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   4680篇
  免费   279篇
  国内免费   30篇
耳鼻咽喉   27篇
儿科学   108篇
妇产科学   131篇
基础医学   460篇
口腔科学   111篇
临床医学   340篇
内科学   1147篇
皮肤病学   52篇
神经病学   179篇
特种医学   201篇
外国民族医学   1篇
外科学   883篇
综合类   124篇
一般理论   3篇
预防医学   285篇
眼科学   140篇
药学   413篇
中国医学   16篇
肿瘤学   368篇
  2023年   49篇
  2022年   49篇
  2021年   220篇
  2020年   120篇
  2019年   155篇
  2018年   208篇
  2017年   122篇
  2016年   113篇
  2015年   141篇
  2014年   192篇
  2013年   235篇
  2012年   356篇
  2011年   343篇
  2010年   227篇
  2009年   186篇
  2008年   270篇
  2007年   279篇
  2006年   247篇
  2005年   253篇
  2004年   170篇
  2003年   166篇
  2002年   162篇
  2001年   71篇
  2000年   81篇
  1999年   52篇
  1998年   24篇
  1997年   18篇
  1996年   15篇
  1995年   17篇
  1994年   12篇
  1993年   21篇
  1992年   44篇
  1991年   51篇
  1990年   35篇
  1989年   26篇
  1988年   27篇
  1987年   19篇
  1986年   29篇
  1985年   13篇
  1984年   19篇
  1983年   15篇
  1979年   8篇
  1978年   9篇
  1977年   14篇
  1976年   7篇
  1975年   8篇
  1974年   15篇
  1970年   11篇
  1969年   11篇
  1968年   9篇
排序方式: 共有4989条查询结果,搜索用时 46 毫秒
1.
2.
Investigational New Drugs - Although many cancer drugs are clinically approved, they still suffer from no adequate efficiency or drug resistance, or bad side effects. Therefore, developing safer...  相似文献   
3.
4.

Background

The rate of noninterventional treatment (NIT) in prostate cancer (PCa) active surveillance (AS) candidates is on the rise. However, contemporary data are unavailable. We described community-based NIT rates within 16 Surveillance Epidemiology and End Results (SEER) registries between 2010 and 2014.

Patients and Methods

We identified 23,360 PCa patients who fulfilled the University of California San Francisco AS criteria (prostate-specific antigen [PSA] < 10 ng/mL, clinical T stage ≤ T2a, Gleason score ≤ 6, and positive cores < 33%). Annual NIT rates as well as patient distribution according to PSA, age, number of positive cores, and clinical T stage were studied. Multivariable logistic regression analysis tested NIT predictors.

Results

Between 2010 and 2014, the NIT rate increased from 30.2% to 57.5% (P = .004). Within 16 SEER registries, NIT rates ranged from 25.9% to 62%. NIT rate increased uniformly within all examined registries. Of patient and tumor characteristics (PSA > 4 ng/mL, cT2a and > 1 positive core) only the proportion of NIT patients aged < 65 years increased over time from 47.3% to 53.2% (P = .03). By multivariable logistic regression analysis predicting NIT rate, older age (odd ratio [OR] = 1.05), more contemporary year of diagnosis (OR = 1.41), and being unmarried (OR = 1.45) and uninsured (OR = 2.41) were independent predictors.

Conclusion

The NIT rate has markedly increased across all examined SEER registries. Nonetheless, important differences distinguish those who received high-end NIT from low-end NIT. PCa characteristics of NIT patients remained unchanged over time. However, in addition to geographical differences in NIT rates, patient characteristics such as age, marital status, and insurance status represent potential NIT access barriers.  相似文献   
5.
6.
Traumatic brain injury (TBI) is the leading cause of trauma-related death and disability in children worldwide. The outcome from TBI can be improved by early aggressive management of oxygenation and blood pressure. There is evidence to suggest that adhering to guidelines when managing these patients can have a positive effect on the outcomes. In this article we review the general supportive and targeted neuroprotective measures that are outlined in international paediatric guidelines and are most widely used in the critical care management of patients with TBI; we further review how these measures can influence the underlying evolving pathophysiology in these patients. The aim of critical care management of patients with TBI is to prevent or limit secondary brain injury by optimizing cerebral perfusion and oxygenation to improve survival and clinical outcomes. We also discuss how to monitor patients with traumatic brain injury on the paediatric intensive care unit and we give a practical approach on how to respond to deteriorating patients and to the complications arising during the course of their management.  相似文献   
7.
This study aimed to evaluate changes in sleep during the COVID‐19 outbreak, and used data‐driven approaches to identify distinct profiles of changes in sleep‐related behaviours. Demographic, behavioural and psychological factors associated with sleep changes were also investigated. An online population survey assessing sleep and mental health was distributed between 3 April and 24 June 2020. Retrospective questions were used to estimate temporal changes from before to during the outbreak. In 5,525 Canadian respondents (67.1% females, 16–95 years old: Mean ± SD = 55.6 ± 16.3 years), wake‐up times were significantly delayed relative to pre‐outbreak estimates (p < .001,  = 0.04). Occurrences of clinically meaningful sleep difficulties significantly increased from 36.0% before the outbreak to 50.5% during the outbreak (all p < .001, g ≥ 0.27). Three subgroups with distinct profiles of changes in sleep behaviours were identified: “Reduced Time in Bed”, “Delayed Sleep” and “Extended Time in Bed”. The “Reduced Time in Bed” and “Delayed Sleep” subgroups had more adverse sleep outcomes and psychological changes during the outbreak. The emergence of new sleep difficulties was independently associated with female sex, chronic illnesses, being employed, family responsibilities, earlier wake‐up times, higher stress levels, as well as heavier alcohol use and television exposure. The heterogeneity of sleep changes in response to the pandemic highlights the need for tailored interventions to address sleep problems.  相似文献   
8.
9.
10.
BackgroundAt ketamine and esketamine doses at which antidepressant doses are achieved, these agents are relatively selective, noncompetitive, N-methyl-D-aspartate receptor antagonists. However, at substantially higher doses, ketamine has shown mu-opioid receptor (MOR–gene symbol: OPRM1) agonist effects. Preliminary clinical studies showed conflicting results on whether naltrexone, a MOR antagonist, blocks the antidepressant action of ketamine. We examined drug-induced or endogenous MOR involvement in the antidepressant and dissociative responses to esketamine by assessing the effects of a functional single nucleotide polymorphism rs1799971 (A118G) of OPRM1, which is known to alter MOR agonist-mediated responses.MethodsParticipants with treatment-resistant depression from 2 phase III, double-blind, controlled trials of esketamine (or placebo) nasal spray plus an oral antidepressant were genotyped for rs1799971. Participants received the experimental agents twice weekly for 4 weeks. Antidepressant responses were rated using the change in Montgomery–Åsberg Depression Rating Scale (MADRS) score on days 2 and 28 post-dose initiation, and dissociative side effects were assessed using the Clinician-Administered Dissociative-States Scale at 40 minutes post-dose on days 1 and 25.ResultsIn the esketamine + antidepressant arm, no significant genotype effect of single nucleotide polymorphism rs1799971 (A118G) on MADRS score reductions was detected on either day 2 or 28. By contrast, in the antidepressant + placebo arm, there was a significant genotype effect on MADRS score reductions on day 2 and a nonsignificant trend on day 28 towards an improvement in depression symptoms in G-allele carriers. No significant genotype effects on dissociative responses were detected.ConclusionsVariation in rs1799971 (A118G) did not affect the antidepressant response to esketamine + antidepressant. Antidepressant response to antidepressant + placebo was increased in G-allele carriers, compatible with previous reports that release of endorphins/enkephalins may play a role in mediating placebo effect.Trial RegistrationNCT02417064 and NCT02418585; www.clinicaltrials.gov  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