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   1791篇
  免费   123篇
  国内免费   26篇
儿科学   153篇
妇产科学   27篇
基础医学   153篇
口腔科学   67篇
临床医学   179篇
内科学   421篇
皮肤病学   40篇
神经病学   39篇
特种医学   342篇
外科学   105篇
综合类   27篇
预防医学   126篇
眼科学   36篇
药学   124篇
  1篇
中国医学   2篇
肿瘤学   98篇
  2023年   6篇
  2022年   7篇
  2021年   19篇
  2020年   12篇
  2019年   18篇
  2018年   29篇
  2017年   20篇
  2016年   24篇
  2015年   32篇
  2014年   29篇
  2013年   56篇
  2012年   24篇
  2011年   29篇
  2010年   51篇
  2009年   89篇
  2008年   32篇
  2007年   50篇
  2006年   48篇
  2005年   49篇
  2004年   36篇
  2003年   43篇
  2002年   35篇
  2001年   33篇
  2000年   31篇
  1999年   37篇
  1998年   108篇
  1997年   121篇
  1996年   117篇
  1995年   80篇
  1994年   88篇
  1993年   100篇
  1992年   22篇
  1991年   26篇
  1990年   26篇
  1989年   53篇
  1988年   44篇
  1987年   32篇
  1986年   35篇
  1985年   34篇
  1984年   22篇
  1983年   16篇
  1982年   25篇
  1981年   39篇
  1980年   26篇
  1979年   9篇
  1978年   8篇
  1977年   23篇
  1976年   24篇
  1975年   8篇
  1974年   3篇
排序方式: 共有1940条查询结果,搜索用时 24 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.
The granulocyte colony-stimulating factor (G-CSF) has been shown to accelerate recovery from severe neutropenia and to decrease the incidence of documented infections after intensive chemotherapy in cancer patients. However, the routine prophylactic use of G-CSF is expensive. This study was conducted to determine the role of G-CSF as adjunct therapy for septicemia following neutropenia caused by chemotherapy in children with acute leukemia. Fifty consecutive episodes of septicemia were studied involving 34 episodes of Gram-negative, 7 episodes of Gram-positive, 5 episodes of polymicrobial bacterial septicemia, one episode of fungemia, and 3 episodes of disseminated fungal infection. In the first 25 episodes, G-CSF was not used (group A). For the next 16 episodes, G-CSF 200 μg per square meter per day subcutaneously was given immediately after the septicemia was documented until the absolute neutrophil count was maintained at more than 1,500 per cubic millimeter (group B). Thereafter, G-CSF at the same dose as that of group B was prophylactically used in all the children who received high-dose cytosine arablnc-side-containing regimens. Nine episodes of septicemia occurred (group C). The incidences of mortality per episode of septicemia in groups A, B, and C were 12.0% (3/25), 12.5% (2/16) and 0% (0/9), respectively. Statistically, there was no difference between the three groups overall and in pair-wise comparisons (all P > 0.5). The durations of G-CSF administration in group B ranged from 6 to 26 days with a median of 12 days and the durations of G-CSF administration in group C ranged from 10 to 23 days with a median of 19 days. With or without G-CSF, there may be no significant difference in the mortality of septicemia following neutropenia caused by chemotherapy in children with acute leukemia.  相似文献   
4.
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   
5.
6.
BACKGROUND: The reasons for mis-reporting food consumption warrant investigation. OBJECTIVE: To document intention to mis-report food consumption and its associations with psychological measures in women. DESIGN: A total of 184 female volunteers aged 18-65 years, comprising 50 seeking help in primary care to lose weight with a body mass index (BMI) >/=30 kg m(-2) (obese-clinical group) and 134 nurses (nonclinical groups) (BMI <25 kg m(-2), n = 52; BMI 25-29.9 kg m(-2), n = 45; BMI >/=30 kg m(-2), n = 37) were studied. A questionnaire was administered containing three psychological tests (self-esteem, psychological well-being and Stunkard's three-factor eating questionnaire) and new items to address food intake mis-reporting. RESULTS: Overall, 68% of participants declared an inclination to mis-report (64% nonclinical, 78% clinical). Inclination to under-report was 29, 33 and 51% in the three nonclinical groups; and 46% among the obese clinical patients. Among the same groups, inclination to over-report were 39, 29, 11 and 32%. After adjusting for social deprivation and BMI, women inclined to mis-report had higher hunger (P = 0.008) and disinhibition (P = 0.005) scores than those intending to report accurately. These variables were associated with current dieting, frequency of dieting, self-reported bingeing and dissatisfaction with body weight. CONCLUSIONS: These findings indicate that intentional under-reporting and over-reporting of food consumption are common in women of all BMI categories and are associated with eating behaviour. Current dieting, frequency of dieting in the past, self-reported bingeing and dissatisfaction with body weight seem to mediate this relationship.  相似文献   
7.
8.
9.
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   
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