首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   530798篇
  免费   28294篇
  国内免费   500篇
耳鼻咽喉   6687篇
儿科学   17024篇
妇产科学   12585篇
基础医学   92804篇
口腔科学   12388篇
临床医学   48606篇
内科学   95657篇
皮肤病学   11914篇
神经病学   34129篇
特种医学   19771篇
外国民族医学   53篇
外科学   78119篇
综合类   7640篇
现状与发展   2篇
一般理论   107篇
预防医学   38656篇
眼科学   12055篇
药学   41559篇
  1篇
中国医学   1136篇
肿瘤学   28699篇
  2021年   3962篇
  2018年   5793篇
  2017年   4168篇
  2016年   4926篇
  2015年   5403篇
  2014年   7175篇
  2013年   10574篇
  2012年   15665篇
  2011年   17497篇
  2010年   10003篇
  2009年   8871篇
  2008年   15782篇
  2007年   17498篇
  2006年   16997篇
  2005年   16325篇
  2004年   15922篇
  2003年   15311篇
  2002年   14816篇
  2001年   22451篇
  2000年   22994篇
  1999年   18928篇
  1998年   5240篇
  1997年   4371篇
  1996年   4404篇
  1995年   4126篇
  1992年   14424篇
  1991年   15829篇
  1990年   15962篇
  1989年   15638篇
  1988年   14322篇
  1987年   14206篇
  1986年   13175篇
  1985年   12697篇
  1984年   9400篇
  1983年   8003篇
  1982年   4180篇
  1979年   8946篇
  1978年   6382篇
  1977年   5152篇
  1976年   5509篇
  1975年   6614篇
  1974年   7420篇
  1973年   7160篇
  1972年   6598篇
  1971年   6312篇
  1970年   5888篇
  1969年   5468篇
  1968年   5161篇
  1967年   4623篇
  1966年   3963篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.
Objectives: The steeling effect suggests that early-life adversity can have a beneficial impact later in life. However, little is known about its underlying mechanisms and long-term outcomes . The study aimed to examine the role of early-life adversity (ELA) on successful aging, and whether this relationship can be explained by mental and physical health.

Method: Socio-demographics, early-life adversity (ELA), individual quality of life (iQoL), and mental and physical health of 270 individuals (Mage = 66.82 years, 71.5% female) were assessed. Polynomial regressions and mediation analyses were conducted.

Results: Significant inverse U-shaped associations were found between ELA and iQoL (β = ?.59, p = .005) and between ELA and mental health (β = ?.64, p = .002), but not between ELA and physical health. Furthermore, mental health significantly mediated the relationship between ELA and iQoL (b = ?.84, BCa CI [?1.66, ?.27]).

Conclusion: Highest level of individual quality of life (i.e. successful aging) was related to a moderate amount of ELA. Additionally, mental health significantly mediated this relationship. These findings suggest that some amount of ELA could be beneficial for successful aging. Resource-focused interventions are needed to improve health and promote successful aging for an underdetected, at-risk subgroup with low early-life adversity.  相似文献   

33.
At this study a multi-criteria model was developed to examine the available procedures, techniques and methods of handling infectious waste in the large healthcare unit of University Regional General Hospital of Patras, Western Greece. Particularly, this study examined the: a) current legislation and Directives issued for medical waste management at Greece and among the other EU-members, b) contribution of healthcare wastes (HCW) generation rate on social and economic parameters in selected European countries, c) available procedures, techniques, and methods upon the disposal of infectious wastes at the healthcare studied, and, d) propositions for integrated management of such hazardous wastes. Specifically, the Analytic Hierarchy Process (AHP) methodology was applied under pair wise comparison matrices in two stages: 1) the scale factors and the indicators, and 2) the criteria and their sub–criteria. The assessment of these pair wise matrices included the indicators and the sub–criteria. Subsequently, two pair wise comparison matrices, upon a) the “Fulfillment of environmental objectives” indicator and b) the “Energy consumption” sub criterion, were denoted. The AHP methodology yielded good results; however there is still space of improving the environmental performance. The normalized relative weights obtained for the criteria and sub criteria motivated specific actions that have to be handled. Particularly, the results indicated a very good value in environmental management criteria due the values obtained for the commitment towards the environmental policy standards and the waste management procedures. However, further improvements on staff awareness (such as development programs to enhance sensitivity) and more green purchasing suppliers, should be further addressed.  相似文献   
34.
Neuroscience and Behavioral Physiology - Objective. To determine the frequency, structure, and severity of cognitive impairments in patients with bipolar affective disorder (BAD) in remission....  相似文献   
35.
36.

Purpose

A hydrogel rectal spacer (HRS) is a medical device that is approved by the U.S. Food and Drug Administration to increase the separation between the prostate and rectum. We conducted a cost-effectiveness analysis of HRS use for reduction in radiation therapy (RT) toxicities in patients with prostate cancer (PC) undergoing external beam RT (EBRT).

Methods and Materials

A multistate Markov model was constructed from the U.S. payer perspective to examine the cost-effectiveness of HRS in men with localized PC receiving EBRT (EBRT alone vs EBRT + HRS). The subgroups analyzed included site of HRS placement (hospital outpatient, physician office, ambulatory surgery center) and proportion of patients with good baseline erectile function (EF). Data on EF, gastrointestinal and genitourinary toxicities incidence, and potential risks associated with HRS implantation were obtained from a recently published randomized clinical trial. Health utilities and costs were derived from the literature and the 2018 Physician Fee Schedule and were discounted 3% annually. Quality-adjusted life years (QALYs) and costs were modeled for a 5-year period from receipt of RT. Probabilistic sensitivity analysis and value-based threshold analyses were conducted.

Results

The per-patient 5-year incremental cost for spacers administered in a hospital outpatient setting was $3578, and the incremental effectiveness was 0.0371 QALYs. The incremental cost-effectiveness ratio was $96,440/QALY for patients with PC undergoing HRS insertion in a hospital and $39,286/QALY for patients undergoing HRS insertion in an ambulatory facility. For men with good baseline EF, the incremental cost-effectiveness ratio was $35,548/QALY and $9627/QALY in hospital outpatient and ambulatory facility settings, respectively.

Conclusions

Based on the current Medicare Physician Fee Schedule, HRS is cost-effective at a willingness to pay threshold of $100,000. These results contain substantial uncertainty, suggesting more evidence is needed to refine future decision-making.  相似文献   
37.
38.
39.
The recognition that neurogenesis does not stop with adolescence has spun off research towards the reduction of brain disorders by enhancing brain regeneration. Adult neurogenesis is one of the tougher problems of developmental biology as it requires the generation of complex intracellular and pericellular anatomies, amidst the danger of neuroinflammation. We here review how a multitude of regulatory pathways optimized for early neurogenesis has to be revamped into a new choreography of time dependencies. Distinct pathways need to be regulated, ranging from neural growth factor induced differentiation to mitochondrial bioenergetics, reactive oxygen metabolism, and apoptosis. Requiring much Gibbs energy consumption, brain depends on aerobic energy metabolism, hence on mitochondrial activity. Mitochondrial fission and fusion, movement and perhaps even mitoptosis, thereby come into play. All these network processes are interlinked and involve a plethora of molecules. We recommend a deep thinking approach to adult neurobiology.  相似文献   
40.
Bulletin of Experimental Biology and Medicine - Fast neutron therapy, which previously has demonstrated effective results, but along with a large number of complications, can again be considered a...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号