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   2936598篇
  免费   222341篇
  国内免费   33018篇
耳鼻咽喉   37008篇
儿科学   89767篇
妇产科学   75514篇
基础医学   401511篇
口腔科学   75473篇
临床医学   285463篇
内科学   561587篇
皮肤病学   66238篇
神经病学   230046篇
特种医学   113016篇
外国民族医学   960篇
外科学   416889篇
综合类   119553篇
现状与发展   91篇
一般理论   994篇
预防医学   222025篇
眼科学   66768篇
药学   226957篇
  439篇
中国医学   29483篇
肿瘤学   172175篇
  2022年   21956篇
  2021年   37605篇
  2020年   26443篇
  2019年   31864篇
  2018年   40865篇
  2017年   33866篇
  2016年   36447篇
  2015年   45686篇
  2014年   60703篇
  2013年   78689篇
  2012年   107341篇
  2011年   115137篇
  2010年   71777篇
  2009年   66001篇
  2008年   99446篇
  2007年   103948篇
  2006年   104733篇
  2005年   100116篇
  2004年   90661篇
  2003年   87653篇
  2002年   82770篇
  2001年   135824篇
  2000年   138659篇
  1999年   118003篇
  1998年   36280篇
  1997年   32763篇
  1996年   32024篇
  1995年   30976篇
  1994年   28078篇
  1993年   25331篇
  1992年   87250篇
  1991年   83424篇
  1990年   80357篇
  1989年   77421篇
  1988年   70577篇
  1987年   68959篇
  1986年   64337篇
  1985年   61073篇
  1984年   45251篇
  1983年   38166篇
  1982年   22569篇
  1979年   39062篇
  1978年   27491篇
  1977年   23291篇
  1976年   21521篇
  1975年   22835篇
  1974年   26818篇
  1973年   25393篇
  1972年   23780篇
  1971年   21970篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
肿瘤免疫检查点抑制剂治疗为肿瘤患者带来生存获益的同时,也面临了许多挑战,例如免疫介导的肝毒性的发生。深入了解免疫检查点抑制剂治疗肿瘤过程中导致肝损伤的发生情况、可能机制、危险因素等,有助于更好地临床管理。  相似文献   
82.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  相似文献   
83.

Purpose

Endovascular treatment with mechanical thrombectomy devices demonstrated high recanalization rates but functional outcome did not correlate with high rates of recanalization obtained. Patient selection prior to the endovascular treatment is very important in the final outcome of the patient. The primary aim of our study was to evaluate the prognostic value of posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) and Pons-Midbrain Index (PMI) scores in patients with Basilar Artery Occlusion (BAO) treated with successful angiographic recanalization after mechanical thrombectomy.

Methods

Retrospective single-center study including 18 patients between 2008 and 2013 who had acute basilar artery occlusion managed with endovascular treatment within 24 hours from symptoms onset and with successful angiographic recanalization. The patients were initially classified into two groups according to clinical outcome and mortality at 90 days. For analysis we also divided patients into groups based on pc-ASPECTS (≥8vs.< 8) and PMI (≥3vs.< 3) on non-contrast CT (NCCT) and CT Angiography Source Images (CTASI). Imaging data were correlated to clinical outcome and mortality rate.

Results

CTASI pc-ASPECTS, dichotomized at < 8 versus≥8, was associated with a favorable outcome (RR: 2.6; 95% CI: 1.3-5.2) and a reduced risk of death (RR: 6.5: 95% CI: 7.8-23.3). All patients that survived and were functionally independent had pc-ASPECTS score≥8. None of the 5 patients with CTASI pc-ASPECTS score less than 8 survived.

Conclusion

PC-ASPECTS on CTASI is helpful for predicting functional outcome after BAO recanalization with endovascular treatment. These results should be validated in a randomized controlled trial in order to decide whether or not to treat a patient with BAO.  相似文献   
84.
85.
Purpose: To use polymerase chain reaction (PCR) and Goldmann-Witmer coefficient (GWC) calculation to diagnose infectious uveitis.

Methods: Prospective cross-sectional study.

Results: Twenty-seven of 106 patients had positive PCR and/or GWC results on aqueous humor (AH) sampling and 15 of 27 (55.6%) were HIV-positive. Patients with non-anterior uveitis (NAU) were more likely to be HIV+ (p = 0.005). More than 1 possible pathogen was identified in 9 of 27 patients of whom 7 were HIV+. The final clinical diagnosis was discordant with AH findings in 9 of 27 cases. A positive EBV PCR result was associated with a discordant diagnosis (p = 0.001). All cases of herpetic anterior uveitis (42.9% HIV+) tested PCR-/GWC+ while all cases of herpetic NAU tested PCR+/GWC- (83.3% HIV+). All rubella virus cases were PCR+/GWC+.

Conclusion: PCR is useful to diagnose herpetic NAU in HIV+ patients while GWC is useful to diagnose herpetic anterior uveitis.  相似文献   

86.
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria.  相似文献   
87.
88.
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