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   2028617篇
  免费   147039篇
  国内免费   2785篇
耳鼻咽喉   27622篇
儿科学   60716篇
妇产科学   54397篇
基础医学   296149篇
口腔科学   58943篇
临床医学   184291篇
内科学   394727篇
皮肤病学   43073篇
神经病学   160579篇
特种医学   77204篇
外国民族医学   338篇
外科学   304733篇
综合类   41058篇
现状与发展   3篇
一般理论   776篇
预防医学   155266篇
眼科学   46250篇
药学   152879篇
  10篇
中国医学   3916篇
肿瘤学   115511篇
  2018年   20474篇
  2017年   15813篇
  2016年   17387篇
  2015年   20027篇
  2014年   27544篇
  2013年   41580篇
  2012年   56643篇
  2011年   59960篇
  2010年   35066篇
  2009年   33720篇
  2008年   57494篇
  2007年   60909篇
  2006年   61420篇
  2005年   59668篇
  2004年   57444篇
  2003年   55128篇
  2002年   53770篇
  2001年   100049篇
  2000年   102624篇
  1999年   86320篇
  1998年   22365篇
  1997年   20003篇
  1996年   20439篇
  1995年   19120篇
  1994年   17800篇
  1993年   16555篇
  1992年   67346篇
  1991年   65444篇
  1990年   63434篇
  1989年   61660篇
  1988年   56828篇
  1987年   55480篇
  1986年   52349篇
  1985年   49579篇
  1984年   36756篇
  1983年   31718篇
  1982年   17881篇
  1981年   15895篇
  1979年   34101篇
  1978年   24176篇
  1977年   20386篇
  1976年   18398篇
  1975年   20109篇
  1974年   24486篇
  1973年   23658篇
  1972年   22460篇
  1971年   21101篇
  1970年   19988篇
  1969年   18928篇
  1968年   17469篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare malignant tumour of the skin, with an estimated incidence of 0.8 to five cases per 1 million people per year. OBJECTIVE: To study epidemiological, immunohistochemical and clinical features, delay in diagnosis, type of treatment and outcome of DFSP from 1982 to 2002. METHODS: Using data from the population-based cancer registry, 66 patients with pathologically proved DFSP were included (fibrosarcomatous DFSP were excluded). Each patient lived in one of the four departments of Franche-Comté (overall population of 1 million people) at the time of diagnosis. The main data sources came from public and private pathology laboratories and medical records. The rules of the International Agency for Research on Cancer were applied. RESULTS: The estimated incidence of DFSP in Franche-Comté was about three new cases per 1 million people per year. Male patients were affected 1.2 times as often as female patients were. The trunk (45%) followed by the proximal extremities (38%) were the most frequent locations. DFSP occurred mainly in young adults between 20 and 39 years of age. Mean age at diagnosis was 43 years, and the mean delay in diagnosis was 10.08 years. Our 66 patients initially underwent a radical local excision. Among them, 27% experienced one or more local recurrences during 9.6 years of follow-up. There was one regional lymph node recurrence without visceral metastases. These recurrences were significantly related to the initial peripheral resection margins. We observed a local recurrence rate of 47% for margins less than 3 cm, vs. only 7% for margins ranging from 3 to 5 cm [P=0.004; OR=0.229 (95%, CI=0.103-0.510)]. The mean time to a first local recurrence was 2.65 years. Nevertheless, there was no death due to the DFSP course at the end of the follow-up, and the final outcome was favourable. CONCLUSION: Our study emphasizes the importance of wide local excision with margins of at least 3 cm in order to prevent local recurrence. However, the recent development of inhibitors of signal transduction by the PDGFB pathway should soon modify the surgical strategy, which is often too mutilating.  相似文献   
73.
74.
In rare cases the usage of the internal thoracic vessels as recipient vessels in reconstructive surgery of the head and neck region with free tissue transfer is a challenging but valid alternative if local recipient vessels are unusable.  相似文献   
75.
AIM: The intention was to investigate cerebrospinal fluid pressure (CSFP) and volume of cerebrospinal fluid (CSF) drained during and after thoracic- and thoracoabdominal aneurysm repair. The findings were related to the occurrence of postoperative neurologic deficits. METHODS: Twenty-nine patients (12 with thoracic and 17 with thoracoabdominal aortic aneurysm) were operated without shunting or extracorporeal circulation. For monitoring of CSFP an intrathecal catheter was placed in all patients. The volume of CSF withdrawn intraoperatively, on the day of operation as well as on the 1st and 2nd postoperative day was recorded. RESULTS: Twenty-six patients had no postoperative neurologic sequelae. One patient had postoperative paraplegia while 2 had paraparesis. The three patients with neurologic sequelae had higher CSFP intraoperatively than those without neurologic symptoms (P=0.04). Median CSFP during aortic cross-clamping was 19 mmHg and 10 mmHg and the median volumes of CSF drained on the day of operation 210 and 85 mL in the two groups, respectively. There was a significant positive correlation between CSFP and central venous pressure. CONCLUSIONS: A higher intraoperative CSFP was observed in patients with neurologic sequelae following thoracic- and thoracoabdominal aneurysm repair. Further, there was a tendency of higher volumes of CSF drained in this group of patients. Although, the series is too small to allow firm conclusions, it supports the view that CSFP monitoring and drainage is beneficial during thoracic- and thoracoabdominal aneurysm repair.  相似文献   
76.
77.
78.
79.
80.
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