全文获取类型
收费全文 | 1113篇 |
免费 | 73篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 41篇 |
妇产科学 | 25篇 |
基础医学 | 125篇 |
口腔科学 | 10篇 |
临床医学 | 148篇 |
内科学 | 196篇 |
皮肤病学 | 6篇 |
神经病学 | 62篇 |
特种医学 | 164篇 |
外科学 | 140篇 |
综合类 | 24篇 |
预防医学 | 131篇 |
眼科学 | 37篇 |
药学 | 46篇 |
2篇 | |
肿瘤学 | 47篇 |
出版年
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 8篇 |
2018年 | 17篇 |
2017年 | 9篇 |
2016年 | 11篇 |
2015年 | 16篇 |
2014年 | 23篇 |
2013年 | 41篇 |
2012年 | 42篇 |
2011年 | 30篇 |
2010年 | 26篇 |
2009年 | 30篇 |
2008年 | 34篇 |
2007年 | 48篇 |
2006年 | 28篇 |
2005年 | 43篇 |
2004年 | 39篇 |
2003年 | 33篇 |
2002年 | 44篇 |
2001年 | 27篇 |
2000年 | 31篇 |
1999年 | 27篇 |
1998年 | 31篇 |
1997年 | 29篇 |
1996年 | 31篇 |
1995年 | 25篇 |
1994年 | 24篇 |
1993年 | 26篇 |
1992年 | 23篇 |
1991年 | 18篇 |
1990年 | 17篇 |
1989年 | 46篇 |
1988年 | 29篇 |
1987年 | 36篇 |
1986年 | 24篇 |
1985年 | 33篇 |
1984年 | 21篇 |
1983年 | 15篇 |
1982年 | 10篇 |
1981年 | 12篇 |
1980年 | 17篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 16篇 |
1976年 | 13篇 |
1973年 | 7篇 |
1915年 | 4篇 |
1910年 | 8篇 |
1909年 | 5篇 |
排序方式: 共有1206条查询结果,搜索用时 93 毫秒
1.
2.
3.
V Allen PhD DW Ryan MB FRCA A Murray PhD FIPSM 《International journal of clinical practice》1994,48(3):125-129
SUMMARY Four specialised air mattresses had interface pressure measured under six body sites prone to pressure sores in 10 subjects, supine and sitting. The mattresses were the Clinirest (SSI) and FirstStep (KCI) continuous airflow mattress overlays, and Airwave (Pegasus) and Nimbus (Huntleigh) alternating pressure air mattresses. On the mattress overlays, average supine interface pressures were 2.33 kPa (scapula), 4.15 kPa (elbow), 1.94 kPa (sacrum) and 2.79 kPa (buttock), although they were higher at the occiput (7.97 kPa) and heel (11.7 kPa). The alternating pressure air mattresses had an average minimum interface pressure close to zero for three sites, rising to 4.28 kPa under the heel. Average maximum interface pressures were 8.61 kPa (occiput), 5.21 kPa (scapula), 4.90 (elbow), 4.85 kPa (sacrum), 4.61 kPa (buttock) and 13.2 kPa (heel). No accepted scientific method exists for comparing the two types of mattress. Our data suggest a clinical benefit at the occiput and heel (supine) in using an alternating pressure air mattress and a benefit in using a continuous airflow mattress overlay at other sites. 相似文献
4.
5.
6.
Timothy J Beebe Stephen E Asche Patricia A Harrison Kathryn B Quinlan 《The Journal of adolescent health》2004,35(2):116-123
PURPOSE: To profile adolescent Internet chat room users in terms of demographic characteristics, psychological and environmental factors, and behavioral risk factors. METHODS: The study sample was drawn from respondents to an anonymous statewide survey of 50,168 9th-grade public school students and included 40,376 students who reported Internet access at home and 19,511 who accessed chat rooms. Data were collected by the Minnesota Student Survey (MSS), a survey that has been administered triennially by the state's education department to public school students in grades 6, 9, and 12 since 1989. The MSS includes more than 117 questions (300 variables) addressing attitudinal, behavioral, and environmental issues. Data analysis consisted of comparing the odds of a particular characteristic or behavior for chat room users with that of nonusers. Analyses were run separately for boys and girls. The homogeneity of odd ratios was tested with the Breslow-Day statistic using SPSS for Windows. RESULTS: For boys and girls, use of Internet chat rooms was associated with psychological distress, a difficult living environment, and a higher likelihood of risky behaviors. Although most chat room users did not report serious problems, this group included a disproportionate number of troubled individuals. CONCLUSIONS: Because chat room use serves as an indicator of heightened vulnerability and risk-taking, parents and others need to be aware of potential dangers posed by online contact between strangers and youth. 相似文献
7.
8.
Eleven radiologists appointed by the major radiological societies participated for the past 5 years in the development of the Health Policy Agenda for the American People. The Agenda is an action plan to address a wide variety of serious problems in medicine. The first phase involved establishment of 159 principles, broad value statements that were the foundation of the project. Phase 2 involved the development of policy proposals on 38 urgent issues for action in medical science; education; health resources; delivery mechanisms; evaluation, assessment, and control; and payment for services. These proposals are summarized in this report. The activities and recommendations of representatives for the field of radiology are described. The Agenda has been released, and an implementation phase has begun. It will likely be of great importance to the practice of radiology over the next decade. Important issues can be addressed by acting with the coalitions that are being formed from among the more than 150 participating organizations. 相似文献
9.
10.