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   5838篇
  免费   440篇
  国内免费   31篇
耳鼻咽喉   38篇
儿科学   156篇
妇产科学   131篇
基础医学   969篇
口腔科学   81篇
临床医学   583篇
内科学   1300篇
皮肤病学   172篇
神经病学   668篇
特种医学   112篇
外科学   558篇
综合类   9篇
一般理论   1篇
预防医学   480篇
眼科学   58篇
药学   450篇
中国医学   10篇
肿瘤学   533篇
  2024年   8篇
  2023年   51篇
  2022年   130篇
  2021年   195篇
  2020年   93篇
  2019年   151篇
  2018年   170篇
  2017年   153篇
  2016年   195篇
  2015年   221篇
  2014年   252篇
  2013年   338篇
  2012年   491篇
  2011年   523篇
  2010年   289篇
  2009年   269篇
  2008年   414篇
  2007年   385篇
  2006年   362篇
  2005年   352篇
  2004年   310篇
  2003年   285篇
  2002年   237篇
  2001年   33篇
  2000年   32篇
  1999年   41篇
  1998年   52篇
  1997年   43篇
  1996年   35篇
  1995年   26篇
  1994年   17篇
  1993年   23篇
  1992年   11篇
  1991年   20篇
  1990年   8篇
  1989年   12篇
  1988年   5篇
  1987年   7篇
  1986年   5篇
  1985年   10篇
  1984年   3篇
  1983年   5篇
  1982年   5篇
  1981年   4篇
  1980年   4篇
  1972年   2篇
  1971年   6篇
  1970年   5篇
  1969年   6篇
  1966年   3篇
排序方式: 共有6309条查询结果,搜索用时 0 毫秒
991.
992.
Background: A total colectomy and a frequent life-long endoscopic surveillance are guaranteed to patients with Familial Adenomatous Polyposis (FAP) to reduce their risk of duodenal and rectal stump cancers. However, after surgery, individuals with FAP suffer from an increased number of diarrheal discharges that force them to dietary restrictions. A non-randomized pilot study was conducted to assess whether a three-month low-inflammatory Mediterranean dietary intervention reduces gastro-intestinal markers of inflammation in FAP individuals. The aim of the present work is to evaluate the participant’s adherence to the proposed dietary recommendations and the change in their number of diarrheal discharges. Methods: 26 FAP individuals aged >18 years, who underwent a total colectomy with ileo-rectal anastomosis and were involved in the surveillance program at the Fondazione IRCCS Istituto Nazionale Tumori of Milan, were included in the present analysis. Results: FAP individuals significantly reduced the Not recommended foods (p-value: 0.002) and increased the consumption of the Recommended ones (p-value: 0.075). The adherence to the proposed dietary recommendations was accompanied by a significant decrease in the number of diarrheal discharges (p-value: 0.008). Conclusions: This study suggests that adhering to a low-inflammatory Mediterranean diet has a potential protective effect on the number of diarrheal discharges in FAP individuals.  相似文献   
993.
994.
995.
Most familial breast or ovarian cancers are thought to be due to highly penetrant mutations in the predisposing genes BRCA1 and BRCA2. The cloning of these genes has opened a new era for the genetic counseling of women with a family history of breast or ovarian cancer. To estimate the incidence of detectable BRCA1 mutations and to define the eligibility criteria for genetic testing in the Italian population, a total of 53 patients belonging to 46 families clustering multiple cases of breast and/or ovarian cancer were investigated. Seven families presented with ovarian cancer only, 16 had both ovarian and breast cancers, and 23 were characterized by breast cancer only. Using a combination of protein truncation test (PTT) and single strand conformational polymorphism (SSCP) analysis followed, when necessary, by direct sequencing, we found 8 distinct mutations, 2 of these not reported before. Five frameshift and 2 nonsense mutations led to a truncated protein. One mutation was a missense substitution involving a cysteine in the zinc finger domain. One variant creating an ETS binding site in intron 1 was found but its role was not defined. The percentage of families carrying mutations was 17%. Among the families characterized by ovarian cancer only and by breast and ovarian cancer, the percentage of BRCA1 mutations was 57% and 12.5%, respectively. In contrast, the percentage of altered BRCA1 in families with only breast cancers was 9%. In the 46 Italian families studied, BRCA1 mutations were detected in fewer kindreds than those previously hypothesized based on linkage analysis, especially when these were characterized by breast cancers only. Our results indicate that families with a low number of cancer patients should be referred for BRCA1 genetic testing mainly when ovarian cancer is present. Int. J. Cancer 78:581–586, 1998. © 1998 Wiley-Liss, Inc.  相似文献   
996.
The morphology, distribution, proportion, size, and synaptic organization of periaqueductal gray matter neurons labeled with immunocytochemical techniques by an anti-glutamate (Glu) polyclonal serum were investigated in six adult cats (PAG-GLU 1-6). At the light microscopic level, numerous Glu-positive neurons were found throughout each subdivision of the periaqueductal gray matter. Their proportion and size, calculated in semi-thin sections (1-μm-thick), varied slightly among the subdivisions of the periaqueductal gray matter. The morphology of Glu-positive neurons was similar to that of the multipolar, triangular, and fusiform cells described in previous Golgi studies. Numerous puncta, interpreted as dendrites, axons, and axon terminals were also present in all subdivisions without preferential distribution. At the electron microscopic level, all synaptic contacts made by Glu-positive axon terminals were of the asymmetric type, but not all presynaptic elements making asymmetric synapses were labeled. The vast majority of postsynaptic elements contacted by Glu-positive axon terminals were labeled and unlabeled dendrites. The present results describe for the first time the presence of both Glu-positive neurons and terminals in the feline periaqueductal gray matter and provide further evidence that Glu is the probable neurotransmitter of numerous excitatory neurons of this structure. J. Comp. Neurol. 383:381-396, 1997. © 1997 Wiley-Liss, Inc.  相似文献   
997.
998.
999.
1000.
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