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   4236篇
  免费   151篇
  国内免费   23篇
耳鼻咽喉   63篇
儿科学   102篇
妇产科学   25篇
基础医学   576篇
口腔科学   106篇
临床医学   258篇
内科学   972篇
皮肤病学   61篇
神经病学   321篇
特种医学   210篇
外科学   656篇
综合类   16篇
预防医学   171篇
眼科学   106篇
药学   349篇
中国医学   3篇
肿瘤学   415篇
  2023年   33篇
  2022年   45篇
  2021年   97篇
  2020年   57篇
  2019年   80篇
  2018年   74篇
  2017年   91篇
  2016年   86篇
  2015年   96篇
  2014年   116篇
  2013年   133篇
  2012年   268篇
  2011年   286篇
  2010年   135篇
  2009年   140篇
  2008年   293篇
  2007年   286篇
  2006年   285篇
  2005年   298篇
  2004年   311篇
  2003年   231篇
  2002年   282篇
  2001年   34篇
  2000年   40篇
  1999年   50篇
  1998年   60篇
  1997年   60篇
  1996年   38篇
  1995年   53篇
  1994年   39篇
  1993年   43篇
  1992年   33篇
  1991年   20篇
  1990年   20篇
  1989年   12篇
  1988年   18篇
  1987年   11篇
  1986年   7篇
  1985年   11篇
  1984年   14篇
  1983年   13篇
  1982年   16篇
  1981年   17篇
  1980年   17篇
  1979年   11篇
  1978年   15篇
  1977年   8篇
  1976年   3篇
  1975年   3篇
  1964年   3篇
排序方式: 共有4410条查询结果,搜索用时 109 毫秒
71.
Microsurgeons rarely encounter a situation that includes multiple downstream arteries requiring reperfusion with only one feeding artery being available. To cope with the difficulty of such a case, a unique microvascular anastomosis is described. This surgical technique is based on the assumption of the presence of a single large outflowing vessel and two small downstream vessels. The axial incisions were made on the cut end of the two small vessels. The ends of the two small vessels were sutured side-to-side and remodeled as one vessel. The partially coalesced small vessels were then anastomosed with the outflowing large vessel in an end-to-end fashion. Case presentation: a crush injury of the foot required reconstruction of the blood flow. The first dorsal metatarsal artery (FDMA) was damaged and occluded by thrombosis. The first and second toes had no blood supply. The original plan was simply to remove the damaged area of the FDMA and replace it with a straight vein graft, as the bifurcation to the two digital arteries appeared to be intact. At the time of microvascular anastomosis, however, the FDMA was found to still be damaged, and it required additional debridement. As a suboptimal method, the vein graft and the two digital arteries were anastomosed by the above-described atypical method. The digits all survived, and the patient subsequently returned to work, with no complications as of 10 months postoperatively. This atypical microvascular anastomosis is not an established method, but it has potential utility in similar situations.Level of Evidence: Level V, therapeutic study.  相似文献   
72.
Ionized calcium binding adaptor molecule 1 (Iba1) is associated with membrane ruffling and motility of cells. Galectin-3 (Gal-3) is a β-galactoside binding animal lectin, and regulates fibrogenesis probably through transforming growth factor-β1. To evaluate macrophage properties, expressions of Iba1 and Gal-3 were investigated, in relation to macrophages expressing CD68 (ED1; reflecting increased phagocytosis) and CD163 (ED2; implying proinflammatory factor productions) in centrilobular lesions induced in rat livers with thioacetamide (TAA; 300 mg/kg body weight, once intraperitoneally). In agreement with expression patterns of CD68+ and CD163+ macrophages, cells reacting to Iba1 and Gal-3 were increased in numbers on post-injection (PI) days 1–5, peaking on day 2; thereafter, the positive cells gradually decreased to control levels until PI days 7 and 10. The increased expressions of Iba1 and Gal-3 were confirmed at mRNA levels by the RT-PCR. Double immunofluorescence staining on PI days 2 and 3 demonstrated Iba1 expression in 15–46% of CD68+ and CD163+ macrophages, and Gal-3 expression in 65–82% of CD68+ and CD163+ macrophages; Gal-3 expression was observed in 84–93% of Iba1+ cells. Interestingly, Gal-3 was also expressed in a small number of α-smooth muscle actin-positive myofibroblasts in fibrotic lesions developed in injured centrilobular areas. These findings indicate that macrophages with various functions can participate in development of liver lesions and resultant fibrosis. Besides CD68 and CD163, Iba1 and Gal-3 immunohistochemistry for macrophages would be useful to analyze the pathogenesis behind developing hepatotoxicity.  相似文献   
73.
74.
75.
76.
A successful surgical palliative procedure, consisting of an arterial switch operation, pulmonary artery banding, and arch repair, was performed in a neonate with Taussig-Bing anomaly and aortic arch interruption, subaortic stenosis, and multiple muscular ventricular septal defects. Such anatomical complexity made treatment difficult. This palliative procedure allows future biventricular repair.  相似文献   
77.
Androgen-deprivation therapy (ADT) of patients with prostate cancer (PCa) is known to reduce bone mineral density (BMD). However, the most studies examined Caucasian or black patients and the effects of ADT on the bone metabolism of East Asians are unclear. Therefore, we performed a cross-sectional study to elucidate the influence of ADT on bone metabolism in Japanese patients. In total, 101 native Japanese patients with PCa were enrolled. They consisted of 58 ADT-treated and 43 hormone-naive patients. The BMD in the lumbar spine, total hip, and femoral neck was measured by dual energy X-ray absorptiometry and expressed in s.d. units relative to young adult men (T-score) or age-matched men (Z-score). Serum levels of bone metabolism markers were also measured. The BMDs at the three sites revealed that 2.3% (1/43) and 8.6% (5/58) of the hormone-naive and ADT-treated PCa patients had osteoporosis respectively, but this difference failed to achieve statistical significance (P=0.294). The two groups also did not differ significantly in their Z-scores of the three sites, and univariate and multivariate analyses indicated that ADT was not a significant risk factor for decreased BMD. In addition, a significant correlation between the duration of ADT and BMD was not observed for all three sites measured. However, the ADT-treated patients had significantly higher serum levels of N-terminal telopeptide of type I collagen (NTx) than the hormone-naive patients (P=0.017). To our knowledge, this is the first study to demonstrate the low prevalence of osteoporosis in both ADT-treated and hormone-naive Japanese PCa patients. Moreover, ADT did not significantly increase the prevalence of osteoporosis in this Japanese population.  相似文献   
78.
Familial hypertrophic cardiomyopathy (HC) can be caused by mutations in 9 different genes encoding sarcomere proteins expressed in cardiac muscle. To date, only 13 different mutations in the cardiac troponin T (cTnT) gene have been reported to cause HC. Clinical characteristics and prognosis associated with mutations of this gene have not been well characterized owing to the small size and composition of affected families. The aim of this study was to determine the characteristic phenotype of patients with HC caused by a novel cTnT gene mutation, Lys273Glu. Two hundred Japanese probands with HC were screened for mutations in the cTnT gene. The Lys273Glu missense mutation was present in 9 persons from 2 unrelated pedigrees. They exhibited different cardiac morphologies: 1 had a dilated cardiomyopathy-like feature, 7 had left ventricular hypertrophy with normal left ventricular systolic function, and the 6 of them had asymmetric septal hypertrophy. A 1-year-old boy was not evaluated with echocardiography. The mean maximum wall thickness was 18.0 +/- 5.5 mm (range 8 to 24). There were 7 histories of sudden death in 1 of the 2 families. The Lys273Glu substitution in the cTnT gene shows a high degree of penetrance (100% in persons aged >20 years), a high incidence of sudden death, and a partial transition from hypertrophic to dilated cardiomyopathy. Because the location of a mutation appears to influence the development of a phenotype, we suggest that the precise definition of the disease-causing mutation can provide important prognostic information about affected members.  相似文献   
79.
Background: Achieving long-term gene expression in kidney will be beneficial for gene therapy of renal and congenital diseases, genetic studies constructing animal disease models, and the functional analysis of disease-related genes.

Purpose: The purpose of this study was to develop an in vivo long-term gene expression system in murine kidney using ?C31 integrase.

Methods: Gene expression in cultured RENCA, TCMK-1, and HEK293 cells was assessed. The long-term in vivo gene expression system in the kidney was achieved by co-transfecting 5?µg of pORF-luc/attB as a donor plasmid and 20?µg of pCMV-luc as a helper plasmid into the right kidney of mice by electroporation. Luciferase expression levels were measured to determine longevity of the expression.

Results: Significantly high luciferase expression levels were observed in cultured RENCA, TCMK-1, and HEK293 cells over 1 month compared with controls (non-integrase system). The luciferase cDNA sequence was integrated at a pseudo attP site termed mpsL1. In vivo luciferase expression levels in the integrase group were sustained and significantly higher than those in the control group over 2 months. Furthermore, ?C31 integrase-transfected cells had less genomic DNA damage caused by integrase expression.

Discussion and conclusion: These results demonstrated that the ?C31 integrase system could produce long-term (2 months) in vivo gene expression in mouse kidney.  相似文献   
80.
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