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   1124篇
  免费   35篇
  国内免费   3篇
耳鼻咽喉   4篇
儿科学   15篇
妇产科学   9篇
基础医学   64篇
口腔科学   10篇
临床医学   89篇
内科学   134篇
皮肤病学   10篇
神经病学   141篇
特种医学   269篇
外科学   201篇
综合类   11篇
一般理论   1篇
预防医学   83篇
眼科学   7篇
药学   14篇
中国医学   1篇
肿瘤学   99篇
  2021年   6篇
  2019年   6篇
  2018年   12篇
  2017年   11篇
  2016年   12篇
  2015年   22篇
  2014年   36篇
  2013年   57篇
  2012年   58篇
  2011年   43篇
  2010年   39篇
  2009年   28篇
  2008年   43篇
  2007年   67篇
  2006年   74篇
  2005年   39篇
  2004年   35篇
  2003年   33篇
  2002年   21篇
  2001年   23篇
  2000年   33篇
  1999年   31篇
  1998年   23篇
  1997年   28篇
  1996年   16篇
  1995年   14篇
  1994年   18篇
  1993年   13篇
  1992年   14篇
  1991年   15篇
  1990年   10篇
  1989年   18篇
  1988年   30篇
  1987年   28篇
  1986年   22篇
  1985年   24篇
  1984年   7篇
  1983年   8篇
  1982年   8篇
  1979年   24篇
  1978年   16篇
  1977年   6篇
  1976年   6篇
  1975年   7篇
  1974年   6篇
  1970年   4篇
  1968年   4篇
  1967年   5篇
  1966年   6篇
  1964年   5篇
排序方式: 共有1162条查询结果,搜索用时 31 毫秒
61.
62.
Detrusor hyperreflexia long has been recognized as a condition associated with certain neurological disorders (that is multiple sclerosis, cerebrovascular accidents, spinal cord injuries and parkinsonism). Bladder outlet obstruction (primarily benign prostatic hypertrophy) recently has been added to the list. Hyperreflexia associated with bladder outlet obstruction does not always resolve with relief of the obstruction. Our study of age-matched female controls indicates that there is a baseline rate of hyperreflexia associated with the aging process alone. This baseline hyperreflexia probably explains persistent symptoms in men with hyperreflexia following relief of the obstruction.  相似文献   
63.
64.
Repeated neuropsychological assessments are common with older adults, and the determination of true neurocognitive change is important for diagnostic assessment. Several statistical formulas are available to assist in this determination, but they rely on access to test-retest stability coefficients and practice effect values. The current study presents data on these psychometric properties of the RBANS in a large community dwelling elderly sample. Across a one-year retest interval, stability coefficients ranged from .58 to .83 for the Index scores, and from .51 to .83 for the subtest scores. Practice effects were largely absent, with most performances slightly decreasing at retest. These psychometric properties are contrasted with those reported in the RBANS manual, and possible reasons for these differences are discussed. A case example is provided that demonstrates the use of the current findings in conjunction with existing change formulas.  相似文献   
65.
OBJECTIVE: The objective of this study was to improve delineation of small and large bowel (SB, LB) anatomy and pathology with postoperative or complex multisegmental inflammatory changes using dual-contrast-technique (DCT) for magnetic resonance enteroclysis (MRE) with luminal contrast media of opposed signal characteristics. MATERIALS AND METHODS: Sixty patients underwent MRE with iron oxide-based negative contrast in the SB. Thirty patients received additional rectal instillation of water for positive contrast (DCT). Two observers evaluated the degree of distention and the ease of identification of bowel anatomy and pathologies (none n=22, stenosis n=16, abscess n=4, fistulae n=5, postoperative changes and adhesions n=13) using a 4-point scale. Mann-Whitney U-test and kappa statistics were applied. RESULTS: LB and the terminal ileum were significantly better distended and identified with DCT (P相似文献   
66.
The purpose of this study was to integrate parallel acquisition techniques into a comprehensive whole-body cardiovascular screening protocol to image all relevant organ systems without compromising spatial or temporal resolution. The study was approved by the institutional review board, and oral and written informed consent was obtained from each subject. Fifty subjects underwent whole-body magnetic resonance imaging that included imaging of heart, blood vessels, brain, lungs, and abdominal organs with a standard eight-channel imager. Image quality and pathologic findings were evaluated by two readers. The same protocol was then implemented with a new 32-channel whole-body imager. Depiction of 1476 (73.2%) of 2016 vessel segments was rated as good to excellent, and that of 1744 (86.5%), as without venous overlay. Interobserver agreement was good in evaluation of image quality and excellent in evaluation of pathologic findings. Acquisition time was reduced significantly (P < .05) with use of the whole-body imager and parallel acquisition techniques, which provided high-quality fast cardiovascular imaging.  相似文献   
67.
PURPOSE: To compare high-resolution T2-weighted images of the liver with and without integrated parallel acquisition techniques (iPAT) using either breath-hold sequences in combination with prospective acquisition motion correction (PACE) or respiratory triggering. MATERIALS AND METHODS: Ten volunteers and 10 patients underwent each four different high-resolution fast spin echo (FSE) T2-weighted sequences with 5 mm slice thickness and a full 320 matrix: a multi-breath-hold FSE sequence with and without iPAT and PACE and a respiratory-triggered FSE sequence with and without iPAT. Image quality was rated with a five-point scale by two independent readers. Signal intensity measurements were performed on a water phantom. RESULTS: The sequences with iPAT required a substantially shorter acquisition time without loss of image quality. Overall image quality was rated equal for all sequences by both readers. Image time for nine slices with iPAT was 13 seconds (19 seconds without iPAT) with multi-breath-hold and on average 4:00 minutes (7:02 minutes without iPAT) with respiratory triggering. Imaging with the PACE technique resulted in more correct positioning of the image stacks. CONCLUSION: T2-weighted fast imaging with iPAT is feasible and results in high-quality images within a short acquisition time. Overall image quality is not negatively affected by iPAT.  相似文献   
68.
BACKGROUND: We sought to determine whether pancreas transplantation reduced the incidence of peripheral vascular complications in diabetics with renal insufficiency. METHODS: A retrospective single-center review was done of 36 kidney-pancreas (KP) and 88 kidney-alone (KA) recipients with a diagnosis of diabetes and end-stage renal disease (ESRD) transplanted between May 1997 and July 2002. Risk factors studied included type of transplant, age, gender, history of smoking, coronary artery disease, hypertension, and peripheral vascular disease (PVD). The endpoint was first peripheral vascular event occurring after transplantation, defined as either an amputation or revascularization procedure. RESULTS: The mean age of the cohort was 51 +/- 9 years, 64% of patients were of male gender, 20% with a history of smoking, 98% with hypertension, 15% with coronary artery disease (CAD), and 12% with a history of PVD. With a median follow-up of 45 months (12 to 79 months), 3/36 (8%) of KP recipients suffered a PVD complication, compared to 10/88 (11%) of KA recipients (P = NS). Similarly, age, gender, a past history of smoking, CAD, and hypertension were not predictive of PVD complications. Five of 15 patients (33%) with a pretransplant history of PVD suffered a postoperative PVD event compared to only 8 of 109 patients (7%) with no prior history of PVD (P =.008). CONCLUSIONS: Restoration of normoglycemia by pancreas transplantation did not reduce the risk of PVD complications in diabetics with renal failure. A pretransplant history of PVD was the only risk factor associated with posttransplant PVD events.  相似文献   
69.
BACKGROUND: A link between patient psychologic factors and bladder carcinoma outcome has not been demonstrated. The purpose of the current study was to assess the association of psychologic factors measured preoperatively with bladder carcinoma progression after cystectomy. METHODS: The Brief Symptom Inventory (BSI)-18 was administered prospectively to 65 patients with clinically localized bladder carcinoma before surgery. The BSI-18 measures distress in three specific domains-depression, anxiety, and somatization (i.e., distress due to somatic symptoms)-as well as general distress. Preoperative BSI-18 scores, tumor pathologic stage, and certain clinical variables were compared with disease status. Disease progression was defined as the development of either local disease recurrence or distant metastasis. Univariate and multivariate Cox proportional hazards models were constructed for statistical analysis. RESULTS: Of the 65 patients, 49 (79.4%) had no evidence of disease, 4 (6.2%) had local disease recurrence, and 12 (18.5%) had metastatic disease at last follow-up. The mean follow-up time was 1.3 years and did not differ significantly between survival outcomes (P = 0.577). Both tumor pathologic stage and preoperative somatic distress scores were associated with time to disease progression by univariate analysis (P = 0.038 and P = 0.055, respectively). After adjusting for tumor pathologic stage, a somatic distress score of > or = 2.00 was a significant predictor of disease progression (P = 0.044, hazard ratio = 3.31, 95% confidence interval = 1.03-10.60). Patient age, gender, reconstruction type, and BSI-18 scores for depression, anxiety, and general distress were not significantly associated with disease outcome. CONCLUSIONS: The authors found no correlation between psychologic symptoms measured preoperatively (i.e., depression, anxiety, and general distress) and bladder carcinoma progression. However, they reported an association between somatic symptoms and cancer outcome. If confirmed by other studies, these results may have important implications for the diagnosis, staging, and potential treatment of patients with bladder carcinoma.  相似文献   
70.
Data from the WAIS-III standardization sample (The Psychological Corporation, 1997) was used to generate VIQ and PIQ estimation formulae using demographic variables and current WAIS-III subtest performances. The sample (n = 2450) was randomly divided into two groups; the first was used to develop formulas and the second to validate the regression equations. Age, education, ethnicity, gender, region of the country as well as Vocabulary, Matrix Reasoning, and Picture Completion subtests raw scores were used as predictor variables. Prediction formulas were generated using a single verbal and two performance subtest algorithms. The VIQ OPIE-3 model combined Vocabulary raw scores with demographic variables. The PIQ estimation algorithm used Matrix Reasoning and Picture Completion raw scores with demographic variables. The formulas for estimating premorbid VIQ and PIQ were highly significant and accurate in estimation. Differences in estimated VIQ and PIQ scores were evaluated and the OPIE-3 algorithms were found to accurately predict VIQ and PIQ differences within the WAIS-III standardization sample.  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