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   1135篇
  免费   91篇
  国内免费   105篇
耳鼻咽喉   10篇
儿科学   39篇
妇产科学   6篇
基础医学   84篇
口腔科学   75篇
临床医学   196篇
内科学   148篇
皮肤病学   10篇
神经病学   60篇
特种医学   101篇
外科学   172篇
综合类   46篇
预防医学   48篇
眼科学   8篇
药学   74篇
中国医学   1篇
肿瘤学   253篇
  2021年   7篇
  2019年   15篇
  2018年   12篇
  2017年   14篇
  2016年   13篇
  2015年   18篇
  2014年   14篇
  2013年   41篇
  2012年   37篇
  2011年   33篇
  2010年   29篇
  2009年   26篇
  2008年   34篇
  2007年   93篇
  2006年   39篇
  2005年   46篇
  2004年   36篇
  2003年   43篇
  2002年   43篇
  2001年   33篇
  2000年   50篇
  1999年   33篇
  1998年   56篇
  1997年   49篇
  1996年   50篇
  1995年   31篇
  1994年   25篇
  1993年   22篇
  1992年   50篇
  1991年   44篇
  1990年   30篇
  1989年   32篇
  1988年   43篇
  1987年   29篇
  1986年   27篇
  1985年   12篇
  1984年   11篇
  1983年   12篇
  1982年   7篇
  1981年   11篇
  1980年   11篇
  1977年   7篇
  1976年   7篇
  1975年   5篇
  1973年   5篇
  1972年   6篇
  1971年   7篇
  1970年   5篇
  1969年   4篇
  1968年   4篇
排序方式: 共有1331条查询结果,搜索用时 11 毫秒
961.
The recycling perfusion of a fasted rat liver with an apoprotein E-enriched synthetic triglyceride emulsion revealed a significantly greater hepatic uptake of both the apoprotein and the triglyceride than did the liver of a chow-fed animal. This greater hepatic triglyceride uptake by the perfused fasted liver in comparison to the fed was also noted for emulsions containing no added apoprotein or supplemented with both the E and CIII-1 proteins. However, no difference in the uptake of the triglyceride emulsion was seen for the fed and fasted livers when evaluated by a nonrecycling single pass perfusion. The isolated hepatocyte plasma membranes from fasted rats failed to demonstrate enhanced binding of apoprotein or lipid when compared to those from fed animals. If the residual E loaded triglyceride emulsion was recovered from the recycling perfusates of fed and fasted livers and evaluated in a non-recycling single-pass system, the emulsion from the fasted perfusion was cleared as facilely as previously, whereas that from the fed was less actively cleared. The emulsions retrieved from the perfusion of the fed liver contained significantly more protein than did the fasted; in particular apo C. This apparent alteration of emulsion apoproteins by the fed liver possibly results in a less active hepatic retrieval and may be important in downregulating the entry of lipoprotein triglyceride in the postabsorptive liver.  相似文献   
962.
963.
The addition of apoprotein E isolated from human very low density lipoproteins to both rat lymph chylomicrons and a triglyceride emulsion significantly increased the hepatic uptake of these particles in a nonrecycling isolated rat liver perfusion system. The cleared triglyceride was removed without apparent hydrolysis by the hepatocyte. When lymph chylomicrons were loaded with both Apo E and Apo C proteins by exposure to rat plasma, no increment in hepatic clearance was observed. Sequential evalutions of the influence of the C apoproteins on the hepatic clearance of both emulsions and chylomicrons revealed that the CIII (CIII-1) protein had a pronounced inhibitory effect on hepatic removal. The inhibition was observed for both Apo E-enriched chylomicrons and those containing little of this apoprotein.  相似文献   
964.
965.
966.
The incidence of delayed breast abscess as a complication following the treatment of breast cancer has not been reported. A retrospective review of 112 patients (pts) undergoing lumpectomy and radiation therapy (RT) in our institution revealed a six per cent incidence of delayed breast abscess (range 1.5-8 months, median 5 months). Prophylactic antibiotics (P = 1.0), postoperative chemotherapy (P = 1.0), primary vs. re-excisional lumpectomy (P = 1.0), and different surgeons (P = 0.514) were not associated with increased risk of delayed abscess. All abscesses occurred in the first 32 pts of this series. The size of the lumpectomy cavity correlated with the incidence of infection (P = 0.0440). Since six of seven abscess cultures grew staphylococci (coagulase negative three pts, coagulase positive three pts), and four of these pts experienced prior biopsy site infection, skin necrosis or repeated seroma aspirations, a skin source for contamination was suggested. Treatment of the abscesses with antibiotics and immediate drainage produced acceptable but inferior cosmesis. We conclude that a small but significant subset of patients treated with lumpectomy and RT will develop delayed wound infections and that expeditious treatment affords satisfactory cosmesis.  相似文献   
967.
Incidental carcinoma of the prostate is a protean disease with a natural course which may be indolent or aggressive, with prognosis correlated with histologic grade and extent of disease. Treatment of this pathologic entity has varied over time and has been governed by institutional policy rather than randomized comparison of therapies. This report reviews the literature on incidental prostate cancer focusing on outcomes of patients as related to different therapeutic maneuvers. Observation alone with careful follow-up is appropriate therapy only for those patients with well differentiated disease of limited extent. Patients with diffuse or less differentiated disease required definitive therapy to prevent symptomatic progression. Hormonal manipulation alone has not been demonstrated to be of benefit. Radioactive implants have yielded poor disease-free survival. Radical prostatectomy by an experienced surgeon for patients with adequate health to tolerate the procedure has been associated with acceptable morbidity and excellent local control and survival. Radiation therapy has yielded similar excellent local control and survival and appears to be appropriate for a broader range of patients regardless of health or age.  相似文献   
968.
PURPOSE: To offer evidence-based clinical recommendations concerning prognosis in advanced cancer patients. METHODS: A Working Group of the Research Network of the European Association for Palliative Care identified clinically significant topics, reviewed the studies, and assigned the level of evidence. A formal meta-analysis was not feasible because of the heterogeneity of published studies and the lack of minimal standards in reporting results. A systematic electronic literature search within the main available medical literature databases was performed for each of the following four areas identified: clinical prediction of survival (CPS), biologic factors, clinical signs and symptoms and psychosocial variables, and prognostic scores. Only studies on patients with advanced cancer and survival < or = 90 days were included. RESULTS: A total of 38 studies were evaluated. Level A evidence-based recommendations of prognostic correlation could be formulated for CPS (albeit with a series of limitations of which clinicians must be aware) and prognostic scores. Recommendations on the use of other prognostic factors, such as performance status, symptoms associated with cancer anorexia-cachexia syndrome (weight loss, anorexia, dysphagia, and xerostomia), dyspnea, delirium, and some biologic factors (leukocytosis, lymphocytopenia, and C-reactive protein), reached level B. CONCLUSION: Prognostication of life expectancy is a significant clinical commitment for clinicians involved in oncology and palliative care. More accurate prognostication is feasible and can be achieved by combining clinical experience and evidence from the literature. Using and communicating prognostic information should be part of a multidisciplinary palliative care approach.  相似文献   
969.
Bile duct carcinoma. Diagnosis and treatment.   总被引:2,自引:0,他引:2       下载免费PDF全文
Fifty-three patients were evaluated for carcinoma of the extrahepatic bile ducts at the University of Virginia from 1951 to April 1984. This population was retrospectively reviewed and 33 preoperative and postoperative variables were analyzed to evaluate the predictors of increased survival. No preoperative data, including symptoms, admitting laboratory data, or tumor location, predicted increased survival. Whipple resection yielded a median survival of 12 months; palliative resections, 1.5 months; and laparotomy, only 5.5 months; these differences were not statistically significant. Experience with six patients treated with internal radiation (iridium-192), plus as much as 4000 rads of external beam irradiation, suggests that this combination of radiation treatment may aid palliation.  相似文献   
970.
RTOG 77-06 and 75-06 were studies of nodal irradiation in prostate cancer, for which the status of nodes was determined by lymph node dissection (LND), lymphangiography (LAG), or computer assisted tomography (CT) based on investigator preference. Actuarial 5 year endpoints of survival, NED survival, local recurrence and distant metastasis have been determined by stage for 805 eligible patients with a comparison of pathologic vs clinical (imaging test) determined nodal status. Patients with pathologically negative lymph nodes show significantly improved 5 year survival (Stage T-2 (B) 84% vs 77%, Stage T-3,4 (C) 82% vs 65%) and NED survival (Stage T-2 (B) 72% vs 63%, Stage T-3,4 (C) 64% vs 44%) compared to patients clinically negative. Free of metastasis rates are increased in Stage T-3,4 (C) pathologic negative patients compared to imaging negative patients (75% vs 60%). A comparison of clinical positive versus clinical negative patients shows no difference in survival, NED survival or rate of metastasis, while a similar comparison of pathologic positive versus pathologic negative shows significant difference for all three endpoints (survival: Stage T-2 (B) 84% vs 61%, Stage T-3,4 (C) 82% vs 66%, NED survival: Stage T-2 (B) 72% vs 32%, Stage T-3,4 (C) 64% vs 32%; free of metastasis: Stage T-2 (B) 82% vs 64%, Stage T-3,4 (C) 75% vs 44%). The clinical determination of nodal status, therefore, has no prognostic value in contrast to pathologic determination and should not be used for stratifying patients in clinical trials. The CT scans often used to evaluate nodal status are more useful if delayed until they can be done as part of the treatment planning process where the CT has value. When imaging tests suggest positive lymph nodes in prostate cancer patients, the imaging finding is confirmed by biopsy.  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