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   9105篇
  免费   739篇
  国内免费   60篇
耳鼻咽喉   64篇
儿科学   336篇
妇产科学   303篇
基础医学   1170篇
口腔科学   290篇
临床医学   858篇
内科学   1898篇
皮肤病学   78篇
神经病学   536篇
特种医学   371篇
外科学   1520篇
综合类   228篇
一般理论   10篇
预防医学   426篇
眼科学   346篇
药学   489篇
中国医学   31篇
肿瘤学   950篇
  2023年   57篇
  2022年   26篇
  2021年   196篇
  2020年   149篇
  2019年   186篇
  2018年   251篇
  2017年   137篇
  2016年   193篇
  2015年   257篇
  2014年   342篇
  2013年   363篇
  2012年   551篇
  2011年   631篇
  2010年   402篇
  2009年   390篇
  2008年   555篇
  2007年   607篇
  2006年   591篇
  2005年   515篇
  2004年   465篇
  2003年   411篇
  2002年   318篇
  2001年   311篇
  2000年   262篇
  1999年   216篇
  1998年   105篇
  1997年   92篇
  1996年   88篇
  1995年   57篇
  1994年   67篇
  1993年   61篇
  1992年   113篇
  1991年   106篇
  1990年   100篇
  1989年   104篇
  1988年   91篇
  1987年   78篇
  1986年   69篇
  1985年   72篇
  1984年   48篇
  1983年   42篇
  1982年   30篇
  1981年   30篇
  1980年   24篇
  1979年   23篇
  1978年   17篇
  1977年   27篇
  1976年   20篇
  1975年   16篇
  1973年   8篇
排序方式: 共有9904条查询结果,搜索用时 31 毫秒
1.
2.
IntroductionThe coronavirus disease 2019 (COVID-19) pandemic was expected to have a negative impact on organ donation. With the differences in health care systems and lockdown policies in various regions, the pandemic's effect on organ donation and transplant service may vary. Most of the deceased donor organ referrals in our hospital came from non–intensive care units (ICUs). The objective of this study is to report our experience and quantify the effects of the COVID-19 pandemic on deceased donor organ donation in our center.MethodsThis was a retrospective observational study comparing the deceased donor organ donation activity during the period January 23 to November 30, 2020 with the same period in 2018 in Queen Elizabeth Hospital, Hong Kong.ResultsThere was a 26.9% reduction in deceased donor organ donor referral in 2020 compared with 2018. No significant difference in the proportion of referrals from ICU or non-ICU areas between the 2 time periods was observed. The brain death confirmation rate was significantly higher in 2020 (40.8% vs 20.2%, P = .003). Nine patients had family consent for organ donation in 2020 (vs 7 patients in the same period in 2018). There were no significant differences in consent rate and number of recovered organs between the 2 periods.ConclusionsWith effective measures to limit the spread of COVID-19 in a community, it is possible to support the needs of both patients with COVID-19 and deceased donor organ donation services.  相似文献   
3.
(R)-[18F]MH.MZ ([18F]MH.MZ) is a promising positron emission tomography (PET) radiotracer for in vivo study of the 5-HT2A receptor. To facilitate clinical trials, a fully automated radiosynthesis procedure for [18F]MH.MZ was developed using commercially available materials on the iPhase Flexlab module. The overall synthesis time was 100 min with a radiochemical yield of 7 ± 0.9% (n = 3). The radiochemical purity was greater than 99% for [18F]MH.MZ with a molar activity of 361 ± 57 GBq/μmol (n = 3). The protocol described herein reliably provides [18F]MH.MZ that meets all relevant release criteria for a GMP radiopharmaceutical.  相似文献   
4.
5.
6.
7.
8.
Survivors of childhood acute lymphoblastic leukemia (ALL) treated with chemotherapy only are at risk for neurocognitive impairment. Regions of interest were identified a priori based on glucocorticoid receptor distribution, and sex‐stratified multivariable linear regression models were used to test associations between brain MRI morphology and total number of intrathecal injections, and serum concentration of dexamethasone and methotrexate. Compared with controls, ALL survivors have persistently smaller volumes in the bilateral cerebellum (P < 0.005), hippocampal subregions (P < 0.03), temporal lobe regions (P < 0.03), frontal lobe regions (P < 0.04), and parietal lobe regions (precuneus; P < 0.002). Long‐term problems with learning may be related to residual posttreatment brain differences.  相似文献   
9.
10.

There is growing interest in using cannabinoids for chronic pain. We performed a systematic review and meta-analysis of randomized controlled trials to evaluate the analgesic efficacy and adverse effects of cannabinoids for chronic non-cancer pain. PubMed, EMBASE, Web of Science, Cochrane CENTRAL and clinicaltrials.gov were searched up to December 2018. Information on the type, dosage, route of administration, pain conditions, pain scores, and adverse events were extracted for qualitative analysis. Meta-analysis of analgesic efficacy was performed. Meta-regression was performed to compare the analgesic efficacy for different pain conditions (neuropathic versus non-neuropathic pain). Risk of bias was assessed by The Cochrane Risk of Bias tool, and the strength of the evidence was assessed using the Grade of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Forty-three randomized controlled trials were included. Meta-analysis was performed for 33 studies that compared cannabinoids to placebo, and showed a mean pain score (scale 0–10) reduction of −0.70 (p < 0.001, random effect). Meta-regression showed that analgesic efficacy was similar for neuropathic and non-neuropathic pain (Difference = −0.14, p = 0.262). Inhaled, oral, and oromucosal administration all provided statistically significant, but small reduction in mean pain score (−0.97, −0.85, −0.45, all p < 0.001). Incidence of serious adverse events was rare, and non-serious adverse events were usually mild to moderate. Heterogeneity was moderate. The GRADE level of evidence was low to moderate. Pain intensity of chronic non-cancer patients was reduced by cannabinoids consumption, but effect sizes were small. Efficacy for neuropathic and non-neuropathic pain was similar.

  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