首页 | 官方网站   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   3169篇
  免费   233篇
  国内免费   234篇
医药卫生   3636篇
  2024年   7篇
  2023年   45篇
  2022年   61篇
  2021年   86篇
  2020年   78篇
  2019年   86篇
  2018年   86篇
  2017年   97篇
  2016年   117篇
  2015年   123篇
  2014年   165篇
  2013年   235篇
  2012年   205篇
  2011年   225篇
  2010年   142篇
  2009年   156篇
  2008年   150篇
  2007年   165篇
  2006年   146篇
  2005年   127篇
  2004年   100篇
  2003年   100篇
  2002年   73篇
  2001年   88篇
  2000年   74篇
  1999年   51篇
  1998年   61篇
  1997年   67篇
  1996年   53篇
  1995年   62篇
  1994年   60篇
  1993年   52篇
  1992年   56篇
  1991年   33篇
  1990年   32篇
  1989年   29篇
  1988年   31篇
  1987年   17篇
  1986年   17篇
  1985年   25篇
  1984年   15篇
  1983年   9篇
  1982年   9篇
  1981年   4篇
  1980年   7篇
  1978年   3篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
  1973年   2篇
排序方式: 共有3636条查询结果,搜索用时 312 毫秒
1.
COVID-19 is a novel coronavirus disease with a higher incidence of bilateral pneumonia and pleural effusion. The high pulmonary tropism and contagiousness of the virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have stimulated new approaches to combat its widespread diffusion. In developing new pharmacological strategies, the chemical characteristic of volatility can add therapeutic value to the hypothetical drug candidate. Volatile molecules are characterized by a high vapor pressure and are consequently easily exhaled by the lungs after ingestion. This feature could be exploited from a pharmacological point of view, reaching the site of action in an uncommon way but allowing for drug delivery. In this way, a hypothetical molecule for COVID-19 should have a balance between its lung exhalation characteristics and both antiviral and anti-inflammatory pharmacological action. Here, the feasibility, advantages, and disadvantages of a therapy based on oral administration of possible volatile drugs for COVID-19 will be discussed. Both aerosolized antiviral therapy and oral intake of volatile molecules are briefly reviewed, and an evaluation of 1,8-cineole is provided in view of a possible clinical use and also for asymptomatic COVID-19.  相似文献   
2.
The progress of modern medicine would be impossible without the use of general anesthetics (GAs). Despite advancements in refining anesthesia approaches, the effects of GAs are not fully reversible upon GA withdrawal. Neurocognitive deficiencies attributed to GA exposure may persist in neonates or endure for weeks to years in the elderly. Human studies on the mechanisms of the long-term adverse effects of GAs are needed to improve the safety of general anesthesia but they are hampered not only by ethical limitations specific to human research, but also by a lack of specific biological markers that can be used in human studies to safely and objectively study such effects. The latter can primarily be attributed to an insufficient understanding of the full range of the biological effects induced by GAs and the molecular mechanisms mediating such effects even in rodents, which are far more extensively studied than any other species. Our most recent experimental findings in rodents suggest that GAs may adversely affect many more people than is currently anticipated. Specifically, we have shown that anesthesia with the commonly used GA sevoflurane induces in exposed animals not only neuroendocrine abnormalities (somatic effects), but also epigenetic reprogramming of germ cells (germ cell effects). The latter may pass the neurobehavioral effects of parental sevoflurane exposure to the offspring, who may be affected even at levels of anesthesia that are not harmful to the exposed parents. The large number of patients who require general anesthesia, the even larger number of their future unexposed offspring whose health may be affected, and a growing number of neurodevelopmental disorders of unknown etiology underscore the translational importance of investigating the intergenerational effects of GAs. In this mini review, we discuss emerging experimental findings on neuroendocrine, epigenetic, and intergenerational effects of GAs.  相似文献   
3.
目的:从16种植物(香茅、香叶、松节、山苍子、薄荷、干姜、丁香、姜黄、红花椒、肉桂、罗勒、迷迭香、青花椒、竹叶花椒、八角茴香、肉豆蔻)挥发油中筛选出对黄曲霉菌生长有较好抑制效果的植物挥发油。方法:采用平板培养法从柏子仁药材表面分离得到黄曲霉菌,利用水蒸气蒸馏法提取16种植物挥发油,采用滤纸片熏蒸后测定黄曲霉菌的菌落直径,对16种植物挥发油抑制黄曲霉菌生长的效果进行研究。结果:采用性状、显微及DNA条形码鉴定的方法从柏子仁药材上成功分离了黄曲霉菌,上述16种植物挥发油对黄曲霉菌的抑菌率分别为2. 93%,0. 05%,0. 37%,76. 07%,0. 34%,0. 15%,50. 05%,8. 51%,1. 43%,58. 20%,0. 07%,2. 60%,8. 73%,100. 00%,52. 62%,0. 07%。结论:16种植物挥发油对黄曲霉菌均有着不同程度的抑菌活性,其中竹叶花椒挥发油、山苍子挥发油、肉桂挥发油的抑菌效果较好,可为柏子仁生长储藏过程中防治黄曲霉菌的污染提供参考,并为植物挥发油作为中药仓储过程中的抑菌剂提供应用依据。  相似文献   
4.
目的探讨白芷酒炖前后对挥发性成分的影响。方法采用顶空固相微萃取技术(HS-SPME)结合气相色谱-质谱法(GC-MS)对白芷酒炖前后挥发性成分及其相对百分含量进行对比分析。结果从白芷生品中初步检测出53个峰,鉴定出36个成分;从白芷酒炖中检测出32个峰,鉴定出26个成分;与生品成分比较,酒炖白芷中有22种成分未测到,但新增了12种成分,表明酒炖白芷中的挥发性成分的组成和含量均发生了变化。结论白芷酒炖后由于受热及辅料黄酒的作用使挥发性成分的种类及含量发生了明显变化,并存在成分转化,本研究为白芷酒炖的炮制机理及其在都梁丸中应用的物质基础研究提供了科学依据。  相似文献   
5.
刘丽  张笑敏  许浚  张纪红  张铁军  陈常青  刘昌孝 《中草药》2020,51(10):2689-2702
吴茱萸是我国常用的大宗中药材,资源丰富且分布较广,具有广阔的开发利用前景。吴茱萸中化学成分类型丰富,包括生物碱、苦味素、挥发油、黄酮等类成分,传统认为生物碱和苦味素为其主要药效成分。对其化学成分、药理作用综述的基础上,根据中药质量标志物(Q-marker)理论,从生源途径、化学成分与传统功效、传统药性、新的临床用途、毒性、可测成分、入血成分及不同配伍环境几方面对吴茱萸Q-marker成分进行预测分析,为明确吴茱萸Q-marker和制定科学的质量标准提供基础。  相似文献   
6.
研究了栀子萃取的最佳工艺条件及其挥发油中的化学成分。以L9(3^4)正交设计对超临界萃取条件进行优化,GC-MS联用技术对挥发性成分进行定性及半定量分析。结果显示:55℃,35MPa,120min的萃取条件下挥发性成分的收率最高,超临界萃取产物的主要成分为亚油酸,棕榈酸,反,反-2,4-癸二烯醛,而传统水蒸汽蒸馏工艺下主要成分为反,反-2,4-癸二烯醛。与水蒸汽蒸馏工艺相比较。超临界流体萃取工艺且有革取率高。生产周期短的优点.  相似文献   
7.
OBJECTIVES: Physicians commonly use etomidate for adult rapid-sequence intubation (RSI), but the manufacturer does not recommend its use for children under 10 years of age due to a lack of data. The authors present their experience with etomidate for pediatric RSI in order to further develop its risk-benefit profile in this age group. METHODS: Trained abstractors reviewed the medical records for all children under 10 years old who received etomidate for RSI between July 1996 and April 2001. RESULTS: 105 children, with an average age of 3 (+/-2.9) years, received a median dose of 0.32 (+/-0.12) mg/kg of etomidate. The systolic blood pressure increased an average of 4 mm Hg (95% CI = -3.3 to 9.2); the diastolic blood pressure increased 7 mm Hg (95% CI = -3.1 to 11) within 10 minutes of receiving etomidate. The heart rate increased an average of 10 beats/min (95% CI = 4.0 to 17.4). Complications included three patients who vomited within 10 minutes of etomidate administration. There were no cases of documented myoclonus, status epilepticus, or new-onset seizures. Thirty-eight patients received corticosteroids during the hospital course, none for suspected adrenal insufficiency. Three patients died, all from severe brain injury. CONCLUSIONS: In children less than 10 years old, etomidate seems to produce minimal hemodynamic changes, and appears to have a low risk of clinically important adrenal insufficiency, myoclonus, and status epilepticus. The association between etomidate and emesis (observed in less than 3% of enrolled patients) remains unclear. For clinical situations in which minimal blood pressure changes during RSI are critical, etomidate appears to have a favorable risk-benefit profile for children under 10 years old.  相似文献   
8.
分瓶法测定果蝇吸入麻醉药半数麻醉有效浓度   总被引:2,自引:1,他引:1  
目的 建立测定果蝇吸入麻醉药半数麻醉有效浓度 (ED50 )的方法学。方法 在 11个 32 5ml的三角烧瓶中各放入 30只雄性果蝇 ,分别加入不同容量的异氟醚标准气 ,使 11个烧瓶中异氟醚浓度分布在零效应浓度与百分之百效应浓度之间。以果蝇失去附壁及运动能力为标准计算各瓶中被麻醉果蝇数 ,用正规法计算出ED50 。结果  11次实验在 2 5及 5 0min时的量 -效关系曲线均呈S形 ,用各自的对数浓度与概率单位作图都呈直线相关 ,相关系数分别为 0 .972± 0 .0 14和 0 .971± 0 .0 2 5 ,ED50 值分别为 (0 .5 1± 0 .0 6 8) %和 (0 .4 7± 0 .0 85 ) % ,变异系数分别为 13.3%和 18.0 %。结论 本法稳定性较好 ,实用可行  相似文献   
9.
在过去的20多年中,对吸入麻醉药作用机制的合理解释大量增多,同时也提出了更多目前还不能回答的问题。Eger等提出了吸入麻醉药产生对伤害性刺激无体动反应的作用靶位可能是两个相距5埃的位点的假设,简称5埃理论。现就相关问题作一综述。  相似文献   
10.
乳剂依托咪酯对心脏手术病人麻醉诱导期循环功能的影响   总被引:1,自引:0,他引:1  
目的 本文应用乳剂依托咪酯,观察其对心脏手术病人麻醉诱导期的循环影响。方法 选择心脏手术病人80例,心功能Ⅲ~Ⅳ级,随机分为两组,每组2 0例:Ⅰ组(水剂组) :水剂依托咪酯0 2 5mg kg-1;Ⅱ组(乳剂组) :乳剂依托咪酯0 2 5mg kg-1。记录麻醉前、注射依托咪酯前、后,气管插管后1min和3min时段的各监测参数。观察不自主肌肉颤动,注射疼痛感及过敏反应等不良反应。结果 显示两种剂型的依托咪酯各时间点的SBP、DBP、MAP、HR各组间无显著差异(P >0 0 5 )。两组在注射依托咪酯后SBP、DBP、MAP、HR轻度下降,但与注射前均无统计学差异(P >0 0 5 )。不自主肌肉运动Ⅰ组8例、Ⅱ组6例:两组间无显著差异(P >0 0 5 )。静脉注射处疼痛Ⅰ组14例、Ⅱ组1例,两组间显著差异(P >0 0 5 )。结论 乳剂依托咪酯具有麻醉诱导平稳,心血管影响轻微,副作用少在应用上优于水剂依托咪酯,可用于高龄及心脏功能受损害患者的麻醉诱导。  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-23

京公网安备 11010802026262号