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   44511篇
  免费   3107篇
  国内免费   153篇
耳鼻咽喉   583篇
儿科学   1446篇
妇产科学   1242篇
基础医学   6147篇
口腔科学   557篇
临床医学   6366篇
内科学   8514篇
皮肤病学   746篇
神经病学   4557篇
特种医学   855篇
外国民族医学   1篇
外科学   3598篇
综合类   782篇
一般理论   42篇
预防医学   5094篇
眼科学   895篇
药学   3069篇
中国医学   79篇
肿瘤学   3198篇
  2023年   230篇
  2022年   478篇
  2021年   881篇
  2020年   493篇
  2019年   813篇
  2018年   947篇
  2017年   734篇
  2016年   825篇
  2015年   995篇
  2014年   1333篇
  2013年   2026篇
  2012年   3064篇
  2011年   3227篇
  2010年   1647篇
  2009年   1595篇
  2008年   2881篇
  2007年   3114篇
  2006年   3197篇
  2005年   3148篇
  2004年   3069篇
  2003年   2885篇
  2002年   2686篇
  2001年   459篇
  2000年   340篇
  1999年   428篇
  1998年   516篇
  1997年   436篇
  1996年   401篇
  1995年   379篇
  1994年   282篇
  1993年   311篇
  1992年   249篇
  1991年   249篇
  1990年   219篇
  1989年   210篇
  1988年   223篇
  1987年   184篇
  1986年   165篇
  1985年   191篇
  1984年   200篇
  1983年   205篇
  1982年   247篇
  1981年   185篇
  1980年   192篇
  1979年   136篇
  1978年   116篇
  1977年   121篇
  1976年   96篇
  1975年   83篇
  1974年   90篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Azathioprine, a well-known immunosuppressive agent, is used extensively in renal transplantation. There have been several case reports of pure red cell aplasia induced by this drug following a successful kidney transplant. Previous management of azathioprine-induced red cell aplasia included reduction of azathioprine dose, or treatment with cyclophosphamide. We propose the substitution of cyclosporine for azathioprine, in this clinical setting. Not only does cyclosporine allow recovery of bone marrow function, but it maintains a level of immunosuppression which stabilizes renal function in the post-transplant patient.  相似文献   
82.
In a double-blind, randomized, controlled clinical trial, progression of Alzheimer's disease was significantly reduced in patients who received acetyl-carnitine (2 g/day) for one year.  相似文献   
83.
Intrauterine growth retardation (IUGR) occurs in 3% to 10% of all pregnancies. Although it is an uncommon occurrence in a low-risk nurse-midwifery practice, as many as 65% of the cases of IUGR are not identified until after the birth of the infant. Identification of IUGR is important because it carries a high risk of antepartum fetal death, anomalies, intrapartum asphyxia, and long-term morbidity. Additionally, identification of IUGR is essential for appropriate prenatal and intrapartum management. A review of etiologic factors, current assessment, and management of the pregnancy complicated by IUGR is presented, The use and interpretation of new technologies that the clinician may use in diagnosing and managing IUGR is reviewed.  相似文献   
84.
Crohn's disease is a complex disorder, with multiple genetic traits. A frameshift mutation (Leu1007fsinsC) and two missense mutations (Gly908Arg and Arg702Trp) in the NOD2/CARD15 gene are strongly associated with susceptibility to Crohn's disease. The presence of one of these risk alleles confers a 2- to 4-fold increase in the risk of developing Crohn's disease, and the presence of two mutant alleles increases the risk over 20-fold. To facilitate the analysis of these polymorphisms, we developed three LightCycler assays to detect the missense mutations Arg702Trp and Gly908Arg and the frameshift mutation Leu100fsinsC in the NOD2/ CARD15 gene. All three assays can be run simultaneously on one LightCycler using identical cycling parameters. Analysis of 53 DNAs from Crohn's patients helped to identify carriers at allele frequencies similar to other Caucasian populations. The sequencing of such DNAs confirmed the accuracy of the assays. In conclusion, we present three rapid and robust assays to detect the Arg702Trp, the Gly908Arg and the Leu1007fsinsC ins mutations in the NOD2/CARD15 gene [corrected]  相似文献   
85.
Parkinson's disease (PD) is a major cause of disability. To date, there have been no large-scale efforts to measure the quality of PD care because of a lack of quality indicators for conducting an explicit review of PD care processes. We present a set of quality indicators for PD care. Based on a structured review of the medical literature, 79 potential indicators were drafted. Through a two-round modified Delphi process, an expert panel of seven movement disorders specialists rated each indicator on criteria of validity, feasibility, impact on outcomes, room for improvement, and overall utility. Seventy-one quality indicators met validity and feasibility thresholds. Applying thresholds for impact on outcomes, room for improvement, and overall utility, a subset of 29 indicators was identified, spanning dopaminergic therapy, assessment of functional status, assessment and treatment of depression, coordination of care, and medication use. Multivariable analysis showed that overall utility ratings were driven by validity and impact on outcomes (P < 0.01). An expert panel can reach consensus on a set of highly rated quality indicators for PD care, which can be used to assess quality of PD care and guide the design of quality improvement projects.  相似文献   
86.
Earlier onset of menarche and tallness in adult women are mainly confirmed as risk markers for breast cancer. Recent disparate case-control studies have reported abdominal-type obesity and higher circulating levels of insulin, testosterone and insulin-like growth factor 1, to be further risk markers for breast cancer. There is evidence that abdominal-type obesity is recognisable in girls even before puberty, and disparate studies have shown it to be correlated with earlier onset of menarche, insulin resistance leading to hyperinsulinaemia, and an abnormal sex steroid profile. The implications are that earlier onset of puberty in a subset of girls can lead to more prolonged exposure of developing breast tissue to an abnormal sex steroid profile and also to a higher circulating level of insulin. It is postulated that these metabolic/endocrine concomitants of abdominal-type obesity could play a role in promoting mammary carcinogenesis at a young age, particularly if genetic predisposition is present.  相似文献   
87.
BACKGROUND: Synapsin III plays a role in neuronal plasticity and maps to chromosome 22q12-13, a region suggested to be linked to schizophrenia. To determine if synapsin III plays a role in this disease, we searched for polymorphisms in this gene in patients with schizophrenia and controls. METHODS: The synapsin III gene was initially sequenced from 10 individuals with schizophrenia to identify polymorphisms. Association analysis was then performed using 118 individuals with schizophrenia and 330 population controls. Synapsin III expression was studied by immunoblot analyses, and phosphorylation sites were mapped by sequencing trypsin-digested synapsin III fragments phosphorylated with phosphorus-32. RESULTS: A rare, missense polymorphism, S470N, was identified in the synapsin III gene and appeared more frequently in individuals with schizophrenia than in controls (p =.0048). The site affected by the polymorphism, Ser470, was determined to be a substrate for mitogen-activated protein kinase, a downstream effector of neurotrophin action. Phosphorylation at Ser470 was increased during neonatal development and in response to neurotrophin-3 in cultured hippocampal neurons. CONCLUSIONS: Our observations suggest an association of a rare polymorphism in synapsin III with schizophrenia, but further studies will be required to clarify its role in this disease.  相似文献   
88.
Identification of Alcohol Abuse and Alcoholism with Biological Parameters   总被引:3,自引:0,他引:3  
The prevalence and incidence of heavy alcohol consumption are major problems which have been increasing in many countries in recent years. It is crucial for physicians to consistently identify early drinking problems as well as the various end disease states in order to minimize suffering and maximize recovery. This paper reviews the evolutionary development of clinical tools for detection of alcohol abuse. The focus is primarily on clinical/biochemical indicators of alcohol abuse, emphasizing but not limited to changes in hematological characteristics, liver enzyme activity, lipids, immune function factors, hormones, neurological factors, and some physically based tests. Use of test combinations and sophisticated statistical analysis of pattern changes in test batteries evidence increased diagnostic efficiency.  相似文献   
89.
PURPOSE: Surgical closure of oroantral communications (OACs) has several disadvantages. An animal study was performed to test whether OACs can be closed nonsurgically with a biodegradable polyurethane (PU) foam. MATERIALS AND METHODS: In 6 rabbits, an OAC was created on both sides of the maxilla. Three rabbits were used to evaluate the animal model by applying a surgical treatment on 1 side and by leaving the other defects untreated. In the 3 other rabbits, OACs were closed with PU foam. Wound healing was evaluated clinically and histologically. RESULTS: The surgically treated defects healed without complications. The untreated defects showed complicated and delayed healing. Healing of the foam-treated OACs was dependent on the type of foam that was used. CONCLUSIONS: The rabbit is a suitable animal model for OAC investigations. It is possible to close an OAC with a biodegradable PU foam. Further research is needed to show the most suitable composition of the PU for this purpose.  相似文献   
90.
BACKGROUND: Systemic sclerosis (SSc) is a connective tissue disorder of unknown etiology characterized by fibrosis of the skin and visceral organs, in which the heart is frequently (40-70% of patients) and severely involved. Pulmonary hypertension affects 10-15% of patients with SSc and is one of the most important complications adversely influencing their survival. CASE REPORT: The case report presents a 59-year-old male patient with advanced systemic sclerosis whose initial examination revealed pulmonary hypertension, rhythm and atrioventricular conduction disturbances, and elevated level of NT-proBNP. After six months the patient deteriorated; an increase in NT-proBNP level and progression of pulmonary hypertension were observed. CONCLUSIONS: The described case is followed by a discussion of cardiovascular involvement in systemic sclerosis and emphasizes that heart involvement in SSc may have very serious clinical implications.  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