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   1838篇
  免费   128篇
  国内免费   63篇
耳鼻咽喉   28篇
儿科学   99篇
妇产科学   21篇
基础医学   157篇
口腔科学   20篇
临床医学   356篇
内科学   393篇
皮肤病学   21篇
神经病学   150篇
特种医学   318篇
外国民族医学   1篇
外科学   182篇
综合类   51篇
一般理论   1篇
预防医学   67篇
眼科学   51篇
药学   58篇
中国医学   3篇
肿瘤学   52篇
  2021年   15篇
  2019年   14篇
  2018年   30篇
  2017年   14篇
  2016年   13篇
  2015年   30篇
  2014年   20篇
  2013年   85篇
  2012年   45篇
  2011年   54篇
  2010年   44篇
  2009年   36篇
  2008年   49篇
  2007年   73篇
  2006年   47篇
  2005年   55篇
  2004年   43篇
  2003年   34篇
  2002年   42篇
  2001年   33篇
  2000年   30篇
  1999年   42篇
  1998年   62篇
  1997年   40篇
  1996年   65篇
  1995年   50篇
  1994年   48篇
  1993年   64篇
  1992年   51篇
  1991年   43篇
  1990年   41篇
  1989年   58篇
  1988年   75篇
  1987年   72篇
  1986年   46篇
  1985年   56篇
  1984年   37篇
  1983年   34篇
  1982年   14篇
  1981年   42篇
  1980年   29篇
  1979年   25篇
  1978年   24篇
  1977年   26篇
  1976年   22篇
  1975年   27篇
  1974年   20篇
  1972年   16篇
  1971年   14篇
  1970年   13篇
排序方式: 共有2029条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
In a randomized, double-masked study, 41 patients with primary open-angle glaucoma or ocular hypertension were treated with betaxolol 0.5% or timolol 0.5% drops for 26 weeks. The average decrease in intraocular pressure (IOP) over the total study period was significant with both betaxolol (-6.3 mmHg) and timolol (-7.2 mmHg) in patients receiving no adjunctive therapy. There was no difference between betaxolol and timolol with respect to changes from baseline IOP. Significantly decreased mean brachial arterial pressure (MAP) was seen only with timolol, although the difference between the two groups was not significant. Pulse, pupil size, and basal tear secretion were unchanged in both groups. Burning upon instillation of the drops was more frequent with betaxolol.  相似文献   
5.
6.
7.
The records of 95 consecutive children less than or equal to 21 years of age with previously untreated diffuse histology NHL registered in our protocols from 1978 to 1983 were reviewed. Seventy-nine patients were considered eligible for analysis. The histologic subtypes represented included lymphoblastic (LB) 37%; histiocytic (DHL) 29%; undifferentiated (DU) 19%; poorly differentiated (DPDL) 9%; and unclassified (UNHL) 6%. Distribution of the patients according to stage showed Stage I, 0%; Stage II, 11%; Stage III, 53%; Stage IV, 36%. Four different Memorial Hospital protocols for systemic chemotherapy were used (LSA2L2 73%; L10 9%; L17 10%; L17M 8%); however, the IT (intrathecal) chemotherapy was uniform (Methotrexate: 6.0-6.25 mg/M2 per treatment course) and was included in the induction, consolidation, and maintenance phases of all treatment protocols. Cranial radiation was included in the induction, consolidation, and maintenance phases of all treatment protocols. Cranial radiation was not included in the CNS prophylaxis program. The overall median time of follow-up was 43 months. The overall CNS relapse rate was 6.3%, however, the incidence of CNS lymphoma presenting as the first isolated site of relapse in patients in otherwise complete remission (minimum follow-up of 19 months with 97% of patients off treatment) was only 1/58 (1.7%). Our data suggests that IT chemotherapy when given in combination with modern aggressive systemic combination chemotherapy, and without cranial radiation appears to be a highly effective modality for CNS prophylaxis regardless of stage, histology, or bone marrow or mediastinal involvement. Therefore, with the commonly used aggressive combination chemotherapy for the management of all stage diffuse pediatric NHL, and the known increased risk of leukoencephalopathy with combination of cranial radiation and intensive systemic and intrathecal chemotherapy, we believe that cranial radiation may not be indicated for CNS prophylaxis in pediatric NHL.  相似文献   
8.
9.
Inversion recovery (IR), commonly considered a pulse sequence capable of producing T1-weighted images with excellent display of normal anatomy, is versatile: The null point and peak time provide a useful, succinct summary of the properties of IR and its capacity for producing both T1- and T2-weighted images. Shortening of the inversion time (TI) and creation of a short-TI inversion-recovery (STIR) pulse sequence increases sensitivity to malignancy and other abnormalities by making the effects of prolonged T1 and T2 on signal intensity additive and by nulling the signal from fat. The authors examined over 300 patients with various malignancies and compared STIR images with T1- and T2-weighted images obtained at 0.5 T. In 43 cases, signal-difference-to-noise ratios (SD/Ns) were calculated between tumor, fat, and muscle. In general, STIR images demonstrated tumor as a conspicuously high-intensity area in a background of muted, discernible anatomic detail. The good contrast achieved with STIR sequences between tumor and fat (SD/N = 18.1) and tumor and muscle (SD/N = 12.9) consolidated into a single image the information contained separately on T1- and T2-weighted images, which facilitates efficient detection and localization of malignancy.  相似文献   
10.
Goei  R; Baeten  C; Arends  JW 《Radiology》1988,168(2):303-306
Sixteen cases of histopathologically proved solitary rectal ulcer syndrome were encountered. Fifteen patients underwent barium enema study; in nine cases the findings--including rectal stricture, granularity of the mucosa, and thickened rectal folds-were nonspecific. In six cases the study was normal. All patients had a long history of defecation disorders, and defecography was performed in all. In seven cases, intussusception of the rectal wall was seen; in another case the intussusception was accompanied by a rectocele. One case showed rectal prolapse. In four cases, failed relaxation of the puborectalis occurred and prevented the passage of the bolus; in another case there was abnormal perineal descent. In two patients studies were normal. In patients with defecation disorders, the possibility of this syndrome should be considered. Defecography is the method of choice for establishing the diagnosis.  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