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   1464篇
  免费   89篇
  国内免费   6篇
耳鼻咽喉   28篇
儿科学   98篇
妇产科学   20篇
基础医学   234篇
口腔科学   20篇
临床医学   134篇
内科学   236篇
皮肤病学   19篇
神经病学   156篇
特种医学   46篇
外科学   145篇
综合类   9篇
一般理论   1篇
预防医学   172篇
眼科学   24篇
药学   127篇
中国医学   4篇
肿瘤学   86篇
  2024年   2篇
  2023年   15篇
  2022年   25篇
  2021年   65篇
  2020年   46篇
  2019年   44篇
  2018年   63篇
  2017年   44篇
  2016年   56篇
  2015年   46篇
  2014年   63篇
  2013年   89篇
  2012年   131篇
  2011年   116篇
  2010年   74篇
  2009年   58篇
  2008年   108篇
  2007年   90篇
  2006年   72篇
  2005年   66篇
  2004年   71篇
  2003年   56篇
  2002年   64篇
  2001年   10篇
  2000年   12篇
  1999年   12篇
  1998年   10篇
  1997年   7篇
  1996年   3篇
  1995年   7篇
  1994年   3篇
  1993年   1篇
  1992年   2篇
  1991年   1篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
  1986年   3篇
  1985年   5篇
  1984年   4篇
  1983年   3篇
  1982年   2篇
  1980年   1篇
排序方式: 共有1559条查询结果,搜索用时 15 毫秒
41.
During the past ten years, the efforts to improve and organize the national transplantation system in Croatia have resulted in a steadily growing donor rate, which reached its highest level in 2011, with 33.6 utilized donors per million population (p.m.p.). Nowadays, Croatia is one of the leading countries in the world according to deceased donation and transplantation rates. Between 2008 and 2011, the waiting list for kidney transplantation decreased by 37.2% (from 430 to 270 persons waiting for a transplant) and the median waiting time decreased from 46 to 24 months. The Croatian model has been internationally recognized as successful and there are plans for its implementation in other countries. We analyzed the key factors that contributed to the development of this successful model for organ donation and transplantation. These are primarily the appointment of hospital and national transplant coordinators, implementation of a new financial model with donor hospital reimbursement, public awareness campaign, international cooperation, adoption of new legislation, and implementation of a donor quality assurance program. The selection of key factors is based on the authors'' opinions; we are open for further discussion and propose systematic research into the issue.Transplantation is a widely accepted and successful life-saving treatment providing the best therapeutic benefit for hundreds of thousands of patients (1). Unfortunately, many people die while awaiting an organ transplant. A global shortage of organs available for transplantation raises many bioethical concerns, including the dilemma how to allocate limited resources to an unlimited number of needs and thus offer a fair and equal access to organ transplantation to all patients. Great efforts have been made to increase organ donation worldwide, but with only a moderate success in most of the countries. In contrast with this general trend, Croatia has recently experienced a boom in organ donation and transplantation. In 2011, Croatia had the highest rates of utilized cadaveric donors, kidney transplantations, and liver transplantations in the world (2-5) (Figure 1).Open in a separate windowFigure 1The number of kidney transplantations and the number of patients on the waiting list in Croatia between 2008 and 2011.Remarkably, only one decade ago, Croatia was lagging far behind other European countries with a low donation rate (2.7 donors per million population [p.m.p.] in 2000). The continuous improvement of the organization of the Croatian transplant program resulted in a steadily growing donor rate, which reached the highest level in 2011, with 33.6 utilized donors p.m.p (2). We analyzed the factors that might have contributed mostly to this great success.  相似文献   
42.
Obstructive sleep apnea (OSA) is linked to an increased mortality rate. However, the severity of individual obstruction events is rarely considered quantitatively in clinical practice. We hypothesized that OSA with especially severe obstruction events would predispose a patient to greater health risks than OSA with a similar apnea–hypopnea index (AHI), but lower severity of individual events. This hypothesis was tested in a follow‐up (198.2 ± 24.7 months) of a population of 1068 men referred for ambulatory polygraphic recording due to suspected OSA. The recordings were analysed according to the guidelines of the American Academy of Sleep Medicine. Furthermore, a novel obstruction severity parameter was determined; this was defined as the product of duration of the individual obstruction event and area of the related desaturation event. Patients treated with continuous positive airway pressure (CPAP) were omitted. We identified 125 deceased patients from our original population and for 113 of these a matching alive patient with similar AHI, age, body mass index (BMI), smoking habits and follow‐up time could be found. The deceased patients with severe OSA (based on conventional AHI) showed higher obstruction severity values than their AHI‐matched alive controls. Based on the multivariate logistic regression analysis, obstruction severity was the only parameter which was related statistically significantly to mortality in the severe OSA category. Furthermore, 59% of all deceased patients and 83% of those who had severe OSA displayed higher obstruction severity than the AHI‐matched alive counterparts. To conclude, the obstruction severity parameter provided valuable prognostic information supplementing AHI. The obstruction severity parameter might improve recognition of the patients with the highest risk.  相似文献   
43.
Herein, well dispersed Ag–Cu NPs supported on modified graphene have been synthesized via a facile and rapid approach using sodium borohydride as a reducing agent under ambient conditions. Dicyandiamide is selected as an effective nitrogen source with TiO2 as an inorganic material to form two kinds of supports, labelled as TiO2–NGO and NTiO2–GO. Initially, the surface area analysis of these two support materials was carried out which indicated that N-doping of GO followed by anchoring with TiO2 has produced support material of larger surface area. Using both types of supports, ten nano-metal catalysts based on Ag and Cu were synthesized. Benefiting from the bimetallic synergistic effect and larger specific surface area of TiO2–NGO, Cu@Ag–TiO2–NGO is found to be a highly active and reusable catalyst out of other synthesized catalysts. It exhibits excellent catalytic activity for oxidation of alcohols and hydrocarbons as well as Chan–Lam coupling reactions. The nanocatalyst is intensively characterized by BET, SEM, HR-TEM, ICP-AES, EDX, CHN, FT-IR, TGA, XRD and XPS.

Cu@Ag–TiO2–NGO prepared from modified graphene by simple methodology exhibits enhanced catalytic activity towards oxidation and Chan–Lam coupling due to the synergistic effect between Ag and Cu NPs.  相似文献   
44.

Background

Children are vulnerable to musculoskeletal injuries both at home and on the street for various reasons. Morbidity and disabilities resulting from these, mostly preventable, injuries, make them a burden to their families and society. The role of various factors associated with injuries is often not documented.

Methods

This prospective study, done on 100 children aged up to 12 years with musculoskeletal trauma, analysed in details, the various modes of injuries.

Results

One in every five patient was a child below 12 years of age. Boys were injured more than girls. Injuries, especially fractures, were most common in the extremities, the upper limb more commonly injured than the lower limb. Most of the injuries occurred at home. The most common mode of injuries was falls that happened while playing both within and outside the home, followed by road traffic accidents. Most injuries occurred during daytime.

Conclusions

Injuries in children were found to be preventable. Small interventions while constructing homes can contribute tremendously to injury prevention and control in children. Parental awareness about the various modes of injury, role of supervised playing and their responsibility towards injury prevention can play a key role in reducing the morbidity associated with childhood fractures.  相似文献   
45.
Expression of thioredoxin-interacting protein (TxNIP), an endogenous inhibitor of the thiol oxidoreductase thioredoxin, is augmented by high glucose (HG) and promotes oxidative stress. We previously reported that TxNIP-deficient mesangial cells showed protection from HG-induced reactive oxygen species, mitogen-activated protein kinase phosphorylation, and collagen expression. Here, we investigated the potential role of TxNIP in the pathogenesis of diabetic nephropathy (DN) in vivo. Wild-type (WT) control, TxNIP−/−, and TxNIP+/− mice were rendered equally diabetic with low-dose streptozotocin. In contrast to effects in WT mice, diabetes did not increase albuminuria, proteinuria, serum cystatin C, or serum creatinine levels in TxNIP−/− mice. Whereas morphometric studies of kidneys revealed a thickened glomerular basement membrane and effaced podocytes in the diabetic WT mice, these changes were absent in the diabetic TxNIP−/− mice. Immunohistochemical analysis revealed significant increases in the levels of glomerular TGF-β1, collagen IV, and fibrosis only in WT diabetic mice. Additionally, only WT diabetic mice showed significant increases in oxidative stress (nitrotyrosine, urinary 8-hydroxy-2-deoxy-guanosine) and inflammation (IL-1β mRNA, F4/80 immunohistochemistry). Expression levels of Nox4-encoded mRNA and protein increased only in the diabetic WT animals. A significant loss of podocytes, assessed by Wilms’ tumor 1 and nephrin staining and urinary nephrin concentration, was found in diabetic WT but not TxNIP−/− mice. Furthermore, in cultured human podocytes exposed to HG, TxNIP knockdown with siRNA abolished the increased mitochondrial O2 generation and apoptosis. These data indicate that TxNIP has a critical role in the progression of DN and may be a promising therapeutic target.  相似文献   
46.
BACKGROUND: Natural immunity to Streptococcus pneumoniae is thought to be induced by exposure to S. pneumoniae or cross-reactive antigens. No longitudinal studies of carriage of and immune responses to S. pneumoniae have been conducted using sophisticated immunological laboratory techniques. METHODS: We enrolled 121 families with young children into this study. Nasopharyngeal (NP) swabs were collected monthly for 10 months from all family members and were cultured in a standard fashion. Cultured S. pneumoniae isolates were serotyped. At the beginning (month 0) and end (month 10) of the study, venous blood was collected from family members >18 years old. Serotype-specific antipolysaccharide immunoglobulin G (IgG) and functional antibody and antibodies to pneumolysin, pneumococcal surface protein A (PspA), and pneumococcal surface antigen A (PsaA) were measured in paired serum samples. RESULTS: Levels of anticapsular IgG increased significantly after carriage of serotypes 9V, 14, 18C, 19F, and 23F by an individual or family member. For serotype 14, a higher level of anticapsular IgG at the beginning of the study was associated with reduced odds of carriage (P = .006). There was a small (approximately 20%) but significant increase in titers of antibodies to PsaA and pneumolysin but no change in titers of antibody to PspA. CONCLUSIONS: Adults respond to NP carriage by mounting anticapsular and weak antiprotein antibody responses, and naturally induced anticapsular IgG can prevent carriage.  相似文献   
47.
A 72‐year‐old woman with a history of paroxysmal atrial fibrillation (AF) and sinus node dysfunction is seen in clinic for routine follow‐up.  相似文献   
48.
Inclusion body myositis is a rare sporadic inflammatory‐degenerative myopathy of the elderly. Despite being the commonest type of acquired myopathy after the age of 50, misdiagnosis is extremely common. The most frequent hurdle in identifying new cases is the wrong diagnosis of polymyositis or motor neuron disease. Novel insights into pathogenic mechanisms have heralded the quest for newer therapeutics as well as drug repurposing in this otherwise progressive disorder.  相似文献   
49.
50.
Increased physical activity (PA) is associated with improvement of cardiac risk factors and prevention of cardiovascular disease, yet many women remain sedentary. With rising Internet use, Web-based interventions provide an alternative to improve PA, but their effectiveness for change in PA and quality of life (QOL) in a real-world setting is unknown. Participants were United States women ≥18 years old who received 12 weekly PA modules and completed surveys on PA, QOL, and readiness for PA at registration (registration cohort, n = 3,796) or registration and 12 weeks (evaluation cohort, n = 892). QOL was assessed with a modified Short Form-36 with subscores for energy and well-being. Participants showed significant (p <0.001) favorable changes in PA (baseline, median 240 kcal/week, interquartile range 62 to 667; 12 weeks, 343 kcal/week, 131 to 828), stage of readiness for PA, and body mass index (baseline, 29.3 kg/m(2), 24.9 to 34.7; 12 weeks, 28.9 kg/m(2), 24.6 to 34.2). Significant improvements (p <0.0001) were also found in composite scores for energy and well-being. Compliance with PA guideline recommendations increased from 15.8% to 21.4%. Program weeks completed (p = 0.03), energy (p = 0.04), and well-being (p = 0.002) were significantly associated with achieving guideline compliance. In women reporting no PA at baseline (n = 88), program participation resulted in 54.6% achieving some PA and another 9.1% achieving total compliance with recommendations. In conclusion, in this national cohort of women, a 12-week Web-based intervention improved PA and QOL measurements, resulting in higher short-term PA guideline compliance and better QOL. Increasing use of this simple Web-based tool could improve PA and promote disease prevention.  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