全文获取类型
收费全文 | 3740篇 |
免费 | 395篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 72篇 |
妇产科学 | 40篇 |
基础医学 | 267篇 |
口腔科学 | 73篇 |
临床医学 | 467篇 |
内科学 | 336篇 |
皮肤病学 | 38篇 |
神经病学 | 336篇 |
特种医学 | 75篇 |
外科学 | 235篇 |
综合类 | 479篇 |
一般理论 | 1篇 |
预防医学 | 1019篇 |
眼科学 | 54篇 |
药学 | 319篇 |
5篇 | |
中国医学 | 87篇 |
肿瘤学 | 252篇 |
出版年
2024年 | 8篇 |
2023年 | 63篇 |
2022年 | 126篇 |
2021年 | 167篇 |
2020年 | 203篇 |
2019年 | 171篇 |
2018年 | 157篇 |
2017年 | 138篇 |
2016年 | 178篇 |
2015年 | 200篇 |
2014年 | 316篇 |
2013年 | 354篇 |
2012年 | 270篇 |
2011年 | 302篇 |
2010年 | 193篇 |
2009年 | 181篇 |
2008年 | 169篇 |
2007年 | 163篇 |
2006年 | 133篇 |
2005年 | 108篇 |
2004年 | 75篇 |
2003年 | 71篇 |
2002年 | 50篇 |
2001年 | 50篇 |
2000年 | 40篇 |
1999年 | 33篇 |
1998年 | 26篇 |
1997年 | 30篇 |
1996年 | 21篇 |
1995年 | 15篇 |
1994年 | 10篇 |
1993年 | 18篇 |
1992年 | 18篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 6篇 |
1985年 | 10篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 9篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1973年 | 3篇 |
1972年 | 1篇 |
排序方式: 共有4173条查询结果,搜索用时 834 毫秒
1.
目的 了解某设备实验条件下不同位置脉冲X射线电离辐射水平,提出适当的防护建议。方法 采用热释光测量方法,分别在设备舱周围不同方向不同距离布放热释光剂量计,累积一定数量脉冲辐射后进行测量;采用电离室型X、γ剂量率仪(FJ-347A)实时测量工作状态下不同距离处电离辐射剂量率水平。依据《电离辐射防护与辐射源安全基本标准》(GB18871—2002)规定的职业照射人员和公众个人剂量限值提出不同工作位辐射防护建议。结果 热释光剂量计累计接收3 000个脉冲辐射,设备舱外壁0.01~8.98 mGy,顶部0.01~15.67 mGy,距外壁1~12 m之间0.01~2.18 mGy,工作位0 mGy。工作状态下,X射线剂量率仪测得距设备舱外侧壁1~20 m之间空气比释动能率范围0.26~16 mGy/h。结论 热释光剂量计、电离室型剂量率仪测量结果基本一致,说明两种方法均可用于脉冲X射线测量;工作状态下设备舱外近距离处辐射剂量率较高,可通过采取防护措施或者限制人员工作量以满足辐射防护要求。 相似文献
2.
《Bulletin du cancer》2019,106(4):389-394
3.
4.
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
5.
目的:考核HFRS地鼠肾细胞Ⅱ型灭活疫苗的安全性、免疫法及其流行病学效果。方法:采用间接免疫荧光抗体试验(IFA)、微量细胞变性中和试验(MCPENT),检测接种者血中荧光抗体及中和抗体水平;调查接种组与对照组发病情况。结果:以怀宁、广德两县18个村为疫苗观察现场,接种组7499人,对照组7261人,中强反应率为224%(5/223)。3针全程免疫后中和抗体阳转率为63.33%(19/30),荧光抗体阳转率为38.58%(27/70);接种后1年内接种组无发病,对照组发病3例。结论:该疫苗的安全性较好;有一定水平的免疫应答,但防病效果应进一步观察确证。 相似文献
6.
This paper describes a response directed stress management intervention (SMI) in the form of a Jungian based preference awareness education (PAE). It uses the Insights System of personality types to increase awareness of behaviour and communication preferences of self and different others. Eighteen self‐recruited academic employees participated for 7 weeks and received feedback about work preferences and personality type. The aim was to reduce perceptions of stress and interpersonal stress and to increase feelings of job satisfaction and interpersonal satisfaction. The data were analysed using two‐tailed t‐tests. No significant findings were observed for the total sample after training, however, interesting results were found for certain sub‐sample groups. Extravert‐thinking types, reported decreased stress levels (p > 0.018), and participants suffering high stress/interpersonal stress pre‐PAE, reported decreased stress levels (p > 0.010–0.018). Participants suffering low job/interpersonal satisfaction pre‐PAE, reported increased job satisfaction (p > 0.015–0.016). These results suggest that individuals who report high levels of stress and dissatisfaction are most likely to benefit from this type of intervention. Future PAE research might: (a) use pilot studies to meet the intervention preferences of employees that are reluctant to participate in SMIs; (b) include a wait‐list control group; use: (c) a follow up education/measures; (d) and organizational level (stressor directed) SMIs at the same time as response directed initiatives. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
7.
支架术治疗颈动脉狭窄的临床研究 总被引:11,自引:1,他引:10
目的 观察支架术治疗颈动脉狭窄的近期疗效 ,探讨临床应用中的相关问题。方法 将临床经颈部B超、脑血管造影确诊的颈动脉狭窄患者 10 8例 ,实施颈动脉支架术 ,15例行预扩张 ,12例后扩张成形 ,9例使用滤器装置 ,围手术期给予抗血小板聚集等治疗。结果 2例手术失败 ;术后 2例发生脑出血 ,1例脑栓塞 ,1例支架内血栓形成 ,除 1例脑出血死亡外 ,3例治疗后恢复 ;1~ 6个月的随访中 ,10 5例患者无复发。手术并发症发生率低 ,近期疗效满意。结论 颈动脉狭窄段支架术治疗颈动脉狭窄具有可行性 ,近期疗效肯定 ,是临床上有推广潜力的治疗颈动脉狭窄的方法 ,但远期疗效尚需进一步观察。 相似文献
8.
Gilberto Goissis Sergio Akinobu Yoshioka Domingo Marcolino Braile & Vladimir Donizeti Aparecido Ramirez 《Artificial organs》1998,22(3):210-214
This work describes the results of the controlled crosslinking of collagen matrices by glutaraldehyde based on a double protection strategy, glutaraldehyde acetals and lysine protonation due to the acidic conditions of acetal formation. Materials crosslinked by this approach were characterized by thermal stability comparable to those obtained by conventional procedures with mechanical properties expected for bioprosthesis manufacture and with a higher stability toward collagenase hydrolysis. The integrity of the microfibrillar structure was confirmed by optical and scanning electronic microscopy. The results indicate that the glutaraldehyde acetals procedure may be of potential use for the crosslinking of bovine pericardium used in the manufacture of bioprosthetic devices. Advantages may be related to the production of materials with homogeneous crosslinking distributions, associated with better definition in the nature of the chemical link that they introduce, due to a better distribution of glutaraldehyde within the tissue matrix before the crosslinking reaction is allowed to occur. As a result, materials with improved biological and mechanical properties are expected. 相似文献
9.
Two hundred forty-two patients referred for various gastrointestinal complaints were evaluated for clinical parameters that would predict findings of lactose malabsorption. Breath hydrogen and blood glucose lactose tests were performed after ingestion of 50 g lactose. Presenting complaints, duration of symptoms, and patient demographics such as age, sex, and ethnic heritage were not different between lactose malabsorbers and absorbers as defined by the breath hydrogen lactose test. Foodrelated symptoms in general and after specific foods such as milk, ice cream, cheese, and yogurt were also similar between groups. Prior to testing, 30% of malabsorbers (N=161) and 36% of absorbers (N=81) reported lactoserelated symptoms (P=NS). The blood glucose response to lactose was abnormal in 60% of malabsorbers and 15% of absorbers. This study confirmed our impression that it is difficult to predict lactose absorption status by clinical parameters. The majority of our lactose malabsorber patients were unaware of lactose-associated symptoms. Furthermore, symptom assessment, demographics, food history, and blood glucose testing did not predict abnormal hydrogen responses to lactose.The opinions and assertations expressed herein are those of the authors and are not to be construed as reflecting opinions of the United States Air Force or the Department of Defense.This work has been presented in part at the Annual Scientific Session of the American Gastroenterological Association, San Francisco, California, May 19, 1986, and published as an abstract (Gastroenterology 90:1562, 1986). 相似文献
10.
近些年来对A群多糖脑膜炎菌苗最适免疫剂量进行了一系列现场流行病学及血清学效果的对比研究。首先肯定了我国生产的菌苗与法国Merieux研究所生产的苗苗在人体接种后观察一年内具有同等杀菌抗体反应。以后在严格对比下观察了国内生产的多糖菌苗接种30μg及50μg一年内的血清杀菌抗体反应。结果完全相同;而全身反应则30μg为50μg剂量的五分之一。在我国80年代流脑流行地区内确证了30μg免后人群保护率为99%与国外50μg的保护率(97.2%)相似。国内连续三年在流行地区内对比观察了30μg、与50μg的流行病学预防效果,其人群保护率相似.与国外(Reingold).的报告亦相似。最后结论是本菌苗的最适免疫剂量为30μg.不但其预防效果与50μg相同,而且菌苗反应轻微,经济效益高,有利于在发展中国家推广使用。 相似文献