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   1687篇
  免费   114篇
  国内免费   25篇
耳鼻咽喉   3篇
儿科学   129篇
妇产科学   18篇
基础医学   175篇
口腔科学   17篇
临床医学   139篇
内科学   345篇
皮肤病学   20篇
神经病学   91篇
特种医学   337篇
外科学   103篇
综合类   35篇
预防医学   156篇
眼科学   35篇
药学   82篇
中国医学   1篇
肿瘤学   140篇
  2021年   20篇
  2019年   16篇
  2018年   23篇
  2017年   19篇
  2016年   12篇
  2015年   17篇
  2014年   22篇
  2013年   37篇
  2012年   33篇
  2011年   49篇
  2010年   25篇
  2009年   32篇
  2008年   43篇
  2007年   59篇
  2006年   39篇
  2005年   54篇
  2004年   44篇
  2003年   49篇
  2002年   56篇
  2001年   43篇
  2000年   43篇
  1999年   36篇
  1998年   64篇
  1997年   56篇
  1996年   77篇
  1995年   55篇
  1994年   42篇
  1993年   49篇
  1992年   29篇
  1991年   26篇
  1990年   32篇
  1989年   54篇
  1988年   50篇
  1987年   49篇
  1986年   47篇
  1985年   59篇
  1984年   30篇
  1983年   31篇
  1982年   36篇
  1981年   27篇
  1980年   16篇
  1979年   11篇
  1978年   11篇
  1977年   34篇
  1976年   22篇
  1975年   20篇
  1974年   11篇
  1971年   10篇
  1970年   16篇
  1969年   15篇
排序方式: 共有1826条查询结果,搜索用时 9 毫秒
1.
Changing attentional demands in left hemispatial neglect.   总被引:1,自引:0,他引:1  
Seven variations of a letter cancellation test were used to examine how varying attentional demands affect hemispatial neglect in patients with right hemisphere lesions. While the 14 targets always remained in the same location, the number of distractors (zero, nine, 28, or 82) as well as their complexity (one letter or nine different letters) were varied. The percentage of targets canceled in the left hemispace was linearly related to the number of distractors. There were no differences between the complexity conditions. In a second study, the same 14 targets were presented but the distractors (zero, 14, or 41) were all placed on the right. Increasing the number of distractors on the right increased neglect on both sides of the space. Taken together, these results suggest that, while the limited attentional resources of the left hemisphere are biased toward the right hemispace, the absence of contralateral attentional demands allows these resources to be directed ipsilaterally.  相似文献   
2.
The Childrens Cancer Study Group has assessed serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and pubertal development in 97 long-term female survivors of childhood acute lymphoblastic leukemia (ALL). All patients received identical induction and maintenance therapy with either 18 or 24 Gy of radiation therapy (RT) to one of the following fields: cranial, craniospinal, or craniospinal plus 12 Gy abdominal RT including the ovaries. Thirty-six percent (35 patients) were found to have above normal levels of FSH and/or LH. The percentages of elevated values for RT fields were 93% for craniospinal plus abdominal RT, 49% for craniospinal RT, and 9% for cranial RT (P less than .001). A dose-response relationship was observed between 18 Gy and 24 Gy in females receiving only craniospinal RT (P = .01). Craniospinal plus abdominal RT and abnormal FSH/LH levels were significantly associated with lack of pubertal development and delayed onset of menses. Duration of maintenance chemotherapy was not associated with abnormal gonadotropin levels or the development of secondary sexual characteristics. Additional follow-up of this cohort is needed to establish the ultimate pubertal development and fertility of these patients.  相似文献   
3.
4.
To determine the appropriate role of surgical intervention in non-Hodgkin's lymphoma primary to the abdomen, we analyzed the effect of multiple prognostic determinants on event-free survival for patients entered into the CCG-551 study. Eighty-four patients were identified with abdominal lymphoma and of these adequate data for analysis was available on 68 (81%). Variables of interest included: extent of disease at diagnosis, completeness of resection, use of bowel resection, radiation to the primary site, and sex/age/race. The median age on study was 8 years; 79% of patients were white and 85% were male. Thirty-three patients (49%) presented with localized disease. Laparotomy was performed in 67 children (99%) with complete gross resection in 28 (42%). Of the 10 reported surgical complications, 8 occurred in those with extensive disease who were incompletely resected. Radiation to the primary site was given in 60% of patients with median dose of 2,000 cGy. Analysis was performed both for the overall group and for the subgroup receiving optimal chemotherapy for histopathology. Variables with significant predictive effect on event-free survival in univariate analysis included extent of disease (P less than or equal to .001), complete resection (P less than or equal to .002), and use of bowel resection (P less than or equal to .004). However, in multivariate analysis, only extent of disease was an independent predictor of outcome. The data support a role for complete operative excision of localized lymphomas especially when accomplished with bowel resection. Aggressive attempts at debulking extensive retroperitoneal or mesenteric lymphomas are contraindicated.  相似文献   
5.
6.
P A Nathan  R C Keniston  L D Myers  K D Meadows 《JAMA》1992,268(6):787; author reply 787-787; author reply 780
  相似文献   
7.
8.
OBJECTIVE: The aim was to establish the potential efficacy, tolerabilityand side-effect profile of electromagnetic therapy as an adjunctto conventional dressings in the treatment of venous leg ulcers. METHOD: A prospective, randomized, double blind controlled clinicaltrial was carried out in a dedicated leg ulcer clinic basedin one urban general practice. Nineteen patients with leg ulcersof confirmed venous aetiology were assessed. The main outcomemeasures were rate and scale of venous leg ulcer healing, changesin patient-reported pain levels, quality of life, degree ofmobility, side effect profile and acceptability to patientsand staff. RESULTS: Sixty-eight per cent of patients attending this dedicated clinicachieved improvements in the size of their ulcer (4, 21%, healedfully) and in reduced pain levels (P < 0.05) during the trial,despite the chronicity of ulcer histories. Patients treatedwith electromagnetic therapy at 800 Hz were found at day 50to have significantly greater healing (P < 0.05) and paincontrol (P < 0.05) than placebo therapy or treatment with600 Hz. All patients reported improved mobility at the end ofthe study. The electromagnetic therapy was well tolerated bypatients, with no differences between groups in reporting adverseevents, and proved acceptable to staff. CONCLUSION: Despite the small numbers in this pilot study, electromagnetictherapy provided significant gains in the healing of venousleg ulcers and reduction in pain. Keywords. Electromagnetic therapy, RCT, leg ulcers, primary care.  相似文献   
9.
Bile duct calculi in patients with primary sclerosing cholangitis   总被引:1,自引:0,他引:1  
  相似文献   
10.
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