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   3870篇
  免费   275篇
  国内免费   65篇
耳鼻咽喉   16篇
儿科学   42篇
妇产科学   42篇
基础医学   560篇
口腔科学   76篇
临床医学   290篇
内科学   802篇
皮肤病学   173篇
神经病学   308篇
特种医学   109篇
外科学   451篇
综合类   129篇
预防医学   258篇
眼科学   97篇
药学   383篇
  1篇
中国医学   58篇
肿瘤学   415篇
  2023年   15篇
  2022年   67篇
  2021年   132篇
  2020年   70篇
  2019年   89篇
  2018年   109篇
  2017年   111篇
  2016年   128篇
  2015年   139篇
  2014年   206篇
  2013年   225篇
  2012年   305篇
  2011年   275篇
  2010年   172篇
  2009年   138篇
  2008年   198篇
  2007年   204篇
  2006年   152篇
  2005年   191篇
  2004年   163篇
  2003年   137篇
  2002年   128篇
  2001年   100篇
  2000年   73篇
  1999年   62篇
  1998年   22篇
  1997年   24篇
  1996年   12篇
  1995年   16篇
  1994年   22篇
  1993年   13篇
  1992年   45篇
  1991年   33篇
  1990年   28篇
  1989年   21篇
  1988年   36篇
  1987年   29篇
  1986年   22篇
  1985年   19篇
  1984年   13篇
  1983年   14篇
  1982年   16篇
  1980年   12篇
  1977年   12篇
  1976年   14篇
  1972年   22篇
  1970年   19篇
  1969年   11篇
  1968年   14篇
  1967年   15篇
排序方式: 共有4210条查询结果,搜索用时 15 毫秒
1.
TL1A is a TNF‐like cytokine which has been shown to co‐stimulate TH1 and TH17 responses during chronic inflammation. The expression of this novel cytokine has been investigated in inflammatory disorders like rheumatoid arthritis and inflammatory bowel disease, but little is known about expression and induction in psoriasis. Indeed, the pathogenesis in psoriasis is still not fully understood and it is speculated that cytokines other than TNF‐α are important in subsets of patients. Also, for patients with severe disease that are treated with systemic anti‐TNF‐α blockade, novel candidates to be used as disease and response biomarkers are of high interest. Here, we demonstrate TL1A expression in biopsies from psoriatic lesions. Also, we investigated spontaneous and induced TL1A secretion from PBMCs and blood levels from a cohort of psoriasis patients. Here, increased spontaneous secretion from PBMCs was observed as compared to healthy controls and a small subset of patients had highly elevated TL1A in the blood. Interestingly, activation of PBMCs with various cytokines showed a decreased sensitivity for TL1A activation in psoriasis patients compared to healthy controls.TL1A levels in blood and biopsies could not be correlated with disease activity with this patient cohort. Thus, additional large‐scale studies are warranted to investigate TL1A as a biomarker.  相似文献   
2.
3.
OBJECTIVES: Dental lasers have been used for uncovering submerged implants as well as decontaminating implant surfaces when treating peri-implantitis. The objective of this study was to compare the possible alterations of the smooth surface and resorbable blast material (RBM) surface implants after using NdYAG and CO(2) lasers at various energies. MATERIALS AND METHODS: Ten smooth surface implants and 10 RBM surface implants were used. Two smooth surface implants and 2 RBM surface implants served as a control group that was not lased. The remaining implants were treated using NdYAG and CO(2) lasers. The surface of each implant was treated for 10 seconds on the second and third threads. The smooth surface implants (group 1) were treated using a pulsed contact NdYAG laser at power settings of 1, 2, 3.5, and 5 W, which are commonly used for soft tissue surgery; the corresponding energy and frequency were 50 mJ and 20 Hz, 100 mJ and 20 Hz, 350 mJ and 10 Hz, and 250 mJ and 20 Hz, respectively. The group 2 RBM implants were treated using a pulsed contact NdYAG laser. The group 3 smooth surface implants were treated using a pulsed wave non-contact CO(2) laser at 1, 2, 3.5, and 5 W, and the group 4 RBM implants were treated using a pulsed wave non-contact CO(2) laser. Data were analyzed using scanning electron microscopy. RESULTS: The control surface was very regular and smooth. After NdYAG laser treatment, the implant surface showed alterations of all the surfaces. The amount of damage was proportional to the power. A remarkable finding was the similarity of the lased areas on the smooth and RBM surfaces. CO(2) laser at power settings of 1.0 or 2.0 W did not alter the implant surface, regardless of implant type. At settings of 3.5 and 5 W, there was destruction of the micromachined groove and gas formation. CONCLUSION: This study supports that CO(2) laser treatment appears more useful than NdYAG laser treatment and CO(2) laser does not damage titanium implant surface, which should be of value when uncovering submerged implants and treating peri-implantitis.  相似文献   
4.
5.
6.
Palmar advancement flap with V-Y closure for thumb tip injuries   总被引:1,自引:0,他引:1  
The palmar advancement flap with V-Y closure was used in two patients with thumb tip injuries. This technique allows more distal advancement of the flap than does a conventional palmar advancement flap and does not require skin graft coverage.  相似文献   
7.
BACKGROUND. Deposition of fibrin in glomeruli and renal failure are characteristic features of the hemolytic uremic syndrome. An inhibitor of glomerular fibrinolysis has been detected in plasma from children with this disorder. In this study, we define the inhibitor and show that its plasma level is correlated with the outcome of the disease. METHODS AND RESULTS. Plasminogen-activator inhibitor type 1 (PAI-1) in plasma was measured with an assay employing a specific monoclonal antibody in 40 consecutive children hospitalized with the hemolytic uremic syndrome: 12 who recovered adequate renal function (serum creatinine, less than or equal to 2.0 mg per deciliter [177 mumol per liter]) without dialysis, 23 who recovered adequate renal function after peritoneal dialysis, and 5 who did not recover adequate renal function after undergoing dialysis. At presentation, plasma PAI-1 levels were higher in the patients with the hemolytic uremic syndrome than in nine children with other forms of acute renal failure. That the inhibitor was PAI-1 was indicated by the fact that it was a potent inhibitor of tissue plasminogen activator, was acid-resistant, and was not inhibited by denaturation (all unique traits of PAI-1) and that it was neutralized by an antibody specific for PAI-1. Multivariate discriminant-function analysis revealed that the duration of elevated PAI-1 activity was strongly correlated with the outcome of the disease (P less than 0.001). Peritoneal dialysis reduced plasma PAI-1 levels dramatically. CONCLUSIONS. Our studies suggest that PAI-1 is the circulating inhibitor of fibrinolysis in the hemolytic uremic syndrome. Normalization of plasma PAI-1 levels (e.g., by peritoneal dialysis) is correlated with improvement in renal function. However, the possibility that increased plasma levels of PAI-1 are either causes or effects of the hemolytic uremic syndrome is not unequivocally established by these studies.  相似文献   
8.
We report here our 10-year experience of a biopsy performed at day 14 after transplantation in 304 patients with stable graft function. The factors that may have influenced subclinical rejection were analyzed according to histology. The incidence of subclinical rejection was 13.2%. Addition of mycophenolate mofetile (MMF) as a primary immunosuppressant significantly decreased the incidence of subclinical rejection compared with patients without such treatment (odds ratio, 0.23; p < 0.05). On the other hand, HLA-DR antigen mismatch (odds ratio, 2.39) and unrelated donor (odds ratio, 2.10) were also significantly associated with decreased subclinical rejection (p < 0.05). The incidence of acute rejection in patients with normal findings was lower than in those with borderline changes or subclinical rejection (0.23 +/- 0.05 vs. 0.48 +/- 0.07 and 0.60 +/- 0.11, respectively; p < 0.05). The graft survival rates in patients with subclinical rejection were lower than in patients with normal or borderline changes at 1 (88.4% vs. 97.9% and 99.1%; p < 0.05), 5 (77.8% vs. 96.2% and 95.9%; p < 0.05) and 10 (62.3% vs. 96.2% and 93.7%; p < 0.05) years. Thus, a protocol biopsy performed on day 14 after transplantation is useful for predicting graft survival. Triple therapy including MMF, related donor and HLA-DR antigen match are important factors for reducing subclinical rejection in living-donor renal transplantation.  相似文献   
9.
10.
The effects on primary haemostasis of unfractionated heparin and of the two low molecular weight heparins, enoxaparin and fragmin, were compared in two rat models, one employing the gastric mucosa and the other the tail skin. All three heparin preparations prolonged the bleeding time and increased the blood loss dose dependently. The prolongation of the bleeding time per unit dose caused by unfractionated heparin was significantly greater than the prolongation caused by either one of the two low molecular weight heparins. In the gastric mucosa, but not in the tail skin, enoxaparin prolonged the bleeding time significantly less than fragmin (p less than 0.05).  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