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   1181篇
  免费   112篇
  国内免费   38篇
耳鼻咽喉   8篇
儿科学   62篇
妇产科学   18篇
基础医学   172篇
口腔科学   6篇
临床医学   133篇
内科学   206篇
皮肤病学   3篇
神经病学   109篇
特种医学   127篇
外科学   246篇
综合类   23篇
一般理论   1篇
预防医学   80篇
眼科学   7篇
药学   61篇
中国医学   3篇
肿瘤学   66篇
  2021年   9篇
  2019年   10篇
  2018年   10篇
  2017年   8篇
  2016年   12篇
  2015年   14篇
  2014年   31篇
  2013年   40篇
  2012年   34篇
  2011年   49篇
  2010年   26篇
  2009年   32篇
  2008年   43篇
  2007年   69篇
  2006年   62篇
  2005年   46篇
  2004年   50篇
  2003年   39篇
  2002年   44篇
  2001年   38篇
  2000年   30篇
  1999年   25篇
  1998年   19篇
  1997年   16篇
  1996年   19篇
  1995年   23篇
  1994年   14篇
  1993年   16篇
  1992年   38篇
  1991年   32篇
  1990年   38篇
  1989年   35篇
  1988年   21篇
  1987年   32篇
  1986年   21篇
  1985年   26篇
  1984年   18篇
  1983年   14篇
  1982年   11篇
  1981年   20篇
  1979年   13篇
  1978年   18篇
  1977年   22篇
  1976年   8篇
  1975年   16篇
  1974年   17篇
  1973年   10篇
  1972年   13篇
  1969年   12篇
  1968年   9篇
排序方式: 共有1331条查询结果,搜索用时 15 毫秒
1.
Development, reliability, and validity of a dissociation scale   总被引:20,自引:0,他引:20  
Dissociation is a lack of the normal integration of thoughts, feelings, and experiences into the stream of consciousness and memory. Dissociation occurs to some degree in normal individuals and is thought to be more prevalent in persons with major mental illnesses. The Dissociative Experiences Scale (DES) has been developed to offer a means of reliably measuring dissociation in normal and clinical populations. Scale items were developed using clinical data and interviews, scales involving memory loss, and consultations with experts in dissociation. Pilot testing was performed to refine the wording and format of the scale. The scale is a 28-item self-report questionnaire. Subjects were asked to make slashes on 100-mm lines to indicate where they fall on a continuum for each question. In addition, demographic information (age, sex, occupation, and level of education) was collected so that the connection between these variables and scale scores could be examined. The mean of all item scores ranges from 0 to 100 and is called the DES score. The scale was administered to between 10 and 39 subjects in each of the following populations: normal adults, late adolescent college students, and persons suffering from alcoholism, agoraphobia, phobic-anxious disorders, posttraumatic stress disorder, schizophrenia, and multiple personality disorder. Reliability testing of the scale showed that the scale had good test-retest and good split-half reliability. Item-scale score correlations were all significant, indicating good internal consistency and construct validity. A Kruskal-Wallis test and post hoc comparisons of the scores of the eight populations provided evidence of the scale's criterion-referenced validity.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
2.
3.
Traumatic pseudoaneurysms of the superior mesenteric artery (SMA) are extremely rare. We describe two cases of posttraumatic proximal SMA pseudoaneurysms with symptoms of gastric outlet obstruction. Repair was accomplished by aorta-SMA bypass with saphenous vein. Injuries to the proximal SMA are easily missed at laparotomy, especially if intestinal ischemia or hematomas are absent. Recognition and repair are stressed to avoid the complications associated with pseudoaneurysm formation.  相似文献   
4.
FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease.  相似文献   
5.
Background. The optimal management of patients with renal cell carcinoma with inferior vena cava tumor thrombus remains unresolved. Traditional approaches have included resection with or without the use of cardiopulmonary bypass. Chemotherapy has played a minor role except for biotherapeutic agents used for metastatic disease.

Methods. From January 1989 to January 1996, 37 patients with renal cell carcinoma and inferior vena cava tumor thrombus underwent surgical resection. The 27 men and 10 women had a median age of 57 years (range, 29 to 78 years). Thirty-six patients presented with symptoms; 21 had hematuria. Distant metastases were present in 12 patients. Tumor thrombi extended to the infrahepatic inferior vena cava (n = 16), the intrahepatic inferior vena cava (n = 16), the suprahepatic inferior vena cava (n = 3), and into the right atrium (n = 2). All tumors were resected by inferior vena cava isolation and, when necessary, extended hepatic mobilization and Pringle maneuver, with primary or patch closure of the vena cavotomy. Cardiopulmonary bypass was necessary in only 2 patients with intraatrial thrombus.

Results. Complications occurred in 11 patients, and 1 patient died 2 days postoperatively of a myocardial infarction (mortality, 2.7%). Twenty patients are alive; overall 2- and 5-year survival rates were 61.7% and 33.6%, respectively. For patients without lymph node or distant metastases (stage IIIa), 2- and 5-year survival rates were 74% and 45%, respectively. The presence of distant metastatic disease (stage IV) at the time of operation did not have a significant adverse effect on survival, as reflected by 2- and 5-year survival rates of 62.5% and 31.3%, respectively. Lymph node metastases (stage IIIc) adversely affected survival as there were no long-term survivors.

Conclusions. Resection of an intracaval tumor thrombus arising from renal cell carcinoma can be performed safely and can result in prolonged survival even in the presence of metastatic disease. In our experience, extracorporeal circulatory support was required only when the tumor thrombus extended into the heart.  相似文献   

6.
7.
The management of patients through the use of evidence-based medicine has become the 'mantra' of medicine within many Western countries. Evidence-based medicine is aimed at providing the best objective, scientific care to all patients, and reducing as far as possible patients' risks of disease and complications from disease. Based on family physicians' discussions of the use of evidence-based recommendations for two cardiac diseases, this paper explores how subjectively-based trust enters into family physicians' decision to use evidence-based medicine. In addition, we show how trust influences physicians' work of recommending evidence-based medicine to patients, and physicians' perceptions of why patients follow recommendations aimed at risk reduction. We conclude that although much of the current discussion about evidence-based medicine assumes a 'rational' model of physician behaviour based on the application of the 'best objective scientific' results, subjectively-based perceptions of trust influence physician practices, and point to the need to understand the power of relational issues in influencing physician practices even when utilizing evidence-based knowledge.  相似文献   
8.
Prior studies have shown that pneumothorax is one of the more difficult entities to diagnose with digitized radiography. This study was designed to test whether increasing resolution from 1.25 to 2.5 line pairs per millimeter (lp/mm) and image processing (edge enhancement from unsharp masking) would increase accuracy and confidence in the diagnosis of pneumothorax, as well as normal cases and other forms of lung disease. Conventional radiographs were digitized with use of a laser reader and then reformatted as film hard copy. Eleven observers read 35 cases reformatted in three different ways (1.25 lp/mm, 2.5 lp/mm, 1.25 lp/mm unsharp mask). The images with finer resolution (2.5 lp/mm) and unsharp mask images were superior to those with coarser resolution (1.25 lp/mm) for the diagnosis of pneumothorax. There was no difference in diagnostic accuracy for normal patients. For abnormalities other than pneumothorax, the unsharp mask images were significantly worse. Confidence in the diagnosis of pneumothorax and other abnormalities was highest with the finest resolution (2.5 lp/mm).  相似文献   
9.
ALG raised against lymphoblasts grown in pure culture for many generations contained antiplatelet activity. The thromboagglutinins could be completely removed by absorption with lymphoblasts, indicating that they had been raised to antigens shared by lymphoblasts and platelets. Anti-spleen ALG possessed levels of such anti-platelet antibodies but in substantially higher titres, because an additional contribution was made by contaminating thrombocytes in the immunizing injectate. By chromatographic separation and immunoelectrophoretic analysis of the eluate from platelet–antibody complexes generated during the absorption of anti-spleen ALG with thrombocytes, the thromboagglutinins were shown to reside almost exclusively (97·7%) in the area of the IgA fraction. The direct Coombs' test, reacting platelets from patients receiving equine anti-spleen ALG with guinea-pig antisera against normal horse serum, showed a highly significant, but not invariable correlation with clinical platelet depression, which was not, however, clearly related to the thromboagglutinin titre of the ALG being administered.  相似文献   
10.
A quantitative competitive PCR (QC-PCR) assay for Epstein-Barr virus (EBV) has been developed to provide accurate measurement of EBV genome load in pediatric transplant recipients at risk for developing posttransplant lymphoproliferative disorder (PTLD). The assay quantifies between 8 and 5,000 copies of the EBV genome in 10(5) lymphocytes after a 30-cycle amplification reaction. For 14 pediatric patients diagnosed with PTLD, the median EBV genome load was 4,000, and 13 of the 14 patients had values of >500 copies per 10(5) lymphocytes. Only 3 of 12 control transplant recipients not diagnosed with PTLD had detectable viral genome loads (median value, 40). This median was calculated by using the highest value obtained by PCR testing on each of these patients posttransplantation. PCR values of >500 copies per 10(5) lymphocytes appear to correlate with a diagnosis of PTLD. By a modified protocol, the EBV genome copy number in latently infected adults was estimated to be <0.1 copy per 10(5) lymphocytes.  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