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   278030篇
  免费   72766篇
  国内免费   10291篇
耳鼻咽喉   4150篇
儿科学   7453篇
妇产科学   3703篇
基础医学   29539篇
口腔科学   11666篇
临床医学   49427篇
内科学   59274篇
皮肤病学   11101篇
神经病学   27873篇
特种医学   9753篇
外国民族医学   58篇
外科学   41548篇
综合类   23573篇
现状与发展   67篇
一般理论   43篇
预防医学   24920篇
眼科学   5773篇
药学   19032篇
  108篇
中国医学   8890篇
肿瘤学   23136篇
  2024年   1151篇
  2023年   6645篇
  2022年   5585篇
  2021年   9371篇
  2020年   14495篇
  2019年   15864篇
  2018年   18531篇
  2017年   20128篇
  2016年   20782篇
  2015年   22730篇
  2014年   26532篇
  2013年   28410篇
  2012年   16132篇
  2011年   16968篇
  2010年   21173篇
  2009年   19011篇
  2008年   11636篇
  2007年   9670篇
  2006年   10635篇
  2005年   8366篇
  2004年   6275篇
  2003年   5832篇
  2002年   5306篇
  2001年   5577篇
  2000年   4441篇
  1999年   4345篇
  1998年   3683篇
  1997年   3428篇
  1996年   3140篇
  1995年   2773篇
  1994年   1974篇
  1993年   1445篇
  1992年   1324篇
  1991年   1107篇
  1990年   947篇
  1989年   907篇
  1988年   838篇
  1987年   666篇
  1986年   582篇
  1985年   469篇
  1984年   368篇
  1983年   355篇
  1982年   265篇
  1981年   234篇
  1980年   145篇
  1979年   83篇
  1978年   129篇
  1977年   117篇
  1976年   87篇
  1972年   76篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
Laparoscopic surgery has several advantages over traditional surgery because it has been shown to be less invasive. The next logical step in the evolution of minimally invasive surgery may be to eliminate all abdominal incisions. The natural orifices provide a port of entry via the gastrointestinal tract to the peritoneal cavity. This approach would require the creation of a perforation, which is considered to be a major complication of endoscopy with significant morbidity and mortality. However, there are several recent studies that have described the technical feasibility and safety of a per‐oral transgastric approach to the peritoneal cavity using conventional endoscopes. Theoretically, this approach could reduce postoperative abdominal wall pain, wound infection, hernia formation, and adhesions. This article aims to summarize the current status of transgastric surgery, currently referred to as natural orifice transluminal endoscopic surgery (NOTES), and to address some of its future challenges.  相似文献   
13.
We report the case of a littoral‐cell angioma of the spleen, a recently described benign vascular tumour, whose imaging and pathological characteristics have been discussed only by a few authors. The diagnosis was made after elective splenectomy. The CT images, scintigraphy and histological specimens are presented, and differential diagnoses discussed.  相似文献   
14.
BACKGROUND AND PURPOSE: There is concern about the increase of radiation-induced malignancies with the application of modern radiation treatment techniques such as intensity-modulated radiotherapy (IMRT) and proton radiotherapy. Therefore, X-ray scatter and neutron radiation as well as the impact of the primary dose distribution on secondary cancer incidence are analyzed. MATERIAL AND METHODS: The organ equivalent dose (OED) concept with a linear-exponential and a plateau dose-response curve was applied to dose distributions of 30 patients who received radiation therapy of prostate cancer. Three-dimensional conformal radiotherapy was used in eleven patients, another eleven patients received IMRT with 6-MV photons, and eight patients were treated with spot-scanned protons. The treatment plans were recalculated with 15-MV and 18-MV photons. Secondary cancer risk was estimated based on the OED for the different treatment techniques. RESULTS: A modest increase of 15% radiation-induced cancer results from IMRT using low energies (6 MV), compared to conventional four-field planning with 15-MV photons (plateau dose-response: 1%). The probability to develop a secondary cancer increases with IMRT of higher energies by 20% and 60% for 15 MV and 18 MV, respectively (plateau dose-response: 2% and 30%). The use of spot-scanned protons can reduce secondary cancer incidence as much as 50% (independent of dose-response). CONCLUSION: By including the primary dose distribution into the analysis of radiation-induced cancer incidence, the resulting increase in risk for secondary cancer using modern treatment techniques such as IMRT is not as dramatic as expected from earlier studies. By using 6-MV photons, only a moderate risk increase is expected. Spot-scanned protons are the treatment of choice in regard to secondary cancer incidence.  相似文献   
15.
16.
17.
Although psychoanalysis was the first-choice treatment for premature ejaculation (PE) between 1920 and 1960, hardly any reports on its efficacy have been published. Moreover, a scientific debate about its findings has never been fully developed. The recent progress that has been made in the classification of three different PE syndromes creates a new opportunity for psychoanalytic investigations of men with complaints of PE, distinguished by the actual duration of their intravaginal ejaculation latency time (IELT). The term premature-like ejaculatory dysfunction has been introduced to distinguish men with self-perceived PE at normal and long IELT durations from those men with lifelong, acquired and normal variable PE. Psychoanalytic research may contribute to a better understanding of the consequences of objective early ejaculations on the unconscious mental life of men with the four forms of PE. By integrating neurobiological, clinical and epidemiological data of ejaculatory performance, a revival of psychoanalytic research of PE in the four distinct, classified PE groups, will probably contribute to a deeper insight in to the unconscious mental life of men affected by PE.  相似文献   
18.
19.
20.
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