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   5423篇
  免费   315篇
  国内免费   49篇
耳鼻咽喉   37篇
儿科学   137篇
妇产科学   43篇
基础医学   622篇
口腔科学   99篇
临床医学   410篇
内科学   1475篇
皮肤病学   155篇
神经病学   338篇
特种医学   172篇
外科学   1033篇
综合类   22篇
预防医学   110篇
眼科学   90篇
药学   337篇
中国医学   8篇
肿瘤学   699篇
  2024年   8篇
  2023年   65篇
  2022年   125篇
  2021年   237篇
  2020年   124篇
  2019年   139篇
  2018年   223篇
  2017年   161篇
  2016年   191篇
  2015年   187篇
  2014年   193篇
  2013年   258篇
  2012年   385篇
  2011年   444篇
  2010年   233篇
  2009年   186篇
  2008年   284篇
  2007年   316篇
  2006年   308篇
  2005年   274篇
  2004年   297篇
  2003年   297篇
  2002年   260篇
  2001年   40篇
  2000年   35篇
  1999年   44篇
  1998年   55篇
  1997年   43篇
  1996年   46篇
  1995年   41篇
  1994年   39篇
  1993年   33篇
  1992年   22篇
  1991年   28篇
  1990年   14篇
  1989年   24篇
  1988年   14篇
  1987年   12篇
  1986年   11篇
  1985年   8篇
  1984年   8篇
  1983年   10篇
  1982年   6篇
  1981年   10篇
  1980年   10篇
  1979年   9篇
  1978年   7篇
  1977年   4篇
  1975年   4篇
  1973年   3篇
排序方式: 共有5787条查询结果,搜索用时 15 毫秒
81.
BACKGROUND: The future burden of heart failure in Japan was projected to 2055 in order to prospectively estimate of the number of these patients. METHODS AND RESULTS: The statistics are based on prevalence data of left ventricular dysfunction (LVD) in Sado City using the Sado Heart Failure Study (2003) and population estimates from the Japanese National Institute of Population and Social Security Research Report (2006). The number of Japanese outpatients with LVD was 979,000 in 2005, and is predicted to increase gradually as the population ages, reaching 1.3 million by 2030. CONCLUSION: LVD is expected to precipitate a future epidemic of heart failure in Japan.  相似文献   
82.

Purpose

Liposomal amphotericin B (L-AMB) is an essential antifungal agent for patients with hematologic diseases; however, the drug causes severe hypokalemia at a high frequency. Meanwhile, there is little evidence regarding the risk factors for L-AMB–induced severe hypokalemia, and the prevention protocol has not been established. The goal of this study was to identify the risk factors related to severe hypokalemia induced by L-AMB in hematologic patients.

Methods

Seventy-eight hematologic patients with a first administration of L-AMB were enrolled in the study. Eleven patients who had serum potassium levels <3.0 mmol/L before L-AMB administration and 12 patients who received L-AMB administration within 3 days were excluded. Patients who had a serum potassium level <3.0 mmol/L during L-AMB administration were classified into a hypokalemia group (n = 26), and those who had a serum potassium level ≥3.0 mmol/L were classified into a non-hypokalemia group (n = 29). The patient characteristics were analyzed retrospectively. In addition, the usefulness of potassium supplementation was analyzed for those patients who received potassium formulations (non-hypokalemia group, n = 15; hypokalemia group, n = 24).

Findings

Twenty-six patients had hypolalemia after L-AMB administration. Hypokalemia with serum potassium levels <3.0 mmol/L was observed ~7 days after starting L-AMB administration. The patient characteristics, L-AMB dose, and L-AMB administration period did not differ between the 2 groups. In the patients who received potassium formulations, the period between starting L-AMB administration and starting potassium supplementation was significantly shorter in the non-hypokalemia group than in the hypokalemia group (median, 0 vs 4 days, respectively; P < 0.01); the potassium dose was not different between the 2 groups. A receiver-operating characteristic curve revealed that the cutoff time for the start of potassium supplementation to reduce the incidence of L-AMB–induced hypokalemia was 3 days. Multivariate logistic regression analysis revealed that beginning potassium supplementation within 2 days from the start of L-AMB administration was an independent factor reducing the risk of L-AMB–induced hypokalemia (odds ratio, 0.094 [95% CI, 0.019–0.47]).

Implications

This study showed that starting administration of a potassium formulation within 2 days from the start of L-AMB administration was a risk reduction factor for L-AMB–induced hypokalemia. This finding indicates that early potassium supplementation should be incorporated into the regimen of hypokalemia management when L-AMB is used.  相似文献   
83.

Purpose

To investigate temporal variations in dispatcher-assisted and bystander-initiated resuscitation efforts and their association with survival after bystander-witnessed out-of-hospital cardiac arrests (OHCAs).

Methods

We retrospectively analyzed the neurologically favorable 1-month survival and the parameters related to dispatcher assisted cardiopulmonary resuscitation (DA-CPR) and bystander CPR (BCPR) for 227,524 OHCA patients between 2007 and 2013 in Japan. DA-CPR sensitivity for OHCAs, bystander's compliance to DA-CPR assessed by the proportion of bystanders who follow DA-CPR, and performance of BCPR measured by the rate of bystander-initiated CPR in patients without DA-CPR were calculated as indices of resuscitation efforts.

Results

Performance of BCPR was only similar to temporal variations in the survival (correlation between hourly paired values, R2 = 0.263, P = 0.01): a lower survival rate (3.4% vs 4.2%) and performance of BCPR (23.1% vs 30.8%) during night-time (22:00–5:59) than during non-night-time. In subgroup analyses based on interaction tests, all three indices deteriorated during night-time when OHCAs were witnessed by non-family (adjusted odds ratio, 0.73–0.82), particularly in non-elderly patients. The rate of public access defibrillation for these OHCAs markedly decreased during night-time (adjusted odds ratio, 0.49) with delayed emergency calls and BCPR initiation. Multivariable logistic regression analyses revealed that the survival rate of non-family-witnessed OHCAs was 1.83-fold lower during night-time than during non-night-time.

Conclusions

Dispatcher-assisted and bystander-initiated resuscitation efforts are low during night-time in OHCAs witnessed by non-family. A divisional alert system to recruit well-trained individuals is needed in order to improve the outcomes of night-time OHCAs witnessed by non-family bystanders.  相似文献   
84.
85.
86.
Cronkhite-Canada syndrome (CCS) is a rare polyposis disorder accompanied by alopecia and onychodystrophy. A 63-year-old man with a history of CCS and repeated embolism developed progressive thrombocytopenia and mild anemia. Laboratory testing, a bone marrow examination, and magnetic resonance imaging of the spine resulted in a diagnosis of concurrent aplastic anemia (AA). Paroxysmal nocturnal hemoglobinuria (PNH)-type cells were detected in a peripheral blood specimen. In addition, human leukocyte antigen (HLA) included DRB1*15:01 and DRB1*15:02. Mesalazine was discontinued in consideration of possible drug-induced pancytopenia. Immunosuppressive therapy ameliorated both the gastrointestinal symptoms of CCS and pancytopenia. A common autoimmune abnormality might underlie both CCS and AA.  相似文献   
87.
Caspase-3 is a major cell death effector protease in the adult and neonatal nervous system. We found a greater number and higher density of cells in the cortex of caspase-3(-/-) adult mice, consistent with a defect in developmental cell death. Caspase-3(-/-) mice were also more resistant to ischemic stress both in vivo and in vitro. After 2 h of ischemia and 48 h of reperfusion, cortical infarct volume was reduced by 55%, and the density of terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling-positive cells was decreased by 36% compared with wild type. When subjected to oxygen-glucose deprivation (2 h), cortical neurons cultured from mice deficient in caspase-3 expression were also more resistant to cell death by 59%. Mutant brains showed caspase-specific poly(ADP-ribose) polymerase cleavage product (85-kDa fragment) in vivo and in vitro, suggesting redundant mechanisms and persistence of caspase-mediated cell death. In the present study, we found that caspase-8 mediated poly(ADP-ribose) polymerase cleavage in caspase-3(-/-) neurons in vivo and in vitro. In addition, mutant neurons showed no evidence of compensatory activation by caspase-6 or caspase-7 after ischemia. Taken together, these data extend the pharmacological evidence supporting an important role for caspase-3 and caspase-8 as cell death mediators in mammalian cortex and indicate the potential advantages of targeting more than a single caspase family member to treat ischemic cell injury.  相似文献   
88.
Controlled proteolytic degradation of specialized junctional structures, corneodesmosomes, by epidermal proteases is an essential process for physiological desquamation of the skin. Corneodesmosin (CDSN) is an extracellular component of corneodesmosomes and, although considerable debate still exists, genetic studies have suggested that the CDSN gene in the major psoriasis-susceptibility locus (PSORS1) may be responsible for susceptibility to psoriasis, a human skin disorder characterized by excessive growth and aberrant differentiation of keratinocytes. CDSN is also expressed in the inner root sheath of hair follicles, and a heterozygous nonsense mutation of the CDSN gene in humans is associated with scalp-specific hair loss of poorly defined etiology. Here, we have investigated the pathogenetic roles of CDSN loss of function in the development of skin diseases by generating a mouse strain with targeted deletion of the Cdsn gene. Cdsn-deficient mouse skin showed detachment of the stratum corneum from the underlying granular layer and/or detachment within the upper granular layers due to the disrupted integrity of the corneodesmosomes. When grafted onto immunodeficient mice, Cdsn-deficient skin showed rapid hair loss together with epidermal abnormalities resembling psoriasis. These results underscore the essential roles of CDSN in hair physiology and suggest functional relevance of CDSN gene polymorphisms to psoriasis susceptibility.  相似文献   
89.
90.
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