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   8123篇
  免费   439篇
  国内免费   78篇
耳鼻咽喉   54篇
儿科学   186篇
妇产科学   646篇
基础医学   917篇
口腔科学   123篇
临床医学   917篇
内科学   1677篇
皮肤病学   79篇
神经病学   527篇
特种医学   258篇
外科学   1073篇
综合类   187篇
预防医学   428篇
眼科学   72篇
药学   596篇
  1篇
中国医学   115篇
肿瘤学   784篇
  2024年   29篇
  2023年   47篇
  2022年   103篇
  2021年   184篇
  2020年   99篇
  2019年   145篇
  2018年   245篇
  2017年   169篇
  2016年   158篇
  2015年   208篇
  2014年   245篇
  2013年   383篇
  2012年   573篇
  2011年   589篇
  2010年   375篇
  2009年   322篇
  2008年   499篇
  2007年   544篇
  2006年   539篇
  2005年   437篇
  2004年   383篇
  2003年   327篇
  2002年   316篇
  2001年   274篇
  2000年   272篇
  1999年   204篇
  1998年   59篇
  1997年   63篇
  1996年   61篇
  1995年   34篇
  1994年   47篇
  1993年   27篇
  1992年   130篇
  1991年   92篇
  1990年   67篇
  1989年   46篇
  1988年   51篇
  1987年   46篇
  1986年   48篇
  1985年   29篇
  1984年   35篇
  1983年   11篇
  1982年   9篇
  1981年   14篇
  1979年   16篇
  1977年   7篇
  1976年   7篇
  1973年   7篇
  1972年   7篇
  1971年   10篇
排序方式: 共有8640条查询结果,搜索用时 15 毫秒
121.
122.
123.
124.
125.
Superior mesenteric venous thrombosis (SMVT) is an uncommon but potentially life-threatening disorder. We describe a cirrhotic patient with hepatocellular carcinoma who had partial SMVT for at least 28 months. Our experience may help in the management of such patients. The partial SMVT was not treated at the time of discovery because there was no evidence of bowel infarction. Moreover, the patient had a tendency to bleed severely and was in a poor condition. SMVT was followed using regular ultrasonography and the pattern of SMVT did not change significantly during the follow-up period. A symptom that may have been related to SMVT was abdominal colic pain after meals, which was sometimes followed by diarrhea and / or nausea and vomiting. There was no evidence of bowel ischemia or infarction during follow-up. Abdominal discomfort can be successfully treated using anticholinergic drugs with or without analgesia.  相似文献   
126.
OBJECTIVE: In utero hematopoietic cell transplantation (IUHCT) typically achieves low-level mixed hematopoietic chimerism. However, the goal of IUHCT is to achieve therapeutic levels of chimerism. We hypothesized that prenatal adoptive immunotherapy might achieve high-level donor chimerism after IUHCT. MATERIALS AND METHODS: BALB/CE15 fetal mice were transplanted with a mixture of C57BL/6 (B6) T-cell-depleted bone marrow (TCD BM) cells and splenocytes from B6 mice presensitized to BALB/C alloantigen. The splenocytes were preincubated in L-leucyl-L-leucine methyl ester (LLME), to minimize graft vs host disease (GVHD). Recipients were followed after birth for donor cell chimerism and GVHD. RESULTS: Full donor hematopoietic chimerism following a single prenatal transplant was achieved in seven transplanted animals. Fully chimeric animals were healthy, without evidence of GVHD, and maintained their engraftment for the duration of the study (48 weeks). However, the addition of presensitized LLME-treated cells decreased survival until weaning relative to TCD BM alone, suggesting that some animals were lost to acute GVHD. Surviving chimeric animals demonstrated increased frequencies of T-regulatory cell populations in their spleen and BM, suggesting that they had successfully suppressed GVHD, allowing survival. CONCLUSIONS: This study represents "proof in principle" that prenatal immunotherapeutic strategies may achieve complete hematopoietic engraftment across full MHC barriers when combined with IUHCT. However, strategies with greater hematopoietic specificity must be developed prior to consideration of clinical application.  相似文献   
127.
128.
129.
BACKGROUND/AIMS: Central vein catheters for patients receiving total parenteral nutrition have a high incidence of colonized catheters and catheter-related bloodstream infections. However, the actual incidence and bacterial pattern have not been well studied. This study was undertaken to investigate the difference in bacteriology between colonized catheters and catheter-related bloodstream infections. METHODOLOGY: From January 1997 to March 1998, 354 patients receiving total parenteral nutrition were included in this study. The patients ranged in age from 49 to 80 years, 151 women and 203 men. Colonized catheters and catheter-related bloodstream infections were defined. RESULTS: The culture was performed in 249 catheter tips (249 of 614, 40.6%). Sixty tips were found to have organisms. The organisms cultured from colonized catheters were Gram(+) aerobic bacteria (34, 56.7%), fungi (14, 23.3%), and Gram(-) aerobic bacteria (12, 20%). The organisms cultured from catheter-related bloodstream infections were fungi (16, 64%), Gram(-) aerobic bacteria (5, 20%), and Gram(+) aerobic bacteria (4, 16%). Dermatogenic infection in colonized catheters should be stressed, but systemic fungal infection in catheter-related bloodstream infections should be emphasized. CONCLUSIONS: A striking difference exists in bacterial species between colonized catheters and catheter-related bloodstream infections. Further studies on different treatment strategy for colonized catheters and catheter-related bloodstream infections should be undertaken. The combined approach of a total parenteral nutrition team, sterile protocols, and early diagnosis of fungemia should be advocated for the total parenteral nutrition patients.  相似文献   
130.
BACKGROUND: In the Dukes' B and C stages of colorectal carcinoma there are considerable variations in the observed courses of the disease. Since post-operative chemotherapy in patients with Dukes' C (node-positive) colon carcinoma has been demonstrated to be effective in improving overall-survival, a more exact prognosis assessment gains additional significance and therapeutic relevance. DISCUSSION: One also hopes to derive improved prognostic factors from the clarification of the molecular pathogenesis. Because of its frequency and the accessibility and recognizability of its developmental stages colorectal carcinoma is among the best investigated of all solid tumors. Despite a multitude of suggested molecular candidate markers none of these changes has yet been able enter the everyday life of the clinic. However, it is to be expected that some of the molecular alterations presently discussed will gain importance before long in the clinical treatment of patients with colorectal carcinoma. CONCLUSION: Considering also our own findings, this review presents the latest developments in the scientific discussion of the tumor suppressor/oncogenes p53, k-ras, and DCC, biochemical determinants of the 5-fluorouracil metabolism, and defects of the DNA repair system.  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