全文获取类型
收费全文 | 2454篇 |
免费 | 251篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 87篇 |
妇产科学 | 31篇 |
基础医学 | 345篇 |
口腔科学 | 63篇 |
临床医学 | 338篇 |
内科学 | 434篇 |
皮肤病学 | 29篇 |
神经病学 | 165篇 |
特种医学 | 172篇 |
外科学 | 314篇 |
综合类 | 110篇 |
一般理论 | 2篇 |
预防医学 | 266篇 |
眼科学 | 54篇 |
药学 | 193篇 |
中国医学 | 26篇 |
肿瘤学 | 84篇 |
出版年
2021年 | 37篇 |
2020年 | 24篇 |
2019年 | 29篇 |
2018年 | 33篇 |
2017年 | 31篇 |
2016年 | 29篇 |
2015年 | 39篇 |
2014年 | 50篇 |
2013年 | 79篇 |
2012年 | 122篇 |
2011年 | 108篇 |
2010年 | 68篇 |
2009年 | 72篇 |
2008年 | 107篇 |
2007年 | 133篇 |
2006年 | 119篇 |
2005年 | 85篇 |
2004年 | 97篇 |
2003年 | 86篇 |
2002年 | 107篇 |
2001年 | 97篇 |
2000年 | 85篇 |
1999年 | 60篇 |
1998年 | 62篇 |
1997年 | 52篇 |
1996年 | 68篇 |
1995年 | 36篇 |
1994年 | 33篇 |
1993年 | 43篇 |
1992年 | 55篇 |
1991年 | 46篇 |
1990年 | 40篇 |
1989年 | 56篇 |
1988年 | 37篇 |
1987年 | 40篇 |
1986年 | 32篇 |
1985年 | 43篇 |
1984年 | 28篇 |
1983年 | 31篇 |
1982年 | 15篇 |
1981年 | 18篇 |
1980年 | 18篇 |
1979年 | 32篇 |
1977年 | 19篇 |
1976年 | 21篇 |
1975年 | 23篇 |
1974年 | 23篇 |
1973年 | 27篇 |
1972年 | 18篇 |
1971年 | 17篇 |
排序方式: 共有2728条查询结果,搜索用时 0 毫秒
901.
902.
Humans are the longest living and slowest growing of all primates. Although most primates are social, humans are highly cooperative and social in ways that likely co-evolved with the slow human life history. In this paper we highlight the role of resource transfers and non-material assistance within and across generations in shaping low human mortality rates. The use of complex cooperative strategies to minimize risk is a necessary precursor for selecting further reductions in mortality rate in late adulthood. In conjunction with changes in the age-profile of production, the impacts of resource transfers and other forms of cooperation on reducing mortality likely played an important role in selection on post-reproductive lifespan throughout human evolution. Using medical data and ethnographic interviews, we explore several types of common risks experienced by Tsimane forager-horticulturalists, and quantify the types and targets of aid. Our results illustrate the importance of transfers in several key domains and suggest that the absence of transfers would greatly increase human mortality rates throughout the life course. 相似文献
903.
904.
905.
Fat embolism syndrome presenting primarily with cerebral manifestations is rarely reported. We report here two such patients who showed complete recovery following initial deterioration. The aim of these reports is to highlight that prolonged intensive care and good rehabilitation can lead to normal neurologic recovery despite poor clinical picture initially. The importance of adequate oxygenation to prevent secondary brain damage is emphasized during prolonged recovery. 相似文献
906.
907.
908.
909.
910.
Una M O'Doherty Helen A McNair Andrew R Norman Elizabeth Miles Simon Hooper Mark Davies Naomi Lincoln Jan Balyckyi Peter Childs David P Dearnaley Robert A Huddart 《Radiotherapy and oncology》2006,79(3):335-340
BACKGROUND AND PURPOSE: Patients receiving radical radiotherapy to the prostate are requested to maintain a full bladder to displace the dome of the bladder and small bowel from the target volume. This study investigated patients' ability to consistently maintain a full bladder throughout planning and treatment before (Study 1) and after (Study 2) the introduction of a patient information sheet. PATIENTS AND METHODS: Bladder volumes were measured on 41 patients at CT scanning, simulation and once weekly during treatment using a portable ultrasound device, BladderScan BVI 3000. Patients were asked their assessment of bladder fullness, time since last urination and the volume of fluid drank. A patient information sheet on bladder filling was then introduced and the study repeated on 25 patients (Study 2). The ultrasound bladder volumes measured at CT were compared to the CT scan data. RESULTS: There was a strong correlation between the ultrasound and CT bladder volumes r = 0.88 (P < 0.01). There was a significant decrease between the volume at CT (mean 362 ml, SD 229 ml) and treatment (mean 251 ml, SD 171 ml) in Study 1 (P = 0.002). In Study 2 the mean volume at CT was 286 ml (SD 164 ml) compared to a mean of 312 ml (SD 196 ml) during treatment. The measured volume correlated with patient self-assessment (r = 0.47, P < 0.01). The median volume drank by patients in Study 2 was 350 ml (range 50-825 ml) compared to 450 ml (range 75-1500 ml) in Study 1. CONCLUSIONS: Our initial results showed patients were unable to maintain a constant bladder volume during planning and treatment. Implementation of written bladder filling instructions was shown to improve bladder volume consistency. 相似文献