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   637篇
  免费   40篇
  国内免费   13篇
耳鼻咽喉   1篇
儿科学   43篇
妇产科学   13篇
基础医学   108篇
口腔科学   9篇
临床医学   43篇
内科学   101篇
皮肤病学   19篇
神经病学   20篇
特种医学   138篇
外科学   65篇
综合类   20篇
预防医学   27篇
眼科学   6篇
药学   29篇
肿瘤学   48篇
  2021年   7篇
  2019年   6篇
  2018年   9篇
  2017年   5篇
  2016年   7篇
  2015年   18篇
  2014年   8篇
  2013年   18篇
  2012年   11篇
  2011年   21篇
  2010年   27篇
  2009年   33篇
  2008年   20篇
  2007年   27篇
  2006年   19篇
  2005年   26篇
  2004年   21篇
  2003年   15篇
  2002年   14篇
  2001年   23篇
  2000年   11篇
  1999年   4篇
  1998年   23篇
  1997年   37篇
  1996年   23篇
  1995年   23篇
  1994年   17篇
  1993年   7篇
  1992年   8篇
  1991年   4篇
  1990年   14篇
  1989年   17篇
  1988年   17篇
  1987年   21篇
  1986年   11篇
  1985年   11篇
  1984年   6篇
  1983年   9篇
  1982年   8篇
  1981年   9篇
  1980年   13篇
  1979年   3篇
  1978年   4篇
  1977年   11篇
  1976年   8篇
  1975年   9篇
  1974年   5篇
  1969年   2篇
  1966年   2篇
  1965年   3篇
排序方式: 共有690条查询结果,搜索用时 12 毫秒
61.
62.
A follow up study was performed in the rehabilitation centre for patients with leprosy in Hôchiminhville - Vietnam. All patients had claw-hand deformity due to ulnar and median nerve intrinsic paralysis. Thirty-two affected hands (128 long fingers) were included in the study. A Bunnel-Littler tendon transfer procedure was performed using a four-tailed graft of the flexor digitorum superficialis of the third finger. Clinical evaluation included anatomical measurements of interphalangeal and metacarpal joints in complete extension and in the intrinsic position. In the open hand assessment, 48.5% reported good results, 14.8% medium results and 36.7% poor results. With the hand in the intrinsic position, 53.9% achieved good results, while 33.6% achieved medium results and poor in 12.5%. Poor functional outcome is related to a failure of this procedure and seems to be due to extensor tendon laxity, with or without stiffness of the interphalangeal joints. There were many anatomical deformities (27.3%) found at the time of follow up, notably boutonniere (51.4%) and mallet finger deformities (31.4%) The fourth and fifth fingers had the worst results. We have therefore decided to change our protocol for claw-hand correction and use the Bouvier test in deciding on our surgical indications. Preoperative physiotherapy is absolutely necessary to reduce stiffness of the interphalangeal joints.  相似文献   
63.
64.

Background  

Recent studies have reported the clinical importance of CYP2C19 and ABCB1 polymorphisms in an individualized approach to clopidogrel treatment. The aims of this study were to evaluate the frequencies of CYP2C19 and ABCB1 polymorphisms and to identify the clopidogrel-predicted metabolic phenotypes according to ethnic groups in a sample of individuals representative of a highly admixtured population.  相似文献   
65.
CD146 is an adhesion molecule expressed by both melanoma and endothelial cells and thus is well positioned to control melanoma extravasation. Nevertheless, during melanoma metastasis, the involvement of CD146 expressed within tumor microenvironment has never been analyzed. To investigate whether host CD146 mediates the extravasation of melanoma cells across the endothelium, we generated CD146 KO mice. We demonstrated that host CD146 did not affect melanoma growth or tumor angiogenesis but promoted hematogenous melanoma metastasis to the lung. Accordingly, the survival of CD146‐deficient mice was markedly prolonged during melanoma metastasis. Interestingly, vascular endothelial growth factor‐induced vascular permeability was significantly decreased in CD146 KO mice. We also provided evidence that VEGF‐induced transendothelial migration of melanoma cells was significantly reduced across CD146 KO lung microvascular endothelial cells (LMEC). CD146 deficiency decreased the expression of VEGFR‐2/Ve‐cadherin and altered focal adhesion kinase (FAK) activation in response to VEGF. In addition, inhibition of FAK phosphorylation reduced transmigration of B16 melanoma cells across WT LMEC at the same level that across CD146 KO LMEC. Altogether, we propose a novel mechanism involving the VEGF/CD146/FAK/Ve‐cadherin network in melanoma extravasation across the vessel barrier that identifies CD146‐targeted therapy as a potential strategy for the treatment of melanoma metastasis.  相似文献   
66.

Aim

Several methods permit the measurement of geometric parameters of the cornea, but until now biomechanical conditions of the cornea have been ignored (e.g. in refractive corneal surgery). Besides the geometric condition, biomechanical properties of the cornea have been shown to influence applanation measurement of intra-ocular pressure (IOP) and epidemiological studies have identified corneal thickness as an independent risk factor for the development and progression of glaucoma. The aim of this investigation was to characterize the biomechanical properties of the cornea using the ocular response analyzer (ORA).

Methods

The ocular response analyzer (ORA) is a new method available for non-contact measurement of the biomechanical properties of the cornea. We evaluated the reproducibility of measurements, the difference between static and dynamic factors and the impact of independent factors (e.g. IOP, age, CCT, swelling of the cornea) on 2,500 measurements of corneal hysteresis (CH) and corneal resistance factor (CRF).

Results

In a large sample size we observed changes in CH and CRF after refractive surgery procedures (LASIK, UV-A cross-linking, keratoplasty) and in other corneal disorders (keratoconus, corneal dystrophies).

Conclusions

CRF and CH changes may reflect structural changes of the cornea. Thus, the ORA provides valuable information for a better understanding and characterization of the biomechanical condition of the cornea, especially with regard to diseases such as keratoconus and glaucoma.  相似文献   
67.
One case of "campomélique" dysplasia discovered by echography at 17 weeks is reported. The details of the syndrome are recalled. In this particular case, only the histology enabled the exact diagnosis to be made. The distinction between "syndrome campomélique" and other syndromes involving deformation of long bones (imperfect osteogenesis of the foetal type and isolated curvature of the tibia) is not easy during early pregnancy using echography alone. At a later stage, the signs and symptoms become more distinct and an exact diagnosis is probably easier.  相似文献   
68.
Background  Bacterial overgrowth may cause cobalamin deficiency through competition for dietary cobalamin in the small intestine. The objective of this study was to prospectively determine the prevalence of small bowel bacterial overgrowth in patients with documented cobalamin deficiency in a tertiary referral centre.
Methods  Patients identified with cobalamin deficiency underwent diagnostic investigations including: Endoscopy (with gastric antrum, gastric body and duodenal biopsies and duodenal aspirate), 14C-D-Xylose breath test, intrinsic factor antibody, anti-endomysial antibody and red cell folate level. 'Definite' small bowel bacterial overgrowth was defined as either a positive 14C-D-Xylose breath test or > 100 000 CFU/mL of culture of duodenal aspirate. 'Suspected' small bowel bacterial overgrowth was defined as an elevated red cell folate in the absence of supplemental folate therapy.
Results  Over a 2-year period, 62 patients with cobalamin deficiency were identified, of whom, 26 (42%) had 'definite' small bowel bacterial overgrowth, whilst a further nine (15%) had 'suspected' small bowel bacterial overgrowth. Nineteen (31%) had pernicious anaemia, and no cause for cobalamin deficiency could be found in eight (13%) patients. The diagnosis found in the remaining patients included coeliac disease (4), Crohn's Disease (1), gastric resection (2), vegan (2), homozygotes of the MTHFR gene (C677T) mutation (2), and one had enteropathy associated with common variable immunodeficiency (CVID). 'Definite' small bowel bacterial overgrowth was found to coexist with nine of the 19 cases of pernicious anaemia, two coeliac subjects, one CVID enteropathy and one patient with the MTHFR gene mutation.
Conclusion  Small bowel bacterial overgrowth is commonly associated with cobalamin deficiency.  相似文献   
69.
OBJECTIVE: To evaluate the occurrence of variants of the interleukin 4 (IL-4) and IL-4 receptor (IL-4R) genes in patients with rheumatoid arthritis (RA) and their possible contribution to joint destruction. METHODS: Allelic frequencies for polymorphisms in the IL-4 [variable number of tandem repeat (VNTR) polymorphism in intron 3] and IL-4 receptor alpha chain (transition at nucleotide 1902) genes were assessed in 335 RA patients and 104 controls. Clinical indices of disease activity, disability and joint destruction and plasma levels of IL-1beta, IL-1Ra and sCD23 were assessed to evaluate a possible functional effect. RESULTS: Carriage of the rare IL-4(2) allele was higher in patients with non-destructive RA (40%) than in those with destructive RA (22.3%; odds ratio = 1.9, 95% confidence interval 1. 1-3.5, P = 0.0006) and in controls (26%, P = 0.002). Patients positive for this rare allele had significantly less joint destruction, assessed by the Larsen wrist index (P = 0.004) and a lower erythrocyte sedimentation rate (P = 0.04). A significantly higher carriage rate of IL-4(2) was seen in HLA-DR4/DR1(-) patients with non-destructive RA than in those with destructive RA. The IL-4 receptor polymorphism was not over-represented. Plasma levels of IL-1beta, IL-1Ra and sCD23, known to be modified by IL-4, were not different in individuals having different alleles. CONCLUSION: This IL-4 VNTR gene polymorphism may be a protective factor for severe joint destruction in RA that could be used as a prognostic marker early in the course of the disease.  相似文献   
70.
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