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   23595篇
  免费   1675篇
  国内免费   183篇
耳鼻咽喉   372篇
儿科学   449篇
妇产科学   491篇
基础医学   3114篇
口腔科学   537篇
临床医学   2222篇
内科学   4840篇
皮肤病学   672篇
神经病学   1666篇
特种医学   1188篇
外科学   3034篇
综合类   783篇
现状与发展   1篇
一般理论   18篇
预防医学   1344篇
眼科学   813篇
药学   1824篇
中国医学   173篇
肿瘤学   1912篇
  2023年   213篇
  2022年   390篇
  2021年   896篇
  2020年   519篇
  2019年   671篇
  2018年   833篇
  2017年   605篇
  2016年   718篇
  2015年   905篇
  2014年   1124篇
  2013年   1242篇
  2012年   1970篇
  2011年   1909篇
  2010年   1028篇
  2009年   940篇
  2008年   1335篇
  2007年   1302篇
  2006年   1258篇
  2005年   1210篇
  2004年   963篇
  2003年   796篇
  2002年   672篇
  2001年   543篇
  2000年   520篇
  1999年   416篇
  1998年   149篇
  1997年   127篇
  1996年   90篇
  1995年   99篇
  1994年   89篇
  1993年   73篇
  1992年   163篇
  1991年   170篇
  1990年   143篇
  1989年   130篇
  1988年   125篇
  1987年   134篇
  1986年   107篇
  1985年   100篇
  1984年   77篇
  1983年   72篇
  1982年   41篇
  1979年   62篇
  1977年   40篇
  1975年   39篇
  1974年   39篇
  1973年   36篇
  1972年   37篇
  1970年   35篇
  1969年   40篇
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
31.
32.
33.
Background.Physical inactivity is recognized as an important public health issue. Yet little is known about doctors' knowledge, attitude, skills, and resources specifically relating to the promotion of physical activity. Our survey assessed the current practice, perceived desirable practice, confidence, and barriers related to the promotion of physical activity in family practice.Methods.A questionnaire was developed and distributed to all 1,228 family practitioners in Perth, Western Australia.Results.We received a 71% response (n= 789). Family practitioners are most likely to recommend walking to sedentary adults to improve fitness and they are aware of the major barriers to patients participating in physical activity. Doctors are less confident at providing specific advice on exercise and may require further skills, knowledge, and experience. Although they promote exercise to patients through verbal advice in the consultation, few use written materials or referral systems.Conclusions.There are significant differences between self-reports of current practice and perceived desirable practice in the promotion of physical activity by doctors. Future strategies need to address the self-efficacy of family physicians and involve resources of proven effectiveness. The potential of referral systems for supporting efforts to increase physical activity by Australians should be explored.  相似文献   
34.
It is well known that long-term use of steroids plays a decisive role in the development of glucose intolerance and diabetes mellitus (DM). Deflazacort, an oxazoline derivative of prednisolone, has been introduced as a potential substitute for conventional steroids in order to ameliorate glucose intolerance. We initiated a randomized study of conversion from prednisone to deflazacort in kidney transplantation (Tx) recipients presenting with pre-Tx or post-Tx DM to ascertain whether or not the switch to deflazacort would ameliorate the diabetic state. Forty-two recipients in the conversion group were compared with 40 patients on prednisone (the control group) in a prospective manner. The dose reduction of insulin or oral blood glucose-lowering agents, the adequacy of glucose control, and the development of side effects were the criteria for evaluating outcome. In the conversion group, patients were switched to deflazacort at a dose ratio of 6 mg deflazacort to 5 mg prednisone. During the mean follow-up period of 13.2 months, neither graft dysfunction nor acute rejection developed in the conversion group. Improvement in blood glucose control in the conversion group was noted. When the conversion group was stratified into pre- or post-Tx DM, promising effects were clearly evident in the post-Tx DM patients. More than 50 % dose reduction of blood glucose-lowering agents was possible in 42.3 % of post-Tx DM patients. In conclusion, it was readily possible to control blood glucose better in post-Tx DM recipients without seriously affecting the immunosuppressive activity after conversion to deflazacort. Received: 20 August 1996 Received after revision: 25 November 1996 Accepted: 6 December 1996  相似文献   
35.
Abstract The aim of this study was to describe the periodontal conditions in 372 35–44-yr-old and 537 noninstitutionalized 65–74-yr-old Hong Kong Chinese who were examined clinically for loss of attachment, recession, probing depth, calculus, and bleeding after probing. Community Periodontal Index (CPI) data and treatment need indications were compiled from index teeth or their substitutes. The prevalence of loss of attachment varied considerably in both cohorts according to the definition of the threshold (≥6, ≥9, and ≥12 mm, respectively). The mean numbers of teeth with loss of attachment at the ≥6-mm threshold and at higher thresholds were small. In both age cohorts, about one-fifth of subjects had probing depths ≥6-mm, while al the ≥9-mm threshold only 2–3% were so affected. Although recession was an important component of loss of attachment in the younger cohort, in the older cohort the prevalence and extent of recession were greater than for probing depths at thresholds ≥4 mm. All subjects had one or more teeth with calculus, bleeding, or both, most teeth being so affected. Eighty-four of the 537 65–74-yr-old subjects were excluded either because of edentulousness or because extractions indicated for the remaining teeth would have rendered the subjects edentulous. The distribution of subjects according to their highest CPI score was remarkably similar for the two cohorts. No subjects in either age group were assessed as “healthy” (CPI code 0) or had “bleeding only” (code 1) as their highest score. While most subjects scored CPI code 2 or 3 us their highest score, only 17% of the younger and 15% of the older cohort scored Community Periodontal Index of Treatment Needs (CPITN) code 4. Differences in the mean number of sextants affected by CPI codes between the two cohorts were mainly due to a greater number of excluded sextants in the older cohort. CPI findings for 35–44-yr-olds differed little from those reported in 1984.  相似文献   
36.
The efficacy and safety of using umbilical venous catheters vs. peripheral venous catheters for the delivery of parenteral nutrition was studied in 129 critically ill premature infants who were treated in a neonatal intensive care unit for the first 3 weeks of life. Infants who received parenteral nutrition by umbilical venous catheter had greater parenteral caloric intake, lower physiologic weight loss and greater weight gain during the study as compared to infants who received parenteral nutrition by peripheral vein. While the overall incidence of sepsis was comparable in both groups (19% vs 19.7%), benign and transient episodes of hyperglycemia were seen more commonly in infants receiving parenteral nutrition by umbilical catheters. None of the hyperglycemic infants, however, required insulin therapy. The incidence of other metabolic complication was comparable in both groups. At follow up, no evidence of portal hypertension was detected in any of the infants up to 66 months of age treated with umbilical venous catheters. We conclude that the use of umbilical venous catheter allows for a comparably safe and a more appropriate parenteral nutrition support than peripheral catheters in critically ill premature neonates.  相似文献   
37.
38.
39.
OBJECTIVE: Many patients with haemorrhoids are investigated because of the fear of missing colorectal cancer (CRC). The aim of this study was to determine whether a primarily clinical approach regarding the need for investigation was safe and did not miss patients with CRC. PATIENTS AND METHODS: Data was collected prospectively on 589 consecutive patients with the principle diagnosis of haemorrhoids at first clinic visit. All had clinical assessment including rigid sigmoidoscopy and were treated by phenol injection or banding. They were categorized for (1) no review unless symptoms persisted -'One Stop SOS' (2) outpatient review or (3) investigation. To check for the development of CRC they were contacted by postal questionnaire or telephone interview with a minimum of one year from diagnosis and treatment. All 589 patients were cross-referenced with the Pathology database and the Hospital Information Services System. RESULTS: Four hundred and sixty-nine (80%) answered the questionnaire; 352 patients (60% of the total group) fell in the 'one stop SOS' outpatient category; 95 (16%) patients were followed up to review response to treatment for large haemorrhoids; 105 (18%) were investigated with barium enema (12%), flexible sigmoidoscopy (4%), colonoscopy (1%) and miscellaneous (1%); 37 (6%) patients were either given a haemorrhoidectomy date or referred on with a different diagnosis. No patients selected for 'one-stop' treatment developed CRC. Five (0.8%) patients were diagnosed with CRC after appropriate investigation was instituted for suspicious symptoms. One patient with distal transverse colon cancer had a delayed diagnosis as she was investigated initially by flexible sigmoidoscopy. CONCLUSION: Most patients with the primary diagnosis of symptomatic haemorrhoids do not need investigation.  相似文献   
40.
Context One in seven US children and adolescents is obese, yet little is known about their health‐related quality of life (QOL). Objective To examine the health‐related QOL of obese children and adolescents compared with children and adolescents who are healthy or those diagnosed as having cancer. Design, setting and participants Cross‐sectional study of 106 children and adolescents (57 males) between the ages of 5 and 18 years [mean (SD) 12.1 (3) years], who had been referred to an academic children's hospital for evaluation of obesity between January and June 2002. Children and adolescents had a mean (SD) body mass index (BMI) of 34.7 (9.3) and BMI z‐score of 2.6 (0.5). Main outcome measures Child self‐report and parent‐proxy report using a paediatric QOL inventory generic core scale (range 0–100). The inventory was administered by an interviewer for children aged 5 through 7 years. Scores were compared with previously published scores for healthy children and adolescents and children and adolescents diagnosed as having cancer. Results Compared with healthy children and adolescents, obese children and adolescents reported significantly (P < 0.001) lower health‐related QOL in all domains [mean (SD) total score, 67 (16.3) for obese children and adolescents; 83 (14.8) for healthy children and adolescents]. Obese children and adolescents were more likely to have impaired health‐related QOL than healthy children and adolescents [odds ratio (OR) 5.5; 95% confidence interval (CI) 3.4–8.7] and were similar to children and adolescents diagnosed as having cancer (OR 1.3; 95% CI 0.8–2.3). Children and adolescents with obstructive sleep apnoea reported a significantly lower health‐related QOL total score [mean (SD), 53.8 (13.3)] than obese children and adolescents without obstructive sleep apnoea [mean (SD), 67.9 (16.2)]. For parent‐proxy report, the child or adolescent's BMI z‐score was significantly inversely correlated with total score (r = ?0.246; P = 0.01), physical functioning (r = ?0.263; P < 0.01), social functioning (r = ?0.347; P < 0.001), and psychosocial functioning (r = ?0.209; P = 0.03). Conclusions Severely obese children and adolescents have lower health‐related QOL than children and adolescents who are healthy and similar QOL as those diagnosed as having cancer. Physicians, parents and teachers need to be informed of the risk for impaired health‐related QOL among obese children and adolescents to target interventions that could enhance health outcomes.  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