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   9068篇
  免费   418篇
  国内免费   82篇
耳鼻咽喉   58篇
儿科学   258篇
妇产科学   141篇
基础医学   1107篇
口腔科学   259篇
临床医学   488篇
内科学   2718篇
皮肤病学   107篇
神经病学   670篇
特种医学   481篇
外科学   1403篇
综合类   24篇
预防医学   149篇
眼科学   99篇
药学   505篇
中国医学   19篇
肿瘤学   1082篇
  2023年   63篇
  2022年   127篇
  2021年   207篇
  2020年   118篇
  2019年   182篇
  2018年   203篇
  2017年   181篇
  2016年   237篇
  2015年   206篇
  2014年   313篇
  2013年   354篇
  2012年   540篇
  2011年   593篇
  2010年   373篇
  2009年   304篇
  2008年   508篇
  2007年   541篇
  2006年   527篇
  2005年   602篇
  2004年   568篇
  2003年   516篇
  2002年   513篇
  2001年   150篇
  2000年   143篇
  1999年   160篇
  1998年   117篇
  1997年   84篇
  1996年   77篇
  1995年   67篇
  1994年   62篇
  1993年   53篇
  1992年   85篇
  1991年   74篇
  1990年   87篇
  1989年   102篇
  1988年   76篇
  1987年   60篇
  1986年   46篇
  1985年   39篇
  1984年   34篇
  1983年   29篇
  1982年   32篇
  1981年   19篇
  1980年   16篇
  1979年   20篇
  1978年   22篇
  1977年   24篇
  1974年   16篇
  1973年   14篇
  1966年   11篇
排序方式: 共有9568条查询结果,搜索用时 15 毫秒
51.
A phase I study ofN 4-behenoyl-1-β-d-arabinofuranosylcytosine (BHAC) was conducted in 66 patients, 41 with solid tumors and 25 with hematological malignancies. The patients received either a 2-h single intravenous (i.v.) drip infusion (Schedule 1) or consecutive daily 2-h i.v. infusions (Schedule 2). In Schedule 1 the daily dose was initiated with 1.5 mg kg?1 which was escalated up to 7 mg kg?1. Side-effects were mild, and included nausea, vomiting, epilation, and hot flushes. Because of the presence of the solvent vehicle, HCO-60 and in consideration of the mechanism of action of BHAC, the dose escalation was stopped at 7 mg kg?1. In Schedule 2, the daily dose was started with 1.5 mg kg?1 which was escalated up to 8 mg kg?1 and given for 2–16 days. Myelosuppression was found to be dose-limiting toxicity. The maximum tolerated dose (MTD) in patients with non-hematological solid tumors was assumed to be 5 mg kg?1 daily × 5 days. The plasma disappearance curve of BHAC looked biphasic, and when 4 mg kg?1 of BHAC were administered the half-lives of the initial phase (t 1/2α) and the second phase (t 1/2β) were calculated as 0.798 and 5.76 h respectively. In Schedule 2 complete remission was observed in 5 out of 21 patients with acute leukemia, one partial remission in Hodgkin’s disease, and one 1-B response (Karnofsky) in thyroid papillary adenocarcinoma.  相似文献   
52.
53.
54.
55.
The present study was designed to determine potential associations between the brain damage induced by hypoxic-ischemic (HI) insult and spatial learning impairment in an eight-arm radial maze task. We first determined the pathological outcomes after 2, 5, 9, and 17 weeks of recovery following the HI insult. The results show that the brain damage progressed from 2 up to 17 weeks of recovery. To clarify the time course of the brain damage changes, we investigated the histological changes of the same individual with magnetic resonance imaging (MRI) after 5, 9, and 57 weeks of recovery following the HI insult. The MRI changes were similar to the histological changes, and the brain damages were exacerbated in the contralateral hemisphere after 57 weeks of recovery following the HI insult. To investigate whether alteration in brain function was correlated with MRI and histological changes, the rats were made to find their way through an eight-arm radial maze was performed at either 7th or 16th weeks of recovery. According to the results, the spatial learning impairments of rats in the maze starting at 16 weeks of recovery were more severe than those at 7 weeks of recovery, indicating that the impairments were progressive and depended on the degree of brain damage. The results of the present study are the first demonstration that the evolutional and specific brain damage following the HI insult is slowly and progressively exacerbated to the contralateral hemisphere and rats who experience the HI are at risk for showing a late impairment of brain function.  相似文献   
56.
57.
After the conclusion of the trial was carried out on december 25th in the 18th year of the Meiji era, write-ups decreased graduallly. Under these circumstances, the traders of medicine began their own publication at their convenience and they put advertisements in them. "Eisei-tebako" by "Kishida ginko" and "Houtan-keikenroku" by "Morita Jihei" were the typical of them. While patent medicines were extremely popular, pharmacists at that time never denied the necessity of patent medicines. Junichiro Shimoyama and Keizo Tanba, who were representatives of pharmacists in Japan, suggested that pharmacists had ought to manage patent medicines and pointed out that excessive write-ups exacerbated the situation.  相似文献   
58.
In February 1869, the government first permitted newspapers to be published. The Yokohama-mainichi, the Tokyo-nichi-nichi, the Nisshin-shinjishi and so on were published. The traders of medicine quickly turned their attention to the newspapers. Jihei Morita put an advertisement about "Houtan" in the newspaper issued in July in the 4th year of the Meiji era (1871) and Ginko Kishida put an advertisement about "Seikisui" in the Mainichi in Yokohama dated August 18th in the 4th year of the Meiji era. After that, the traders of medicine advertised in newspapers one after another, and the contents of advertisements were expressly the efficacy of medicine. As Yukichi Fukuzawa doubted if the trend was really desirable, he carried his comment against the trend in the Katei Sodan published by Keio-Gijuku, but the contents of advertisements were not changed. Advertisements emphasising the efficacy of medicine were prominent.  相似文献   
59.
Hepatic vitronectin expression was assessed in 27 patients with chronic hepatitis C before and after interferon alpha treatment and in 7 control patients. Before interferon therapy, vitronectin was localized in the hepatocytes and in the portal and central venous regions. A high correlation was found for the vitronectin expression level with the histological grading and staging scores in the hepatocytes as well as in the portal region. After interferon therapy, the hepatic vitronectin was significantly decreased in the sustained and transient responders, but it was not as markedly decreased in the nonresponders and the non-treated group. A good correlation was found for the vitronectin expression with the staging scores but not with the grading scores in the portal region. These findings suggest that hepatic vitronectin is influenced by interferon therapy and that it may play an important role as a hepatic adhesion molecule through the improvement of inflammation, necrosis and fibrogenesis.  相似文献   
60.
Iodine-123-MIBG (123I-MIBG) scintigraphy were performed for 23 patients with neuroblastoma at diagnosis. The intensity of MIBG activity in the primary tumor was evaluated visually (grade 3; intense uptake-grade 0; no definite uptake), and its relationship to the size, degree of tumor spread, urinary catecholamine metabolites (VMA, HVA), and histological types were investigated. The results of 123I-MIBG uptake grade were as follows: grade 3; 44% (10/23), grade 2; 30% (7/23), grade 1; 17% (4/23), grade 0; 9% (2/23). The grade was not associated with the tumor size, or the degree of tumor extension to the distant lesion, either. The more catecholamine metabolites were excreted in the urine, the tumor tended to have more intense uptake. The tumors of neuroblastoma rosette fibrillary type, and ganglioneuroblastoma poorly differentiated type had more intense uptake than neuroblastoma round cell type and ganglioneuroblastoma well differentiated type. The case of ganglioneuroma did not have definite MIBG uptake. The intensity of MIBG uptake is not relevant to the pathological grade of neuroblastoma, but considering the electromicroscopical features of neuroblastoma reported previously, it is thought to reflect the histological type.  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