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   2286篇
  免费   124篇
  国内免费   13篇
耳鼻咽喉   15篇
儿科学   112篇
妇产科学   62篇
基础医学   366篇
口腔科学   34篇
临床医学   217篇
内科学   460篇
皮肤病学   29篇
神经病学   294篇
特种医学   66篇
外科学   184篇
综合类   9篇
一般理论   2篇
预防医学   115篇
眼科学   5篇
药学   189篇
中国医学   10篇
肿瘤学   254篇
  2023年   10篇
  2022年   33篇
  2021年   40篇
  2020年   28篇
  2019年   32篇
  2018年   53篇
  2017年   44篇
  2016年   48篇
  2015年   51篇
  2014年   74篇
  2013年   98篇
  2012年   143篇
  2011年   162篇
  2010年   108篇
  2009年   86篇
  2008年   182篇
  2007年   162篇
  2006年   167篇
  2005年   137篇
  2004年   155篇
  2003年   143篇
  2002年   116篇
  2001年   19篇
  2000年   27篇
  1999年   17篇
  1998年   28篇
  1997年   25篇
  1996年   21篇
  1995年   18篇
  1994年   20篇
  1993年   11篇
  1992年   11篇
  1991年   11篇
  1990年   9篇
  1989年   24篇
  1988年   13篇
  1987年   9篇
  1986年   7篇
  1985年   4篇
  1984年   15篇
  1983年   12篇
  1982年   4篇
  1981年   6篇
  1980年   4篇
  1979年   3篇
  1978年   4篇
  1977年   4篇
  1976年   5篇
  1975年   5篇
  1970年   3篇
排序方式: 共有2423条查询结果,搜索用时 15 毫秒
31.
In a study conducted on 114 patients undergoing unrelated donor haematopoietic stem cell transplantation (HSCT) for thalassaemia, we observed that the lack of activating killer immunoglobulin-like receptors (KIRs) on donor natural killer (NK) cells significantly increased the risk of graft-versus-host disease (GvHD) [hazard risk (HR) 4.2, 95% confidence interval (CI) 1.7-10.1, P = 0.002] and transplantation-related mortality (HR 4.7, 95% CI 1.6-14.2, P = 0.01). The risk of GvHD furthermore increased when recipients heterozygous for HLA-C KIR ligand groups (C1/C2) were transplanted from donors completely lacking activating KIRs (HR 6.1, 95% CI 1.9-19.2, P = 0.002). We also found that the risk of rejection was highest when the recipient was homozygous for the C2 HLA-KIR ligand group and the donor carried two or more activating KIRs (HR 6.8, 95% CI 1.9-24.4, P = 0.005). By interpolating the number of donor activating KIRs with recipient HLA-C KIR ligands, we created an algorithm capable of stratifying patients according to the immunogenetic risk of complications following unrelated HSCT. In clinical practice, this predictive tool could serve as an important supplement to clinical judgement and decision-making.  相似文献   
32.
Developmental topographical disorientation (DTD) causes impaired spatial orientation and navigation from early childhood with no evidence of cerebral damage. Using fMRI and a landmark sequencing task, we investigated the hypothesis that Dr Wai’s abnormal cerebral activation pattern was related to his peculiar behavioral profile. Although Dr Wai was able to correctly perform landmark sequencing, he showed a lack of activity in regions activated in all control subjects and activity in areas that were not activated in any control subject. These results are discussed in light of cognitive and functional model of navigation, with relevant implications for DTD physiology.  相似文献   
33.
Based on our previous finding of the p.A382T founder mutation in ALS patients with concomitant parkinsonism in the Sardinian population, we hypothesized that the same variant may underlie Parkinson's disease (PD) and/or other forms of degenerative parkinsonism on this Mediterranean island. We screened a cohort of 611 patients with PD (544 cases) and other forms of degenerative parkinsonism (67 cases) and 604 unrelated controls for the c.1144G > A (p.A382T) missense mutation of the TARDBP gene. The p.A382T mutation was identified in nine patients with parkinsonism. Of these, five (0.9 % of PD patients) presented a typical PD (two with familiar forms), while four patients (6.0 % of all other forms of parkinsonism) presented a peculiar clinical presentation quite different from classical atypical parkinsonism with an overlap of extrapyramidal–pyramidal–cognitive clinical signs. The mutation was found in eight Sardinian controls (1.3 %) consistent with a founder mutation in the island population. Our findings suggest that the clinical presentation of the p.A382T TARDBP gene mutation may include forms of parkinsonism in which the extrapyramidal signs are the crucial core of the disease at onset. These forms can present PSP or CBD-like clinical signs, with bulbar and/or extrabulbar pyramidal signs and cognitive impairment. No evidence of association has been found between TARDBP gene mutation and typical PD.  相似文献   
34.
35.
Adenine phosphoribosyltransferase (APRT) deficiency, cystinuria, Dent disease, familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC), and primary hyperoxaluria (PH) are rare but important causes of severe kidney stone disease and/or chronic kidney disease in children. Recurrent kidney stone disease and nephrocalcinosis, particularly in pre-pubertal children, should alert the physician to the possibility of an inborn error of metabolism as the underlying cause. Unfortunately, the lack of recognition and knowledge of the five disorders has frequently resulted in an unacceptable delay in diagnosis and treatment, sometimes with grave consequences. A high index of suspicion coupled with early diagnosis may reduce or even prevent the serious long-term complications of these diseases. In this paper, we review the epidemiology, clinical features, diagnosis, treatment, and outcome of patients with APRT deficiency, cystinuria, Dent disease, FHHNC, and PH, with an emphasis on childhood manifestations.  相似文献   
36.

Introduction

Antithrombin (AT), protein C (PC) and protein S (PS) deficiencies are risk factors for venous thromboembolism. Overlapping values between heterozygous carriers and normal individuals often make a correct classification of a deficiency difficult. The aim of this study was to investigate the effect of sex, age, menopause and hormone therapy on natural anticoagulant plasma levels in a large group of healthy individuals, and to evaluate the need of separate reference ranges.

Materials and Methods

AT and PC were measured with a chromogenic assay, antigenic free PS with an ELISA test. To evaluate the effect of sex, age, oral contraception, hormonal status (and their interaction) on AT, PC and PS levels, linear regression models were used. Biological relevance and the value of the normal deviate z were chosen as rules to decide for separate reference ranges.

Results

The study population consisted of 1837 healthy adult individuals (741 men, 1096 women), aged 18-85 years (median age: 44 years). In men AT levels decreased after the age of 50 years. Men had higher levels of PS than women, particularly at young ages. In women, after correction for menopause, only PC levels increased with age. Menopause affected AT and PS, but not PC levels. Oral contraceptive intake was associated with a decrease of AT and PS, and an increase of PC levels.

Conclusions

For AT, PC and PS, sex- and age-specific normal reference ranges can be useful, in order to better discriminate true carriers of a natural anticoagulant deficiency.  相似文献   
37.
This study aimed at exploring the relationship between severe neuromotor and/or sensory disability in very preterm infants assessed at 2 years corrected age and their mothers’ psychological health. Data on 581 Italian singletons born at 22–31 weeks of gestation in five Italian regions and their mothers were analyzed. Maternal psychological distress was measured through the General Health Questionnaire short version (GHQ-12). The prevalence of any maternal distress (GHQ scores  2) and of clinical distress (scores  5) were 31.3% and 8.1% respectively. At multivariable analysis, we found a statistically significant association between child's disability and mothers’ GHQ scoring ≥5 (OR 3.45, 95% CI 1.07–11.15). Also lower maternal education appeared to increase the likelihood of psychological distress (OR 1.38, 95% CI 1.14–1.66). The impact of child disability was weaker in women who had experienced additional stressful life events since delivery, pointing to the existence of a “ceiling” effect. Maternal psychological assessment and support should be included in follow-up programs targeting very preterm infants.  相似文献   
38.
There are huge demands on multifunctional nanocarriers to be used in nanomedicine. Herein, we present a simple and efficient method for the preparation of multifunctional magnetically responsive polymeric-based nanocarriers optimized for biomedical applications. The hybrid delivery system is composed of drug-loaded polymer nanoparticles (poly(caprolactone), PCL) coated with a multilayer shell of polyglutamic acid (PGA) and superparamagnetic iron oxide nanoparticles (SPIONs), which are known as bio-acceptable components. The PCL nanocarriers with a model anticancer drug (Paclitaxel, PTX) were formed by the spontaneous emulsification solvent evaporation (SESE) method, while the magnetically responsive multilayer shell was formed via the layer-by-layer (LbL) method. As a result, we obtained magnetically responsive polycaprolactone nanocarriers (MN-PCL NCs) with an average size of about 120 nm. Using the 9.4 T preclinical magnetic resonance imaging (MRI) scanner we confirmed, that obtained MN-PCL NCs can be successfully used as a MRI-detectable drug delivery system. The magnetic hyperthermia effect of the MN-PCL NCs was demonstrated by applying a 25 mT radio-frequency (f = 429 kHz) alternating magnetic field. We found a Specific Absorption Rate (SAR) of 55 W g−1. The conducted research fulfills the first step of investigation for biomedical application, which is mandatory for the planning of any in vitro and in vivo studies.

There are huge demands on multifunctional nanocarriers to be used in nanomedicine.  相似文献   
39.
Sport Sciences for Health - In this cross-sectional study, we examined the association of selected basic motor abilities with biological (sex, age, and BMI), sociodemographic [socio-economic status...  相似文献   
40.
Journal of Neurology - Skew deviation results from a dysfunction of the graviceptive pathways in patients with an acute vestibular syndrome (AVS) leading to vertical diplopia due to vertical ocular...  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