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   197583篇
  免费   14096篇
  国内免费   4933篇
耳鼻咽喉   1517篇
儿科学   2729篇
妇产科学   3345篇
基础医学   24293篇
口腔科学   3536篇
临床医学   13424篇
内科学   24348篇
皮肤病学   2399篇
神经病学   12254篇
特种医学   6729篇
外国民族医学   2篇
外科学   21842篇
综合类   26244篇
现状与发展   21篇
一般理论   8篇
预防医学   15769篇
眼科学   2421篇
药学   27151篇
  74篇
中国医学   14710篇
肿瘤学   13796篇
  2024年   300篇
  2023年   2691篇
  2022年   4274篇
  2021年   8608篇
  2020年   7140篇
  2019年   6970篇
  2018年   7104篇
  2017年   7739篇
  2016年   7428篇
  2015年   6961篇
  2014年   8602篇
  2013年   12554篇
  2012年   10085篇
  2011年   12113篇
  2010年   7708篇
  2009年   7710篇
  2008年   9179篇
  2007年   10188篇
  2006年   9513篇
  2005年   8739篇
  2004年   7431篇
  2003年   6665篇
  2002年   5242篇
  2001年   4686篇
  2000年   3945篇
  1999年   3401篇
  1998年   2637篇
  1997年   2725篇
  1996年   2500篇
  1995年   2188篇
  1994年   2086篇
  1993年   1759篇
  1992年   1618篇
  1991年   1514篇
  1990年   1314篇
  1989年   1071篇
  1988年   1036篇
  1987年   936篇
  1986年   864篇
  1985年   1255篇
  1984年   1010篇
  1983年   764篇
  1982年   789篇
  1981年   651篇
  1980年   624篇
  1979年   499篇
  1978年   315篇
  1977年   276篇
  1976年   259篇
  1975年   192篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
《Vaccine》2022,40(16):2370-2378
Porcine reproductive and respiratory syndrome virus (PRRSV) and Mycoplasma hyopneumoniae (M. hyopneumoniae, Mhp) are two of the most common pathogens involved in the porcine respiratory disease complex (PRDC) resulting in significant economic losses worldwide. Vaccination is the most effective approach to disease prevention. Since PRRSV and Mhp co-infections are very common, an efficient dual vaccine against these pathogens is required for the global swine industry. Compared with traditional vaccines, multi-epitope vaccines have several advantages, they are comparatively easy to produce and construct, are chemically stable, and do not have an infectious potential. In this study, to develop a safe and effective vaccine, B cell and T cell epitopes of PRRSV-GP5, PRRSV-M, Mhp-P46, and Mhp-P65 protein had been screened to construct a recombinant epitope protein rEP-PM that has good hydrophilicity, strong antigenicity, and high surface accessibility, and each epitope is independent and complete. After immunization in mice, rEP-PM could induce the production of high levels of antibodies, and it had good immunoreactivity with anti-rEP-PM, anti-PRRSV, and anti-Mhp antibodies. The anti-rEP-PM antibody specifically recognizes proteins from PRRSV and Mhp. Moreover, rEP-PM induced a Th1-dominant cellular immune response in mice. Our results showed that the rEP-PM protein could be a potential candidate for the development of a safe and effective multi-epitope peptide combined vaccine to control PRRSV and Mhp infections.  相似文献   
12.
13.
14.
15.
MicroRNAs (miRNAs) play important roles in prostate cancer development. However, it remains unclear how individual miRNAs contribute to the initiation and progression of prostate cancer. Here we show that a basal layer‐enriched miRNA is required for prostate tumorigenesis. We identify miR‐205 as the most highly expressed miRNA and enriched in the basal cells of the prostate. Although miR‐205 is not required for normal prostate development and homeostasis, genetic deletion of miR‐205 in a Pten null tumor model significantly compromises tumor progression and does not promote metastasis. In Pten null basal cells, loss of miR‐205 attenuates pAkt levels and promotes cellular senescence. Furthermore, although overexpression of miR‐205 in prostate cancer cells with luminal phenotypes inhibits cell growth in both human and mouse, miR‐205 has a minimal effect on the growth of a normal human prostate cell line. Taken together, we have provided genetic evidence for a requirement of miR‐205 in the progression of Pten null‐induced prostate cancer.  相似文献   
16.
This study is focussed on micro-encapsulation of essential oils in polylactic acid (PLA) and a poly(methyl methacrylate) (PMMA) matrix as well as blends of the same. Microspheres were prepared by the solvent evaporation technique and characterised by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR). The encapsulation efficiencies and release profiles of the essential oils were studied by gas chromatography mass spectrometry (GC-MS) and head-space solid-phase microextraction GC-MS, respectively. Furthermore, the microspheres were tested for antibacterial activity against both Gram-negative and Gram-positive bacterial strains.

The results showed that the microspheres compositions (PLA/PMMA ratio) have significant effect on their characteristics. The process adopted for preparing the microspheres promoted formation of spherical particles at the sizes of 1.5–9.5?µm. The highest encapsulation efficiency of the prepared microspheres was observed in systems consisting of linalool (81.10?±?10.0?wt. % for PLA system and 76.0?±?3.3?wt. % for PMMA system). Confirmation was also made that the release rate of the microspheres was affected by the size of the same.  相似文献   

17.
18.
全膝关节置换术是目前治疗终末期膝关节骨性关节炎最有效的方法之一,全膝关节置换术后膝关节功能、术后膝关节疼痛与术后下肢力线有着密切的关系。目前膝关节置换术下肢对线方式主要采用机械力学对线方法,该方法可以改善膝关节功能,但是有部分患者也会产生术后膝关节的疼痛、活动受限等并发症,导致术后患者满意度较差。近些年越来越多的研究开始关注运动力学对线技术并应用于临床。运动学对线技术旨在重建患者的解剖结构,将膝关节假体运动轴与膝关节生理性运动轴保持一致,减少膝关节周围软组织和韧带的松解,实现膝关节生理性运动。该文就运动力学对线方法在全膝关节置换术中的应用进展作一综述。  相似文献   
19.
20.
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