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   2409篇
  免费   173篇
  国内免费   17篇
耳鼻咽喉   20篇
儿科学   85篇
妇产科学   66篇
基础医学   278篇
口腔科学   46篇
临床医学   274篇
内科学   516篇
皮肤病学   80篇
神经病学   155篇
特种医学   52篇
外科学   272篇
综合类   12篇
预防医学   221篇
眼科学   49篇
药学   158篇
中国医学   26篇
肿瘤学   289篇
  2023年   31篇
  2022年   58篇
  2021年   170篇
  2020年   75篇
  2019年   146篇
  2018年   131篇
  2017年   85篇
  2016年   88篇
  2015年   82篇
  2014年   120篇
  2013年   111篇
  2012年   170篇
  2011年   170篇
  2010年   107篇
  2009年   77篇
  2008年   125篇
  2007年   108篇
  2006年   100篇
  2005年   94篇
  2004年   80篇
  2003年   86篇
  2002年   86篇
  2001年   33篇
  2000年   41篇
  1999年   28篇
  1998年   12篇
  1997年   18篇
  1996年   10篇
  1995年   10篇
  1994年   9篇
  1993年   4篇
  1992年   14篇
  1991年   11篇
  1990年   16篇
  1989年   14篇
  1988年   6篇
  1987年   14篇
  1986年   6篇
  1985年   4篇
  1984年   5篇
  1982年   5篇
  1981年   4篇
  1979年   5篇
  1978年   4篇
  1977年   3篇
  1976年   4篇
  1972年   2篇
  1969年   2篇
  1966年   2篇
  1965年   2篇
排序方式: 共有2599条查询结果,搜索用时 15 毫秒
21.
The management tool of benchmarking, widely used in industry for more than a decade, is today being adapted for health care organizations. Hospitals and other health care providers are developing ways to compare their practices, processes, and resulting outcomes with other organizations in order to discover "best practices." This article describes a team approach to health care benchmarking and details several projects being conducted by hospitals in The SunHealth Alliance. The examples include benchmarking for both operational and clinical processes.  相似文献   
22.
BACKGROUND: The purpose of this study is that of assessing the validity of the computerized diagnoses of hospital discharges of congenital defects by comparing them with the information included in the medical history. METHODS: Based on the discharge records generated over a one-year period at 7 hospitals in the Autonomous Region of Valencia, 100 children were selected at random from each hospital. As a standard, the diagnoses stated in the medical histories were indexed and coded. Solely those discharges having taken place during the first year of life were considered. A study was also made of the type, seriousness and individual or combinations of congenital defects. A calculation was made of the sensitivity, specificity, predictive values and the 95% confidence intervals thereof by the exact binomial method for the case studies (children) and the positive predictive value and sensitivity for the study of diagnoses. RESULTS: 126 children were detected as having congenital defects, and 201 diagnoses in medical records, and 83 children with congenital defects and 108 diagnoses on record. For the detection of cases, the records showed a 64% sensitivity, a 99.1% specificity and some positive and negative predictive values of over 90%. With regard to the detection of diagnoses, the sensitivity was 46% and the positive predictive value 83%. The sensitivity varied a great deal depending upon the diagnoses. CONCLUSIONS: The hospital discharge records revealed a high degree of specificity and high predictive values, but a low degree of sensitivity. These facts must be considered when these records are used as a source of cases for the epidemiological studies of congenital defects.  相似文献   
23.
24.
Presentation of one case of scrotal hernia in a man of 64 years old patient. Diagnosed by cistography and ultrasound and treated by herniorraphy and posterior transuretral litolaplaxy of a vesical litiasis and RTU of prostate. Postoperative urography showed normal vesical morphology.  相似文献   
25.
Lower urinary tract obstruction in women is an uncommon condition resulting from multiple either organic or functional disorders. This paper contributes one case of obstructive uropathy secondary to presence of almost complete vulvar synechia due to extreme genital atrophy, a rare entity that may appear in postmenopausal women. Partial and incomplete vulvar fusion usually occurs in significant postmenopausal atrophies, sometimes associated to urethral meatus stricture; this, however, has no significant repercussion on urination dynamics. No other comparable case was found in the reviewed literature.  相似文献   
26.
We performed this case–control study to evaluate the risk of hypoglycemia associated with the use of antihypertensive drugs in older hospitalized diabetic patients treated with sulfonylureas and/or insulin. All diabetic patients admitted during 4 months in 1988, 1 month in 1991, 4 months in 1993 and 4 months in 1995 (n = 3477, mean age 71.4 ± 0.2 years, 1542 males and 1935 females) were enrolled in the study. During the four annual surveys 86 patients (mean age 71.1 ± 1.4 years, 33 males and 53 females) presented hypoglycemia during hospital stay. The patients who presented hypoglycemia were less frequently users of sulfonylureas and more frequently users of a combination of insulin and sulfonylureas. Use of antihypertensive drugs was similar in the two groups studied, and among potentially interacting drugs considered in the analysis, sulfonamides were more frequently used in patients who experienced hypoglycemia. Moreover, patients with hypoglycemia used a higher number of drugs, had a longer length of stay and had a greater prevalence of hypoglycemia as admission problem. Finally, although not significant, liver and renal diseases were more frequent among patients with hypoglycemia. In the multivariate analysis, contemporary use of insulin and sulfonylureas, liver disease and length of stay were significantly associated with hypoglycemia, while none of the antihypertensive drugs showed a significant association with the occurrence of hypoglycemia during hospital stay. Our results indicate that antihypertensive drugs do not increase the risk of hypoglycemia in elderly diabetic patients.  相似文献   
27.
Advanced stage ovarian cancer has a high rate of recurrence even after surgery followed by chemotherapy combining carboplatin and a taxane. New strategies are currently under way to combat this situation and one of the most promising ones is based on the knowledge that angiogenesis, the mechanism of formation of new blood vessels coupled with the degradation of the extracellular matrix for metalloproteinases, could be crucial in the development of this tumor. The principal molecule implicated in angiogenesis process of ovarian cancer is the vascular endothelial growth factor (VEGF). Several studies are now in progress to clarify its role as a diagnostic tool or its therapeutic implication. Presently, there is no indication for the use of VEGF in a preliminary diagnosis seeing that an increase in levels can be seen in both benign and malignant ovarian conditions. VEGF is also responsible for an increase in vascular permeability and is directly related to symptoms such as ascites and pleural effusion, both of which are frequent in ovarian cancer. Several papers have analised the role of VEGF as a prognostic factor and some of them do confirm VEGF as an independent prognostic factor in ovarian cancer. VEGF and the metalloproteinase system coupled with angiogenesis are currently being evaluated as therapeutic targets but no positive results have yet to be seen in this field.   相似文献   
28.
Loss of beta-catenin expression in metastatic gastric cancer.   总被引:10,自引:0,他引:10  
PURPOSE: Beta-catenin (beta-catenin) participates in intercellular adhesion and is an integral part of the Wnt signaling pathway. The role of beta-catenin in the pathogenesis of gastric cancer and its metastasis is largely unknown. PATIENTS AND METHODS: Immunohistochemistry and Western blot analysis were used to analyze the expression of beta-catenin in 87 human gastric cancers, in metastasis and cancer cell lines. The beta-catenin and the adenomatous polyposis coli (APC) genes were analyzed for gene mutations. Furthermore, methylation of the beta-catenin promoter in cell lines was assessed by treatment with 5'-azadeoxycytidine and sodium bisulfite genomic sequencing. RESULTS: beta-Catenin expression was present at either the cell membrane or the cytoplasm in 34 of 75 primary gastric cancers. Expression of beta-catenin was significantly more frequent in intestinal-type (P =.0049) and well-differentiated gastric cancers (P <.001). There were no quantitative differences between gastric cancers and the nonmalignant gastric tissues, as determined by Western blot analysis. One of 18 metastatic cancer lesions and four of five gastric cancer cell lines expressed beta-catenin protein. N87 cells, derived from the liver metastasis of a gastric cancer, did not express beta-catenin. Treatment with 5'-azadeoxycytidine restored beta-catenin protein levels in this cell line, which exhibited significantly more 5-methylcytosines in the beta-catenin promoter compared with the other cell lines. CONCLUSION: beta-Catenin expression is lost in a subgroup of primary gastric cancers, is frequently absent in metastases, and exhibits nuclear localization in cancers with either beta-catenin or APC gene mutations. Interestingly, the loss of beta-catenin expression in metastatic gastric cancers may result from hypermethylation of the beta-catenin promoter.  相似文献   
29.
30.
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