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   295488篇
  免费   9327篇
  国内免费   451篇
耳鼻咽喉   2728篇
儿科学   9838篇
妇产科学   5020篇
基础医学   32041篇
口腔科学   3880篇
临床医学   24524篇
内科学   56253篇
皮肤病学   2549篇
神经病学   27989篇
特种医学   13025篇
外国民族医学   4篇
外科学   46088篇
综合类   4181篇
现状与发展   1篇
一般理论   167篇
预防医学   28727篇
眼科学   5608篇
药学   17930篇
  2篇
中国医学   795篇
肿瘤学   23916篇
  2023年   510篇
  2022年   831篇
  2021年   2070篇
  2020年   1229篇
  2019年   2023篇
  2018年   23920篇
  2017年   18881篇
  2016年   21150篇
  2015年   3272篇
  2014年   4177篇
  2013年   6029篇
  2012年   14511篇
  2011年   28823篇
  2010年   23034篇
  2009年   15786篇
  2008年   27013篇
  2007年   29719篇
  2006年   8785篇
  2005年   10656篇
  2004年   11403篇
  2003年   12176篇
  2002年   9926篇
  2001年   1423篇
  2000年   1308篇
  1999年   1374篇
  1998年   1890篇
  1997年   1615篇
  1996年   1240篇
  1995年   1240篇
  1994年   1034篇
  1993年   1013篇
  1992年   786篇
  1991年   784篇
  1990年   787篇
  1989年   691篇
  1988年   624篇
  1987年   580篇
  1986年   565篇
  1985年   690篇
  1984年   848篇
  1983年   849篇
  1982年   1186篇
  1981年   1052篇
  1980年   989篇
  1979年   466篇
  1978年   582篇
  1977年   550篇
  1976年   457篇
  1975年   413篇
  1974年   384篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
A 35-year-old man discovered a 1-cm nodule at the upper pole of the left testicle after blunt focal trauma. While the pain, tenderness, and location suggested hematoma or appendiceal torsion, the demonstration by ultrasound of the size, cystic nature, and extraparenchymal location was consistent with the rarely documented cyst of the tunica albuginea.  相似文献   
112.
113.
114.
115.
116.
117.
118.
PURPOSE: To delineate gene expression patterns and profile changes in metastatic tumor biopsies at baseline and 1 month after treatment with the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor erlotinib in patients with metastatic breast cancer. EXPERIMENTAL DESIGN: Patients were treated with 150 mg of oral erlotinib daily. Gene expression profiles were measured with Affymetrix U133A GeneChip and immunohistochemistry was used to validate microarray findings. RESULTS: Estrogen receptor (ER) status by immunohistochemistry is nearly coincided with the two major expression clusters determined by expression of genes using unsupervised hierarchical clustering analysis. One of 10 patients had an EGFR-positive tumor detected by both microarray and immunohistochemistry. In this tumor, tissue inhibitor of metalloproteinases-3 and collagen type 1 alpha 2, which are the EGF-down-regulated growth repressors, were significantly increased by erlotinib. Gene changes in EGFR-negative tumors are those of G-protein-linked and cell surface receptor-linked signaling. Gene ontology comparison analysis pretreatment and posttreatment in EGFR-negative tumors revealed biological process categories that have more genes differentially expressed than expected by chance. Among 495 gene ontology categories, the significant differed gene ontology groups include G-protein-coupled receptor protein signaling (34 genes, P = 0.002) and cell surface receptor-linked signal transduction (74 genes, P = 0.007). CONCLUSIONS: ER status reflects the major difference in gene expression pattern in metastatic breast cancer. Erlotinib had effects on genes of EGFR signaling pathway in the EGFR-positive tumor and on gene ontology biological process categories or genes that have function in signal transduction in EGFR-negative tumors.  相似文献   
119.
Background: This is the second of two papers using qualitative methods from a study of an intervention for family members affected by close relatives' substance misuse problems.

Participants: 168 primary healthcare professionals (PHCPs: GPs, practice nurses and health visitors) working in general practices in two areas of England, and who took part in the study.

Data sources: Recruitment and post-session forms completed by PHCPs; telephone interviews with each PHCP 12 weeks after recruitment of a family member; interviews with PHCPs at the end of the study.

Results: At the end of the project PHCPs were overwhelmingly positive about the family member intervention and about primary care as the appropriate site. Difficulties were encountered, however, in identifying and engaging affected family members, who were often excluded on grounds of the complexity of their problems or the level of their distress. Shortage of PHCP time and other practice-related factors added to the difficulty. Active work by a PHCP was often necessary in order to make the link between presenting symptoms of physical or mental ill-health and the existence of a family substance misuse problem. When family members were identified and recruited, PHCPs were usually positive about what was achieved. Nearly all were in favour of an approach that combined giving a self-help manual with some follow-up contact with a family member as needed.

Conclusions: Taken in conjunction with statistical outcome findings of significant reductions in symptoms and changes in ways of coping, plus qualitative analysis of the views of family members, the present results encourage the view that a flexible form of this intervention should be developed for use in primary healthcare, and that further work should build on existing strengths and attempt to overcome weaknesses identified.  相似文献   
120.
The treatment of deep cartilage defects in load-bearing joints is a problem that still has no satisfactory solution. Full-thickness defects of the articular cartilage rarely heal spontaneously, usually leaving damage that can lead to early arthrosis. Techniques currently available for the treatment of chondral defects include abrasion, drilling, micro-fracturing, transplantation of tissue autografts and allografts, and cell transplantation. Osteochondral autograft transplantation is currently the only surgical cartilage repair technique known to lead to the formation of genuine hyaline articular cartilage and its retention at least in the medium term. The Draenert method, in which a water-cooled diamond bone-cutting system is used, is an effective procedure for resurfacing the joints affected by localised cartilaginous defects, even when there is also severe bone loss. Donor-side morbidity can be kept to a minimum by filling the defect caused by harvesting with a press-fit cylinder of cancellous bone covered with periosteum for protection.  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