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   1757篇
  免费   126篇
  国内免费   27篇
耳鼻咽喉   11篇
儿科学   149篇
妇产科学   19篇
基础医学   192篇
口腔科学   71篇
临床医学   165篇
内科学   401篇
皮肤病学   43篇
神经病学   37篇
特种医学   334篇
外科学   185篇
综合类   21篇
预防医学   71篇
眼科学   17篇
药学   93篇
  1篇
中国医学   1篇
肿瘤学   99篇
  2023年   4篇
  2022年   11篇
  2021年   15篇
  2020年   10篇
  2019年   17篇
  2018年   25篇
  2017年   20篇
  2016年   25篇
  2015年   33篇
  2014年   32篇
  2013年   58篇
  2012年   22篇
  2011年   18篇
  2010年   45篇
  2009年   89篇
  2008年   31篇
  2007年   53篇
  2006年   53篇
  2005年   50篇
  2004年   44篇
  2003年   38篇
  2002年   35篇
  2001年   31篇
  2000年   34篇
  1999年   43篇
  1998年   104篇
  1997年   119篇
  1996年   116篇
  1995年   79篇
  1994年   83篇
  1993年   100篇
  1992年   28篇
  1991年   30篇
  1990年   23篇
  1989年   52篇
  1988年   41篇
  1987年   31篇
  1986年   35篇
  1985年   36篇
  1984年   19篇
  1983年   16篇
  1982年   19篇
  1981年   34篇
  1980年   20篇
  1979年   10篇
  1978年   8篇
  1977年   21篇
  1976年   20篇
  1975年   6篇
  1970年   5篇
排序方式: 共有1910条查询结果,搜索用时 15 毫秒
1.
Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight.  相似文献   
2.
Background: Pemetrexed and cisplatin have recently been shown to significantly improve survival compared with cisplatin alone. However, there are only limited data reflecting teaching hospital experience outside a clinical trial. Pemetrexed has only been available in Australia on a restricted basis since 2002. We reviewed our experience of patients treated on the Australian ‘Special Access Scheme’ at three major thoracic oncology units. Methods: Charts were reviewed for all patients enrolled on the scheme. Data was extracted on age, World Health Organization (WHO) performance status, histology, prior therapy, time from diagnosis to starting pemetrexed, chemotherapy (pemetrexed alone or with a platinum), cycle number, response rate, actuarial progression‐free and overall survival. Doses were cisplatin 75 mg/m2 or carboplatin AUC = 5 and pemetrexed 500 mg/m2 every 21 days. Results: 52 patients (32 male and 20 female) were reviewed. Median age was 58 years and 88% were WHO 0–1. Histology included 54% epithelial, 17% biphasic (epithelial and sarcomatoid) and 21% undefined. The median time from diagnosis to administration of pemetrexed was 145 days. Sixty‐five percent had minimal surgical intervention with video assisted thoracoscopy, pleurodesis and biopsy, while 19% had received prior palliative radiation. Seventy‐one percent were chemotherapy naïve, the remaining 29% having received previous platinum and/or gemcitabine regimens. Twenty‐three percent had pemetrexed alone, 35% in combination with carboplatin and 42% with cisplatin. The median number of cycles was 4 (range 1–13). The response rate was 33%. No toxicity was observed in 20% grade 3–4 toxicity in 10% (majority nausea/vomiting). The median progression‐free and overall survival times from starting pemetrexed were 184 days and 298 days, respectively. Conclusions: Pemetrexed‐based regimens are safe and effective in a community setting in malignant mesothelioma.  相似文献   
3.
1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.  相似文献   
4.
The triglyceride connection in atherosclerosis.   总被引:4,自引:0,他引:4  
OBJECTIVE: To examine the proposed mechanism of triglyceride-induced atherogenesis, to address the controversy surrounding serum triglycerides as a coronary heart disease (CHD) risk factor, and to recommend an appropriate therapeutic approach to hypertriglyceridemia. DATA SOURCES: Studies, review articles, and editorials published since 1976. A MEDLINE search of English-language literature was conducted using the terms triglyceride and hypertriglyceridemia. STUDY SELECTION: Studies, review articles, and editorials were selected for detailed review if they addressed the pathogenesis of triglyceride-induced atherosclerosis, the controversy associated with elevated serum triglyceride as a CHD risk factor, and hypertriglyceridemia treatment options. DATA EXTRACTION: Data were reviewed that described the atherogenicity of chylomicron and very low-density lipoprotein (VLDL) remnants, the inverse relationship that exists between high-density lipoprotein (HDL) and serum triglyceride, the hypertriglyceridemia treatment controversy, and the treatment options of diet, exercise, weight control, alcohol restriction, and medication. DATA SYNTHESIS: Hypertriglyceridemia is a well-known risk factor for pancreatitis. However, its role in atherogenesis is less well defined. Several proposed connections appear to exist between hypertriglyceridemia and atherosclerosis, including the inverse correlation between triglycerides and HDL, the presumed atherogenicity of triglyceride-rich lipoprotein remnant particles, the potential resultant increase in the serum concentration and atherogenicity of low-density lipoprotein (LDL), and the proposed interaction between serum triglyceride and the fibrinolytic/coagulation system. Clinical trials addressing this issue offer mixed results that are subject to interpretation. Diet, exercise, weight control, alcohol restriction, and certain lipid-lowering medications are effective at reducing serum triglyceride. CONCLUSIONS: Hypertriglyceridemia is a theoretical risk factor for CHD because of the increased production of atherogenic chylomicron and VLDL remnants, the inverse relationship present between serum triglyceride and HDL, the possible resultant increase in LDL attributable to remnant-reduced hepatic LDL-receptors as well as the formation of more dense and, therefore, more atherogenic LDL, and to the interaction between serum triglyceride and the fibrinolytic/coagulation system. However, most clinical trials that have found hypertriglyceridemia to be a risk factor for CHD do not include other CHD risk factors in their analyses. Therapeutic intervention to lower serum triglyceride with diet, exercise, and/or drugs is definitely recommended in the treatment and/or prevention of pancreatitis; however, the role of triglyceride-lowering to reduce CHD risk remains controversial.  相似文献   
5.
6.
Neither computed tomography (CT) nor ultrasonography reliably distinguishes neoplastic from non-neoplastic pancreatic cysts. More invasive tests such as angiography or biopsy fail to differentiate these lesions in up to a third of patients. Because appropriate treatment differs greatly for these two classes of lesions, the clinician requires a more accurate means of confirming or excluding neoplasia. In an effort to refine the preoperative diagnosis of pancreatic cysts and evaluate the utility of endoscopic retrograde pancreatography (ERCP), we evaluated 11 patients with proven pancreatic neoplasia associated with cysts who underwent preoperative ERCP and CT scanning. Four patients had microcystic cystadenomas, two had a mucinous cystadenoma, one had a mucinous cystadenocarcinoma, and four had adenocarcinomas associated with cysts. CT identified a pancreatic cystic lesion in each patient. In all patients, ERCP showed either focal irregular narrowing, occlusion, or displacement of the main pancreatic duct at the corresponding location without the ductal changes of chronic pancreatitis. This helped to preoperatively differentiate these lesions from pseudocysts, hastening appropriate operation, obviating further testing and consultation, and aiding the intraoperative surgical strategy.  相似文献   
7.
Pediatric knee MR imaging: pattern of injuries in the immature skeleton   总被引:3,自引:0,他引:3  
  相似文献   
8.
9.
During the first 24 months of the Oregon Liver Transplantation Program, which began in October 1988, 94 patients were formally evaluated and 47 adults underwent 54 liver transplantations. Thirty-four percent of patients were veterans. The recipient operation lasted a mean of 7.4 hours (range: 4 to 16 hours). Veno-venous bypass was used routinely at first but selectively later (7 of the last 26 cases), resulting in reduced operating time. Hepatic artery reconstruction was end-to-end anastomosis in 52 cases and iliac conduit in 2. No arterial thrombosis occurred. Biliary reconstruction was choledochocholedochostomy in 83% and choledochojejunostomy in 17%. Biliary complications occurred in 28%. Operative mortality was 2%, and 1-year actual survival was 80%. Patients with hepatitis B fared worse, with four of six dying at a mean of 7.6 months. Overall, the median hospital stay was 30 days. Patients surviving more than 3 months had a mean Karnofsky score of 82%. No significant difference in outcome was noted in patients receiving prophylactic OKT3 monoclonal antibody (used in 45%) versus conventional immunosuppressive therapy. Overall, allograft rejection occurred in 55% of patients. Retransplantation was required in seven patients, three for primary graft nonfunction, two for uncontrolled rejection during induction therapy with OKT3, and two for graft failure secondary to recurrent hepatitis B.  相似文献   
10.
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