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   3574篇
  免费   175篇
  国内免费   67篇
耳鼻咽喉   76篇
儿科学   56篇
妇产科学   153篇
基础医学   600篇
口腔科学   77篇
临床医学   290篇
内科学   596篇
皮肤病学   96篇
神经病学   219篇
特种医学   120篇
外科学   612篇
综合类   81篇
预防医学   152篇
眼科学   59篇
药学   363篇
中国医学   32篇
肿瘤学   234篇
  2023年   27篇
  2022年   38篇
  2021年   92篇
  2020年   55篇
  2019年   68篇
  2018年   91篇
  2017年   83篇
  2016年   98篇
  2015年   141篇
  2014年   161篇
  2013年   163篇
  2012年   255篇
  2011年   260篇
  2010年   154篇
  2009年   113篇
  2008年   185篇
  2007年   196篇
  2006年   193篇
  2005年   166篇
  2004年   140篇
  2003年   119篇
  2002年   111篇
  2001年   101篇
  2000年   92篇
  1999年   85篇
  1998年   27篇
  1997年   21篇
  1996年   28篇
  1995年   21篇
  1994年   19篇
  1993年   12篇
  1992年   34篇
  1991年   39篇
  1990年   38篇
  1989年   34篇
  1988年   19篇
  1987年   22篇
  1986年   22篇
  1985年   30篇
  1984年   19篇
  1983年   13篇
  1979年   16篇
  1978年   21篇
  1977年   13篇
  1976年   13篇
  1975年   15篇
  1974年   17篇
  1973年   14篇
  1972年   18篇
  1966年   16篇
排序方式: 共有3816条查询结果,搜索用时 15 毫秒
51.
研究生作为PBL指导教师在药理学教改中的探索   总被引:1,自引:0,他引:1  
药理系首次进行聘用研究生作为PBL指导教师的教改尝试,深刻体会到其重要性所在。研究生具有知识面宽、概念清楚、基础知识扎实等诸多优势,有利于提高本科生的教学质量。药理系组织研究生参加教学培训、开展讨论、吸纳有益的建议;提高研究生对PBL教学的重视程度、消除研究生顾虑;争取研究生导师的大力支持;并由教授亲自检查并督促研究生教学工作。作为PBL教学指导教师,研究生是学生与任课教授、讲师之间的中介人和桥梁,有利于提高学生的综合素质、教师教学水平。  相似文献   
52.
Primary immune thrombocytopenia (ITP) of childhood is an autoimmune disease characterized by abnormally increased destruction of platelets and decreased megakaryopoiesis. Stromal‐derived factor‐1 (SDF‐1) plays a role in megakaryopoiesis and may be involved in the pathogenesis of ITP. Five single nucleotide polymorphisms (SNPs) of the SDF‐1 gene, including rs1801157, rs2839693, rs2297630, rs1065297, and rs266085, were assessed in 100 children with ITP and 126 healthy controls. The genotypes were analyzed by tetra ARMS polymerase chain reaction and confirmed by direct sequencing. Compared with controls, the rs2839693 A/A and rs266085 C/T genotypes were decreased in ITP patients (P = 0.004 and 0.007, respectively). The odds ratios of the latter genotypes were 0.48, 95% CI 0.28–0.82. Further analysis of the relationship between SDF‐1 polymorphisms and clinical features showed that rs2297630 A/G was associated with protection from chronicity (P = 0.002; OR, 0.07; 95% CI, 0.01–0.61) and steroid dependence (P = 0.007; OR, 0.10; 95% CI, 0.01–0.84) in ITP patients. However, rs266085 genotype C/C was associated with risk of steroid dependence (P = 0.012, OR 3.87, 95% CI 1.27–11.77). The findings of this study suggest that SDF‐1 gene variations may be associated with the occurrence and prognosis of childhood ITP.  相似文献   
53.
54.
Background: Central venous access systems are frequently used for delivery of medications; however, few studies have compared surgical and postoperative complications of right versus left access via the subclavian vein (SCV). The aim of this study was to compare the surgical and postoperative complications associated with Port-A-Cath system insertion via the right and left SCV. Methods: The medical records of patients who received Port-A-Cath insertion via the SCV for parenteral chemotherapy between August 2004 and July 2008 were reviewed. The incidence of surgical and postoperative complications was compared between patients who received right- versus left-SCV Port-A-Cath insertion. Results: A total of 1,848 patients were included in the study. Right-SCV catheterization was attempted in 1,029 (55.7%) patients and was successful in 866 (84.2%). Left-SCV catheterization was attempted in 819 (44.3%) patients and was successful in 651 (79.5%). The mean length of postoperative follow-up was 417.3 ± 401.3 and 396.7 ± 379.9 days for the right- and left-SCV groups, respectively. The incidence of SCV puncture failure was significantly lower in the right-SCV group (12.3%) compared with the left-SCV group (16.8%, p = 0.006). The incidence of catheter knotting at the ipsilateral brachiocephalic vein was also significantly lower in the right-SCV group (0.0%) compared with the left-SCV group (0.5%, p = 0.038), as was the incidence of catheter occlusion (1.0% for right SCV vs. 3.5% for left SCV, p = 0.001). Conclusion: These findings suggest that the right-SCV approach is superior to the left-SCV approach for Port-A-Cath insertion.  相似文献   
55.
56.
57.
In recent years, a constant growth of knowledge and clinical applications of stem cells have been observed. Mesenchymal stromal cells, also described as mesenchymal stem cells (MSCs) represent a particular cell type for research and therapy because of their ability to differentiate into mesodermal lineage cells. The most investigated source of MSCs is bone marrow (BM). Yet, collection of BM is an invasive procedure associated with significant discomfort to the patient. The procedure results in a relatively low number of these cells, which can decrease with donor's age. Therefore, it seems to be very important to find other sources of mesenchymal stem cells nowadays. A human placenta, which is routinely discarded postpartum, in spite of its natural aging process, is still a rich source of stem cells capable to proliferate and in vitro differentiate in many directions. Besides homing and differentiation in the area of injury, MSCs there elicit strong paracrine effects stimulating the processes of repair. In this review, we focus on the biology, characteristics and potential clinical applications of cells derived from human fetal membranes: amnion and chorion.  相似文献   
58.
59.
Protein tyrosine phosphatase sigma (PTPσ) is a promising target for the development of therapeutics for the neurological diseases caused by the impaired recovery from neural injury. Based on the virtual screening with the scoring function involving a new accurate solvation energy term and in vitro enzyme assay, we identified seven competitive PTPσ inhibitors with the associated IC50 values ranging from 5 to 11 μM. These inhibitors are structurally diverse and expected to have desirable physicochemical properties as a drug candidate. Therefore, they deserve consideration for further development by structure–activity relationship studies to optimize the inhibitory activities against the neurological diseases. Structural features relevant to the stabilization of the newly identified inhibitors in the active site of PTPσ are discussed in detail.  相似文献   
60.
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