全文获取类型
收费全文 | 21180篇 |
免费 | 1496篇 |
国内免费 | 72篇 |
专业分类
耳鼻咽喉 | 304篇 |
儿科学 | 654篇 |
妇产科学 | 475篇 |
基础医学 | 3168篇 |
口腔科学 | 561篇 |
临床医学 | 2201篇 |
内科学 | 4253篇 |
皮肤病学 | 328篇 |
神经病学 | 1921篇 |
特种医学 | 955篇 |
外国民族医学 | 1篇 |
外科学 | 2817篇 |
综合类 | 224篇 |
一般理论 | 50篇 |
预防医学 | 1684篇 |
眼科学 | 453篇 |
药学 | 1572篇 |
中国医学 | 23篇 |
肿瘤学 | 1104篇 |
出版年
2022年 | 93篇 |
2021年 | 299篇 |
2020年 | 177篇 |
2019年 | 311篇 |
2018年 | 375篇 |
2017年 | 318篇 |
2016年 | 347篇 |
2015年 | 360篇 |
2014年 | 476篇 |
2013年 | 933篇 |
2012年 | 1104篇 |
2011年 | 1244篇 |
2010年 | 711篇 |
2009年 | 611篇 |
2008年 | 1144篇 |
2007年 | 1185篇 |
2006年 | 1093篇 |
2005年 | 1105篇 |
2004年 | 1148篇 |
2003年 | 1075篇 |
2002年 | 1070篇 |
2001年 | 361篇 |
2000年 | 294篇 |
1999年 | 348篇 |
1998年 | 306篇 |
1997年 | 253篇 |
1996年 | 241篇 |
1995年 | 211篇 |
1994年 | 202篇 |
1993年 | 193篇 |
1992年 | 232篇 |
1991年 | 213篇 |
1990年 | 202篇 |
1989年 | 244篇 |
1988年 | 206篇 |
1987年 | 210篇 |
1986年 | 189篇 |
1985年 | 170篇 |
1984年 | 186篇 |
1983年 | 143篇 |
1982年 | 196篇 |
1981年 | 163篇 |
1980年 | 159篇 |
1979年 | 126篇 |
1978年 | 118篇 |
1977年 | 108篇 |
1976年 | 95篇 |
1975年 | 77篇 |
1974年 | 90篇 |
1973年 | 82篇 |
排序方式: 共有10000条查询结果,搜索用时 319 毫秒
11.
The effects of repeated doses of benzodiazepines, diazepam and midazolam in combination with meperidine on arterial blood gases and transcutaneous PO2 were studied in eight healthy volunteers. The study was designed to mimic a clinical situation. Initially two doses of either midazolam 0.05 mg/kg or diazepam in fat emulsion 0.15 mg/kg were given in a randomized crossover fashion with a 20-min interval, followed by meperidine 0.5 mg/kg another 20 min later. The opioid effects were then antagonized by naloxone 0.4 mg. The initial doses of benzodiazepines caused an increase in PaCO2 and a decrease in PaO2. The changes in PaO2 were of short duration and recovered to baseline levels between injections. However, they came sooner and were more pronounced after midazolam. The changes in PtcO2 paralleled those in PaO2. The PtcO2 index as a measure of cardiac output and peripheral blood flow adequacy was increased immediately after the first injection of midazolam but was otherwise not different from control. There were no differences between the drugs concerning PtcO2 index. PaCO2 increased after the first benzodiazepine injection and remained so throughout the study. Addition of meperidine caused only small changes in PaO2 and PaCO2. These changes were reversed by naloxone. In spite of different elimination kinetics there was no difference in the duration of respiratory depression between the two benzodiazepines. 相似文献
12.
Carl J O'Kane Douglas C Tutt Lyndon A Bauer 《Emergency medicine Australasia : EMA》2002,14(3):296-303
Cannabis and driving is an emerging injury‐prevention concern. The incidence of driving while affected by cannabis is rising in parallel with increased cannabis use in the community. Younger drivers are at particular risk. Improvements in research methodology, technology and laboratory testing methods have occurred in the last 10 years. These cast doubt on earlier results and conclusions. Studies now show that cannabis has a significant impairing effect on driving when used alone and that this effect is exaggerated when combined with alcohol. Of particular concern is the presence of cannabis as the sole psychoactive drug in an increasing number of road fatalities and the lack of any structural response to this problem. A review of testing methods, laboratory and real driving studies, and recent epidemiological studies is presented. Suggestions for methods of further data collection and future public policy are made. 相似文献
13.
Carl N. Patterson 《The Laryngoscope》1981,91(6):939-944
The approach to surgery of the crooked nose has changed significantly in the last two decades due in a large measure to a better understanding of the growth, anatomy, and physiology of the nose. The crooked nose often presents a challenging problem to the surgeon because of the multiplicity of deformities. In most cases, deformities of the external bony and cartilaginous nose, septum and turbinates must all be corrected simultaneously in order to obtain a satisfactory and lasting restoration of the nasal airway as well as of the external nasal configuration. 相似文献
14.
Using the buttock flap in 29 white Yorkshire pigs, blood flow and O2 consumption were measured at dermal temperatures between 35 degrees C and 15 degrees C. Flow was measured with an electromagnetic flowmeter and O2 consumption was calculated as the product of blood flow and the difference in flap A-VO2. Baseline flow was 6.6 +/- .9 (SE) ml/100 g/min at 35 degrees C and 3.1 +/- .02 (SE) ml/10 g/min at 15 degrees C. Blood flow through the flap stopped completely at a dermal temperature of 14 degrees C. Oxygen consumption was 0.16 +/- .02 (SE) ml/100 g/min at 35 degrees C and 0.04 +/- 0.01 (SE) ml/100 g/min at 15 degrees C. At 20 degrees C blood flow was 4.3 ml/100 g/min and metabolism was .04 ml/100 g/min. In other words, blood flow was 65% of baseline, while O2 consumption was only 25% of baseline. The therapeutic effect of local cooling at 20 degrees C deserves further investigation. The cessation of flow at 14 degrees C may be caused by increased plasma viscosity. 相似文献
15.
16.
Carl Reyher 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》1874,4(2-3):296-296
Ohne Zusammenfassung
The online version of the original article can be found at 相似文献
17.
Kathryn Nichol Sean P. Deeny Joseph Seif Kevin Camaclang Carl W. Cotman 《Alzheimer's & dementia》2009,5(4):287-294
BackgroundHuman studies on exercise, cognition, and apolipoprotein E (APOE) genotype show that ε4 carriers may benefit from regular physical activity.MethodsWe examined voluntary wheel-running, memory, and hippocampal plasticity in APOE ε3 and APOE ε4 transgenic mice at 10–12 months of age.ResultsSedentary ε4 mice exhibited deficits in cognition on the radial-arm water maze (RAWM), a task dependent on the hippocampus. Six weeks of wheel-running in ε4 mice resulted in improvements on the RAWM to the level of ε3 mice. Hippocampal brain-derived neurotrophic factor (BDNF) levels were similar in ε3 and ε4 mice, and after exercise BDNF was similarly increased in both ε3 and ε4 mice. In sedentary ε4 mice, tyrosine kinase B (Trk B) receptors were reduced by 50%. Exercise restored Trk B in ε4 mice to the level of ε3 mice, and in ε4 mice, exercise dramatically increased synaptophysin, a marker of synaptic function.ConclusionsOur results support the hypothesis that exercise can improve cognitive function, particularly in ε4 carriers. 相似文献
18.
19.
20.
Dr. Carl Heinemann 《Pflügers Archiv : European journal of physiology》1873,7(1):365-366
Ohne Zusammenfassung 相似文献