全文获取类型
收费全文 | 905篇 |
免费 | 22篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 14篇 |
妇产科学 | 12篇 |
基础医学 | 67篇 |
口腔科学 | 12篇 |
临床医学 | 189篇 |
内科学 | 66篇 |
神经病学 | 108篇 |
特种医学 | 4篇 |
外科学 | 137篇 |
综合类 | 17篇 |
预防医学 | 27篇 |
眼科学 | 1篇 |
药学 | 248篇 |
中国医学 | 3篇 |
肿瘤学 | 24篇 |
出版年
2023年 | 16篇 |
2022年 | 27篇 |
2021年 | 42篇 |
2020年 | 44篇 |
2019年 | 74篇 |
2018年 | 50篇 |
2017年 | 25篇 |
2016年 | 15篇 |
2015年 | 15篇 |
2014年 | 37篇 |
2013年 | 73篇 |
2012年 | 28篇 |
2011年 | 46篇 |
2010年 | 42篇 |
2009年 | 28篇 |
2008年 | 28篇 |
2007年 | 36篇 |
2006年 | 16篇 |
2005年 | 30篇 |
2004年 | 25篇 |
2003年 | 15篇 |
2002年 | 10篇 |
2001年 | 14篇 |
2000年 | 11篇 |
1999年 | 10篇 |
1998年 | 17篇 |
1997年 | 21篇 |
1996年 | 9篇 |
1995年 | 16篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 12篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1988年 | 9篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 16篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有931条查询结果,搜索用时 15 毫秒
1.
2.
3.
Successful pregnancy requires adjustments to multiple maternal homeostatic mechanisms, governed by the maternal brain to support and enable survival of the growing fetus and placenta. Such adjustments fit the concept of allostasis (stability through change) and have a cost: allostatic load. Allostasis is driven by ovarian, anterior pituitary, placental and feto-placental hormones acting on the maternal brain to promote adaptations that support the pregnancy and protect the fetus. Many women carry an existing allostatic load into pregnancy, from socio-economic circumstances, poor mental health and in ‘developed’ countries, also from obesity. These pregnancies have poorer outcomes indicating negative interactions (failing allostasis) between pre-pregnancy and pregnancy allostatic loads. Use of animal models, such as adult prenatally stressed female offspring with abnormal neuroendocrine, metabolic and behavioural phenotypes, to probe gene expression changes, and epigenetic mechanisms in the maternal brain in adverse pregnancies are discussed, with the prospect of ameliorating poor pregnancy outcomes. 相似文献
4.
5.
6.
7.
BackgroundThe U.S. is facing an unprecedented number of opioid-related overdose deaths, and an array of other countries have experienced increases in opioid-related fatalities. In the U.S., naloxone is increasingly distributed to first responders to improve early administration to overdose victims, but its cost-effectiveness has not been studied. Lay distribution, in contrast, has been found to be cost-effective, but rising naloxone prices and increased mortality due to synthetic opioids may reduce cost-effectiveness. We evaluate the cost-effectiveness of increased naloxone distribution to (a) people likely to witness or experience overdose (“laypeople”); (b) police and firefighters; (c) emergency medical services (EMS) personnel; and (d) combinations of these groups.MethodsWe use a decision-analytic model to analyze the cost-effectiveness of eight naloxone distribution strategies. We use a lifetime horizon and conduct both a societal analysis (accounting for productivity and criminal justice system costs) and a health sector analysis. We calculate: the ranking of strategies by net monetary benefit; incremental cost-effectiveness ratios; and number of fatal overdoses.ResultsHigh distribution to all three groups maximized net monetary benefit and minimized fatal overdoses; it averted 21% of overdose deaths compared to minimum distribution. High distribution to laypeople and one of the other groups comprised the second and third best strategies. The majority of health gains resulted from increased lay distribution. In the societal analysis, every strategy was cost-saving compared to its next-best alternative; cost savings were greatest in the maximum distribution strategy. In the health sector analysis, all undominated strategies were cost-effective. Results were highly robust to deterministic and probabilistic sensitivity analysis.ConclusionsIncreasing naloxone distribution to laypeople and first responder groups would maximize health gains and be cost-effective. If feasible, communities should distribute naloxone to all groups; otherwise, distribution to laypeople and one of the first responder groups should be emphasized. 相似文献
8.
BackgroundUrine drug testing (UDT) is a useful tool in monitoring compliance to prescribed medication and can also help identify behaviors of drug misuse, abuse, and diversion. Mass spectrometry (MS)-based screening is recommended as the first-line of UDT for pain management patients; however, this testing comes with an inherent lack of standardization in methodologies and various analytical challenges. The objective of this study was to assess the current state of UDT for pain management in a cross-section of clinical laboratories in North America.Materials and methodsA total of 10 blinded urine samples were sent to 6 laboratories across the United States and Canada. Urine samples containing drugs and/or metabolites of interest were included to represent different clinical scenarios commonly seen in pain management settings. Assessment was based on the ability of the laboratories to correctly identify drugs and provide a meaningful interpretation of the findings (when offered by the performing laboratory).ResultsAcross the laboratories involved in the study, 85% of tests correctly identified and appropriately reported the drugs present in the urine samples. Similarly, 84% of samples were considered to have an accurate interpretation included in the UDT report. Out of the total number of drugs included in the samples, 11% were not offered on every test menu.ConclusionsThis study revealed the lack of standardization in pain management UDT performed in a limited cross-section of clinical laboratories across North America. 相似文献
9.
10.
Canada continues to experience an escalating opioid overdose crisis that has claimed more than 8000 lives in the country since 2016. The presence of the synthetic opioid fentanyl and its analogues is a central contributor to the increases in preventable opioid-related deaths. However, a number of converging social-structural factors (e.g., the continued criminalisation of drug use, political changes) and political barriers are also complicating and contributing to the current crisis. We briefly outline four harm reduction interventions (i.e., injectable opioid agonist treatment, naloxone distribution programs, overdose prevention sites, and drug checking services) as emerging and rapidly expanding responses to this crisis in Canada. These examples of innovation and expansion are encouraging but also occurring at the same time that the opioid overdose crisis shows few signs of abating. To truly address the crisis, Canada needs political environments at all government levels that are responsive and foster harm reduction innovation and drug policy experimentation. 相似文献