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   3281篇
  免费   353篇
  国内免费   4篇
耳鼻咽喉   46篇
儿科学   79篇
妇产科学   88篇
基础医学   518篇
口腔科学   114篇
临床医学   413篇
内科学   566篇
皮肤病学   43篇
神经病学   334篇
特种医学   93篇
外科学   508篇
综合类   78篇
一般理论   2篇
预防医学   347篇
眼科学   40篇
药学   214篇
中国医学   1篇
肿瘤学   154篇
  2022年   31篇
  2021年   57篇
  2020年   35篇
  2019年   75篇
  2018年   64篇
  2017年   54篇
  2016年   49篇
  2015年   64篇
  2014年   74篇
  2013年   114篇
  2012年   154篇
  2011年   160篇
  2010年   81篇
  2009年   76篇
  2008年   126篇
  2007年   150篇
  2006年   161篇
  2005年   128篇
  2004年   116篇
  2003年   96篇
  2002年   105篇
  2001年   89篇
  2000年   93篇
  1999年   67篇
  1998年   36篇
  1997年   37篇
  1996年   25篇
  1994年   27篇
  1993年   28篇
  1992年   65篇
  1991年   45篇
  1990年   55篇
  1989年   60篇
  1988年   52篇
  1987年   63篇
  1986年   55篇
  1985年   65篇
  1984年   54篇
  1983年   45篇
  1982年   25篇
  1981年   33篇
  1979年   43篇
  1978年   34篇
  1977年   32篇
  1976年   34篇
  1975年   26篇
  1974年   38篇
  1973年   27篇
  1972年   33篇
  1968年   29篇
排序方式: 共有3638条查询结果,搜索用时 15 毫秒
151.
The purpose of the Emergency Medical Services Outcomes Project (EMSOP) is to develop a foundation and framework for out-of-hospital outcomes research. In prior work (EMSOP I), discomfort had the highest weighted score among outcome categories for the top 3 adult conditions (ie, minor trauma, respiratory distress, chest pain) and the first and third highest rankings for children's conditions (ie, minor trauma, respiratory distress). In this fourth article in the EMSOP series, we discuss issues relevant to the measurement of pain in the out-of-hospital setting, recommended pain measures that require evaluation, and implications for outcomes research focusing on pain. For adults, adolescents, and older children, 2 verbal pain-rating scales are recommended for out-of-hospital evaluation: (1) the Adjective Response Scale, which includes the responses "none," "slight," "moderate," "severe," and "agonizing," and (2) the Numeric Response Scale, which includes responses from 0 (no pain) to 100 (worst pain imaginable). The Oucher Scale, combining a visual analog scale with pictures, seems most promising for out-of-hospital use among younger children. Future research in out-of-hospital care should be conducted to determine the utility and feasibility of these measures, as well as the effectiveness of interventions for pain relief.  相似文献   
152.
The purpose of the Emergency Medical Services Outcomes Project (EMSOP) is to develop a foundation and framework for out-of-hospital outcomes research. Fundamental to that purpose is the identification of priority conditions, risk-adjustment measures (RAMs), and outcome measures. In this third EMSOP article, we examine the topic of risk adjustment, discuss the relevance of risk adjustment for out-of-hospital outcomes research, and recommend RAMs that should be evaluated for potential use in emergency medical services (EMS) research. Risk adjustment allows better judgment about the effectiveness and quality of alternative therapies; it fosters a better comparison of potentially dissimilar groups of patients. By measuring RAMs, researchers account for an important source of variation in their studies. Core RAMs are those measures that might be necessary for out-of-hospital outcomes research involving any EMS condition. Potential core RAMs that should be evaluated for their feasibility, validity, and utility in out-of-hospital research include patient age and sex, race and ethnicity, vital signs, level of responsiveness, Glasgow Coma Scale, standardized time intervals, and EMS provider impression of the presenting condition. Potential core RAMs that could be obtained through linkage to other data sources and that should be evaluated for their feasibility, validity, and utility include principal diagnosis and patient comorbidity. We recommend that these potential core RAMs be systematically evaluated for use in risk adjustment of out-of-hospital patient groups that might be used for outcomes research  相似文献   
153.
Pre-hospital immediate care for seriously injured children is rarely required, but when it is, the response must be prompt and effective. The key to an effective and confident approach to injured children lies in understanding the age related anatomical and physiological differences between adults and children. These differences are most exaggerated in the first few years of life and excellent training courses and materials are available to help practitioners develop their confidence and skills in this age group. An easy to use length based aide memoire and a set of equipment packed according to size are essential to ensure safe management in the pre-hospital environment. Care of the seriously ill child, emergency childbirth and neonatal resuscitation are beyond the scope of this article. Nonetheless, pre-hospital practitioners should develop an understanding of assessment of ill children and normal delivery and be prepared to assist with emergency childbirth and neonatal resuscitation. Excellent educational material, courses and web based resources are available to achieve this (54). This is the sixth article in the add on series in pre-hospital care. The series is edited by Maj R Mackenzie. Maj RC Sutcliffe is a general practitioner and regimental medical officer. Maj R Mackenzie is a Specialist Registrar in Accident and Emergency Medicine and an immediate care doctor. While every effort has been made to ensure correct drug dosages are quoted, readers should always check these before use.  相似文献   
154.
We have recently described an association between the hypofunctional 7-repeat allele (7R) of the dopamine-4 receptor gene (DRD4), weight gain, and obesity in women with seasonal affective disorder (SAD). In the current study, we examined whether season-of-birth might interact with the 7R allele to influence body weight regulation in SAD. In 182 female probands with SAD, we performed an analysis of covariance predicting maximum lifetime body mass index (BMI) with both the exon-3 variable number of tandem repeat polymorphism of DRD4 and season-of-birth as independent variables, and age as the covariate. The overall model was highly significant (F = 4.42, df = 8, 173, p < 0.0001) with season-of-birth predicting maximal lifetime BMI both on its own and in its interaction with the 7R allele. The latter finding was attributable to 7-repeat carriers born in the spring (N = 17), who had a mean maximal lifetime BMI of 33.7 kg/m2 (SD 8.6), compared to 26.7 kg/m2 (SD 5.4) for all other probands combined (N = 165) (F = 20.01, df = 1, 179, p < 0.0001). The lifetime rate of obesity (maximal BMI > 30 kg/m2) was also significantly higher in the 7R/spring birth group (9/17=52.9% vs 32/165=19.4%; chi2 = 9.94, df = 1, p = 0.002; odds ratio = 4.68, 95% CI = 1.67-13.07). These data may reflect a novel gene-environment interaction, during early brain development, which establishes an increased risk for obesity in women with SAD. Although the mechanism for season-of-birth effects in psychiatric disorders is unknown, a characteristic pattern of melatonin exposure during the second and third trimesters may be of particular relevance in this study population. We speculate that these data may reflect the vestigial expression of a seasonal thrifty phenotype that contributed to the positive selection of the 7R allele over the past 40,000 years.  相似文献   
155.
Two novel pectenotoxins (PTXs), PTX-13 and -14, were isolated from extracts of Dinophysis acuta collected from the west coast of South Island, New Zealand. The compounds were identified as oxidized analogues of PTX-2 by NMR spectroscopic and LC-MS studies. PTX-13 (32R-hydroxyPTX-2) corresponds to the unidentified analogue PTX-11x reported by [Suzuki et al., 2003. Liquid chromatography-mass spectrometry of spiroketal stereoisomers of pectenotoxins and the analysis of novel pectenotoxin isomers in the toxic dinoflagellate Dinophysis acuta from New Zealand. J. Chromatogr. A 992, 141-150]. PTX-13 underwent slow deuteration at the 13beta-position during NMR analysis. PTX-14 corresponds to the 32,36-dehydration product of PTX-13, and may be an artifact.  相似文献   
156.
Mackenzie IR 《Neurology》2000,55(1):132-134
To investigate the role of cerebral inflammation in dementia with Lewy bodies (DLB), activated microglial cells were quantified in postmortem brain tissue. Patients with pure DLB (LB but no AD pathology) had significantly greater numbers of cells than nondemented control subjects, but fewer than patients with either pure AD or DLB combined with AD. There was a positive correlation between the numbers of activated microglia and LB in different brain regions. This study demonstrates the presence of significant inflammation in DLB, even in the absence of AD pathology.  相似文献   
157.
The aim of this study was to evaluate the effectiveness of a practice magnetic resonance unit, in preparing children to undergo magnetic resonance procedures without general anaesthesia (GA) or sedation. The records of children who attended the practice MRI between February 2002 and April 2004 were retrospectively reviewed. Each record was assessed as to whether the child had passed or failed the practice MRI intervention. Those children who were considered to have passed and were proceeded to a clinical non‐GA MRI had the report of the clinical scan reviewed. If the scan had been reported as non‐diagnostic because of movement artefact it was classified as a failed scan, otherwise it was considered a pass. One hundred and thirty‐four children undertook a practice MRI (age range 4.1–16.1 years, median age 7.7 years, 47% boys) and 120/134 (90%) passed the practice session. In all, 117/120 (98%) subsequently had a clinical non‐GA MRI and 110/117 (94%) passed (median age 7.8 years, 47% boys). Preparation is a safe and effective method to reduce the need for sedation and GA in children undergoing a clinical MRI scan. It provides a positive medical experience for children, parents and staff, and results in cost savings for the hospital.  相似文献   
158.
Cyclodialysis clefts occur when the attachment of the ciliary body to the scleral spur is disrupted. The mechanism is usually traumatic or iatrogenic after phacoemulsification or other intraocular manipulation. Treatment becomes necessary when hypotony occurs, with maculopathy being the most visually significant sequela. A patient who failed conventional treatment for hypotony and eventually benefited from a novel surgery to correct his cyclodialysis cleft is described.  相似文献   
159.
160.
Development of methodologically acceptable outcomes models for emergency medical services (EMS) is long overdue. In this article, the Emergency Medical Services Outcomes Project proposes a conceptual framework that will provide a foundation for future EMS outcomes research. The "Episode of Care Model" and the "Out-of-Hospital Unit of Service Model" are presented. The Episode of Care Model is useful in conditions in which interventions and outcomes, especially survival and major physiologic dysfunction, are linked in a time-dependent manner. Conditions such as severe trauma, anaphylaxis, airway obstruction, respiratory arrest, and nontraumatic cardiac arrest are amenable to this methodology. The Out-of-Hospital Unit of Service Model is essentially a subunit of the Episode of Care Model. It is valuable for evaluating conditions that have minimal-to-moderate therapeutic time dependency. This model should be used when studying outcomes limited to the out-of-hospital interval. An example of this is pain management for injuries sustained in motor vehicle crashes. These models can be applied to a wide spectrum of conditions and interventions. With the scrutiny of health care expenditures ever increasing, the identification of clinical interventions that objectively improve patient outcome takes on growing importance. Therefore, the development, dissemination, and use of meaningful methodologies for EMS outcomes research is key to the future of EMS system development and maintenance.  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