全文获取类型
收费全文 | 159182篇 |
免费 | 14874篇 |
国内免费 | 10029篇 |
专业分类
耳鼻咽喉 | 1766篇 |
儿科学 | 2274篇 |
妇产科学 | 2906篇 |
基础医学 | 17316篇 |
口腔科学 | 3211篇 |
临床医学 | 20837篇 |
内科学 | 23214篇 |
皮肤病学 | 1384篇 |
神经病学 | 7742篇 |
特种医学 | 5674篇 |
外国民族医学 | 61篇 |
外科学 | 16404篇 |
综合类 | 27235篇 |
现状与发展 | 34篇 |
一般理论 | 22篇 |
预防医学 | 10960篇 |
眼科学 | 3997篇 |
药学 | 17324篇 |
142篇 | |
中国医学 | 9145篇 |
肿瘤学 | 12437篇 |
出版年
2024年 | 572篇 |
2023年 | 2499篇 |
2022年 | 6313篇 |
2021年 | 8028篇 |
2020年 | 5956篇 |
2019年 | 4979篇 |
2018年 | 5332篇 |
2017年 | 4759篇 |
2016年 | 4482篇 |
2015年 | 7100篇 |
2014年 | 8858篇 |
2013年 | 8405篇 |
2012年 | 12277篇 |
2011年 | 13225篇 |
2010年 | 8893篇 |
2009年 | 7124篇 |
2008年 | 8753篇 |
2007年 | 8945篇 |
2006年 | 8452篇 |
2005年 | 8190篇 |
2004年 | 5834篇 |
2003年 | 5226篇 |
2002年 | 4588篇 |
2001年 | 3616篇 |
2000年 | 3488篇 |
1999年 | 3236篇 |
1998年 | 1874篇 |
1997年 | 1768篇 |
1996年 | 1511篇 |
1995年 | 1334篇 |
1994年 | 1140篇 |
1993年 | 732篇 |
1992年 | 1081篇 |
1991年 | 871篇 |
1990年 | 764篇 |
1989年 | 646篇 |
1988年 | 632篇 |
1987年 | 562篇 |
1986年 | 443篇 |
1985年 | 340篇 |
1984年 | 220篇 |
1983年 | 166篇 |
1982年 | 85篇 |
1981年 | 101篇 |
1980年 | 85篇 |
1979年 | 116篇 |
1978年 | 54篇 |
1977年 | 56篇 |
1975年 | 44篇 |
1974年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
A Well-Balanced Positivity-Preserving Quasi-Lagrange Moving Mesh DG Method for the Shallow Water Equations 下载免费PDF全文
A high-order, well-balanced, positivity-preserving quasi-Lagrange moving
mesh DG method is presented for the shallow water equations with non-flat bottom
topography. The well-balance property is crucial to the ability of a scheme to simulate perturbation waves over the lake-at-rest steady state such as waves on a lake or
tsunami waves in the deep ocean. The method combines a quasi-Lagrange moving
mesh DG method, a hydrostatic reconstruction technique, and a change of unknown
variables. The strategies in the use of slope limiting, positivity-preservation limiting,
and change of variables to ensure the well-balance and positivity-preserving properties are discussed. Compared to rezoning-type methods, the current method treats
mesh movement continuously in time and has the advantages that it does not need to
interpolate flow variables from the old mesh to the new one and places no constraint
for the choice of a update scheme for the bottom topography on the new mesh. A selection of one- and two-dimensional examples are presented to demonstrate the well-balance property, positivity preservation, and high-order accuracy of the method and
its ability to adapt the mesh according to features in the flow and bottom topography. 相似文献
52.
Calculus bovis is commonly used for the treatment of stroke in traditional Chinese medicine. Hyodeoxycholic acid(HDCA) is a bioactive compound extracted from calculus bovis. When combined with cholic acid, baicalin and jas-minoidin, HDCA prevents hypoxia-reoxygenation-induced brain injury by suppressing endoplasmic reticulum stress-mediated apoptotic signaling. However, the effects of HDCA in ischemic stroke injury have not yet been studied. Neurovascular unit(NVU) dysfunction occurs in ischemic stroke. Therefore, in this study, we investigated the effects of HDCA on the NVU under ischemic conditions in vitro. We co-cultured primary brain microvascular endothelial cells, neurons and astrocytes using a transwell chamber co-culture system. The NVU was pre-treated with 10.16 or 2.54 μg/mL HDCA for 24 hours before exposure to oxygen-glucose deprivation for 1 hour. The cell counting kit-8 assay was used to detect cell activity. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling were used to assess apoptosis. Enzyme-linked immunosorbent assay was used to measure the expression levels of inflammatory cytokines, including interleukin-1β, interleukin-6 and tumor necrosis factor-α, and neurotrophic factors, including brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor. Oxidative stress-related factors, such as superoxide dismutase, nitric oxide, malondialdehyde and γ-glutamyltransferase, were measured using kits. Pretreatment with HDCA significantly decreased blood-brain barrier permeability and neuronal apoptosis, significantly increased transendothelial electrical resistance and γ-glutamyltransferase activity, attenuated oxidative stress damage and the release of inflammatory cytokines, and increased brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor expression. Our findings suggest that HDCA maintains NVU morphological integrity and function by modulating inflammation, oxidation stress, apoptosis, and the expression of neurotrophic factors. Therefore, HDCA may have therapeutic potential in the clinical management of ischemic stroke. This study was approved by the Ethics Committee of Experimental Animals of Beijing University of Chinese Medicine(approval No. BUCM-3-2016040201-2003) in April 2016. 相似文献
53.
Yuanqing Yao Jun Qian Shunkang Rong Yuwen Huang Bo Xiong Gang Yang Dengqing Zhang Shimin Deng Jie Tan Que Zhu Changming Deng Dichuan Liu Haitao Ran Zhigang Wang Jing Huang 《Ultrasound in medicine & biology》2019,45(2):490-499
Stellate ganglion (SG) modification has been investigated for arrhythmia treatment. In this study, transesophageal SG imaging and intervention were explored using a homemade 30F integrated focused ultrasonic catheter in healthy mongrel canines in vivo. Anatomic details of SGs were ultrasonically imaged and evaluated. SG had a heterogeneous echoic structure and characteristic profiles sketched by hyper-echoic outlines in an ultrasonogram. Left SGs in the experimental group were successfully ablated through the esophagus under ultrasonic guidance provided by the catheter itself. Two weeks after the ablation, the QT and QTc of the experimental group decreased compared with those of the sham group and at baseline (both p values < 0.001). Histologic examination revealed that left SGs were destroyed. No major complications were observed. This approach may be further explored as a method for ganglia remodeling evaluation and as a strategy of ganglia modification for arrhythmia and for other diseases. 相似文献
54.
Peng Cheng Linlin Yang Xiaodan Huang Xuejun Wang Maoqing Gong 《Archiv der Pharmazie》2020,353(4):1900350
Malaria, one of the most striking, re-emerging infectious diseases caused by the genus Plasmodium, places a huge burden on global healthcare systems. A major challenge in the control and eradication of malaria is the continuous emergence of increasingly widespread drug-resistant malaria, creating an urgent need to develop novel antimalarial agents. Chalcone derivatives are ubiquitous in nature and have become indispensable units in medicinal chemistry applications due to their diverse biological profiles. Many chalcone derivatives demonstrate potential in vitro and in vivo antimalarial activity, so chalcone could be a useful template for the development of novel antimalarial agents. This review covers the recent development of chalcone hybrids as antimalarial agents. The critical aspects of the design and structure–activity relationship of these compounds are also discussed. 相似文献
55.
56.
To examine the knowledge level, behaviors, and psychological status of the Chinese population during the COVID-19 pandemic, and to explore the differences between urban and rural areas.We carried out a cross-sectional survey of the knowledge, behaviors related to COVID-19, and mental health in a probability sample of 3001 community residents in 30 provinces or districts across China from February 16–23, 2020. Convenience sampling and a snowball sampling were adopted. We used General Anxiety Disorder (GAD), the 9-item Patient Health Questionnaire (PHQ-9), and knowledge and behaviors questionnaire of community residents regarding COVID-19 designed by us to investigate the psychological status, disease-related knowledge, and the behavior of Chinese urban and rural residents during the pandemic.The average score of anxiety and depression among urban residents was 9.15 and 11.25, respectively, while the figures in rural areas were 8.69 and 10.57, respectively. There was a statistically significant difference in the levels of anxiety (P < .01) and depression (P < .01). Urban participants reported significantly higher levels of knowledge regarding COVID-19 in all aspects (transmission, prevention measures, symptoms of infection, treatment, and prognosis) (P < .01), compared to their rural counterparts. While a majority of respondents in urban areas obtained knowledge through WeChat, other apps, and the Internet (P < .01), residents in rural areas accessed information through interactions with the community (P < .01). Urban residents fared well in exchanging knowledge about COVID-19 and advising others to take preventive measures (P < .01), but fared poorly in advising people to visit a hospital if they displayed symptoms of the disease, compared to rural residents (P < .01). Regression analysis with behavior showed that being female (OR = 2.106, 95%CI = 1.259–3.522), aged 18 ≤ age < 65 (OR = 4.059, 95%CI = 2.166–7.607), being satisfied with the precautions taken by the community (OR = 2.594, 95%CI = 1.485–4.530), disinfecting public facilities in the community (OR = 2.342, 95%CI = 1.206–4.547), having knowledge of transmission modes (OR = 3.987, 95%CI: 2.039, 7.798), symptoms (OR = 2.045, 95%CI = 1.054–4.003), and outcomes (OR = 2.740, 95%CI = 1.513–4.962) of COVID-19, and not having anxiety symptoms (OR = 2.578, 95%CI = 1.127–5.901) were positively associated with affirmative behavior in urban areas. Being married (OR = 4.960, 95%CI = 2.608–9.434), being satisfied with the precautions taken by the community (OR = 2.484, 95%CI = 1.315–4.691), screening to ensure face mask wearing before entering the community (OR = 8.809, 95%CI = 2.649–19.294), and having knowledge about precautions (OR = 4.886, 95%CI = 2.604–9.167) and outcomes (OR = 2.657, 95%CI = 1.309–5.391) were positively associated with acceptable conduct in rural areas.The status of anxiety and depression among urban residents was more severe compared to those living in rural areas. There was a difference in being positively associated with constructive behaviors between rural and urban areas. 相似文献
57.
58.
目的 分析2007-2017年浙江省24 388例罕见病住院病例特征,为制定罕见病防控策略提供依据。方法 收集2007-2017年浙江省10家三级甲等(三甲)医院罕见病住院病例资料和各年度住院数,进行描述性统计分析。结果 罕见病病例共24 388例,占住院总例数的2.69‰(24 388/9 054 201),病例数居前3位的疾病类型依次为"血液和造血器官疾病以及某些涉及免疫机能的异常"(占32.81%,8 001/24 388)、"先天性畸形、变形和染色体异常"(占24.87%,6 065/24 388)和"神经系统疾病"(占19.01%,4 635/24 388);2007-2017年罕见病病例数呈逐年增长趋势,年均增幅19.69%,而罕见病例数占同期住院总例数比例仅在2016-2017年明显上升,各类型罕见病时间分布呈不同特征;罕见病的病例数男女性别比为1.35:1(13 990/10 398),男女性别比最高的3类疾病依次为"消化系统疾病"(4.45:1,1 180/265)、"损伤、中毒和外因的某些其他后果"(3.51:1,281/80)和"神经系统疾病"(2.26:1,3 213/1 422);各年龄段罕见病类型、各类型罕见病年龄分布均呈不同特征;病例数居前10位的疾病占全部罕见病例数的53.55%(13 060/24 388),其中前3位疾病分别为成人粒细胞缺乏症(14.41%,3 515/24 388)、皮质基底核退化症(7.60%,1 854/24 388)和亨诺克-舍恩莱因紫癜(6.01%,1 466/24 388)。结论 本研究分析的浙江省2007-2017年24 388例罕见病住院病例的特征资料,是推动我国罕见病的研究、监测或登记数据库构建、制定防控策略的参考依据。 相似文献
59.
Tian-Yuan Xiong Fang-Yang Huang Qi Liu Yong Peng Yuan-Ning Xu Jia-Fu Wei 《Annals of medicine》2020,52(7):361-366
Abstract
Background
Comorbidities are commonly seen in patients with coronavirus disease 2019 (COVID-19), but the clinical implication is not yet well-delineated. We aim to characterize the prevalence and clinical implications of comorbidities in patients with COVID-19. 相似文献60.