全文获取类型
收费全文 | 53467篇 |
免费 | 14271篇 |
国内免费 | 219篇 |
专业分类
耳鼻咽喉 | 1239篇 |
儿科学 | 1397篇 |
妇产科学 | 2592篇 |
基础医学 | 1136篇 |
口腔科学 | 3654篇 |
临床医学 | 20519篇 |
内科学 | 11753篇 |
皮肤病学 | 852篇 |
神经病学 | 3238篇 |
特种医学 | 1530篇 |
外科学 | 6615篇 |
综合类 | 244篇 |
现状与发展 | 14篇 |
一般理论 | 6篇 |
预防医学 | 6852篇 |
眼科学 | 709篇 |
药学 | 769篇 |
中国医学 | 8篇 |
肿瘤学 | 4830篇 |
出版年
2024年 | 326篇 |
2023年 | 2398篇 |
2022年 | 606篇 |
2021年 | 1238篇 |
2020年 | 2475篇 |
2019年 | 953篇 |
2018年 | 3046篇 |
2017年 | 3284篇 |
2016年 | 3712篇 |
2015年 | 3817篇 |
2014年 | 4780篇 |
2013年 | 5481篇 |
2012年 | 1771篇 |
2011年 | 1918篇 |
2010年 | 3163篇 |
2009年 | 4228篇 |
2008年 | 1870篇 |
2007年 | 1456篇 |
2006年 | 1843篇 |
2005年 | 1260篇 |
2004年 | 1054篇 |
2003年 | 899篇 |
2002年 | 784篇 |
2001年 | 1163篇 |
2000年 | 822篇 |
1999年 | 1067篇 |
1998年 | 1298篇 |
1997年 | 1309篇 |
1996年 | 1304篇 |
1995年 | 1047篇 |
1994年 | 786篇 |
1993年 | 667篇 |
1992年 | 609篇 |
1991年 | 524篇 |
1990年 | 559篇 |
1989年 | 463篇 |
1988年 | 413篇 |
1987年 | 358篇 |
1986年 | 354篇 |
1985年 | 352篇 |
1984年 | 266篇 |
1983年 | 274篇 |
1982年 | 206篇 |
1981年 | 193篇 |
1980年 | 130篇 |
1979年 | 184篇 |
1978年 | 148篇 |
1977年 | 146篇 |
1976年 | 148篇 |
1972年 | 148篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
241.
242.
Objectives: To validate the accuracy of using probabilistic linkage for matching de‐identified ambulance records to a state trauma registry. Methods: This was a retrospective cohort analysis. Three thousand nine hundred nineteen true matches between ambulance and state trauma registry data from 1998 to 2003 were identified by deterministic matching on trauma identification number and verified by human review. Two thousand thirty‐eight ambulance records from trauma patients not meeting criteria for a true match, and an identical number of trauma registry records randomly selected from the one local county served by a different EMS provider, were included as nonmatches. There were 17 variables considered for linkage, which included the following: age, gender, race, county, hospital, date, rural setting, call and arrival times, mechanism, penetrating injury, vital signs, intubation, and intoxication. Probabilistic linkage was used to link the two data sets, using seven different combinations of common variables (maximum, 17; minimum, 4). The sensitivity and specificity of identifying true matches and nonmatches (95% confidence intervals [95% CI]) were calculated for each combination of variables. Results: Using all 17 available variables, 3,766 of 3,919 true matches were appropriately linked (sensitivity, 96.1%; 95% CI = 95.4% to 96.7%), with eight mismatches (specificity, 99.6%; 95% CI = 99.2% to 99.8%). Sensitivity fell below 95% with < 15 variables; however, sensitivity was very dependent on the inclusion of variables with high discriminatory power. Specificity remained >98% regardless of the number of variables included. Conclusions: Probabilistic linkage is a valid method for matching ambulance records to a trauma registry without the use of patient identifiers; however, the sensitivity of identifying true matches is critically dependent on the number and type of common variables included in the analysis. 相似文献
243.
JENNIFER ORLET FISHER PhD DIANE C. MITCHELL MS RD HELEN SMICIKLAS- WRIGHT PhD LEANN LIPPS BIRCH PhD 《Journal of the American Dietetic Association》2002,102(1)
Objective To evaluate parents’ fruit and vegetable intake and their use of pressure to eat in child feeding as predictors of their 5-year-old daughters’ fruit and vegetable, micronutrient, and fat intakes.Subjects Data were obtained from 191 non-Hispanic white families with 5-year-old girls.Design Parent data included reports of pressure in child feeding and their own fruit and vegetable intake. Girls’ intakes of fruits and vegetables, selected micronutrients, and fat were the main outcomes of interest.Statistical analysis Structural equation modeling was used to test a model describing relationships among parents’ fruit and vegetable intake, parents’ use of pressure in child feeding, and daughters’ fruit and vegetable, micronutrient, and fat intakes.Results The model provided a good fit to the data, revealing that girls’ fruit and vegetable intake was positively related to their parents’ reported fruit and vegetable intake. Parents who consumed fewer fruits and vegetables tended to report greater pressure in child feeding and had daughters who consumed fewer fruits and vegetables. Girls’ reported fruit and vegetable intakes were positively related to their micronutrient intakes and negatively associated with fat intake.Applications/conclusions This research demonstrates that parents’ own fruit and vegetable intake may encourage fruit and vegetable intake in their daughters, leading to higher micronutrient intakes and lower dietary fat intakes. Conversely, pressure to eat may discourage fruit and vegetable intake among young girls. J Am Diet Assoc. 2002;102:58–64. 相似文献
244.
245.
TOPIC: Psychological impact of adoption and resulting core issues for adopted children. PURPOSE: To raise awareness of the psychological impact of adoption. SOURCES: Published literature and personal observations. CONCLUSIONS: Adoption raises unique issues and challenges for the child and adoptive parents. Resolving the issues of adoption is a lifelong process. Through an awareness of the issues inherent in adoption, nurses and parents can use strategies that will enhance children's self-esteem and decrease their emotional vulnerability. Search terms: Adoption, intervention, loss, self-esteem, strategies 相似文献
246.
G M Wood B Sidhu W A Saunders A M Zalin D A Heath 《Postgraduate medical journal》1987,63(743):741-744
Four women presented with symptomatic hypercalcaemia and raised concentrations of serum parathyroid hormone (PTH). In each case, serum calcium returned spontaneously to normal. In two patients serum PTH also fell to the normal range and biochemical relapse has not occurred despite prolonged follow-up. In the others, serum PTH remained elevated and subsequent symptomatic hypercalcaemia necessitated parathyroidectomy. In the first two cases, autoparathyroidectomy is the most likely explanation; the initial fall in serum calcium in the other two patients is unexplained. Large fluctuations in serum calcium may occur in some patients with hyperparathyroidism and prolonged and careful observation is required when this occurs. 相似文献
247.
JO MANION RN MA CNAA 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1986,15(2):103-108
A documentation system that facilitates accurate and complete recording is needed by every obstetric/neonatal nursing service. Developing an individualized system is a major undertaking. However, specific steps can be taken to ease the process. These steps are described, beginning with the assessment phase and concluding with evaluation. 相似文献
248.
249.
250.