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   4061篇
  免费   228篇
  国内免费   50篇
耳鼻咽喉   8篇
儿科学   112篇
妇产科学   27篇
基础医学   582篇
口腔科学   87篇
临床医学   258篇
内科学   1161篇
皮肤病学   22篇
神经病学   252篇
特种医学   180篇
外科学   749篇
综合类   19篇
预防医学   79篇
眼科学   23篇
药学   221篇
中国医学   6篇
肿瘤学   553篇
  2023年   29篇
  2022年   67篇
  2021年   135篇
  2020年   65篇
  2019年   76篇
  2018年   142篇
  2017年   88篇
  2016年   115篇
  2015年   129篇
  2014年   164篇
  2013年   183篇
  2012年   351篇
  2011年   352篇
  2010年   174篇
  2009年   158篇
  2008年   256篇
  2007年   289篇
  2006年   268篇
  2005年   215篇
  2004年   225篇
  2003年   237篇
  2002年   194篇
  2001年   35篇
  2000年   34篇
  1999年   42篇
  1998年   52篇
  1997年   35篇
  1996年   34篇
  1995年   31篇
  1994年   19篇
  1993年   26篇
  1992年   31篇
  1991年   11篇
  1990年   13篇
  1989年   8篇
  1988年   11篇
  1987年   14篇
  1986年   3篇
  1985年   5篇
  1984年   6篇
  1983年   2篇
  1982年   2篇
  1980年   1篇
  1979年   2篇
  1977年   2篇
  1975年   2篇
  1972年   1篇
  1971年   1篇
  1970年   2篇
  1967年   1篇
排序方式: 共有4339条查询结果,搜索用时 265 毫秒
101.
Sleep is known to be essential for proper cognitive functioning. Sleep disturbance, especially respiratory disturbance during sleep, is a risk factor for the development of dementia. However, it is not known whether hypopnoea during sleep is related to severity of cognitive function in patients already diagnosed with dementia. Considering the high prevalence of sleep problems in aged people, it is important to determine if hypopnoea during sleep contributes to dementia. In addition, it would be desirable to develop a feasible method for objectively evaluating sleep in patients with dementia. For this purpose, a simple sleep recorder that employs single or dual bioparameter recording, which is defined as a type‐4 portable monitor, is suitable. In this study, a type‐4 sleep recorder was used to evaluate respiratory function during sleep in 111 patients with dementia, and data suggesting a possible relationship with cognitive function levels were examined. Multivariate logistic regression was used to investigate the association of severity of dementia with sleep‐disordered breathing, age, diabetes, dyslipidaemia and hypertension. It was found that the respiratory disturbance index was associated with severity of cognitive dysfunction in our subjects. Furthermore, patients younger than 80 years were more susceptible to lower cognitive function associated with sleep‐disordered breathing than patients 80 years old or over, because an increase in the respiratory disturbance index was associated with deteriorated cognitive function only in the former age group. These results suggest that proper treatment of sleep apnea is important for the preservation of cognitive function, especially in patients with early‐stage dementia.  相似文献   
102.

Aims/Introduction

The aim of the present study was to examine the short‐ and long‐term effect of sitagliptin on glucose tolerance after near normalization of glycemic control with insulin in poorly controlled type 2 diabetic patients.

Materials and Methods

We consecutively enrolled a total of 30 type 2 diabetic patients whose glycated hemoglobin levels (National Glycohemoglobin Standardization Program) were ≥7.4%, stopped all oral antidiabetic drugs and started insulin therapy. When fasting plasma glucose levels became <140 mg/dL, we carried out the first oral glucose tolerance test (OGTT). After 1‐week sitagliptin treatment (50 mg/day), the second OGTT was carried out. Furthermore, we evaluated the long‐term efficacy of sitagliptin on glucose tolerance after near normalization of glycemic control with insulin.

Results

After 1‐week sitagliptin treatment, the area under the curve of insulin was markedly increased, and the area under the curve of glucagon and glucose was markedly decreased. Duration of diabetes and insulin secretory capacity were correlated with the effect of sitagliptin. Furthermore, interestingly, near normalization of glycemic control with insulin therapy for 1–2 weeks brought out the long‐term effectiveness of sitagliptin on glucose tolerance for 24 weeks, which was not observed with other antidiabetic drugs.

Conclusions

These findings suggest that near normalization of glycemic control with insulin improves the clinical response to sitagliptin in poorly controlled type 2 diabetic patients.  相似文献   
103.
The favorable outcome of the treatment of a disease is influenced by the adherence to therapy. Our objective was to assess factors associated with adherence to treatment of patients included in a clinical trial of equivalence between the standard and alternative treatment schemes with meglumine antimoniate (MA) in the treatment of cutaneous leishmaniasis (CL), in the state of Rio de Janeiro. Between 2008 and 2011, 57 patients with CL were interviewed using a questionnaire to collect socioeconomic data. The following methods were used for adherence monitoring: counting of vial surplus, monitoring card, Morisky test and modified Morisky test (without the question regarding the schedule); we observed 82.1% (vial return), 86.0% (monitoring card), 66.7% (Morisky test) and 86.0% (modified Morisky test) adherence. There was a strong correlation between the method of vial counting and the monitoring card and modified Morisky test. A significant association was observed between greater adherence to treatment and low dose of MA, as well as with a lower number of people sleeping in the same room. We recommend the use of the modified Morisky test to assess adherence to treatment of CL with MA, because it is a simple method and with a good performance, when compared to other methods.  相似文献   
104.
Pancreaticobiliary maljunction is a congenital malformation in which the pancreatic and bile ducts join anatomically outside the duodenal wall. The diagnostic criteria for pancreaticobiliary maljunction were proposed in 1987. The committee of The Japanese Study Group on Pancreaticobiliary Maljunction (JSGPM) for diagnostic criteria for pancreaticobiliary maljunction began to revise the diagnostic criteria from 2011 taking recently advanced diagnostic imaging techniques into consideration, and the final revised version was approved in the 36th Annual Meeting of JSPBM. For diagnosis of pancreaticobiliary maljunction, an abnormally long common channel and/or an abnormal union between the pancreatic and bile ducts must be evident on direct cholangiography, such as endoscopic retrograde cholangiopancreatography, percutaneous transpehatic cholangiography, or intraoperative cholangiography; magnetic resonance cholangiopancreatography; or three‐dimensional drip infusion cholangiography computed tomography. However, in cases with a relatively short common channel, it is necessary to confirm that the effect of the papillary sphincter does not extend to the junction by direct cholangiography. Pancreaticobiliary maljunction can be diagnosed also by endoscopic ultrasonography or multi‐planar reconstruction images provided by multi‐detector row computed tomography. Elevated amylase levels in bile and extrahepatic bile duct dilatation strongly suggest the existence of pancreaticobiliary maljunction.  相似文献   
105.
Synthetic polymer nanoparticles (NPs) that bind venomous molecules and neutralize their function in vivo are of significant interest as "plastic antidotes." Recently, procedures to synthesize polymer NPs with affinity for target peptides have been reported. However, the performance of synthetic materials in vivo is a far greater challenge. Particle size, surface charge, and hydrophobicity affect not only the binding affinity and capacity to the target toxin but also the toxicity of NPs and the creation of a "corona" of proteins around NPs that can alter and or suppress the intended performance. Here, we report the design rationale of a plastic antidote for in vivo applications. Optimizing the choice and ratio of functional monomers incorporated in the NP maximized the binding affinity and capacity toward a target peptide. Biocompatibility tests of the NPs in vitro and in vivo revealed the importance of tuning surface charge and hydrophobicity to minimize NP toxicity and prevent aggregation induced by nonspecific interactions with plasma proteins. The toxin neutralization capacity of NPs in vivo showed a strong correlation with binding affinity and capacity in vitro. Furthermore, in vivo imaging experiments established the NPs accelerate clearance of the toxic peptide and eventually accumulate in macrophages in the liver. These results provide a platform to design plastic antidotes and reveal the potential and possible limitations of using synthetic polymer nanoparticles as plastic antidotes.  相似文献   
106.
107.
108.
109.
The perceived intensity of the taste of a food is enhanced only if the odor of the food is perceptually similar to the taste. For example, a caramel-like odor enhances the perceived intensity of sweetness. The way gustatory and olfactory signals are integrated in the brain depends largely on one’s previous experiences with taste and odor pairings. To elucidate the effects of a sweet, sugary odor, ethylmaltol, on sucrose taste, as perceived by the central integration of flavor, we recorded salivary hemodynamic responses to the odor and taste pairings using near-infrared spectroscopy (NIRS) of seven panelists. First, we observed concentration-dependent increases in the amplitude of the responses to 0 to 6 % sucrose solutions. Second, when ethylmaltol odor was added to a 4 % sucrose solution, we observed a significant increase in the amplitude of the responses from all panelists. The addition of ethylmaltol to a tasteless solution caused no significant change in the amplitude of the salivary hemodynamic response. These results indicate that the sweet odor of ethylmaltol enhances the salivary hemodynamic response when combined with a sweet taste. Therefore, a congruent combination of sweet odor and taste greatly enhances salivary responses, which are dependent on the central integration of odor and taste.  相似文献   
110.
We have evaluated the feasibility of a newly developed single‐use, magnetically levitated centrifugal blood pump, MedTech Mag‐Lev, in a 3‐week extracorporeal membrane oxygenation (ECMO) study in calves against a Medtronic Bio‐Pump BPX‐80. A heparin‐ and silicone‐coated polypropylene membrane oxygenator MERA NHP Excelung NSH‐R was employed as an oxygenator. Six healthy male Holstein calves with body weights of about 100 kg were divided into two groups, four in the MedTech group and two in the Bio‐Pump group. Under general anesthesia, the blood pump and oxygenator were inserted extracorporeally between the main pulmonary artery and the descending aorta via a fifth left thoracotomy. Postoperatively, both the pump and oxygen flow rates were controlled at 3 L/min. Heparin was continuously infused to maintain the activated clotting time at 200–240 s. All the MedTech ECMO calves completed the study duration. However, the Bio‐Pump ECMO calves were terminated on postoperative days 7 and 10 because of severe hemolysis and thrombus formation. At the start of the MedTech ECMO, the pressure drop across the oxygenator was about 25 mm Hg with the pump operated at 2800 rpm and delivering 3 L/min flow. The PO2 of the oxygenator outlet was higher than 400 mm Hg with the PCO2 below 45 mm Hg. Hemolysis and thrombus were not seen in the MedTech ECMO circuits (plasma‐free hemoglobin [PFH] < 5 mg/dL), while severe hemolysis (PFH > 20 mg/dL) and large thrombus were observed in the Bio‐Pump ECMO circuits. Plasma leakage from the oxygenator did not occur in any ECMO circuits. Three‐week cardiopulmonary support was performed successfully with the MedTech ECMO without circuit exchanges. The MedTech Mag‐Lev could help extend the durability of ECMO circuits by the improved biocompatible performances.  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