全文获取类型
收费全文 | 5443篇 |
免费 | 405篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 60篇 |
儿科学 | 131篇 |
妇产科学 | 113篇 |
基础医学 | 702篇 |
口腔科学 | 192篇 |
临床医学 | 476篇 |
内科学 | 902篇 |
皮肤病学 | 58篇 |
神经病学 | 745篇 |
特种医学 | 156篇 |
外科学 | 613篇 |
综合类 | 70篇 |
一般理论 | 33篇 |
预防医学 | 531篇 |
眼科学 | 103篇 |
药学 | 635篇 |
中国医学 | 11篇 |
肿瘤学 | 326篇 |
出版年
2023年 | 29篇 |
2022年 | 60篇 |
2021年 | 130篇 |
2020年 | 90篇 |
2019年 | 115篇 |
2018年 | 130篇 |
2017年 | 80篇 |
2016年 | 134篇 |
2015年 | 145篇 |
2014年 | 179篇 |
2013年 | 250篇 |
2012年 | 390篇 |
2011年 | 357篇 |
2010年 | 223篇 |
2009年 | 197篇 |
2008年 | 319篇 |
2007年 | 342篇 |
2006年 | 340篇 |
2005年 | 307篇 |
2004年 | 306篇 |
2003年 | 286篇 |
2002年 | 270篇 |
2001年 | 74篇 |
2000年 | 45篇 |
1999年 | 56篇 |
1998年 | 78篇 |
1997年 | 49篇 |
1996年 | 49篇 |
1995年 | 43篇 |
1994年 | 53篇 |
1993年 | 45篇 |
1992年 | 72篇 |
1991年 | 56篇 |
1990年 | 47篇 |
1989年 | 40篇 |
1988年 | 30篇 |
1987年 | 44篇 |
1986年 | 34篇 |
1985年 | 29篇 |
1984年 | 30篇 |
1983年 | 19篇 |
1982年 | 23篇 |
1981年 | 33篇 |
1980年 | 22篇 |
1979年 | 23篇 |
1978年 | 17篇 |
1976年 | 19篇 |
1975年 | 15篇 |
1974年 | 15篇 |
1973年 | 14篇 |
排序方式: 共有5857条查询结果,搜索用时 15 毫秒
1.
Recognizing and managing a deteriorating patient: a randomized controlled trial investigating the effectiveness of clinical simulation in improving clinical performance in undergraduate nursing students
下载免费PDF全文
![点击此处可从《Journal of advanced nursing》网站下载免费的PDF全文](/ch/ext_images/free.gif)
2.
Background: It is widely known that a proportion of university students use drugs. However, much less is known about how they source and supply their drugs. Objectives: In this article, we investigate student drug trading activity, including how they obtained their drugs, whether they sold drugs, and the extent to which their drug trading might be described as a form of “social supply”. Methods: A survey was conducted of all students across seven of the nine universities of Wales. In total, 7855 students submitted a questionnaire and 1877 of these reported drug use in the current academic year. All students who reported using one or more illegal drugs in the current academic year were asked how they obtained their drugs, how they funded their drug use, whether they had sold, traded or given away illegal drugs, along with their motives for drug trading. Results: The results showed that about half of users obtained drugs solely from friends and associates and one-fifth obtained them solely from external dealers. One-quarter used friends and associates as well as external markets. In many cases, supplying drugs amounted to sharing them or giving them away. However, over one-third of students said that they had sold drugs. Conclusions: Overall, the methods of sourcing and supplying drug among university students shares features of both “social supply” and “traditional” drug markets. We conclude that the student drug market investigated is best described as a “hybrid” combination of both. 相似文献
3.
Trevor J. Durbin Casper G. Bendixsen Danielle Jensen-Ryan Abigaile Molzer Sarah Strauss 《Journal of agromedicine》2019,24(2):157-166
ABSTRACTForest workers, including loggers, foresters, and wildland firefighters, are regularly exposed to some of the most fatal occupational environments in the United States. These hazardous work environments may become even more complex and dynamic when subject to bark beetle outbreaks that have resulted in significant tree mortality. The impacts of tree death from bark beetles are significant, with the cumulative 17-year (2000–2016) footprint for bark beetle caused tree mortality estimated at 54 million acres. However, how workers think about and act in these environments is understudied. This study, therefore, approaches the issue of beetle kill and forest worker safety by examining the perspectives or workers themselves. Its contribution is to leverage ethnographic research to provide insights that can generate new research questions, better inform outreach, and ultimately improve worker safety outcomes. The resulting insights show that beetle kill was understood by workers as a hazard that increased the complexity and dynamism of the work environment, making situational awareness both more necessary and more difficult to maintain. While much research about situational awareness focuses on hazardous situations, it is suggested that building adequate situational awareness should also include broader considerations of organizational communication, as well as training and experience considered over the course of entire careers. 相似文献
4.
5.
6.
Effect of acute tyrosine depletion in using a branched chain amino-acid mixture on dopamine neurotransmission in the rat brain. 总被引:1,自引:0,他引:1
Marisa Le Masurier Weite Oldenzeil Claire Lehman Philip Cowen Trevor Sharp 《Neuropsychopharmacology》2006,31(2):310-317
Central dopamine function is reduced by decreasing the availability of the catecholamine precursor, tyrosine, using a tyrosine-free amino acid mixture containing multiple large neutral as well as branched chain amino-acids, which compete with tyrosine for uptake into the brain. Current mixtures are cumbersome to make and administer, and unpalatable to patients and volunteers. Here, we investigate whether individual or limited amino-acid combinations could reduce brain tyrosine levels and hence dopamine function. Measurements of regional brain tyrosine levels, catecholamine and indoleamine synthesis (L-DOPA and 5-HTP accumulation, respectively) were used to identify an effective paradigm to test in neurochemical, behavioral and fos immunocytochemical models. Administration of leucine or isoleucine, or a mixture of leucine, isoleucine, and valine reduced tyrosine and 5-HTP, but not L-DOPA accumulation. A mixture of leucine, valine, and isoleucine supplemented with tryptophan reduced brain tyrosine and L-DOPA, but not 5-HTP. In microdialysis experiments this amino-acid mixture reduced basal and amphetamine-evoked striatal dopamine release, as well as amphetamine-induced hyperactivity. This mixture also reduced amphetamine-induced fos expression in striatal areas. In conclusion, the present study identified a small combination of amino acids that reduces brain tyrosine and dopamine function in a manner similar to mixtures of multiple amino acids. This minimal mixture may have use as a dopamine reducing paradigm in patient and volunteer studies. 相似文献
7.
Neonatal autopsy findings are valuable additions to the information base for current cases and future perinatal care, so the reported decline in the autopsy rate is disturbing. In order to estimate the prevalence of the neonatal autopsy among a large population of deaths, we surveyed participating institutions of the Study Group for Complications of Perinatal Care. Investigators from 37 neonatal intensive care units, located in 9 children's hospitals, 4 hospitals for women and infants, and 24 full-service pediatric and adult care hospitals, reported their neonatal death and autopsy rates for 1989. The overall neonatal autopsy rate was 51% among 1645 neonatal deaths. The rate was variable, ranging from 22 to 100%. We found the neonatal autopsy rate to be lower than previously reported and not apparently influenced by the type of center or by the type of medical staff at the centers. In order to assess and potentially reverse the current low rate, the influence of neonatal demographic and clinical factors, as well as physician-related factors, must be studied. 相似文献
8.
The rate of heat storage mediates an anticipatory reduction in exercise intensity during cycling at a fixed rating of perceived exertion 总被引:8,自引:2,他引:6
Ross Tucker Trevor Marle Estelle V. Lambert Timothy D. Noakes 《The Journal of physiology》2006,574(3):905-915
The aim of the present study was to examine the regulation of exercise intensity in hot environments when exercise is performed at a predetermined, fixed subjective rating of perceived exertion (RPE). Eight cyclists performed cycling trials at 15°C (COOL), 25°C (NORM) and 35°C (HOT) (65% humidity throughout), during which they were instructed to cycle at a Borg rating of perceived exertion (RPE) of 16, increasing or decreasing their power output in order to maintain this RPE. Power output declined linearly in all three trials and the rate of decline was significantly higher in HOT than in NORM and COOL (2.35 ± 0.73 W min−1 , 1.63 ± 0.70 and 1.61 ± 0.80 W min−1 , respectively, P < 0.05). The rate of heat storage was significantly higher in HOT for the first 4 min of the trials only, as a result of increasing skin temperatures. Thereafter, no differences in heat storage were found between conditions. We conclude that the regulation of exercise intensity is controlled by an initial afferent feedback regarding the rate of heat storage, which is used to regulate exercise intensity and hence the rate of heat storage for the remainder of the anticipated exercise bout. This regulation maintains thermal homeostasis by reducing the exercise work rate and utilizing the subjective RPE specifically to ensure that excessive heat accumulation does not occur and cellular catastrophe is avoided. 相似文献
9.
10.
This study examines the locations of family homes, medical schools and places of specialist training, and work of doctors qualifying from UK medical schools in 5 calendar years between 1974 and 1993. The contribution of each UK region to the medical workforce relative to its population is assessed and trends over time are examined. The relationship between place of family home and medical school attended is examined for 14,108 doctors. Career appointment location and its relationship to medical school and family home loc‐ation are examined for over 4000 doctors. For the qualifiers of 1983, an additional analysis incorporating place of training is included. Large differences were found in the percentage of medical students from local family homes attending each regional medical school. In some cases differences reflected local populations but other cases had no obvious cause. Over all cohorts studied, 38% of respondents attended a medical school in the region of their family home (32% of 1993 qualifiers), 42% held a career post in the same region as their medical school, and 38% held a career post in the same region as their family home. Among the qualifiers of 1983, 65% had a career post in the same region as their postgraduate training, 34% also attended medical school in the same region, and 19% also came from family homes in the same region. More women than men took up a career post in the same region as their postgraduate training. The relationships to family home and medical school did not differ by gender. Consultants appeared slightly less likely than GPs to have stayed within a region, but this difference was not statistically significant. 相似文献