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   234604篇
  免费   21071篇
  国内免费   13879篇
耳鼻咽喉   2164篇
儿科学   2987篇
妇产科学   4872篇
基础医学   27938篇
口腔科学   4198篇
临床医学   29517篇
内科学   37592篇
皮肤病学   2790篇
神经病学   13219篇
特种医学   8469篇
外国民族医学   96篇
外科学   26075篇
综合类   33763篇
现状与发展   48篇
一般理论   45篇
预防医学   14333篇
眼科学   6585篇
药学   23783篇
  157篇
中国医学   10851篇
肿瘤学   20072篇
  2024年   230篇
  2023年   3081篇
  2022年   4636篇
  2021年   9885篇
  2020年   8293篇
  2019年   7520篇
  2018年   7970篇
  2017年   6954篇
  2016年   6643篇
  2015年   10061篇
  2014年   12675篇
  2013年   11869篇
  2012年   17527篇
  2011年   19203篇
  2010年   11691篇
  2009年   9365篇
  2008年   12748篇
  2007年   12796篇
  2006年   12352篇
  2005年   12432篇
  2004年   8591篇
  2003年   7628篇
  2002年   6585篇
  2001年   5962篇
  2000年   6079篇
  1999年   6362篇
  1998年   3551篇
  1997年   3566篇
  1996年   2706篇
  1995年   2580篇
  1994年   2228篇
  1993年   1492篇
  1992年   2285篇
  1991年   1996篇
  1990年   1664篇
  1989年   1454篇
  1988年   1263篇
  1987年   1151篇
  1986年   933篇
  1985年   748篇
  1984年   491篇
  1983年   380篇
  1982年   224篇
  1981年   201篇
  1980年   191篇
  1979年   243篇
  1978年   141篇
  1977年   112篇
  1976年   97篇
  1974年   116篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
医院建筑功能复杂,改造工程工期紧张,如何能够借助BIM技术更好地实现医院、设计单位、施工单位协同工作、加快推进工程进度、提高管理效率成为亟待解决的问题。北京协和医院西单院区北楼改造工程在设计与实施过程中,以问题为导向,借助BIM技术进行设计、施工、运维管理,最终解决医院改造项目中的棘手难题。结合BIM技术优势与特点,提出该技术在医院运维管理中应用的设想。  相似文献   
103.
Lung and female breast cancers are highly prevalent worldwide. Although the association between exposure to ambient fine particulate matter (PM2.5) and lung cancer has been recognized, there is less evidence for associations with other common air pollutants such as nitrogen dioxide (NO2) and ozone (O3). Even less is known about potential associations between these pollutants and breast cancer. We conducted a population-based cohort study to investigate the associations of chronic exposure to PM2.5, NO2, O3 and redox-weighted average of NO2 and O3 (Ox) with incident lung and breast cancer, using the Ontario Population Health and Environment Cohort (ONPHEC), which includes all long-term residents aged 35–85 years who lived in Ontario, Canada, 2001–2015. Incident lung and breast cancers were ascertained using the Ontario Cancer Registry. Annual estimates of exposures were assigned to the residential postal codes of subjects for each year during follow-up. We used Cox proportional-hazards models adjusting for personal- and neighborhood-level covariates. Our cohorts for lung and breast cancer analyses included ~4.9 million individuals and ~2.5 million women, respectively. During follow-up, 100,146 incident cases of lung cancer and 91,146 incident cases of breast cancer were diagnosed. The fully adjusted analyses showed positive associations of lung cancer incidence with PM2.5 (hazard ratio [HR] = 1.02 [95% CI: 1.01–1.05] per 5.3 μg/m3) and NO2 (HR = 1.05 [95% CI: 1.03–1.07] per 14 ppb). No associations with lung cancer were observed for O3 or Ox. Relationships between PM2.5 and NO2 with lung cancer exhibited a sublinear shape. We did not find compelling evidence linking air pollution to breast cancer.  相似文献   
104.
G protein-coupled estrogen receptor-1 (GPER), a member of the G protein-coupled receptor (GPCR) superfamily, mediates estrogen-induced proliferation of normal and malignant breast epithelial cells. However, its role in breast cancer stem cells (BCSCs) remains unclear. Here we showed greater expression of GPER in BCSCs than non-BCSCs of three patient-derived xenografts of ER/PR+ breast cancers. GPER silencing reduced stemness features of BCSCs as reflected by reduced mammosphere forming capacity in vitro, and tumor growth in vivo with decreased BCSC populations. Comparative phosphoproteomics revealed greater GPER-mediated PKA/BAD signaling in BCSCs. Activation of GPER by its ligands, including tamoxifen (TMX), induced phosphorylation of PKA and BAD-Ser118 to sustain BCSC characteristics. Transfection with a dominant-negative mutant BAD (Ser118Ala) led to reduced cell survival. Taken together, GPER and its downstream signaling play a key role in maintaining the stemness of BCSCs, suggesting that GPER is a potential therapeutic target for eradicating BCSCs.  相似文献   
105.
A low insulin‐like growth factor 1 (IGF‐1) level is known to be associated with many disorders. Several studies have shown that soy consumption may influence IGF‐1, but the findings remain inconclusive. In this work, we conducted a systematic review and meta‐analysis to provide a more accurate estimation of the effect of soy consumption on plasma IGF‐1. A comprehensive systematic search was performed in Scopus, Embase, Web of Science, and PubMed/MEDLINE databases from inception until October 2019. Eight studies fulfilled the eligibility criteria. The pooled weighted mean difference (WMD) of the eligible studies was calculated with random‐effects approach. Overall, a significant increment in plasma IGF‐1 was observed following soy intervention (WMD: 13.5 ng/ml, 95% CI: 5.2, 21.8, I2 = 97%). Subgroup analyses demonstrated a significantly greater increase in IGF‐1, when soy was administered at a dosage of ≤40 g/day (WMD: 11.7 ng/ml, 95% CI: 10.9 to 12.6, I2 = 98%), and when the intervention duration was <12 weeks (WMD: 26.6 ng/ml, 95% CI: 9.1 to 44.1, I2 = 0.0%). In addition, soy intervention resulted in a greater increase in IGF‐1 among non‐healthy subjects (WMD: 36 ng/ml, 95% CI: 32.7 to 39.4, I2 = 84%) than healthy subjects (WMD: 9.8 ng/ml, 95% CI: 8.9 to 10.7, I2 = 90%). In conclusion, this study provided the first meta‐analytical evidence that soy intake may increase IGF‐1 levels, but the magnitude of the increase is dependent on the intervention dosage, duration, and health status of the participants.  相似文献   
106.
肠道菌群作为药物代谢的重要媒介,被认为是人体的又一器官,其在消化系统疾病发生、发展中所起到的重要价值已经得到学术界的公认,近五年来,从肠道菌群的角度出发,人们对中药及其有效组分治疗消化系统疾病的作用机制研究取得了一定成就,本研究将对这些成果进行归纳、总结。  相似文献   
107.
目的:探析对继发性不孕症患者行以深部热疗配合输卵管通水术治疗的疗效。方法:于2018年1月~2019年1月择取某院收治的40例继发性不孕症患者,按照数字奇偶法将其分成对照组和研究组,对照组20例患者予以输卵管通水术治疗,研究组20例患者予以输卵管通水术配合深部热疗治疗,对照分析两组临床效果。结果:从临床总有效率上来看,研究组高于对照组(P<0.05);治疗前两组TNF-α、IL-6对比无统计学差异,治疗后研究组TNF-α、IL-6均优于对照组(P<0.05)。结论:对继发性不孕症患者来说,深部热疗配合输卵管通水术治疗的效果显著。  相似文献   
108.
109.
目的:初步探讨自制极简入路通道(PORT)在单孔腹腔镜子宫肌瘤切除术中应用的可行性及安全性。方法:回顾性分析空军军医大学西京医院妇产科于2017年3月至2018年12月共完成的46例单孔腹腔镜子宫肌瘤切除术患者,其中24例使用商品化PORT,22例使用我科自制极简PORT,所有患者均配合使用常规腹腔镜器械顺利完成手术。比较两组患者年龄、体质量数、手术时间、术中出血量、子宫肌瘤直径、术中及术后相关并发症、手术前后血红蛋白差值、术后排气时间、术后疼痛模拟评分、住院时间、术后随访情况等指标。结果:所有患者均顺利完成手术,无中转开腹或增加穿刺孔,无并发症发生。商品化PORT组和自制极简PORT组患者的一般资料具有可比性。手术相关指标包括手术时间[(75±56.9)min vs (74±55.7)min]、术中出血量[(55±67.9)ml vs (56±65.8)ml]、子宫肌瘤直径[(6±2.8)cm vs (6±3.4)cm],两组比较无明显统计学差异(P>0.05)。术后恢复指标包括术后排气时间[(12.6±4.4)h vs (13.5±3.4)h]、术后疼痛模拟评分[(2.1±1.3)分 vs (2.0±1.2)分]、住院时间[(3.4±2.8)d vs (3.5±2.6)d],同样无统计学差异(P>0.05)。两组手术效果相同,但术中使用自制极简PORT几乎不增加耗材。结论:自制极简PORT在单孔腹腔镜子宫肌瘤切除术中的应用安全性好,效果确切,节约成本,值得推广。  相似文献   
110.
Pericardial involvement of multiple myeloma is a rare and late‐stage complication, with only a few cases reported in the literature. PET/CT has demonstrated a growing role in the diagnosis and follow‐up of patients with multiple myeloma. We present a case of pericardial multiple myeloma in a patient with relapsed/refractory disease, showcasing previously unpublished FDG PET/CT findings.  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