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   2086篇
  免费   170篇
  国内免费   7篇
耳鼻咽喉   10篇
儿科学   114篇
妇产科学   26篇
基础医学   293篇
口腔科学   44篇
临床医学   169篇
内科学   563篇
皮肤病学   47篇
神经病学   155篇
特种医学   19篇
外科学   238篇
综合类   60篇
一般理论   3篇
预防医学   80篇
眼科学   37篇
药学   144篇
中国医学   6篇
肿瘤学   255篇
  2023年   24篇
  2022年   48篇
  2021年   114篇
  2020年   58篇
  2019年   69篇
  2018年   62篇
  2017年   57篇
  2016年   66篇
  2015年   73篇
  2014年   105篇
  2013年   116篇
  2012年   183篇
  2011年   171篇
  2010年   92篇
  2009年   82篇
  2008年   131篇
  2007年   115篇
  2006年   93篇
  2005年   101篇
  2004年   79篇
  2003年   81篇
  2002年   51篇
  2001年   45篇
  2000年   32篇
  1999年   30篇
  1998年   10篇
  1997年   10篇
  1996年   9篇
  1995年   11篇
  1994年   7篇
  1993年   8篇
  1992年   20篇
  1991年   16篇
  1990年   7篇
  1989年   14篇
  1988年   6篇
  1987年   7篇
  1986年   4篇
  1985年   9篇
  1984年   4篇
  1983年   4篇
  1982年   10篇
  1981年   2篇
  1979年   8篇
  1976年   2篇
  1974年   3篇
  1972年   3篇
  1971年   4篇
  1966年   1篇
  1907年   1篇
排序方式: 共有2263条查询结果,搜索用时 31 毫秒
1.
We report on a child with several café au lait spots in association with a lumbar lipomeningomyelocele as an apparently new association. Cutaneous markers, the identification of which plays a crucial role in the early diagnosis and management of spinal malformations, can accompany occult spinal dysraphism. Herein we report a case of lumbar lipomeningomyelocele associated with an overlying café au lait spot that served as a marker of occult spinal dysraphism. The patient also had segmental café au lait spots on the face, making the association unique.  相似文献   
2.
Purpose

The development of Laparoscopic Linear Endostaplers (LLES) is crucial in minimally invasive approaches in bariatric surgery, but there have been very few published studies comparing 6-row LLES in Laparoscopic Sleeve Gastrectomy (LSG). The objective of this study was to compare two 6-row LLES in LSG.

Methods

A total of 60 patients were prospectively randomized to undergo LSG with either Medtronic Endo GIA? Tri-Staple technology (MTS) or AEON ? Endostapler(Lexington Medical) LLES. The measured parameters included patient demographics, comorbidity indices, LLES and specimen characteristics, postoperative symptoms, hospital stay, and total adverse events (AEs). Intraoperative bleeding was evaluated using five laparoscopic and corresponding endoscopic images of staple line before clip application, compared with a 1–5 Visual Analogue Scale (VAS), assessed by an independent bariatric surgeon who was blinded to the LLES used. Images of all cases were reviewed on the same day to increase test–retest reliability.

Results

Both groups were similar in patient demographics. Compared to MTS, AEON LLES group had significantly lower bleeding VAS scores in 4/5 laparoscopic images (pre-pyloric: 1.7?±?0.7 vs. 2.36?±?0.76, p?=?0.0007, mid-sleeve: 1.46?±?0.62 vs. 1.86?±?0.68, p?=?0.019, proximal sleeve: 1.6?±?0.77 vs. 2.0?±?0.83, p?=?0.038, gastro-esophageal junction: 1.43?±?0.67 vs. 1.86?±?0.77, p?=?0.014) and 3/5 endoscopic images (pre-pyloric: 1.56?±?0.56 vs. 2.36?±?0.76, p?=?0.006, incisura: 1.66?±?0.54 vs. 2.0?±?0.52, p?=?0.021, mid-sleeve: 1.63?±?0.49 vs. 2.0?±?0.45, p?=?0.005). There was no statistical difference in other parameters.

Conclusion

Both devices were equally safe and effective in terms of LLES and specimen characteristics, patient symptoms, hospital stay, and AEs. Bleeding VAS scores were significantly lower, favoring the AEON LLES.

Graphical abstract
  相似文献   
3.
Fracture risk in monoclonal gammopathy of undetermined significance.   总被引:3,自引:0,他引:3  
To assess fractures in monoclonal gammopathy of undetermined significance (MGUS), the precursor of multiple myeloma, we followed 488 Olmsted County, MN, residents with MGUS in a retrospective cohort study. There was a 2.7-fold increase in the risk of axial fractures but no increase in limb fractures. The pathophysiologic basis for the increased axial fractures should be determined. INTRODUCTION: Multiple myeloma is often preceded by monoclonal gammopathy of undetermined significance (MGUS). Fractures are common in myeloma as a result of lytic bone lesions, generalized bone loss, and elevated bone turnover from excessive cytokine production. Whether fractures are also increased in MGUS is unknown. MATERIALS AND METHODS: In a population-based retrospective cohort study, 488 Olmsted County, MN, residents with MGUS first diagnosed in 1960-1994 (52% men; mean age, 71.4 +/- 12.8 years) were followed for 3901 person-years; follow-up was censored at progression to myeloma. The relative risk of fractures was assessed by standardized incidence ratios (SIRs), and risk factors were evaluated in proportional hazards models. RESULTS AND CONCLUSIONS: Altogether, 200 patients experienced 385 fractures. Compared with expected rates in the community, statistically significant increases were seen for fractures at most axial sites, for example, vertebrae (SIR, 6.3; 95% CI, 5.2-7.5). There was a slight increase in hip (SIR, 1.6; 95% CI, 1.2-2.2) but not distal forearm fractures (SIR, 0.8; 95% CI, 0.4-1.5). The relative risk (SIR) of any axial fracture was 2.7 (95% CI, 2.3-3.1) compared with only 1.1 (95% CI, 0.9-1.4) for all limb fractures combined. In a multivariate analysis, the independent predictors of any subsequent fracture were age (hazard ratio [HR] per 10-year increase, 1.4; 95% CI, 1.2-1.6) and corticosteroid use (HR, 1.8; 95% CI, 1.2-2.6); greater weight at diagnosis (HR per 10 kg, 0.8; 95% CI, 0.8-0.9), and IgG monoclonal protein (HR, 0.7; 95% CI, 0.5-0.97) were protective. Baseline monoclonal protein level, a determinant of myeloma progression, did not predict fracture risk. Thus, the risk of axial, but not peripheral, fractures is increased among MGUS patients even before progression to myeloma. The pathophysiologic basis for this should be determined because elevated bone turnover, for example, might be treatable.  相似文献   
4.
5.
Retinitis pigmentosa is one of the most common causes of severevisual handicap in middle to late life. Prior to this report,seven loci had previously been mapped for the autosomal dominantform of this disorder (adRP). We now report the identificationof a novel adRP locus on chromosome 17q. To map the new locus,we performed linkage analysis with microsatellite markers ina large South African kindred. After exclusion of 13 RP candidategene loci (including rhodopsin and peripherin-RDS), we obtainedsignificant positive lod scores at zero recombination fraction(  相似文献   
6.
A quantitative chemical analysis of total cholesterol, bilirubin, calcium, inorganic phosphate and iron of three types of biliary calculi (cholesterol, pigment and mixed) of 40 gall stone former was carried out and correlated to with those of there sera. A moderately positive correlation for inorganic phosphate, Ca2+ and Fe2+ content of sera and calculi of cholesterol stone patient was found. A Good positive correlation for total cholesterol, a moderately positive correlation for bilirubin and iron but no correlation for inorganic phosphate and calcium content of sera and calculi of pigment stone patient was observed. A good moderately positive correlation for iron but no correlation for total cholesterol, bilirubin, inorganic phosphate and Ca2+ content of sera and calculi of stone patient was found.  相似文献   
7.
ABSTRACT

Introduction

Biomarkers may help influence long-term outcomes of psoriatic disease by improving the objective assessment of the presence and severity of psoriatic arthritis (PsA) and by guiding treatment selection. However, there are no validated biomarkers for PsA.  相似文献   
8.
Three fowl adenovirus 4 (FAV4) isolates from chicken and one from quail, all from Tamil Nadu, India were analyzed. The L1 loop variable region of hexon gene of these isolates was amplified by PCR and sequenced. The nucleotide sequences (442 bp) and deduced amino acid sequences of the four isolates were compared with those of other isolates of FAV4. The nucleotide sequences of the four isolates had a 98% homology with other Indian isolates and a 96% homology with Belgian and Russian isolates. The amino acid sequences of the four Indian isolates had a more than 98% homology with other Indian isolates and a more than 92% homology with Belgian and Russian isolates. Hence, the variable of L1 loop region of hexon gene was found to be highly homologous in all the FAV4 isolates tested both at nucleotide and amino acid level.  相似文献   
9.
Haemophilus influenzae type b (Hib) is responsible for significant morbidity and mortality worldwide, particularly in children under 5 years of age. In countries where the Hib conjugate vaccine is not routinely used, Hib is a leading cause of childhood pneumonia and meningitis. Routine use of the Hib conjugate vaccines has resulted in a remarkable decline in Hib disease in developed and developing countries. However, Hib conjugate vaccines are not routinely available in most developing countries, many of which have high burdens of Hib disease. This review outlines the pathogenesis and epidemiology of Hib disease, and the various options for prevention.  相似文献   
10.
In addition to their vasoactive action, endothelins are potent peptides in the regulation of both cell proliferation and the turnover of extracellular matrix. Using immunohistochemical, autoradiographic, and molecular analyses, we have studied the localization and expression of endothelin-1 and endothelin A (ETA) and B (ETB) receptors in scleroderma-associated fibrotic lung disease. Increased ET-1 immunoreactivity was found in sclerotic tissue compared with control and was associated with the vasculature, pulmonary interstitium, and bronchial and alveolar epithelium. Microautoradiographic analysis after 125I-labeled ET-1 binding showed a two- to threefold increase in the expression of total ET-1 receptors in scleroderma lung tissue localized to the alveolar epithelium and the pulmonary interstitium which was composed of mainly fibroblastic cells with macrophages and some microvessels. RNAse protection assay revealed significantly reduced ETA receptor and slightly raised ETB message levels in systemic sclerosis lung. Surface expression of functional ET receptors was examined by targeted receptor blocking using mixed and receptor-subtype-selective ligands. A consistent decrease in ETA receptor binding sites was noted primarily within the interstitium and vasculature, in contrast to a slight increase in ETB receptors. Elevated ET-1 and the cell-specific pattern of endothelin receptor expression suggest that the endothelins may represent important mediators that influence the pathology of scleroderma-associated lung disease and other fibrotic conditions.  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