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   9097篇
  免费   2466篇
  国内免费   128篇
耳鼻咽喉   371篇
儿科学   192篇
妇产科学   253篇
基础医学   176篇
口腔科学   150篇
临床医学   2893篇
内科学   1684篇
皮肤病学   348篇
神经病学   692篇
特种医学   327篇
外科学   1310篇
综合类   361篇
现状与发展   2篇
预防医学   1718篇
眼科学   100篇
药学   195篇
  1篇
中国医学   100篇
肿瘤学   818篇
  2024年   80篇
  2023年   411篇
  2022年   116篇
  2021年   259篇
  2020年   495篇
  2019年   170篇
  2018年   561篇
  2017年   600篇
  2016年   620篇
  2015年   711篇
  2014年   710篇
  2013年   1040篇
  2012年   386篇
  2011年   331篇
  2010年   516篇
  2009年   636篇
  2008年   303篇
  2007年   236篇
  2006年   275篇
  2005年   188篇
  2004年   153篇
  2003年   119篇
  2002年   99篇
  2001年   185篇
  2000年   114篇
  1999年   150篇
  1998年   268篇
  1997年   284篇
  1996年   307篇
  1995年   243篇
  1994年   173篇
  1993年   117篇
  1992年   84篇
  1991年   82篇
  1990年   72篇
  1989年   89篇
  1988年   71篇
  1987年   56篇
  1986年   47篇
  1985年   51篇
  1984年   48篇
  1983年   43篇
  1982年   31篇
  1981年   44篇
  1980年   19篇
  1979年   10篇
  1978年   12篇
  1977年   15篇
  1976年   13篇
  1972年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
目的:瘦素受体的信号传到途径、瘦素进入下丘脑的转运系统、可溶性瘦素受体和瘦素受体表达下调现象等都与瘦素抵抗存在着密切的关系,深入研究瘦素抵抗的可能发生机制将有助于肥胖症的预防和治疗。文章通过查阅文献,论述了瘦素,瘦素受体,瘦素抵抗及其产生机制和瘦素抵抗与运动之间的关系。资料来源:通过计算机检索Medline1994-01/2004-04期间的相关文章,检索词“obesity,Leptin,exercise”并限定文章语言种类为英文。同时用计算机检索中国期刊网1994-01/2004-04期间的相关文章,限定文章语言种类为中文,检索词“肥胖,瘦素,运动”。资料选择:对资料进行初审,选取肥胖与瘦素有关文献和运动减肥与瘦素变化有关的文献,然后筛除明显不随机试验研究,对剩余的文献开始查找全文。资料提炼:共收集到50余篇关于肥胖、瘦素、运动减肥有关的随机和未随机试验,21个试验符合纳入标准。排除的20余篇试验中,15篇因系重复的同一研究,其余5篇为肥胖成因的分析研究。资料综合:大多数肥胖者存在高瘦素血症,即存在瘦素抵抗。大多数研究认为一次性运动能量消耗不大时,对血浆瘦素的影响很小或没有作用,但当一次性运动过程中能量消耗很大时血浆瘦素水平下降。长期耐力运动训练使脂肪组织ob-mRNA表达下降和瘦素受体的表达增加,可使  相似文献   
992.
OBJECTIVE: Automated blood pressure (ABP) devices are ubiquitous at emergency department (ED) triage. Previous studies failed to evaluate ABP devices against accepted reference standards or demonstrate triage readings as accurate reflections of blood pressure (BP). This study evaluated ED triage measurements made using an ABP device and assessed agreement between triage BP and BP taken under recommended conditions. METHODS: A prospective study was conducted at an urban teaching hospital. Patients were enrolled by convenience sampling. Simultaneous automated and manual triage BPs were obtained using one BP cuff with a Y-tube connector. Research assistants were certified in obtaining manual BP as described by the British Hypertension Society (BHS). Patients were placed in a quiet setting, and manual BP was repeated by American Heart Association (AHA) standards. Data analysis was performed using methods described by Bland and Altman. The ABP device was assessed using Association for the Advancement of Medical Instrumentation (AAMI) and BHS criteria. RESULTS: One hundred seventy-one patients were enrolled. Systolic BP (sBP) range was 81 to 218 mm Hg; diastolic BP (dBP) range was 43 to 130 mm Hg. Automated vs. manual sBP difference was 3.8 +/- 11.2 mm Hg (95% confidence interval [CI] = 2.1 to 5.4); dBP difference was 6.6 +/- 9.0 mm Hg (95% CI = -7.9 to -5.2). Manual triage BP vs. AHA standard SBP difference was 11.6 +/- 12.8 mm Hg (95% CI = 9.1 to 14.1); dBP difference was 9.9 +/- 10.4 mm Hg (95% CI = 7.9 to 12.0). The ABP device failed to meet AAMI criteria and received a BHS rating of "D." Poor operator technique and extraneous patient and operator movement appeared to hamper accuracy. CONCLUSIONS: ABP triage measurements show significant discrepancies from a reference standard. Repeat measurements following AHA standards demonstrate significant decreases in the measured blood pressures.  相似文献   
993.
In this paper student views on reflective groups, set up as an important element of the new Project 2000 course in a Scottish College of Nursing, are reported. A random sample of 19 students were interviewed. While the reflective groups were very popular with students because they provided support, there was little evidence of a linkage between theory and practice. It was clear that the ambitious objective of stimulating reflection-on-action was not attained. Practice certainly was discussed, but it tended to be dominated by dramatic and emotionally charged aspects of care rather than the more frequent routine concerns. There were, however, indications that the original aim of the reflective groups could be achieved if tutors could establish a common understanding of the purpose of the groups and of reflection, and if the practices on which students reflected consisted less of single day visits where the students saw themselves as non-participant outsiders.  相似文献   
994.
Objectives: To assess emergency physician reporting patterns in Oregon before and after the passage of a mandatory intoxicated driving reporting law. Methods: A one‐page survey was mailed to 504 emergency physicians in Oregon in April 2004. Data on reporting frequency were collected using a four‐point ordinal scale regarding motor vehicle crash–involved drivers (MIDs) and intoxicated persons attempting to drive away from the emergency department (DAEDs). Paired observations were assessed for a stated increase in reporting activity following passage of the law using the Wilcoxon signed‐rank test. Associations of postlaw reporting and demographic and knowledge factors were sought using Spearman rank correlation analysis. Results: Of the 504 surveys mailed, 298 (59%) were adequate for analysis. Many respondents (57%) were already aware of the law. Most (92%) agreed that physicians should be mandated to report some crimes. MIDs were always reported by 18% of physicians before the law and by 47% afterward, whereas DAEDs were always reported by 56% of physicians before the law and by 69% afterward. Emergency medicine–trained physicians, higher emergency department census, and increased years of experience were associated with a significantly higher increase in reporting pattern after passage of the law for both MIDs and DAEDs. Conclusions: Although 44% of responding emergency physicians in Oregon were unaware of a mandated reporting law for intoxicated drivers presenting to the ED, most physicians stated an increase in their reporting practice.  相似文献   
995.
为了研究战伤喷剂杀菌效果及其影响因素,采用悬液定量杀菌试验进行了观察。结果,季铵盐活性物170mg/L喷剂分别作用5min,对金黄色葡萄球菌和大肠杆菌平均杀灭率为99.99%;用850mg/L该喷剂对白色念珠菌作用5min,平均杀灭率为99.99%。该喷剂在54℃放置14d,其杀菌效果无明显降低。受有机物和作用温度等因素对其杀菌效果影响不明显。以该喷剂原液作皮肤喷雾消毒,对自然菌平均除菌率为89.13%。结论,该战伤喷剂可有效杀灭细菌繁殖体和真菌,性能稳定。  相似文献   
996.
利用多聚酶链反应(PCR)方法,从活化的人外周血单个核细胞中克隆了人粒-巨噬系集落刺激因子(GM-CSF)的cDNA。DNA序列测定证实此片段为完整的GM-CSF cDNA。应用DNA重组技术,将此cDNA重组于逆转录病毒载体pDORneo上,以Lipofectin介导转染病毒包装细胞PA317,用NIH3T3细胞测定病毒滴度。选取高滴度病毒上清感染中国仓鼠卵巢(CHO)细胞,经G418筛选获抗性克隆,PCR方法鉴定重组载体整合于CHO细胞的基因组DNA中。用CFU-GM集落形成实验检测GM-CSF活性,证实转染后的CHO细胞有GM-CSF的稳定、高效表达。  相似文献   
997.
Background: The reality of emergency health care in the United States today requires new approaches to mental health in the emergency department (ED). Major depression is a disabling condition that disproportionately affects women.
Objectives: To characterize ED provider–patient discussions about depression.
Methods: This was a secondary analysis of a database of audiotaped ED visits with women patients collected during a clinical trial of computer screening for domestic violence and other psychosocial risks. Nonemergent female patients, ages 18–65 years, were enrolled from two socioeconomically diverse academic EDs. All audio files with two or more relevant comments were identified as "significant depression discussions" and independently coded using a structured coding form.
Results: Of 871 audiorecorded ED visits, 70 (8%) included discussions containing any reference to depression and 20 (2%) constituted significant depression discussions. Qualitative analysis of the 20 significant discussions found that 16 (80%) required less than 90 seconds to complete. Ten included less than optimal provider communication characteristics. Despite the brevity or quality of the communication, 15 of the 20 yielded high patient satisfaction with their ED treatment.
Conclusions: ED providers rarely addressed depression. Qualitative analysis of significant patient–provider interactions regarding depression found that screening for depression in the ED can be accomplished with minimal expenditure of provider time and effort. Attention to psychosocial risk factors has the potential to improve the quality of ED care and patient satisfaction.  相似文献   
998.
Objectives:  To compare charges and payments for outpatient pediatric emergency visits across payer groups to provide information on reimbursement trends.
Methods:  Total charges and payments for emergency department (ED) visits Medicaid/State Children's Health Insurance Program (SCHIP), privately insured, and uninsured pediatric patients from 1996 to 2003 using data from the Medical Expenditure Panel Survey. Average charges per visit and average payments per visit were also tracked, using regression analysis to adjust for changes in patient characteristics.
Results:  While charges for pediatric ED visits rose over time, payments did not keep pace. This led to a decrease in reimbursement rates from 63% in 1996 to 48% in 2003. For all years, Medicaid/SCHIP visits had the lowest reimbursement rates, reaching 35% in 2003. The proportion of visits from children insured by Medicaid/SCHIP also increased over the period examined. In 2003, after adjustment, charges were $792 per visit from children covered by Medicaid/SCHIP, $913 for visits from uninsured children, and $952 for visits from privately insured children.
Conclusions:  Reimbursements for outpatient ED visits in the pediatric population have decreased from the period of 1996 to 2003 in all payer groups: public (Medicaid/SCHIP), private, and the uninsured. Medicaid/SCHIP has consistently paid less per visit than the privately insured and the uninsured. Further research on the effects of these declining reimbursements on the financial viability of ED services for children is warranted.  相似文献   
999.
Objective: To develop an injury scoring system suitable for non–life–threatening injuries.
Methods: A prospective cohort study was conducted using a representative sample of 1,396 injured adults to identify the outcomes of a range of injuries. Data were collected between March 12, 1992, and March 11,1993, in the Australian Capital Territory, a geographically circumscribed urban community of 296,000 people served by two hospital EDs. Outcomes included "injury–related health status immediately following injury occurrence" and "accumulated health loss over the period of recovery." The injury–related health status of each subject at the time of the injury occurrence was measured using the Health Consequences of Injury Questionnaire (HCIQ), which records this outcome as a value on a unitary scale. Injuries were then stratified by injury type, as identified by the Abbreviated Injury Scale numerical identifiers. The median health index value for each type of injury was designated the injury severity score for that injury type. The "accumulated health loss over time until recovery" for each injury was calculated from repeated administrations of the HCIQ over a six–month follow–up period, and the median outcome value for each injury type was designated the injury morbidity score for that injury.
Results: Injury severity scores for 46 types of minor injury and injury morbidity scores for 39 types of minor injury were tabulated to form the Minor Injury Scale.
Conclusion: This new injury scoring system provides a means of categorizing minor injury according to properties relevant to a public health approach to injury control. Expansion of the number of injury types scored requires further work, as does the testing of the results obtained to confirm the predictive power of the scales.  相似文献   
1000.
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