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   209458篇
  免费   14810篇
  国内免费   4263篇
耳鼻咽喉   3057篇
儿科学   3610篇
妇产科学   4270篇
基础医学   30273篇
口腔科学   4313篇
临床医学   21259篇
内科学   38523篇
皮肤病学   4993篇
神经病学   14872篇
特种医学   10212篇
外国民族医学   21篇
外科学   27064篇
综合类   8395篇
现状与发展   18篇
一般理论   84篇
预防医学   12684篇
眼科学   5475篇
药学   18395篇
  38篇
中国医学   3908篇
肿瘤学   17067篇
  2023年   1790篇
  2022年   4681篇
  2021年   7511篇
  2020年   4482篇
  2019年   5394篇
  2018年   6205篇
  2017年   4863篇
  2016年   5728篇
  2015年   7906篇
  2014年   9553篇
  2013年   10919篇
  2012年   16220篇
  2011年   16149篇
  2010年   9702篇
  2009年   8042篇
  2008年   11743篇
  2007年   11599篇
  2006年   10734篇
  2005年   10191篇
  2004年   8738篇
  2003年   7690篇
  2002年   6658篇
  2001年   5372篇
  2000年   4996篇
  1999年   4300篇
  1998年   1907篇
  1997年   1581篇
  1996年   1413篇
  1995年   1273篇
  1994年   1123篇
  1993年   849篇
  1992年   1918篇
  1991年   1833篇
  1990年   1605篇
  1989年   1472篇
  1988年   1372篇
  1987年   1215篇
  1986年   1167篇
  1985年   1003篇
  1984年   726篇
  1983年   628篇
  1982年   425篇
  1981年   414篇
  1980年   364篇
  1979年   555篇
  1978年   428篇
  1977年   410篇
  1976年   374篇
  1974年   385篇
  1973年   345篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The purpose of this study was to examine the levels of anxiety of mothers with children in pediatric intensive care units with different types of visitation policies, both structured and individualized Forty subjects were obtained from two children's hospitals A comparative research design was used Data showed that mothers who experienced individualized visitation had significantly lower anxiety scores (p < 005) than mothers who experienced structured visitation Findings also revealed that mothers viewed their child's illness as less severe when individualized visitation was permitted as opposed to structured visitation.  相似文献   
42.
In medical studies with censored data Kaplan and Meier's product limit estimator has frequent use as the estimate of the survival function. Simultaneous confidence intervals for the survival function at various time points constitute a useful addition to the analysis. This study compares several such methods. We consider in a simulation investigation two whole curve confidence bands and four methods based on the Bonferroni inequality. The results show that three Bonferroni-type methods are essentially equivalent, all being better than the other methods when the number of time points is small (3 or 5).  相似文献   
43.
BACKGROUND AND PURPOSE: Thyroidectomy is a common treatment for thyroid disorders in Taiwan, and constitutes a significant percentage of medical expenses. This study investigated the characteristics of thyroidectomy in Taiwan. METHODS: A total of 21 senior general surgeons from 16 medical centers and 5 regional hospitals participated. One surgeon from each hospital reviewed the hospital's medical records of thyroid operations performed in the year 2001. Medical records for 3846 thyroidectomies were retrospectively analyzed, including surgical indications and modalities, complications, pathology reports, and the use of antibiotics. RESULTS: Most of the patients were women (85%). Indications for surgery included proven malignancy (9%), suspicious malignancy (30%), evident compression symptoms (20%), hyperthyroidism (20%), and cosmetic reasons (12%). The majority of patients (78%) underwent a surgical procedure with lobectomy or bilateral thyroidectomy; 13% had unilateral partial thyroidectomy. Prophylactic antibiotics were administered in 46% of procedures, and continued postoperatively in 12%. Postoperative complications occurred in 12% of patients. Hypocalcemia was the most common complication (8%), and its incidence was significantly correlated with the frequency of total thyroidectomy (p < 0.01). Complete pathology reports for the thyroidectomized specimens were available in only 65% of the cases. The frequency of cosmetic reasons for surgery, unilateral subtotal resection, routine antibiotic administration, and incomplete pathology reports were significantly higher in regional hospitals than in medical centers. CONCLUSIONS: Reduction in the high rates of cosmetic reasons for surgery, unilateral partial thyroidectomy, incomplete pathology reports, and use of antibiotic prophylaxis are needed to improve the quality of thyroidectomy in Taiwan.  相似文献   
44.
X-linked hyper-immunoglobulin M (IgM) syndrome (XHIGM) is a rare genetic primary immunodeficiency disease caused by mutations of the CD40 ligand (CD40L) gene with normal or elevated levels of IgM and markedly decreased serum IgG, IgA, and IgE. Liver disease may occur as a clinical manifestation in XHIGM. This complication appears to increase with age. We report an 18-year-old male patient who had recurrent episodes of acalculous cholecystitis (AC) and sclerosing cholangitis (SC). The diagnosis of XHIGM was confirmed by the finding of CD40L expression < 1% of normal and a tyrosine 169 asparaginase (t526a) mutation in exon 5 (the tumor necrosis factor domain) of the CD40L gene. The patient had direct hyperbilirubinemia (direct bilirubin 5.5 mg/dL, total bilirubin 8.7 mg/dL), cholestasis (alkaline phosphatase 1133 U/L, gamma-glutamyl transferase 1019 U/L) and elevated transaminases (aspartate aminotransferase 70 U/L, alanine aminotransferase 101 U/L). Findings on abdominal ultrasound and abdominal computed tomography were compatible with AC. After the fourth episode of cholecystitis, cholecystectomy and liver biopsy were performed. Operative cholangiography revealed poor opacification of the hepatic duct and proximal common bile duct; the upstream intrahepatic bile ducts were not visualized. The biopsy specimen showed marked fibrosis of the portal areas. Enterococcus species was cultured from the bile. Children or adolescents with recurrent AC and SC should be evaluated for an underlying immunodeficiency syndrome such as XHIGM.  相似文献   
45.
OBJECTIVE: Outcomes analysis in congenital diaphragmatic hernia (CDH) requires a validated risk-adjustment tool. The purpose of this study was to use the Canadian Neonatal Network (CNN) database to validate the Score for Neonatal Acute Physiology, Version II (SNAP-II) for prediction of mortality among CDH infants admitted to a neonatal intensive care unit (NICU), and to compare this to the predictive equation recently developed by the Congenital Diaphragmatic Hernia Study Group (CDHSG). STUDY DESIGN: Infants with CDH in the CNN database were identified. Bivariate and multivariable logistic regression models were used to identify risk factors predictive of mortality. Model predictive performance and calibration were assessed using the area under the receiver operator characteristic curve and the technique of Hosmer-Lemeshow, respectively, and compared with the CDHSG predictive equation. RESULTS: There were 88 patients with CDH among 19,507 admissions to CNN hospitals. The mortality rate among CDH patients surviving to NICU admission was 17%, and 12.5% received extracorporeal membrane oxygenation therapy. Gestational age and admission SNAP-II score predicted mortality. Model predictive performance and calibration were optimized with these variables combined. The CDHSG equation was equally predictive of mortality, but was only marginally calibrated. CONCLUSIONS: SNAP-II is highly predictive of mortality among patients with CDH, and can be used to risk-adjust these patients.  相似文献   
46.
47.
目的 合理应用影像学检查,探讨腰腿痛的病因诊断,为临床治疗提供依据.方法 对38例腰腿痛患者进行随访,观察普通照片后经CT、MRI及B超等复查的最后诊断,对比进行分析.结果 单纯普通照片对椎间盘脱出、椎管狭窄、骶部硬膜外囊肿、股骨头无菌坏死、梨状肌损伤等疾病缺乏直接征象,不能作为诊断依据.结论 应用CT、MRI现代影像技术,同时借助B超、肌电图等相关检查,是确诊腰腿痛病因的有效方法.  相似文献   
48.
The authors compared children (ages 7-13 years) of unipolar depressed mothers with children of nondepressed psychiatric patients, of nondepressed medical patients, and of nondepressed mothers in the community. The children's adjustment was rated by clinicians on the Child Adjustment Schedule and by the mothers on the Child Behavior Checklist. The highest proportion of clinically significant problems was found in the children of the depressed mothers. However, the overlap between the problems of these children and those of the children of the nondepressed psychiatric patients calls into question the formulation that children's adjustment difficulties are specific to parental depression.  相似文献   
49.
We report a case of successful transvenous, catheter-based, cavotricuspid isthmus ablation for treatment of atrial flutter using microwave energy. Microwave energy was delivered at 900–930 MHz using 21 W of power. Bidirectional cavotricuspid isthmus conduction block was achieved by microwave ablation without any patient discomfort or complication during the procedure. Our initial experience suggests that transcatheter microwave ablation is feasible for the cure of typical atrial flutter.  相似文献   
50.
Bradyarrhythmia requiring permanent pacing after heart transplantation remains a common problem. Sinus node dysfunction is the most common indication, and late onset of atrioventricular (AV) block has rarely been reported. We report the case of a patient who developed advanced AV block at 41 months after transplantation. Right bundle branch block with progressive increase of QRS complex duration was noted in serial electrocardiograms. At the time of late AV block development, the patient did not have acute rejection and coronary angiogram was normal. The mechanism of late onset of AV block is unclear, but it may be caused by progressive conduction.  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