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   451176篇
  免费   41008篇
  国内免费   28335篇
耳鼻咽喉   3365篇
儿科学   5755篇
妇产科学   5278篇
基础医学   49928篇
口腔科学   7650篇
临床医学   62364篇
内科学   61488篇
皮肤病学   4863篇
神经病学   22203篇
特种医学   16204篇
外国民族医学   250篇
外科学   40313篇
综合类   81516篇
现状与发展   97篇
一般理论   41篇
预防医学   32724篇
眼科学   12573篇
药学   48120篇
  581篇
中国医学   28980篇
肿瘤学   36226篇
  2025年   105篇
  2024年   5980篇
  2023年   8574篇
  2022年   17368篇
  2021年   21708篇
  2020年   17886篇
  2019年   14675篇
  2018年   14355篇
  2017年   13768篇
  2016年   12761篇
  2015年   19563篇
  2014年   24315篇
  2013年   22387篇
  2012年   33209篇
  2011年   36926篇
  2010年   24864篇
  2009年   20224篇
  2008年   24935篇
  2007年   24696篇
  2006年   23364篇
  2005年   22394篇
  2004年   15000篇
  2003年   14321篇
  2002年   11921篇
  2001年   10126篇
  2000年   9961篇
  1999年   10093篇
  1998年   6365篇
  1997年   6141篇
  1996年   4785篇
  1995年   4530篇
  1994年   3825篇
  1993年   2456篇
  1992年   2936篇
  1991年   2579篇
  1990年   2178篇
  1989年   1902篇
  1988年   1556篇
  1987年   1450篇
  1986年   1160篇
  1985年   850篇
  1984年   484篇
  1983年   343篇
  1982年   194篇
  1981年   209篇
  1980年   147篇
  1979年   193篇
  1978年   91篇
  1977年   67篇
  1974年   59篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
腹主动脉瘤(abdominal aortic aneurysm,AAA)是腹主动脉较常见的疾病,破裂之后致死率极高,因此,及时发现和评估AAA破裂的风险就具有重要意义。近年来随着医学影像、计算机及血流动力学等理论和技术的快速发展,利用计算机模拟技术对AAA进行仿真研究已成为研究的热点,其模拟的结果趋于人体真实的动脉瘤,并在揭示AAA的发生及演变的机制方面发挥了重要作用。本文介绍了AAA仿真研究的原理及模型分类,详细地阐述了瘤体形态、瘤壁的结构及属性、血液及血流的属性、腔内血栓等相关因素在仿真研究中的作用,并对其目前的进展及局限性予以综述。  相似文献   
82.
目的颈动脉粥样硬化斑块的形成是脑血管病变的独立危险因素之一。对颈动脉内膜剥脱术(carotid endarterectomy,CEA)斑块进行充分的组织学判读和研究,将有助于全面把握CEA斑块的组织学表现,进而推进临床辅助诊断。方法本文我们将运用数字病理扫描仪对CEA斑块的切片经H&E染色后进行扫描,介绍数字病理扫描在CEA斑块组织学研究中的应用。结果经数字病理扫描所得的图片,有助于全面掌握和保存CEA斑块组织切片的全层面信息;在软件的帮助下有助于非常方便地测量斑块内各成分的大小;有助于精确评估斑块的狭窄程度。结论综上,数字病理成像应用于CEA斑块,结合MRI,有助于高效且准确地判读斑块组成和预测斑块稳定性,亦有助于人工智能的训练。  相似文献   
83.
Yang  Fan  Li  Yang  Zou  Weilong  Xu  Yanan  Wang  Hao  Wang  Wei  Zhao  Yong 《Inflammation research》2019,68(7):545-555
Inflammation Research - Efficient production of monocytic myeloid-derived suppressor cells (M-MDSCs) with stable immunosuppressive function is crucial for immunomodulatory cell therapy for many...  相似文献   
84.
85.

Background

Atopic dermatitis is a chronic and severe pruritic skin disease. Interlukin-31 (IL-31) has been recently demonstrated to be one of the key pruritogens in atopic dermatitis. However, the mechanisms underlying IL-31-induced itching remains unclear. In our previous study, we have shown that thromboxane (TX) A2 is involved in itch-associated responses in mice with atopy-like skin diseases.

Methods

IL-31 was given intradermally into the rostral back of ICR mice and the hind-paw scratching to the injection site were counted. Expression of TX synthase and IL-31 receptors were analyzed using immunohistochemical staining or RT-PCR in mouse skin or primary cultures of mouse keratinocytes. The concentration of TXB2, a metabolite of TXA2, in the skin and the culture medium of primary cultures of mouse keratinocytes was measured using enzyme immunoassay. The concentration of intracellular Ca2+ ions in mouse keratinocytes was measured using the calcium imaging method.

Results

An intradermal injection of IL-31 elicited scratching, an itch-related response, in mice. The scratching was inhibited by TP TXA2 receptor antagonist DCHCH. The distribution of TX synthase and IL-31RA receptor was mainly epidermal keratinocytes in the skin. The primary cultures of keratinocytes expressed the mRNAs of TX synthase and IL-31 receptors. IL-31 increased the concentration of TXB2, which was inhibited by TX synthase inhibitor sodium ozagrel and EGTA, in the skin and the culture medium of primary cultures of keratinocytes. IL-31 increased the concentration of intracellular Ca2+ ions in mouse keratinocytes.

Conclusion

It is suggested that IL-31 elicits itch-associated responses through TXA2 produced from keratinocytes.  相似文献   
86.
Introduction: Although used as an anesthetic drug for decades, ketamine appears to have garnered renewed interest due to its potential therapeutic uses in pain therapy, neurology, and psychiatry. Ketamine undergoes extensive oxidative metabolism by cytochrome P450 (CYP) enzymes. Considerable efforts have been expended to elucidate the ketamine-induced regulation of CYP gene expression. The safety profile of chronic ketamine administration is still unclear. Understanding how ketamine regulates CYP gene expression is clinically meaningful.

Areas covered: In this article, the authors provide a brief review of clinical applications of ketamine and its metabolism by CYP enzymes. We discuss the effects of ketamine on the regulation of CYP gene expression, exploring aspects of cytoskeletal remodeling, mitochondrial functions, and calcium homeostasis.

Expert opinion: Ketamine may inhibit CYP gene expression through inhibiting calcium signaling, decreasing ATP levels, producing excessive reactive oxygen species, and subsequently perturbing cytoskeletal dynamics. Further research is still needed to avoid possible ketamine–drug interactions during long-term use in the clinic.  相似文献   

87.

Objectives

Treatment landscape in prostate cancer has changed dramatically with the emergence of new medicines in the past few years. The traditional survival partition model (SPM) cannot accurately predict long-term clinical outcomes because it is limited by its ability to capture the key consequences associated with this changing treatment paradigm. The objective of this study was to introduce and validate a discrete-event simulation (DES) model for prostate cancer.

Methods

A DES model was developed to simulate overall survival (OS) and other clinical outcomes based on patient characteristics, treatment received, and disease progression history. We tested and validated this model with clinical trial data from the abiraterone acetate phase III trial (COU-AA-302). The model was constructed with interim data (55% death) and validated with the final data (96% death). Predicted OS values were also compared with those from the SPM.

Results

The DES model’s predicted time to chemotherapy and OS are highly consistent with the final observed data. The model accurately predicts the OS hazard ratio from the final data cut (predicted: 0.74; 95% confidence interval [CI] 0.64–0.85 and final actual: 0.74; 95% CI 0.6–0.88). The log-rank test to compare the observed and predicted OS curves indicated no statistically significant difference between observed and predicted curves. However, the predictions from the SPM based on interim data deviated significantly from the final data.

Conclusions

Our study showed that a DES model with properly developed risk equations presents considerable improvements to the more traditional SPM in flexibility and predictive accuracy of long-term outcomes.  相似文献   
88.
89.
90.

Objectives

We aimed to evaluate the relationship between baseline renal function and changes in telomere length in Han Chinese.

Methods

The telomere restriction fragment (TRF) length of leukocytes in the peripheral blood was measured in healthy volunteers recruited in 2014. The estimated glomerular filtration rate (eGFR) was calculated based on serum creatinine (Scr) and serum cystatin C (CysC)-eGFRcys and eGFRScr-cys through the Cockcroft-Gault formula (eGFRC-G) or the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI / eGFRCKD-EPI) equation. The correlation between telomere length changes over time and renal function was analyzed.

Results

Leukocyte TRF lengths were negatively correlated to age (r = -0.393, p < 0.001) and serum CysC (r = -0.180, p < 0.01), while positively associated with eGFRCKD-EPI, eGFRC-G, eGFRcys, and eGFRScr-cys (r = 0.182, 0.122, 0.290, and 0.254 respectively, p < 0.01). The 3-year change of telomere length was 46 bp/years. When adjusted for age, the associations between telomere length changes and baseline, subsequent TRF lengths, and serum CysC were no longer present. No association was observed between TRF length changes and renal function.

Conclusion

The rate of telomere length changes was affected by age and baseline telomere length. The telomere length changes might be important markers for aging.
  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