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   2719843篇
  免费   202142篇
  国内免费   12126篇
耳鼻咽喉   37147篇
儿科学   83059篇
妇产科学   72811篇
基础医学   394492篇
口腔科学   75330篇
临床医学   246542篇
内科学   523566篇
皮肤病学   59200篇
神经病学   208747篇
特种医学   101828篇
外国民族医学   598篇
外科学   409057篇
综合类   74507篇
现状与发展   33篇
一般理论   907篇
预防医学   202005篇
眼科学   64544篇
药学   210102篇
  123篇
中国医学   12647篇
肿瘤学   156866篇
  2021年   22933篇
  2019年   24769篇
  2018年   33723篇
  2017年   26158篇
  2016年   28215篇
  2015年   33314篇
  2014年   46380篇
  2013年   65566篇
  2012年   90925篇
  2011年   96580篇
  2010年   58512篇
  2009年   54447篇
  2008年   88390篇
  2007年   93882篇
  2006年   94129篇
  2005年   90477篇
  2004年   84833篇
  2003年   81421篇
  2002年   78221篇
  2001年   130501篇
  2000年   133352篇
  1999年   111620篇
  1998年   30288篇
  1997年   26062篇
  1996年   25739篇
  1995年   25778篇
  1994年   23753篇
  1993年   22014篇
  1992年   84230篇
  1991年   81588篇
  1990年   79377篇
  1989年   76600篇
  1988年   70198篇
  1987年   68655篇
  1986年   64037篇
  1985年   61188篇
  1984年   44707篇
  1983年   37728篇
  1982年   21921篇
  1979年   40199篇
  1978年   28238篇
  1977年   23565篇
  1976年   22080篇
  1975年   23924篇
  1974年   28653篇
  1973年   27150篇
  1972年   25544篇
  1971年   24322篇
  1970年   22371篇
  1969年   21450篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
The International Journal of Cardiovascular Imaging - Global longitudinal strain (GLS) has proven to be a powerful prognostic marker in various patient populations, but the prognostic value of...  相似文献   
4.
In the last decade, the development of new radiopharmaceuticals for the imaging and therapy of prostate cancer has been a highly active and important area of research, especially focusing on the prostate-specific membrane antigen (PSMA), an antigen which is upregulated in prostate, as well as in other tumor cells. A large variety of PSMA ligands have been radiolabeled, to date. Among the various derivatives, PSMA-617 resulted to be one of the most interesting in terms of interaction with the antigen and clinical properties, and its lutetium-177 labeled version has recently been approved by regulatory agencies for therapeutic purposes. For this reasons, the radiolabeling with fluorine-18 of a PSMA-617 derivative might be of interest. Beside other methodologies to radiolabel macromolecules with fluorine-18, the “click-chemistry” approach resulted to be very useful, and the copper-catalyzed azide-alkyne cycloaddition (CuAAC) is considered one of most efficient and reliable. This paper proposes the synthesis of a suitable precursor for the radiolabeling with fluorine-18 of a new PSMA-617 derivative. The whole radiosynthetic procedure has been fully automated, and the final product, which proved to be stable in plasma, has been obtained with radiochemical yield and purity suitable for subsequent preclinical studies.  相似文献   
5.
目的 评价多功能套针浮刺疗法对神经根型颈椎病的临床疗效。方法 选取256例神经根型颈椎病患者,按随机数字表法分为观察组与对照组各128例。观察组应用多功能套针浮刺疗法进行干预,对照组为常规针刺治疗。两组患者均治疗7天。分别于治疗前后观察两组患者的简化McGill疼痛问卷(SF-MPQ)、国际标准颈椎功能障碍指数(NDI)和田中靖久颈椎病症状20分法量表评分,并于治疗结束后3个月观察复发率。结果 两组患者治疗后的SF-MPQ量表评分、NDI量表评分及田中靖久颈椎病症状20分法评分与治疗前相比均有改善(P<0.05),且观察组优于对照组(P<0.05);两组患者于治疗后3个月随访,SF-MPQ量表评分与治疗后相比均有改善,且观察组优于对照组(P<0.05);观察组临床疗效总有效率为96.88%,愈显率为81.25%;对照组总有效率为78.13%,愈显率为46.88%,观察组优于对照组(P<0.05)。结论 应用多功能套针浮刺疗法治疗神经根型颈椎病临床疗效显著,见效较快,可有效降低其复发率,且作用稳定,效果持久,值得临床推广应用。  相似文献   
6.
7.
8.
The Earth’s mean surface temperature is already approximately 1.1°C higher than pre-industrial levels. Exceeding a mean 1.5°C rise by 2050 will make global adaptation to the consequences of climate change less possible. To protect public health, anaesthesia providers need to reduce the contribution their practice makes to global warming. We convened a Working Group of 45 anaesthesia providers with a recognised interest in sustainability, and used a three-stage modified Delphi consensus process to agree on principles of environmentally sustainable anaesthesia that are achievable worldwide. The Working Group agreed on the following three important underlying statements: patient safety should not be compromised by sustainable anaesthetic practices; high-, middle- and low-income countries should support each other appropriately in delivering sustainable healthcare (including anaesthesia); and healthcare systems should be mandated to reduce their contribution to global warming. We set out seven fundamental principles to guide anaesthesia providers in the move to environmentally sustainable practice, including: choice of medications and equipment; minimising waste and overuse of resources; and addressing environmental sustainability in anaesthetists’ education, research, quality improvement and local healthcare leadership activities. These changes are achievable with minimal material resource and financial investment, and should undergo re-evaluation and updates as better evidence is published. This paper discusses each principle individually, and directs readers towards further important references.  相似文献   
9.
Objective: Hepatocellular carcinoma (HCC) microenvironment has been recognized as a key contributor for cancer progression, metastasis, and drug resistance. The crosstalk between tumor cells, the vascular endothelial growth factor (VEGF), and the chemokine (C-C motif) ligand 2 (CCL2) signaling networks mediates immunoinhibitory impact and facilitates tumor angiogenesis. The current investigation aimed at exploring the potent anti-cancer activity of the newly designed nano-based anti-cancer therapy comprising anti-VEGF drug, avastin (AV), and CCR2 antagonist (CR) to counteract HCC and tracking its mode of action in vivo. Methods: The prepared AV, CR, and AVCR nanoprototypes were characterized by nanoscale characterization techniques in our previous work. Here, they are applied for unearthing their anti-cancer properties / mechanisms in hepatic cancer-induced rats via analyzing protein levels and genetic expression of the elements incorporated in the angiogenesis, apoptosis, and metastasis signalling pathways. Results: The present results revealed a significant down-regulation in the angiogenesis, survival and metastasis indices along with up-regulation in the pro-apoptotic mediators upon treatment of hepatic cancer-bearing rats with the novel synthesized nanomaterials when compared with the untreated counterparts. We showed across HCC model that anti-VEGF in combination with CCR2 antagonism therapy leads to sensitization and enhanced tumor response over anti-VEGF or CCR2 antagonism monotherapy, particularly in its nanoscale formulation. Conclusion: The present approach provides new mechanistic insights into the powerful anti-hepatic cancer advantage of the novel nanoprototypes which is correlated with modulating critical signal transduction pathways implicated in tumor microenviroment such as angiogenesis, apoptosis and metastasis. This research work presents a substantial foundation for future studies focused on prohibiting cancer progression and recovery by targeting tumor microenviroment.  相似文献   
10.
Bulletin of Experimental Biology and Medicine - We studied the effect of microalgae of various systematic groups added to the ration on the biochemical parameters of blood serum and liver and...  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