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   2615篇
  免费   217篇
  国内免费   4篇
耳鼻咽喉   5篇
儿科学   102篇
妇产科学   68篇
基础医学   95篇
口腔科学   95篇
临床医学   136篇
内科学   342篇
皮肤病学   12篇
神经病学   61篇
特种医学   137篇
外科学   143篇
综合类   17篇
预防医学   1517篇
眼科学   10篇
药学   20篇
肿瘤学   76篇
  2023年   27篇
  2022年   40篇
  2021年   25篇
  2020年   75篇
  2019年   23篇
  2018年   79篇
  2017年   85篇
  2016年   86篇
  2015年   82篇
  2014年   73篇
  2013年   124篇
  2012年   27篇
  2011年   42篇
  2010年   82篇
  2009年   107篇
  2008年   53篇
  2007年   50篇
  2006年   69篇
  2005年   56篇
  2004年   46篇
  2003年   34篇
  2002年   83篇
  2001年   89篇
  2000年   52篇
  1999年   128篇
  1998年   131篇
  1997年   170篇
  1996年   180篇
  1995年   108篇
  1994年   49篇
  1993年   100篇
  1992年   32篇
  1991年   24篇
  1990年   25篇
  1989年   38篇
  1988年   30篇
  1987年   28篇
  1986年   38篇
  1985年   33篇
  1984年   21篇
  1983年   23篇
  1982年   20篇
  1981年   16篇
  1980年   13篇
  1979年   19篇
  1978年   8篇
  1977年   11篇
  1976年   15篇
  1975年   9篇
  1967年   8篇
排序方式: 共有2836条查询结果,搜索用时 62 毫秒
111.
This study describes changes observed during a 2-year period in participants enrolled in The Solution Method, a developmental skills training program for adult weight management. This Intervention is the adult application of a model of treatment previously used only in the management of pediatric obesity (The Shapedown Program). Developmental skills training integrates understandings and methods from developmental, family systems, biomedical, genetic, and behavioral theories of the etiology of obesity. Twenty-two subjects (mean age=43.4±8.5 years and mean body mass index=33.1+5.3) completed a group intervention based on this method, which was conducted by a registered dietitian and a mental health professional. Questionnaire responses indicated the extent to which their weight was a medical and/ or psychosocial risk. Subjects attended 2-hour weekly sessions for an average of 18 weeks during which they were trained in six developmental skills: strong nurturing, effective limits, body pride, good health, balanced eating, and mastery living. Data, which were collected at the beginning of treatment and at 3, 6, 12, and 24 months, included weight, blood pressure, 7-day exercise recalls, and responses to depression and functioning (psychosocial, vocational, and economic) questionnaires. Participants’ weights decreased throughout the 2-year period of the study: mean weight change was −4.2 kg (3 months), −6.0 kg (6 months), −7.0 kg (12 months), and −7.9 kg (24 months). In addition, compared with baseline values, systolic and diastolic blood pressure, exercise, and depression improved throughout the study period. These improvements were statistically significant at 24 months for weight (p<.01), systolic blood pressure (p<.02), diastolic blood pressure (p<.001), and exercise (p<.001); the results were not statistically significant for depression. Most participants reported improvement in a broad range of aspects of functioning. We conclude that this application of developmental skills training for adult weight management may produce significant long-term beneficial effects. J Am Diet Assoc. 1997;97:1133–1138.  相似文献   
112.
Introduction and ObjectivesThe emergence of SARS-CoV-2, which causes the coronavirus disease (COVID-19) has caused a great impact on healthcare systems worldwide, including hepatitis B and C viruses screening and elimination programs. The high number of COVID-19 hospitalizations represent a great opportunity to screen patients for hepatitis B virus (HBV) and hepatitis C virus (HCV), which was the aim of this study.Material and MethodsCross-sectional, retrospective study performed between April 2020 and 20201 at a referral center in Mexico dedicated to the care of adults with severe/critical COVID-19. We retrieved clinical, demographic, and laboratory results from each patient´s medical records, including antibodies against HCV (anti-HCV), HBV surface antigen (HBsAg), antibodies against the HBV core antigen (anti-HBcAg), and antibodies against HBsAg (anti-HBsAg).ResultsOut of 3620 patients that were admitted to the hospital, 24 (0.66%), 4 (0.11%), and 72 (1.99%) tested positive for anti-HCV, HBsAg, and anti-HBcAg, respectively. Of all seronegative patients, 954 (27%) had undetectable anti-HBsAg and 401 (12%) had anti-HBsAg at protective levels. Blood transfusion was the most relevant risk factor. Only 9.7% of the anti-HBc positive, 25% of the HBsAg positive, and 52% of the anti-HCV positive were aware of their serological status.ConclusionsIn this study we found a prevalence of anti-HCV of 0.66%, HBsAg in 0.11%, and isolated anti-HBcAg in 1.99%. We also found that HBV vaccination coverage has been suboptimal and needs to be reinforced. This study gave us a trustworthy insight of the actual seroprevalence in Mexico, which can help provide feedback to the Hepatitis National Elimination Plan.  相似文献   
113.
114.
115.
116.
Concept mapping is an instructional strategy that requires learners to identify, graphically display, and link key concepts in instructional reading material. Although proven effective in numerous disciplines as a means to promote critical thinking and self-directed learning, concept mapping has not been tested in diet therapy. The objective of this study was to implement concept mapping as a small-group, cooperative learning strategy in an upper-division diet therapy course and to evaluate student attitudes about the effect of concept mapping on knowledge, self-directed learning, problem-solving, and collaborative skills. Students in the first semester (n=27) initially learned course material by lecture (4 weeks) followed by an integrated mapping/lecture format (12 weeks); the second semester (n=25) used an integrated mapping lecture format for the full 16 weeks. At the end of both semesters, students completed a 10-item original survey questionnaire. Responses for first (n=25) and second (n=21) semesters were analyzed independently. Results indicated that a majority of students thought participation in concept mapping enhanced knowledge of diet therapy principles (n=19 of 25; 18 of 21), self-directed learning (n=14 of 25; 18 of 21), critical thinking (n=21 of 25; 14 of 21), problem-solving (n=22 of 25; 16 of 21), and collaboration (n=24 of 25; 20 of 21) skills. When noncooperation of teammates was a factor, concept mapping was viewed as more frustrating and time consuming than lecture. This study demonstrated concept mapping as an effective learning strategy for diet therapy; it improves students’ ability to engage in self-directed learning, critical thinking, collaboration, and creative problem solving. Results suggest that concept mapping is most effective when accompanied with comprehensive training, coordinated lectures, instructor guidance, and long-term practice. J Am Diet Assoc. 1995; 95:908–911.  相似文献   
117.
118.
Objective: 1 ) To examine the ordering of head CT scans in elder patients with delirium and cognitive impairment; and 2) to report CT scan findings associated with these conditions.
Methods : This was a 2-part study. Part 1 was a prospective, observational study of 560 adults >70 years of age evaluated at 3 separate EDs using a 200-hour stratified sampling process at each ED. During Part 1, the frequencies of specific findings (i.e., delirium, impaired consciousness, and impaired cognition) and CT scan rates for these groups were determined. Part 2 was a retrospective analysis of CT scan reports and medical records ( n = 279) for patients >70 years of age in the prospective sample ( n = 79) and from a sample ( n = 200) of CT scans obtained at a fourth ED. Part 2 examined clinical findings detected in the ED to determine those factors that were associated with acute findings on CT scan.
Results : Part 1: There were 333 (59.4%) patients prospectively classified as having impaired cognition, impaired consciousness, or delirium; 79 (23.7%) of these patients had a head CT scan. Of these 3 groups, delirious patients were more frequently scanned (p < 0.001). Part 2: Of 279 CT scans, 42 (15.0%) were positive for an acute condition (hemorrhage, hematoma, space-occupying lesion, infarct). Of 42 positive scans, 40 (95.1%) were found in the 102 (36.6%) patients with either impaired consciousness or a new focal neurologic finding detected in the ED.
Conclusions : Considerable variability in ED CT scan ordering exists for elder patients with neurologic findings. Impaired consciousness and/or new focal neurologic signs are associated with acute findings on CT scan in elder patients. Acute CT abnormalities are uncommon in elder ED patients with other neurologic findings. Additional prospective evaluation is warranted prior to guideline development for CT scans in this patient population.  相似文献   
119.
120.
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