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   519篇
  免费   37篇
  国内免费   13篇
耳鼻咽喉   3篇
儿科学   34篇
妇产科学   8篇
基础医学   61篇
口腔科学   10篇
临床医学   32篇
内科学   83篇
皮肤病学   21篇
神经病学   16篇
特种医学   141篇
外科学   59篇
综合类   20篇
预防医学   23篇
眼科学   6篇
药学   24篇
肿瘤学   28篇
  2022年   1篇
  2021年   9篇
  2020年   4篇
  2019年   3篇
  2018年   8篇
  2017年   3篇
  2016年   8篇
  2015年   16篇
  2014年   10篇
  2013年   11篇
  2012年   9篇
  2011年   15篇
  2010年   26篇
  2009年   31篇
  2008年   18篇
  2007年   28篇
  2006年   20篇
  2005年   22篇
  2004年   23篇
  2003年   11篇
  2002年   8篇
  2001年   17篇
  2000年   6篇
  1999年   1篇
  1998年   20篇
  1997年   36篇
  1996年   21篇
  1995年   23篇
  1994年   16篇
  1993年   6篇
  1992年   4篇
  1991年   1篇
  1990年   8篇
  1989年   14篇
  1988年   9篇
  1987年   15篇
  1986年   9篇
  1985年   10篇
  1984年   5篇
  1983年   9篇
  1982年   7篇
  1981年   9篇
  1980年   12篇
  1979年   1篇
  1978年   4篇
  1977年   7篇
  1976年   8篇
  1975年   5篇
  1974年   1篇
  1972年   1篇
排序方式: 共有569条查询结果,搜索用时 15 毫秒
61.
Kitchen  E; Rossi  AG; Condliffe  AM; Haslett  C; Chilvers  ER 《Blood》1996,88(11):4330-4337
Exposure of neutrophils to agents such as lipopolysaccharide, tumor necrosis factor-alpha (TNF-alpha), and the granulocyte-macrophage colony-stimulating factor causes a major upregulation of subsequent agonist-induced NADPH oxidase activation. This priming effect is a prerequisite for neutrophil-mediated tissue damage and has been widely considered to be an irreversible process. We have investigated the potential for neutrophils to recover from a priming stimulus by studying the effects of platelet-activating factor (PAF). PAF did not stimulate respiratory burst activity directly, but caused a rapid (maximal at 10 minutes) and concentration-dependent (EC50 50.2 nmol/L) increase in N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated superoxide anion release. At time-points > 10 minutes, this priming effect spontaneously declined, with return to basal levels of fMLP- stimulated superoxide anion generation by 120 minutes. An identical priming time-course was observed with N-methyl carbamyl PAF, a nonmetabolizable analogue of PAF, indicating that the transient nature of PAF-induced priming was not secondary to PAF metabolism. Two structurally diverse PAF receptor antagonists (UK-74,505 and WEB 2086), added 10 minutes after PAF addition, increased the rate of decay of the priming effect. In contrast, TNF-alpha-induced priming, which was of a similar magnitude to that observed for PAF, was slower to evolve (maximal at 30 minutes) and remained constant for at least 120 minutes. The reversible nature of PAF-induced priming was confirmed by demonstrating that PAF-, but not TNF-alpha-, induced cell polarization (shape change) and CD11b-dependent neutrophil binding of albumin-coated latex beads was also transient, with return to basal, unstimulated levels by 120 minutes. Furthermore, cells that had spontaneously deprimed following PAF exposure retained their capacity to be fully reprimed by a subsequent addition of either PAF or TNF-alpha. These data imply that neutrophil priming is not an irreversible event: the demonstration of a cycle of complete priming, depriming, and repriming offers the potential for functional recycling of neutrophils at sites of inflammation.  相似文献   
62.
To investigate bone turnover in patients with seronegative spondylarthropathy, a bone formation marker, type 1 procollagen carboxy- terminal propeptide (P1CP), and resorption markers, the pyridinium cross-links of collagen [urinary free (f) PYR and DPYR], were measured. The median f-PYR, f-DPYR and P1CP (+/-interquartile range) were 15.8 (6.00) nmol/mmol creatinine, 3.8 (2.2) nmol/mmol creatinine and 101.5 (38) micrograms/1, respectively. There was a positive correlation between resorption markers and acute-phase reactants such as C-reactive protein (r = 0.42 for PYR, r = 0.42 for DPYR, P < 0.05), and a negative correlation observed between P1CP and the erythrocyte sedimentation rate (r = -0.64, P < 0.05). In the subgroup of patients with an elevated CRP concentration, the concentration of PYR and DPYR was significantly increased (f-PYR 25.7 vs 15.8 and f-DPYR 6.6 vs 3.8, P < 0.01 for f-PYR, P < 0.05 for f-DPYR). This study suggests than an elevation in acute-phase response in patients with seronegative spondylarthropathy is associated with increased concentration of bone resorption markers with a tendency for reduction in bone formation markers. This may represent uncoupling of bone formation and resorption, leading to bone loss in such patients.   相似文献   
63.
64.
Baker  DE; Silver  TM; Coran  AG; McMillin  KI 《Radiology》1986,161(2):341-344
At the authors' medical center, most patients with postappendectomy fluid collections are treated conservatively. Thirty-two (15%) of 216 children underwent postoperative sonography following appendectomies. In ten patients (31%), a total of 16 fluid collections were found on the initial postoperative sonogram. In the seven patients (70%) whose fluid collections were confined to the pelvis, the condition was treated conservatively and it resolved in 2-9 weeks. In three patients, fluid collections required surgical drainage and proved to be abscesses. In two of the three patients, abscesses were multiple and widely distributed in the abdomen, and the patients were clinically ill. The authors conclude that clinically symptomatic fluid collections develop postoperatively in approximately 5% of children who have undergone appendectomy for acute appendicitis and that the size and course of the fluid collection can be objectively monitored using sonography. Such fluid collections confined to the pelvis ultimately resolve with conservative, nonoperative therapy, although resolution may take up to 2 months.  相似文献   
65.
66.
67.
68.
INTRODUCTION: The diagnosis of adult-onset Still's disease (AOSD) can be very difficult. There are no specific tests and reliance is usually placed on a symptom complex and the well described typical rash seen in most patients. In recent years, however, other cutaneous manifestations of AOSD have been reported but these are not so well known. OBSERVATIONS: We report a patient with urticaria and fixed plaques and review the other 'atypical' cutaneous findings associated with AOSD. CONCLUSIONS: The diagnosis of AOSD can be made in the absence of the typical Still's rash but in the presence of other atypical cutaneous features.  相似文献   
69.
Abstrakt Ein Vertragsarzt darf seine psychotherapeutischen Leistungen bis zur H?he der EBM-Betr?ge bei dem Kassenpatienten liquidieren, wenn die Krankenkasse die erforderliche Zustimmung versagt und der Patient in Kenntnis der Ablehnung die Therapie fortführt. (Leitsatz des Bearbeiters)  相似文献   
70.
Serum IgG, IgGl, G2, G3, G4, IgM, C3c and C4 concentrations were measured in 24 term neonates with sepsis and 17 healthy normal neonates of similar age, sex and weight (control group). The serum IgG, IgG1, G2, G3, G4, IgM, C3c, and C4 levels were similar in the patients with sepsis and the control group ( p > 0. 05). In the neonates with sepsis, serum IgG, G1, G2, IgM and C4 levels were not significantly different between the 1st and 10th days, while there were significant differences for IgG3, G4 and C3c ( p < 0. 05). We conclude that the serum levels of IgG, IgG1, G2, G3, G4, IgM, C3c and C4 concentrations are of no value for the early diagnosis of neonatal sepsis.  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