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   10498篇
  免费   1085篇
  国内免费   477篇
耳鼻咽喉   66篇
儿科学   82篇
妇产科学   54篇
基础医学   1661篇
口腔科学   554篇
临床医学   1184篇
内科学   1282篇
皮肤病学   83篇
神经病学   981篇
特种医学   274篇
外国民族医学   5篇
外科学   1141篇
综合类   1886篇
一般理论   1篇
预防医学   805篇
眼科学   182篇
药学   678篇
  31篇
中国医学   484篇
肿瘤学   626篇
  2024年   9篇
  2023年   117篇
  2022年   176篇
  2021年   362篇
  2020年   424篇
  2019年   312篇
  2018年   312篇
  2017年   406篇
  2016年   361篇
  2015年   390篇
  2014年   624篇
  2013年   719篇
  2012年   585篇
  2011年   755篇
  2010年   588篇
  2009年   551篇
  2008年   581篇
  2007年   599篇
  2006年   580篇
  2005年   533篇
  2004年   475篇
  2003年   433篇
  2002年   361篇
  2001年   272篇
  2000年   244篇
  1999年   148篇
  1998年   130篇
  1997年   129篇
  1996年   97篇
  1995年   96篇
  1994年   82篇
  1993年   83篇
  1992年   68篇
  1991年   53篇
  1990年   59篇
  1989年   26篇
  1988年   34篇
  1987年   36篇
  1986年   33篇
  1985年   40篇
  1984年   31篇
  1983年   35篇
  1982年   33篇
  1981年   25篇
  1980年   18篇
  1979年   12篇
  1978年   7篇
  1977年   6篇
  1976年   5篇
  1974年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Galactosyl transferase knock-out pig lungs fail rapidly in baboons. Based on previously identified lung xenograft injury mechanisms, additional expression of human complement and coagulation pathway regulatory proteins, anti-inflammatory enzymes and self-recognition receptors, and knock-down of the β4Gal xenoantigen were tested in various combinations. Transient life-supporting GalTKO.hCD46 lung function was consistently observed in association with either hEPCR (n = 15), hTBM (n = 4), or hEPCR.hTFPI (n = 11), but the loss of vascular barrier function in the xenograft and systemic inflammation in the recipient typically occurred within 24 h. Co-expression of hEPCR and hTBM (n = 11) and additionally blocking multiple pro-inflammatory innate and adaptive immune mechanisms was more consistently associated with survival >1 day, with one recipient surviving for 31 days. Combining targeted genetic modifications to the lung xenograft with selective innate and adaptive immune suppression enables prolonged initial life-supporting lung function and extends lung xenograft recipient survival, and illustrates residual barriers and candidate treatment strategies that may enable the clinical application of other organ xenografts.  相似文献   
3.
目的分析核心作者、作者合著网络特征,推测国内健康信息研究的发展阶段、主要研究力量及主要研究主题。方法以CNKI期刊库为数据源,以"健康信息"及相关词为主题词,检索2000—2018年的相关文献,基于普莱斯定律及综合指数法确定核心作者,使用数据统计软件Excel及社会网络分析软件Vcinet,利用综合指数以及社会网络分析法计算作者间联系合作紧密度,并离析高产合作子网。结果文献量以较快指数型速率增长。作者合作率较高且信息传输渠道较通畅,2000—2018年国内研究的合著率稳定在80%,但学者的合作关系较为单一,多集中在同一机构或同一师门,阻碍了跨机构学者的交流合作。主要合作团队活跃度较高且核心成员多为研究领域的核心作者,科研产出量较大且被引频次较高。结论国内研究正处于旺盛发展期,但未形成稳定的核心作者群体。学者间因同机构或师门关系产生固定合作,健康信息管理、公众健康行为、健康教育等为核心作者或活跃团队研究的主要主题。  相似文献   
4.
Breast core biopsies are a standard component of the triple approach that includes clinical examination, imaging and tissue sampling. Conventional cores, diagnostic vacuum assisted biopsy and vacuum assisted excisions are established methods for sampling and managing breast lesions. It is important to be aware of the potential pitfalls in the technical handling and interpretation of the limited core biopsy samples. Here, we present a clinically oriented, well illustrated overview of the common diagnostic pitfalls based on the author's diagnostic and second opinion practice, emphasize the value of clinicopathological correlation and provide histological tips and clues with useful immunohistochemistry to aid the reporting pathologists in their daily interpretation of breast core biopsies.  相似文献   
5.
Liver steatosis is a common complication of chronic hepatitis C virus (HCV) infection, which can result in accelerated liver fibrosis development, especially in patients infected with genotype 3a. The precise mechanisms of HCV-induced liver steatosis remain unclear, but it is often posited that increased intracellular lipid accumulation is the underlying cause of steatosis. To study experimentally how HCV infection in human liver derived cells by different genotypes and subtypes might affect lipid accumulation, we performed detailed cytofluorimetric and microscopy analyses of intracellular lipid droplets (LDs) in relation to the viral Core and to cell endoplasmic reticulum proteins. Following culture infection with HCV genotype 1a, 2a, 2b, 2c, and 3a strains, we found variable levels of intracellular LDs accumulation, associated to the infecting strain rather than to the specific genotype. Although two genotype 3a strains showed high levels of lipid accumulation, as previously observed, some strains of other genotypes displayed a similar phenotype. Moreover, the analyses of LDs size, number, and shape indicated that the apparent increase in lipid accumulation is due to an increase in the overall number rather than in the size of droplets. Finally, differences in total lipid content across genotypes did not correlate to differences in Core distribution nor Core levels. In conclusion, our study provides a quantitative in-depth analysis of the effect of HCV infection on LDs accumulation in cell-culture.  相似文献   
6.
7.
目的 探讨丹红注射液联合乙酰谷酰胺注射液治疗急性脑梗死恢复期的临床疗效.方法 选取2020年1月—2021年8月在濮阳市人民医院确诊并治疗的136例脑梗死恢复期患者,按照随机数字表法,将患者分为对照组和治疗组,每组各68例.对照组患者静脉滴注乙酰谷酰胺注射液,0.6 g加入5%葡萄糖注射液250 mL中,1次/d.治疗组在对照组基础上静脉滴注丹红注射液,40 mL加入5%葡萄糖注射液250 mL中,1次/d.两组患者均连续治疗2周.观察两组患者的临床疗效,比较两组治疗前后相关评分、颈总动脉和大脑中动脉血流动力学指标、氧化应激指标和血管新生促进因子指标的变化情况.结果 治疗后,治疗组总有效率为95.59%,显著高于对照组的86.76%(P<0.05).治疗后,两组患者的NIHSS评分、mRS评分均较治疗前有显著下降,而FMA评分均明显上升(P<0.05),且治疗后,治疗组患者NIHSS、FMA、mRS评分改善优于对照组(P<0.05).治疗后,两组患者颈总动脉、大脑中动脉收缩期峰值血流速度(PSV)、舒张期末血流速度(EDV)水平均较治疗前显著提高,但搏动指数(PI)均显著下降(P<0.05),且治疗后,治疗组患者血流动力学参数水平改善优于对照组(P<0.05).治疗后,两组患者谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)水平均较治疗前显著提高,8-OHdG8-羟基脱氧鸟苷(8-OHdG)、氧化型低密度脂蛋白(ox-LDL)水平均显著下降(P<0.05),且治疗后,治疗组患者氧化应激水平改善优于对照组(P<0.05).治疗后,两组患者血管内皮细胞生长因子(VEGF)、碱性成纤维细胞生长因子(bFGF)、转化生长因子β1(TGF-β1)水平较治疗前均显著提高(P<0.05),且治疗后治疗组患者血管新生促进因子指标改善更明显(P<0.05).结论 丹红注射液联合乙酰谷酰胺注射液可治疗急性脑梗死具有良好的临床疗效,可改善患者的神经功能缺损程度,提高运动功能,调控氧化应激反应,促进血管新生,值得临床广泛应用.  相似文献   
8.
《Molecular therapy》2022,30(2):763-781
  1. Download : Download high-res image (203KB)
  2. Download : Download full-size image
  相似文献   
9.
目的:分析多层次医疗保障制度对重特大疾病的实际保障效果。方法:分地区、总费用水平和病种计算延安市基本医疗保险、大病保险和医疗救助对重特大疾病的保障效果。结果:延安市重特大疾病医疗费用经基本医疗保险、大病保险和医疗救助三个层次的报销后,平均保障水平为77.14%;住院医疗费用的补偿比例随总费用上升而下降;总费用超过20万元的患者,个人自付比例超过35%。结论:持续完善医保药品目录、诊疗项目目录,在目录层面实现对基本诊疗需求的全覆盖,同时重视高额医疗费用的补偿,增强制度的兜底保障作用;各统筹地区应结合本地区实际,出台相适应的重特大疾病保障政策,做到精准施策。  相似文献   
10.
《Vaccine》2022,40(33):4889-4896
BackgroundDuring the COVID-19 pandemic, the number of hepatitis B virus (HBV) vaccinations among men who have sex with men (MSM) has been considerably lower than before the pandemic. Moreover, less frequent HBV testing and a reduction in numbers of sex partners have been reported. We assessed the impact of these COVID-19-related changes on HBV transmission among MSM in the Netherlands.MethodsWe estimated the changes in sexual activity, HBV testing, and HBV vaccination among MSM during the pandemic from Dutch data. We used a deterministic compartmental model and investigated scenarios with small or large declines in sexual activity, testing, and vaccination for the current phase of the pandemic (without available data). We examined the increase in HBV vaccinations needed to prevent further increase in HBV incidence.ResultsWith a decrease in numbers of sex partners of 15–25% during the first lockdown and 5% during the second lockdown, we found a decline of 6.6% in HBV incidence in 2020, despite a >70% reduction in HBV testing and vaccination during the first lockdown. With numbers of sex partners rebounding close to pre-pandemic level in 2021, and a reduction of 15% in testing and 30% in vaccination in 2021, we found an increase of 1.4% in incidence in 2021 and 3.1% in 2026. With these changes, an increase of ≥60% in HBV vaccinations in 2022 would be needed to bring the HBV incidence in 2023 back to the level that it would have had if the COVID-19-related changes had not occurred.ConclusionsDespite reductions in sexual activity during the COVID-19 pandemic, the decrease in HBV vaccinations may result in a small increase in HBV incidence after 2021, which may persist for years. It is important to restore the vaccination level and limit further increase in HBV transmission among MSM.  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