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   966篇
  免费   52篇
  国内免费   5篇
耳鼻咽喉   21篇
儿科学   63篇
妇产科学   40篇
基础医学   84篇
口腔科学   78篇
临床医学   78篇
内科学   162篇
皮肤病学   21篇
神经病学   54篇
特种医学   20篇
外科学   177篇
综合类   17篇
预防医学   46篇
眼科学   46篇
药学   68篇
中国医学   2篇
肿瘤学   46篇
  2023年   7篇
  2022年   15篇
  2021年   25篇
  2020年   23篇
  2019年   22篇
  2018年   19篇
  2017年   19篇
  2016年   40篇
  2015年   34篇
  2014年   36篇
  2013年   39篇
  2012年   77篇
  2011年   91篇
  2010年   51篇
  2009年   31篇
  2008年   68篇
  2007年   85篇
  2006年   64篇
  2005年   59篇
  2004年   37篇
  2003年   41篇
  2002年   43篇
  2001年   14篇
  2000年   13篇
  1999年   8篇
  1998年   11篇
  1997年   5篇
  1996年   8篇
  1995年   6篇
  1994年   4篇
  1992年   8篇
  1991年   4篇
  1990年   1篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   6篇
  1985年   2篇
  1978年   1篇
  1973年   1篇
排序方式: 共有1023条查询结果,搜索用时 15 毫秒
1.
OBJECTIVE: This study aimed to investigate the rate of occupational sensitization to horse hair in grooms and whether occupational exposure to horse hair increases respiratory and allergic symptoms and affects lung function in grooms or not. METHODS: This is a cross-sectional study. Two hundred grooms were randomly selected among 1000 grooms working in Veliefendi Hippodrome of Istanbul. One hundred and twenty-five subjects agreed to enter the study. Ninety-two workers who worked in the different parts of this hippodrome enrolled as the control group. A detailed questionnaire including respiratory and allergic symptoms was filled in, physical examination, skin prick tests and pulmonary function tests were performed. RESULTS: Sensitization to horse hair was 12.8% in grooms and 4.3% in controls. The difference was statistically significant (P = 0.0035). Asthma was found in 14.4% of the grooms and 5.4% of the controls, allergic rhinitis in 42.4% of the grooms and 18.4% of the controls, allergic conjunctivitis in 35.2% of the grooms and 15.2% of the controls, and allergic skin diseases in 32.8% of the grooms and 13% of the controls. The differences were statistically significant (P = 0.043, P = 0.0002, P = 0.001 and P = 0.0008, respectively). The means of FEV1, FEV1/FVC and FVC parameters were significantly lower in the groom group (P = 0.006, P = 0.001 and P = 0.003, respectively). In the multivariate analysis, being in the groom group and working years were found to be predictive factors for impairments of lung function (P < 0.001 and P = 0.002, respectively). CONCLUSION: Occupational exposure to horse increases the sensitization to horse hair, induces asthma and allergic symptoms and also impairs lung functions.  相似文献   
2.
In living donor liver transplantation (LDLT), obtaining the precise volume of the graft is very important to decrease volume-related postoperative complications, especially in cases with suspected small-for size grafts. We used stereology based on the Cavalieri method (CM), a new method to measure liver graft volume, and compared the results with those obtained through intraoperative measurement (IOM) and through multidetector computed tomography (MDCT) measurement. Liver volumes estimated using the 3 methods were well-correlated with each other (r(2) = 0.94 and P < 0.001 for IOM and CM; r(2) = 0.91 and P < 0.001 for IOM and MDCT, and r(2) = 0.95 and P < 0.001 for CM and MDCT); however, they were different from each other (in descending order, 908 +/- 124 cm(2), 861 +/- 121 cm(2), and 777 +/- 168 cm(2) for MDCT, CM, and IOM, respectively). Although MDCT and CM overestimated the volumes, the results of CM were almost similar to those obtained via IOM. In conclusion, our results suggest that CM measured the liver graft volume more reliably. Thus, its use, particularly in cases with suspected small-for-size graft, may prove useful.  相似文献   
3.
OBJECTIVE: The purpose of the present study was to determine the distribution and level of temperature, in a model of a maxillary canine, the surrounding periodontal tissues, and the bones, during a System B heat obturation technique simulation. STUDY DESIGN: The temperature distribution was determined by using a three-dimensional finite element analysis. The tooth was assumed to have undergone an endodontic treatment before the application. Heat applications of 200 degrees C and 100 degrees C were considered. RESULTS: By using the virtual model and the simulation technique, the maximum temperature in the periodontal ligament was found to be 43.5 degrees C. CONCLUSIONS: Within the assumptions and the limitations of the study, it was determined that the simulation of System B technique created no potentially harmful levels of temperature throughout the maxillary canine model.  相似文献   
4.

Background  

The Turkish Association of Medicine founded a Continuing Medical Education Accreditation Committee in 1993 to evaluate and accredit scientific meetings and publications. The aims of this project were to raise the standards of meetings and to introduce compulsory revalidation and re-certification for physicians in Turkey.  相似文献   
5.
BACKGROUND: This study aimed to investigate whether exposure to sunflower pollen (Helianthus annuus) increases both sensitization and respiratory symptoms, and whether or not it affects lung functions in sunflower processing workers. METHODS: The largest sunflower processing factories in the Thrace region of Turkey participated in this study. Workers from the units directly exposed to sunflower seed enrolled as the study group (n = 102) and workers who were not directly exposed to Helianthus annuus pollen (n = 102) were the control group. Detailed questionnaires covering respiratory and allergic symptoms were completed, and skin prick tests and lung function tests were performed. RESULTS: We found a very high rate (23.5%) of sensitization to Helianthus annuus in the study group compared to the controls (P<0.001). Logistic regression analysis showed that the risk of sensitization to H. annuus was increased 4.7-fold (odds ratio = 4.17, 95%) confidence interval = 1.3-16.7) if subjects were exposed to sunflower pollen in the workplace. While asthmatic symptoms and allergic skin diseases were not different between the two groups, workers in the study group had a higher rate of allergic rhinitis and conjunctivitis (P<0.05). We found that pulmonary function was significantly impaired in the study group (P<0.01). Using a multivariate analysis model, inclusion in the study group was found to be a predictive factor for impairment of lung function (P=0.002). CONCLUSIONS: We conclude that sunflower pollen has high allergenic potential, especially when there is close contact, and exposure to sunflower pollen in the workplace can result in impairment in lung function.  相似文献   
6.
Although selenium, an essential trace element and a component of glutathione peroxidase, is known to protect the heart from ischemia-reperfusion (I/R)-induced injury, the mechanisms of this protection are not fully understood. For this purpose, isolated rat hearts were subjected to 30 min of global ischemia followed by 30 min of reperfusion; sodium selenite (25-1,000 nM) was added in the perfusion medium 10 min prior to ischemia, as well as during reperfusion. Selenium caused a dose-dependent improvement in cardiac performance and attenuated the decrease in the ratio of reduced glutathione to oxidized glutathione, as well as the increased level of malondialdehyde in I/R heart. Elevated ratios of nuclear factor-kappaB (NF-kappaB) in particulate and cytosolic fraction and of phosphorylated NF-kappaB and total NF-kappaB in I/R hearts were reduced by selenium. Cardiac dysfunction in hearts perfused with xanthine plus xanthine oxidase mixture, as well as hydrogen peroxide, or subjected to Ca2+ paradox was also attenuated by selenium. These data suggest that selenium protects the heart against I/R injury due to its action on the redox state and deactivation of NF-kappaB in I/R hearts.  相似文献   
7.

This study aims to synthesize and characterize an economical and ecological adsorbent with high adsorption capacity. For this purpose, the peanut shells (Pistacia vera L.) were modified chemically. After the synthesis of activated carbon (AC), the optimum conditions for enrichment steps were performed using parameters: pH and contact time for uranium in the model solutions. The measurements were carried out by inductively coupled plasma-mass spectrometry (ICP-MS). From the shapes of the BET isotherms, the AC obtained exhibits type I. The study indicated that the surface area and total pore volume of the AC were found to be 679.9 m2 g−1 and 0.31 cc g−1, respectively. The adsorption capacity was found to be 260 mg g−1. The optimum pH was found to be 6.0 for enrichment using the AC obtained by sulfuric acid as a chemical-modifier. The optimized method was applied to enrichment of U at ppb levels in the model solutions.

  相似文献   
8.
BACKGROUND: Cauda equina syndrome occurring as a result of spontaneous spinal subarachnoid hemorrhage (SAH) from a spinal tumor is reported to be rare. CASE DESCRIPTION: A 28-year-old woman presented at our clinic with a history of severe back pain for 10 days, progressive paraparesis, and urinary retention. Her physical examination revealed a mass located intradurally at the level of L1-2 and a massive SAH. An L1-L2, laminectomy and a hemilaminectomy from D9 to D12 were performed and the SAH was evacuated and the cord was decompressed. CONCLUSION: At the first year follow-up, her restricted dorsal and plantar flexion continued. Post-gadolinium magnetic resonance imaging revealed no mass.  相似文献   
9.
Di(ethylhexyl)phthalate (DEHP), the most widely used plasticizer, was investigated to determine whether an oxidative stress process was one of the underlying mechanisms for its testicular toxicity potential. To evaluate the effects of selenium (Se), status on the toxicity of DEHP was further objective of this study, as Se is known to play a critical role in testis and in the modulation of intracellular redox equilibrium. Se deficiency was produced in 3‐weeks‐old Sprague–Dawley rats feeding them ≤0.05 mg Se /kg diet for 5 weeks, and Se‐supplementation group was on 1 mg Se/kg diet. DEHP‐treated groups received 1000 mg/kg dose by gavage during the last 10 days of the feeding period. Activities of antioxidant selenoenzymes [glutathione peroxidase 1 (GPx1), glutathione peroxidase 4 (GPx4), thioredoxin reductase (TrxR)], catalase (CAT), superoxide dismutase (SOD), and glutathione S‐transferase (GST); concentrations of reduced glutathione (GSH), oxidized glutathione (GSSG), and thus the GSH/GSSG redox ratio; and thiobarbituric acid reactive substance (TBARS) levels were measured. DEHP was found to induce oxidative stress in rat testis, as evidenced by significant decrease in GSH/GSSG redox ratio (>10‐fold) and marked increase in TBARS levels, and its effects were more pronounced in Se‐deficient rats with ~18.5‐fold decrease in GSH/GSSG redox ratio and a significant decrease in GPx4 activity, whereas Se supplementation was protective by providing substantial elevation of redox ratio and reducing the lipid peroxidation. These findings emphasized the critical role of Se as an effective redox regulator and the importance of Se status in protecting testicular tissue from the oxidant stressor activity of DEHP. © 2011 Wiley Periodicals, Inc. Environ Toxicol 29: 98–107, 2014.  相似文献   
10.
BACKGROUND: Varied vascular and biliary anatomies are common in the liver. Living donor hepatectomy requires precise recognition of the hilar anatomy. This study was undertaken to study donor vascular and biliary tract variations, surgical approaches and implications in living liver transplant patients. METHODS: Two hundred living donor liver transplantations were performed at our institution between 2004 and 2009. All donors were evaluated by volumetric computerized tomography (CT), CT angiography and magn...  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