全文获取类型
收费全文 | 93303篇 |
免费 | 7608篇 |
国内免费 | 4799篇 |
专业分类
耳鼻咽喉 | 826篇 |
儿科学 | 1738篇 |
妇产科学 | 1269篇 |
基础医学 | 11251篇 |
口腔科学 | 1772篇 |
临床医学 | 9949篇 |
内科学 | 13242篇 |
皮肤病学 | 1156篇 |
神经病学 | 5890篇 |
特种医学 | 3657篇 |
外国民族医学 | 24篇 |
外科学 | 10077篇 |
综合类 | 15088篇 |
现状与发展 | 12篇 |
一般理论 | 49篇 |
预防医学 | 7607篇 |
眼科学 | 1757篇 |
药学 | 9068篇 |
71篇 | |
中国医学 | 4777篇 |
肿瘤学 | 6430篇 |
出版年
2024年 | 170篇 |
2023年 | 1035篇 |
2022年 | 2037篇 |
2021年 | 4049篇 |
2020年 | 3092篇 |
2019年 | 3028篇 |
2018年 | 3735篇 |
2017年 | 3086篇 |
2016年 | 3377篇 |
2015年 | 4499篇 |
2014年 | 5231篇 |
2013年 | 5821篇 |
2012年 | 6604篇 |
2011年 | 6301篇 |
2010年 | 5159篇 |
2009年 | 4204篇 |
2008年 | 4401篇 |
2007年 | 4867篇 |
2006年 | 4431篇 |
2005年 | 3939篇 |
2004年 | 3991篇 |
2003年 | 4239篇 |
2002年 | 3664篇 |
2001年 | 2863篇 |
2000年 | 2080篇 |
1999年 | 1523篇 |
1998年 | 975篇 |
1997年 | 870篇 |
1996年 | 601篇 |
1995年 | 518篇 |
1994年 | 451篇 |
1993年 | 335篇 |
1992年 | 449篇 |
1991年 | 393篇 |
1990年 | 370篇 |
1989年 | 323篇 |
1988年 | 309篇 |
1987年 | 265篇 |
1986年 | 220篇 |
1985年 | 201篇 |
1984年 | 153篇 |
1983年 | 105篇 |
1982年 | 104篇 |
1981年 | 63篇 |
1980年 | 73篇 |
1979年 | 92篇 |
1978年 | 66篇 |
1973年 | 79篇 |
1971年 | 76篇 |
1970年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
目的:研究组蛋白去乙酰化酶1(histone deacetylase 1,HDAC1)和细胞周期蛋白依赖性激酶1(cyclin-dependent kinase 1,CDK1)在结肠癌组织中的表达水平及其与患者临床病理特征及预后的关系。方法:收集2012年2月至2013年6月在本院普外科进行手术切除的51例结肠癌患者的肿瘤组织和癌旁非肿瘤组织,采用qRT-PCR法检测组织中HDAC1和CDK1 mRNA相对表达量,采用免疫组织化学染色法检测HDAC1和CDK1蛋白阳性表达率,分析肿瘤组织中HDAC1和CDK1表达的相关性及其与患者肿瘤直径、淋巴结转移等临床病理特征的关系,采用Kaplan-Meier生存函数分析HDAC1和CDK1不同表达情况与患者5年总生存率的关系。结果:肿瘤组织中HDAC1和CDK1 mRNA表达水平和蛋白阳性表达率均高于癌旁非肿瘤组织(P<0.05);肿瘤组织中HDAC1表达水平与CDK1表达水平呈显著正相关(P=0.012);肿瘤组织中HDAC1表达与患者肿瘤直径和组织分化程度有关(P<0.05),CDK1与肿瘤直径、TNM分期、分化程度、淋巴结转移有关(P<0.05);HDAC1、CDK1阳性表达患者5年总生存率均低于其相应阴性表达患者(P<0.05),HDAC1和CDK1共阳性表达患者5年总生存率低于HDAC1和(或)CDK1阴性患者(P<0.05)。结论:HDAC1和CDK1在结肠癌组织中高表达,与患者不良预后有关且两者呈正相关,推测两者在促进结肠癌进展中可能存在协同作用。 相似文献
74.
Christer Lunde Gjerstad Hans Jakob Bøe Erik Falkum Egil Wilhelm Martinsen Andreas Espetvedt Nordstrand Arnfinn Tønnesen Jon Gerhard Reichelt June Ullevoldsæter Lystad 《Journal of traumatic stress》2020,33(5):762-772
Peacekeeping missions involve experiences that may impact the mental health of participating soldiers. However, research on the long-term mental health consequences of peacekeeping is sparse. The present study aimed to find the prevalence of mental health problems (MHPs), possible MHP predictors, and associations between predictors and MHPs in Norwegian peacekeepers 18–38 years after deployment to a United Nations peacekeeping mission. We used data from a cross-sectional, postdeployment survey of Norwegian peacekeepers who served in Lebanon between 1978 and 1998 (N = 10,605). Participants were assessed for posttraumatic stress disorder (PTSD); anxiety; depression; insomnia; alcohol misuse; drug misuse; and exposure to pre-, peri-, and postdeployment stressors. Logistic regressions were executed to explore key variables associated with MHPs. Total MHP prevalence was 15.1%, 95% CI [14.4, 15.8]. The estimates for specific disorders were 0.1% for drug misuse, 3.4% for alcohol misuse, 4.0% for depression, 6.2% for PTSD, 6.4% for anxiety, and 9.3% for insomnia. Postdeployment stressors, OR = 1.91, 95% CI [1.79, 2.04]; employment status, OR = 1.41, 95% CI [1.33, 1.48]; and traumatic exposure during deployment, OR = 1.11, 95% CI [1.09, 1.12], were positively related to PTSD, χ2(17, N = 8,568) = 1,791.299, p < .001. Similar patterns were found for the other MHPs. Considering that most participants (84.9%) reported low symptom levels, our findings challenge the widespread public perception that most peacekeepers have MHPs. Moreover, our results indicate that future peacekeepers should be prepared for challenges they may face not only during deployment but also in the years following their homecoming. 相似文献
75.
76.
Quantitative chemical exchange saturation transfer (qCEST) MRI – omega plot analysis of RF‐spillover‐corrected inverse CEST ratio asymmetry for simultaneous determination of labile proton ratio and exchange rate 下载免费PDF全文
Renhua Wu Gang Xiao Iris Yuwen Zhou Chongzhao Ran Phillip Zhe Sun 《NMR in biomedicine》2015,28(3):376-383
Chemical exchange saturation transfer (CEST) MRI is sensitive to labile proton concentration and exchange rate, thus allowing measurement of dilute CEST agent and microenvironmental properties. However, CEST measurement depends not only on the CEST agent properties but also on the experimental conditions. Quantitative CEST (qCEST) analysis has been proposed to address the limitation of the commonly used simplistic CEST‐weighted calculation. Recent research has shown that the concomitant direct RF saturation (spillover) effect can be corrected using an inverse CEST ratio calculation. We postulated that a simplified qCEST analysis is feasible with omega plot analysis of the inverse CEST asymmetry calculation. Specifically, simulations showed that the numerically derived labile proton ratio and exchange rate were in good agreement with input values. In addition, the qCEST analysis was confirmed experimentally in a phantom with concurrent variation in CEST agent concentration and pH. Also, we demonstrated that the derived labile proton ratio increased linearly with creatine concentration (P < 0.01) while the pH‐dependent exchange rate followed a dominantly base‐catalyzed exchange relationship (P < 0.01). In summary, our study verified that a simplified qCEST analysis can simultaneously determine labile proton ratio and exchange rate in a relatively complex in vitro CEST system. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
77.
78.
Diede L. Loopik Renée M. Ebisch Joanna IntHout Willem J. Melchers Leon F. Massuger Ruud L. Bekkers Albert G. Siebers 《International journal of cancer. Journal international du cancer》2020,147(3):897-900
Women with cervical intraepithelial neoplasia grade 3 (CIN3) have a long-lasting increased risk for noncervical high-risk human papillomavirus (hrHPV)-related (pre)malignancies. The aim of our study was to estimate this risk in women with recurrent CIN3 compared to women without a history of CIN3 and women with a single episode of CIN3. Women with a CIN3 diagnosis between 1990 and 2010 were obtained from the Dutch Pathology Registry (PALGA) and matched with a control group of women without CIN3. Analysis has been conducted in a subset of women with recurrent CIN3, defined as reoccurrence minimally 2 years post-treatment. Cases of noncervical hrHPV-related (pre)malignancies of the anus, vulva, vagina and oropharynx were identified until 2015 and incidence rate ratios (IRRs) were estimated. Then, 1,797 women with recurrent CIN3 were included with a median age of 34 years (range 18–76) and 31,594 person-years of follow-up. Women with recurrent CIN3 had an increased risk of developing noncervical hrHPV-related (pre)malignancies compared to women without CIN3 with an IRR of 25.96 (95%CI 6.32–106.58). The IRR was 2.48 (95% CI 1.87–3.30) compared to women with a single episode of CIN3. Studies on posttreatment follow-up and prophylactic hrHPV vaccination are warranted. 相似文献
79.
80.
Ping Liu Jiang Peng Gong-Hai Han Xiao Ding Shuai Wei Gang Gao Kun Huang Feng Chang Yu Wang 《中国神经再生研究》2019,(8)
Resident and inflammatory macrophages are essential effectors of the innate immune system. These cells provide innate immune defenses and regulate tissue and organ homeostasis. In addition to their roles in diseases such as cancer, obesity and osteoarthritis, they play vital roles in tissue repair and disease rehabilitation. Macrophages and other inflammatory cells are recruited to tissue injury sites where they promote changes in the microenvironment. Among the inflammatory cell types, only macrophages have both pro-inflammatory(M1) and anti-inflammatory(M2) actions, and M2 macrophages have four subtypes. The co-action of M1 and M2 subtypes can create a favorable microenvironment, releasing cytokines for damaged tissue repair. In this review, we discuss the activation of macrophages and their roles in severe peripheral nerve injury. We also describe the therapeutic potential of macrophages in nerve tissue engineering treatment and highlight approaches for enhancing M2 cell-mediated nerve repair and regeneration. 相似文献