehensive investigation into duration of activity of Caninsulin is warranted.  相似文献   
77.
In the present study, modifying effects of diabetes on carcinogenesis induced in type 2 diabetes mellitus model Zucker diabetic fatty (ZDF) rats were investigated using a multiorgan carcinogenesis bioassay. Our re sults demonstrated enhancement of urinary bladder, colon and liver carcinogenesis in ZDF rats treated with five types of carcinogens (DMBDD). Elevated insulin and leptin and decreased adiponectin levels in the serum may be responsible for the high susceptibility of type 2 diabetes mellitus model rats to carcinogenesis in these organs. Possible mechanisms of increased susceptibility of diabetic rats to bladder carcinogenesis could be activation of the PI3K pathway and suppression of p53 in the urothelium in consequence of the above serum protein alterations.  相似文献   
78.
肠道菌群与糖尿病之间的关系正被研究者们所揭示.作为肠道中一类特殊的菌群,益生菌在延缓或治疗糖尿病方面有着独特的优势.本文从机理和优势的角度总结了益生菌防治糖尿病的研究进展,并对其发展趋势进行了展望.  相似文献   
79.
The aim of this study was to estimate the long-term (month-to-month) between-dog, within-dog and analytical components of variance for fasting plasma glucose and serum fructosamine in healthy dogs to assess the usefulness of a single measurement of these analytes in a single dog.Fasting plasma glucose and serum fructosamine were measured in blood samples collected every month for 9 months from 23 clinically healthy dogs, and the results were subjected to nested analysis of variance. The between-dog variation, the within-dog variation, and the analytical variation were 3.8%, 9.5% and 3.7%, respectively, for plasma glucose and 4.2%, 11.1% and 2.8%, respectively, for serum fructosamine.The maximum allowable analytical imprecision, analytical inaccuracy and difference between analytical methods were 4.8%, 2.6% and 3.2%, respectively, for plasma glucose and 5.6%, 3.0% and 3.7%, respectively, for serum fructosamine.The index of individuality, 2.7 for both analytes, indicated that the test results from single dogs can be compared usefully to the corresponding population-based reference intervals.The number of samples required to estimate the true individual mean value ±5% for a single dog was 16 for fasting plasma glucose and 20 for serum fructosamine.The one- and two-sided critical differences expressing the difference needed for two serial results from the same dog to be significantly different at a 5% level was 24% and 28%, respectively, for plasma glucose and 27% and 32%, respectively, for serum fructosamine.  相似文献   
80.
试验旨在测定MKR转基因2型糖尿病小鼠生物学特性数据,为2型糖尿病研究提供技术平台。由美国国立卫生研究院(NIH)授权使用引进的MKR鼠,经自然交配后繁殖的子代作为研究对象,测定MKR鼠的体重、血糖、记忆力、抗疲劳、耐缺氧、麻醉耐受试验,同期采用昆明小鼠和C57BL/6J小鼠作为对照。结果表明,新生MKR鼠自出生3周开始,血糖增高,体重随年龄的增加而减慢,与对照组小鼠同期比较,具有非常显著性意义,MKR鼠抗疲劳、耐缺氧、麻醉耐受能力比昆明小鼠差(P<0.01)。因此,MKR鼠是一种良好的2型糖尿病的动物模型。  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