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   4374篇
  免费   152篇
  国内免费   57篇
耳鼻咽喉   28篇
儿科学   100篇
妇产科学   73篇
基础医学   308篇
口腔科学   156篇
临床医学   303篇
内科学   743篇
皮肤病学   38篇
神经病学   481篇
特种医学   79篇
外科学   363篇
综合类   242篇
一般理论   1篇
预防医学   547篇
眼科学   45篇
药学   845篇
中国医学   177篇
肿瘤学   54篇
  2023年   64篇
  2022年   90篇
  2021年   173篇
  2020年   118篇
  2019年   323篇
  2018年   276篇
  2017年   175篇
  2016年   93篇
  2015年   83篇
  2014年   231篇
  2013年   240篇
  2012年   176篇
  2011年   233篇
  2010年   187篇
  2009年   166篇
  2008年   148篇
  2007年   137篇
  2006年   80篇
  2005年   67篇
  2004年   65篇
  2003年   38篇
  2002年   43篇
  2001年   37篇
  2000年   29篇
  1999年   24篇
  1998年   29篇
  1997年   20篇
  1996年   20篇
  1995年   15篇
  1994年   16篇
  1993年   8篇
  1992年   18篇
  1991年   16篇
  1989年   14篇
  1988年   9篇
  1987年   9篇
  1986年   10篇
  1985年   101篇
  1984年   123篇
  1983年   91篇
  1982年   95篇
  1981年   87篇
  1980年   78篇
  1979年   87篇
  1978年   76篇
  1977年   54篇
  1976年   85篇
  1975年   60篇
  1974年   67篇
  1973年   67篇
排序方式: 共有4583条查询结果,搜索用时 15 毫秒
11.
12.
By their nature, care decisions for patients with severe disorders of consciousness must involve surrogates. Patients, so impaired, have lost their decision-making capacity and the ability to direct their own care. Surrogates—family members, friends, or other intimates—must step in and make decisions about ongoing care or its withdrawal. This article shares the narrative experiences of these surrogate decision makers as they encounter the American health care system and accompany patients from injury through rehabilitation. Through their perspectives, the article considers challenges to ongoing care and rehabilitation that are a function of a prevailing medical infrastructure and reimbursement framework better suited to patients with acute care needs. Specific attention is paid to the ethical challenges posed by reimbursement strategies such as “medical necessity” as well as those proposed for the Affordable Care Act. The argument concludes that when it comes to care for a disorder related to consciousness, its provision is not discretionary, and its receipt is not an entitlement but a civil right.  相似文献   
13.
Objective. The purpose of this investigation was to improve a rankit ordinal model for evaluating and validating dichotomized tests in a prospective Nordic project. Material and methods. The model is based on the assumption that the S‐shaped curve of fractions of positive for increasing concentrations can be de‐convoluted to a histogram and thereby used to calculate the parameters for a ln‐Gaussian distribution. In a Nordic survey, four urine samples with known concentrations of hCG (human chorionic gonadotrophin) and nitrites were distributed to more than 2500 practitioners' offices. Results. The results are presented as parameters (geometric mean and CV) for the components urine‐hCG and urine‐nitrites, together with fractions of positive for clinical critical values (5 and 40?IU/L for hCG), for which fractions should be below 0.01 and above 0.99, respectively, and 7?µmol/L for nitrites. Furthermore, the concentration intervals of varying fractions of positive from 0.01 to 0.99 are estimated as grey zones. The parameters and grey zones for different kits are compared. No urine‐hCG kit fulfilled the low clinical criterion, whereas all fulfilled the high criterion. Seven of the eight nitrites kits had fractions of positive above 0.9 for the company confirmation limit, but varying fractions for the clinically important limit of 7?µmol/L (fractions from 0.06 to 0.83). Conclusions. The present model makes it easy to estimate parameters for the kits, and also to estimate the fractions of measured positives for specified concentrations. It is thus suited for external quality assessment as well as for manufacturers' method validation.  相似文献   
14.
目的探讨高中一年级学生述情障碍与焦虑的关系。方法采用多伦多述情障碍量表(TAS-26)及状态-特质焦虑问卷(STAI)对2013年秋季入学的北京市海淀区某中学282名高中一年级学生的述情障碍和焦虑程度进行调查。结果TAS总评分及TAS-因子Ⅰ、Ⅱ评分分别与STAI总评分、状态焦虑、特质焦虑评分呈正相关(r=0.237~0.431,P0.01),TAS-因子Ⅲ评分与STAI总评分、状态焦虑、特质焦虑评分呈负相关(r=-0.251~-0.229,P0.01)。结论高中一年级学生述情障碍水平与焦虑程度相关,述情障碍可能是焦虑的个性基础。  相似文献   
15.
Exercise-induced changes in the ST segments of the electrocardiogram were compared with the results of coronary arteriography in 73 consecutive patients referred for preoperative evaluation of coronary artery disease. Eighteen patients had single-, 25 double-, and 30 triple-vessel disease. Thirteen were taking digitalis alone, 28 were taking beta blockers alone, 21 had beta blockers and digitalis and 11 had no cardiac drugs. Exercise induced elevation of the ST segment in 11 patients, all with a predominant lesion in the left anterior descending coronary artery. ST depression with an upsloping ST segment was observed in patients with one-, two-, and three-vessel disease and it was the most common type of ST change in patients with single-vessel disease. Horizontal ST depression was most common in two-vessel disease and downsloping ST segment in three-vessel disease. There was a good correlation between the number of stenosed vessels and ST changes caused by exercise, expressed as the sum of ST segment displacements in twelve leads recorded immediately after the end of exercise (sigma/ST/) or as ST depression per unit increase in heart rate during exercise ("m" (ST/HR]. The latter was obtained by linear regression of ST displacement and heart rate measured at three or four different workloads in the lead with the greatest displacement of the ST segment. The mean values of sigma/ST/ were 0.58 +- 0.030 mV in single-vessel, 0.97 +- 0.41 mV in double-vessel and 1.58 +- 0. 46 mV in triple-vessel disease. The mean values of "m" (ST/HR) were 0.0024 +- 0.0013 mV X min-1 X beat-1 in single-vessel, 0.0042 +- 0.0012 in double-vessel, and 0.0078 +- 0.0033 in triple-vessel disease. These differences were highly significant (p less than 0.01 - 0.001) and there was only minimal overlap between the single- and triple-vessel groups. Digitalis caused a slight (statistically nonsignificant) increase in sigma/ST/ but not in "m" (ST/HR).  相似文献   
16.
BackgroundParkinson’s disease (PD) is a chronic and progressive neurodegenerative disease with no cure, presenting a challenging diagnosis and management. However, despite a significant number of criteria and guidelines have been proposed to improve the diagnosis of PD and to determine the PD stage, the gold standard for diagnosis and symptoms monitoring of PD is still mainly based on clinical evaluation, which includes several subjective factors. The use of machine learning (ML) algorithms in spatial-temporal gait parameters is an interesting advance with easy interpretation and objective factors that may assist in PD diagnostic and follow up.Research questionThis article studies ML algorithms for: i) distinguish people with PD vs. matched-healthy individuals; and ii) to discriminate PD stages, based on selected spatial-temporal parameters, including variability and asymmetry.MethodsGait data acquired from 63 people with PD with different levels of PD motor symptoms severity, and 63 matched-control group individuals, during self-selected walking speed, was study in the experiments.ResultsIn the PD diagnosis, a classification accuracy of 84.6 %, with a precision of 0.923 and a recall of 0.800, was achieved by the Naïve Bayes algorithm. We found four significant gait features in PD diagnosis: step length, velocity and width, and step width variability. As to the PD stage identification, the Random Forest outperformed the other studied ML algorithms, by reaching an Area Under the ROC curve of 0.786. We found two relevant gait features in identifying the PD stage: stride width variability and step double support time variability.SignificanceThe results showed that the studied ML algorithms have potential both to PD diagnosis and stage identification by analysing gait parameters.  相似文献   
17.
18.
目的探究人性化护理干预对急诊科患者心理状态和满意度的影响。方法选取我院急诊科在2017年9月至2018年9月期间收治的180例患者,根据随机数字表法将其分为观察组和对照组,每组90例患者。观察组采用人性化护理模式进行护理;对照组采用常规护理模式护理。比较两组患者的心理状态和护理满意度。结果两组患者经过我院临床护理后,观察组患者的护理有效率为64.44%优于对照组42.22%(P<0.05);观察组患者对护理人员的满意率为75.56%;优于对照组52.22%(P<0.05)。结论人性化护理干预可有效提高急诊科患者的心理状态和患者满意度,值得推广。  相似文献   
19.
背景 估算肾小球滤过率(eGFR)是反映慢性肾脏病严重程度的量化指标之一。研究表明糖尿病前期血糖升高可增加慢性肾脏病风险,但对eGFR直接影响报道较少。目的 探讨社区人群中空腹血糖(FPG)受损患者血糖水平对eGFR的影响。方法 选择2020年1—12月于南昌大学第二附属医院体检中心体检的人群,收集一般资料与临床资料(包括既往史、性别、年龄、体质指数、血压、尿酸、血脂、FPG、尿常规、血肌酐),经相应纳入标准与排除标准筛选,最终纳入28 601例受试者。根据FPG水平将受试者分为FPG升高组(5.6 mmol/L≤FPG<7.0mmol/L)、FPG正常组(3.9 mmol/L≤FPG<5.6 mmol/L),比较两组一般资料与临床资料。为明确FPG对e GFR影响,采用个案匹配控制对两组受试者进行多因素(性别、年龄、平均动脉压、尿酸、总胆固醇、体质指数)匹配,采用Mann-Whitney U秩和检验比较匹配后两组一般资料。采用Spearman秩相关检验分析FPG与eGFR在FPG升高组、FPG正常组及匹配后FPG升高组、FPG正常组间的相关性。结果 共获得FPG正常组患者...  相似文献   
20.
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