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   2310篇
  免费   106篇
  国内免费   10篇
耳鼻咽喉   19篇
儿科学   48篇
妇产科学   34篇
基础医学   318篇
口腔科学   59篇
临床医学   118篇
内科学   645篇
皮肤病学   42篇
神经病学   212篇
特种医学   66篇
外科学   437篇
综合类   19篇
预防医学   43篇
眼科学   26篇
药学   143篇
中国医学   3篇
肿瘤学   194篇
  2023年   22篇
  2022年   32篇
  2021年   42篇
  2020年   30篇
  2019年   42篇
  2018年   52篇
  2017年   28篇
  2016年   45篇
  2015年   41篇
  2014年   56篇
  2013年   59篇
  2012年   90篇
  2011年   151篇
  2010年   91篇
  2009年   62篇
  2008年   105篇
  2007年   100篇
  2006年   108篇
  2005年   116篇
  2004年   101篇
  2003年   116篇
  2002年   100篇
  2001年   103篇
  2000年   99篇
  1999年   100篇
  1998年   28篇
  1997年   18篇
  1996年   20篇
  1995年   12篇
  1994年   11篇
  1992年   46篇
  1991年   30篇
  1990年   33篇
  1989年   47篇
  1988年   32篇
  1987年   33篇
  1986年   33篇
  1985年   23篇
  1984年   15篇
  1983年   14篇
  1979年   12篇
  1978年   11篇
  1977年   10篇
  1974年   6篇
  1973年   6篇
  1971年   10篇
  1969年   8篇
  1968年   9篇
  1967年   8篇
  1966年   11篇
排序方式: 共有2426条查询结果,搜索用时 15 毫秒
81.
Aims/IntroductionSodium–glucose cotransporter 2 inhibitors (SGLT2i) improve renal outcome in patients with type 2 diabetes mellitus, but the mechanism is not fully understood. The aim of this retrospective study was to assess the association of achieved blood pressure with renal outcomes in Japanese type 2 diabetes mellitus patients with chronic kidney disease.Materials and MethodsWe assessed 624 Japanese type 2 diabetes mellitus patients with chronic kidney disease taking SGLT2i for >1 year. The patients were classified as those with post‐treatment mean arterial pressure (MAP) of ≥92 mmHg (n = 344) and those with MAP of <92 mmHg (n = 280) for propensity score matching (1:1 nearest neighbor match with 0.04 of caliper value and no replacement). The end‐point was a composite of progression of albuminuria or a decrease in the estimated glomerular filtration rate by ≥15% per year.ResultsBy propensity score matching, a matched cohort model was constructed, including 201 patients in each group. The incidence of renal composite outcome was significantly lower among patients with MAP of <92 mmHg than among patients with MAP of ≥92 mmHg (n = 11 [6%] vs n = 26 [13%], respectively, P = 0.001). The change in estimated glomerular filtration rate was similar in the two groups; however, the change in the albumin‐to‐creatinine ratio was significantly larger in patients with MAP of <92 mmHg.ConclusionsIn Japanese type 2 diabetes mellitus patients with chronic kidney disease, blood pressure after SGLT2i administration influences the renal composite outcome. Blood pressure management is important, even during treatment with SGLT2i.  相似文献   
82.
Aim: Arterial stiffness results in elevated left ventricular filling pressure and can promote atrial remodeling due to chronic pressure overload. However, the impact of arterial stiffness on the process of atrial remodeling in association with atrial fibrillation (AF) has not been fully evaluated. Methods: We enrolled 237 consecutive patients diagnosed with AF who had undergone ablation; data from 213 patients were analyzed. Cardio-ankle vascular index (CAVI) was used as a marker of arterial stiffness. The left atrial (LA) and right atrial (RA) volumes were determined by computed tomography imaging; atrial conduction and voltage amplitude were evaluated using a three-dimensional electromapping system used to guide the ablation procedure. Result: In univariate analysis, CAVI significantly correlated with atrial structural and electrical remodeling (LA volume index, r =0.297, P =0.001; RA volume index, r =0.252, P =0.004; LA conduction velocity, r =0.254, P = 0.003; LA mean voltage, r =−0.343, P =0.001, RA mean voltage; r =−0.245, P =0.015). Multivariate regression analysis revealed that CAVI and plasma levels of N-terminal B-type natriuretic peptide were independent determinants of LA and RA remodeling, respectively. On the other hand, age and LA conduction velocity were independent variables with respect to CAVI. Age-adjusted CAVI was highest in long-standing persistent AF when compared with measures of persistent or paroxysmal AF. Conclusion: CAVI was closely associated with biatrial remodeling in patients diagnosed with AF. These results suggest that arterial stiffness may play a significant role with respect to disease progression.  相似文献   
83.
A 72-year-old man with non-Hodgkin’s lymphoma at the tracheal bifurcation node received combination chemotherapy and subsequently developed a fistula in spite of remission of the lymphoma. Conservative therapy did not heal the fistula formation, and we chose bypass surgery using a gastric tube without thoracotomy. Ten months postoperatively, there is no evidence of lymphoma relapse and the patient lives a normal life. We consider this procedure as an available treatment for esophagobronchial fistula in case of failure to cure fistula communication by conservative therapy.  相似文献   
84.
The effects of T3 and T4 on the iodothyronine 5'-deiodinase (5'-D) activity in FRTL-5 rat thyroid cells were investigated. T3 and T4 stimulated the 5'-D activity in a dose-dependent manner. Kinetic studies showed that the stimulation of the 5'-D by T3 was associated with an increase in maximum velocity (Vmax) in [11.9 +/- 0.2 (mean +/- SE) and 25.4 +/- 0.9 pmol I-released/mg protein.min, respectively, in control and cultured with 10(-9) M T3 for four days] but without a change in apparent Michaelis-Menten constant (Km) (94.8 +/- 5.3 nM and 105.4 +/- 12.1 nM, respectively). Furthermore, cycloheximide (5 microM) completely abolished the stimulatory effect of T3 on the 5'-D activity. T3 and T4 also enhanced the 5'-D activity stimulated by TSH in a dose-dependent manner. Kinetic studies showed that the stimulatory effect of T3 on the 5'-D stimulated by TSH was again associated with an increase in Vmax (86.0 +/- 4.0 and 166.5 +/- 1.9 pmol I- released/mg protein.min, respectively, cultured with 0.3 U/liter TSH and cultured with TSH plus 10(-9) M T3 for four days) without a change in apparent Km (114.0 +/- 7.4 nM and 111.6 +/- 12.5 nM, respectively). Cycloheximide (5 microM) completely abolished the stimulatory effect of TSH plus T3 on the 5'-D activity. There were no significant differences observed between cells cultured with TSH and with TSH plus T3 in either the intra- or extracellular cAMP contents. Furthermore, T3 enhanced the 5'-D activity stimulated by (Bu)2 cAMP. These results strongly suggest that T3 or T4 was synergistic with TSH in stimulating the 5'-D activity in FRTL-5 cells, and that cAMP production would be an important component of the synergism.  相似文献   
85.
86.
We report a case of an extrahepatic bile duct metastasis from a gallbladder cancer that mimicked Mirizzi's syndrome on cholangiography. A 67-yr-old woman was admitted to our hospital with a diagnosis of acute calculous cholecystitis. As obstructive jaundice developed after the admission, percutaneous transhepatic biliary drainage was performed to ameliorate the jaundice and to evaluate the biliary system. Tube cholangiography revealed bile duct obstruction at the hepatic hilus, and extrinsic compression of the lateral aspect of the common hepatic duct, with nonvisualization of the gallbladder. No impacted cystic duct stone was visualized on CT or ultrasonography. Laparotomy revealed a gallbladder tumor as well as an extrahepatic bile duct tumor. We diagnosed that the latter was a metastasis from the gallbladder cancer, based on the histopathological features. This case is unique in that the extrahepatic bile duct metastasis obstructed both the common hepatic duct and the cystic duct, giving the appearance of Mirizzi's syndrome on cholangiography. Metastatic bile duct tumors that mimic Mirizzi's syndrome have not been previously reported. The presence of this condition should be suspected in patients with the cholangiographic features of Mirizzi's syndrome, when the CT or ultrasonographic findings fail to demonstrate an impacted cystic duct stone.  相似文献   
87.
BACKGROUND/AIMS: To clarify changes in the hepatic oxygen metabolism and tissue damage resulting from oxygen-derived free radical generation from polymorphonuclear cells during a hepatic arterial clamp. METHODOLOGY: Subjects were 32 male Wistar rats. Hepatic tissue blood flow, and hepatic venous chemiluminescence, indicating oxygen-derived free radicals from polymorphonuclear cells, and liver lipid peroxide were measured, and hepatic and portal venous blood gas analysis were performed before and after 130 minutes of hepatic arterial clamping. RESULTS: Hepatic tissue blood flow decreased by hepatic arterial clamp. The values of hepatic arterial oxygen pressure (HTBF), hepatic venous oxygen saturation (ShvO2), and O2 contents after hepatic arterial clamp were lower than those before hepatic arterial clamp (P = 0.035, 0.024, and 0.028, respectively). Hepatic venous chemiluminescence decreased and the lipid peroxide level of the liver increased by hepatic arterial clamp (P = 0.001). CONCLUSIONS: ShvO2 is useful for the evaluation of hepatic oxygen metabolism and hepatic tissue blood flow during acute hepatic arterial clamp. This condition should prepare the following tissue damage due to oxygen-derived free radicals from polymorphonuclear cells.  相似文献   
88.
Conclusion: The maximum standardized uptake value (SUVmax) of early oral squamous cell carcinoma (OSCC) may have a role as an imaging biomarker for assessment of malignant potential, including cell metabolism and angiogenesis. Objective: The usefulness of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) has been proven in various cancers, including OSCC. Moreover, in several carcinomas, the SUVmax of the tumor has been shown to correlate with the histological type, tumor stage, differentiation, and prognosis. Here, we investigated whether the SUVmax of early OSCC was associated with the biological features. Methods: Twenty-seven patients with newly diagnosed early OSCC who underwent preoperative FDG-PET and curative surgical resection were included in this study. Tumor sections were stained by immunohistochemistry for glucose transporter 1 (GLUT1), L-type amino acid transporter 1 (LAT1), CD98, microvessels (CD34), cell proliferation marker (Ki-67), and cell cycle regulator (p53). The correlation between SUVmax and clinicopathological findings or the expression level of these molecules was analyzed. Results: SUVmax of primary OSCC was significantly higher in patients with T2 stage. Moreover, patients whose tumors showed vascular invasion had a tendency to show higher SUVmax. A significant correlation was observed between SUVmax and the expression of LAT1 or microvessel density.  相似文献   
89.
90.

Background

Ischemic postconditioning (PostC) protects the liver against ischemia-reperfusion (IR) injury. Milrinone, a phosphodiesterase 3 inhibitor, has been reported to exhibit preconditioning properties against hepatic IR injury; however, its PostC properties remain unknown. This study investigated whether milrinone has PostC properties against hepatic IR injury and the roles of phosphatidylinositol 3-kinase (PI3K) and nitric oxide synthase (NOS).

Materials and methods

Male Wistar rats were separated into six groups: (1) group S: animals that underwent sham operation without ischemia, (2) group C: ischemia followed by reperfusion with no other intervention, (3) group M: milrinone administered immediately after reperfusion, (4) group MW: wortmannin, a PI3K inhibitor, injected before milrinone administration, (5) group MN: l-NAME, a NOS inhibitor, injected before milrinone administration, and (6) group MD, milrinone administered 30 min after reperfusion. Except for group S, all groups underwent 1 h of warm ischemia of median and left lateral lobes, followed by 5 h of reperfusion. Biochemical liver function analysis and histologic examination were performed.

Results

Serum aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase levels, histologic damage scores, and apoptotic rate in group M were significantly lower than those in group C. The inhibition of PI3K or NOS prevented this protective effect. Milrinone administered 30 min after reperfusion did not show obvious protective effects.

Conclusions

Milrinone-induced PostC protects against hepatic IR injury when it is administered immediately after reperfusion, and PI3K and NOS may play an important role in this protective effect.  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