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   10350篇
  免费   945篇
  国内免费   17篇
耳鼻咽喉   100篇
儿科学   377篇
妇产科学   235篇
基础医学   1367篇
口腔科学   124篇
临床医学   1399篇
内科学   2062篇
皮肤病学   165篇
神经病学   887篇
特种医学   262篇
外科学   1241篇
综合类   180篇
一般理论   6篇
预防医学   1428篇
眼科学   229篇
药学   497篇
中国医学   5篇
肿瘤学   748篇
  2023年   123篇
  2022年   198篇
  2021年   451篇
  2020年   247篇
  2019年   390篇
  2018年   384篇
  2017年   287篇
  2016年   315篇
  2015年   309篇
  2014年   424篇
  2013年   559篇
  2012年   808篇
  2011年   765篇
  2010年   382篇
  2009年   372篇
  2008年   564篇
  2007年   548篇
  2006年   494篇
  2005年   510篇
  2004年   458篇
  2003年   403篇
  2002年   318篇
  2001年   149篇
  2000年   113篇
  1999年   130篇
  1998年   90篇
  1997年   59篇
  1996年   57篇
  1995年   43篇
  1994年   54篇
  1993年   55篇
  1992年   80篇
  1991年   86篇
  1990年   89篇
  1989年   81篇
  1988年   70篇
  1987年   69篇
  1986年   69篇
  1985年   57篇
  1984年   34篇
  1983年   44篇
  1982年   26篇
  1979年   32篇
  1978年   29篇
  1977年   38篇
  1976年   31篇
  1974年   38篇
  1973年   44篇
  1972年   25篇
  1970年   28篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
In recent years, epidemiologic and clinical studies, public and regulatory policy activity, and media coverage have focused on issues related to trans fats. To help increase awareness and understanding of trans fats and other fats, the American Heart Association (AHA) launched the “Face the Fats” national consumer education campaign in April 2007. The AHA commissioned a quantitative tracking survey between 2006 and 2007 to measure changes in consumer awareness, knowledge, and behaviors related fats and oils and their perceived impact on heart disease. The survey was conducted by Cogent Research. Data were collected during March 2006 and May 2007. At both time points, the survey included a representative sample of the American population age 18 to 65 years (n=1,000). The sampling plan for the survey was designed based on the 2000 and 2003 US Census. The margin of error was ±3.10 percentage points. Awareness of trans fats increased during the 1-year study period. In 2007, 92% of respondents were aware of trans fats, an increase from 84% in 2006 (P<0.05). The 2007 level was similar to the awareness of saturated fats (93%). Perceptions that certain fats and oils heighten the risk of heart disease increased for trans fats (73% in 2007 vs 63% in 2006; P<0.05), saturated fats (77% in 2007 vs 73% in 2006; P<0.05), and partially hydrogenated oils (56% in 2007 vs 49% in 2006; P<0.05). Knowledge about food sources of different fats remained low. On an unaided basis, 21% could name three food sources of trans fats in 2007, up from 17% in 2006 (P<0.05). Knowledge of food sources of saturated fat remained unchanged at 30% in 2007. Significantly more respondents in 2007 reported behavioral changes related to trans fat information, such as buying food products because they show “zero trans fat” on labels or packages (37% in 2007 vs. 32% in 2006; P<0.05). Between 2006 and 2007, consumer awareness about trans fats increased and attained awareness levels similar to saturated fats. The increased awareness is associated with improved self-reported behaviors in grocery shopping. Nonetheless, overall knowledge, especially regarding food sources of saturated and trans fats, remains relatively low, underscoring the need for heightened consumer education activities. The positive change in consumer awareness about trans fats is likely attributable to the wide range of messages available to them, including the AHA “Face the Fats” national consumer education campaign.  相似文献   
12.
Presentations of acute appendicitis represent an ongoing challenge to surgeons. This case of retrocaecal perforated appendicitis presented clinically as a right lumbar abscess, with the concomitant new diagnosis of type 2 diabetes mellitus in a 66-year-old male. This case emphasises the importance of an abdominal CT scan in any patient presenting with unusual sepsis near the abdomen.  相似文献   
13.
Evaluation of students undertaking fieldwork education placements is a critical process in the health professions. As training programs and practice evolve, systems for assessing students need to be reviewed and updated constantly. In 1995, staff of the occupational therapy training program at the University of Queensland, Australia decided to develop a new tool for assessing student fieldwork performance. Using an action research methodology, a team developed the Student Placement Evaluation Form, a flexible and comprehensive criterion-referenced evaluation tool. The present paper examines action research as an appropriate methodology for considering real-life organisational problems in a systematic and participatory manner. The action research cycles undertaken, including preliminary information gathering, tool development, trial stages and current use of the tool, are detailed in the report. Current and future development of the tool is also described.  相似文献   
14.
Gingival crevicular fluid (GCF) IL-8 and IL-1,1β levels were determined by sandwich enzyme-linked immunosorbent assays. Associations between IL-8 and IL-1β GCF levels, and between these cytokines and patient estrogen status were evaluated. IL-8 and IL-1β were detected more frequently and in higher amounts/30 s GCF sample in estrogen-deficient patients than in estrogensufficient patients. IL-8 and IL-1β GCF levels were significantly correlated. These lindings suggest that GCF IL-8 levels are associated with patient estrogen status and local IL-1β concentrations.  相似文献   
15.

Background  

Cerebrospinal fluid (CSF) pleocytosis may be seen in asymptomatic HIV-infected individuals. This finding complicates interpretation of CSF abnormalities when such individuals are evaluated for other central nervous system infections. The goal of this study was to determine the relationship between CSF pleocytosis, central nervous system (CNS) antiretroviral penetration, adherence to antiretroviral medication regimens, neurological symptoms and performance on neuropsychological tests.  相似文献   
16.
Chlamydia trachomatis is the most prevalent sexually transmitted microbial infection in the United States. The CDC estimates that 3 million people are infected annually, with approximately 50% of infected men and 75% of infected women having few or no recognized symptoms. C. trachomatis is frequently transferred from mother to infant, and the maternal-infant transfer of this disease may have negative consequences for the newborn, such as prematurity, pneumonia, and conjunctivitis. Ocular prophylaxis with silver nitrate and or antibiotics is ineffective in preventing neonatal chlamydial conjunctivitis. By increasing awareness of the potential adverse consequences, initiating screening and treatment of pregnant women, and advocating for newborn assessment and treatment, nurses can enhance the quality of care for mothers and their infants.  相似文献   
17.
OBJECTIVES: The purpose of this work was to assess the prognostic role of glomerular filtration rate (GFR) and NT-terminal pro-B-type natriuretic peptide (NT-proBNP) for mortality end points in the vascular population. BACKGROUND: The GFR and NT-proBNP have been shown to predict mortality end points in free-living and limited vascular populations, independent of traditional risk factors. However, their prognostic power in an unrestricted vascular population is poorly understood. METHODS: A total of 412 subjects from a vascular cohort with a history of either peripheral arterial disease (PAD) and/or other cardiovascular disease (CVD) were included in this prospective cohort analysis and followed for an average of 6.7 years. Outcome variables were all-cause mortality, ischemic heart disease (IHD) mortality, and any cardiovascular mortality. The prognostic roles of GFR and NT-proBNP levels were determined using multivariate survival analysis. RESULTS: Higher GFR (per 10 ml/min/1.73 m2) was significantly protective for all-cause mortality (hazard ratio [HR] 0.81, p < 0.001), IHD mortality (HR 0.82, p = 0.008), and CVD mortality (HR 0.84, p = 0.005). Conversely, NT-proBNP was not a significant predictor of any mortality end point. The GFR showed the strongest association in subjects with a history of other CVD. Although NT-proBNP did not demonstrate a significant prognostic role in any of the subgroups, the data were suggestive for patients with PAD alone. CONCLUSIONS: Glomerular filtration rate was a robust predictor of all-cause, IHD, and cardiovascular mortality in the vascular population, particularly in those with a history of other CVD, while NT-proBNP showed a suggestive association limited to the group with PAD only. These findings suggest that these markers must be selectively applied in the vascular population for greatest clinical utility.  相似文献   
18.
Objectives: To determine the incidence of alcohol use in subcritically injured patients presenting to the ED, by using a saliva alcohol test (SAT) at ED triage during the ED initial assessment; to compare the incidence of alcohol use revealed by the SAT with documentation of alcohol use by ED nurses and emergency physicians (EPs) blinded to the SAT results; and to describe the demographics of the SAT-positive, subcritically injured population.
Methods: A blinded, prospective, observational evaluation of ED patients presenting with subcritical injuries was performed. The patients were tested for alcohol use with an SAT, and a subsequent record review was conducted for extraction of demographic data and evidence of documentation of alcohol use by ED nurses and EPs blinded to the SAT results.
Results: During the study. 791 subcritically injured patients had SATs performed. Twenty-one percent of these patients were found to be alcohol-positive by SAT. Either the ED nurse or the EP documented a clinical impression of alcohol use for 52% of the SAT-positive patients. There were higher SAT-positive rates among men (24%), victims of assault (47%), and patients arriving at night (41%).
Conclusions: While the SAT identified 21% of the subcritically injured patient population as alcohol-positive, ED nurse and EP documentation did not identify half of these alcohol-positive patients. Many of these patients may be at risk for additional injuries related to their drinking behavior.  相似文献   
19.
Immunology     
A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in immunology.  相似文献   
20.
Nineteen patients (20 eyes) underwent epikeratophakia for correction of high myopia. In contrast to the conventional surgical method utilizing an annular keratectomy, no keratectomy was performed in these patients. The surgical procedure is discussed. Preliminary results (up to six months) indicate that the omission of an annular keratectomy has no effect on graft clarity or viability. The weighted-average percent correction over six months postoperatively was 102%.  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