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   1128616篇
  免费   78746篇
  国内免费   4702篇
耳鼻咽喉   15498篇
儿科学   35358篇
妇产科学   29566篇
基础医学   159764篇
口腔科学   30558篇
临床医学   101454篇
内科学   212151篇
皮肤病学   25081篇
神经病学   84088篇
特种医学   45348篇
外国民族医学   235篇
外科学   169638篇
综合类   30587篇
现状与发展   16篇
一般理论   277篇
预防医学   78075篇
眼科学   25736篇
药学   92212篇
  58篇
中国医学   5844篇
肿瘤学   70520篇
  2021年   10335篇
  2019年   9572篇
  2018年   13242篇
  2017年   10654篇
  2016年   11825篇
  2015年   13659篇
  2014年   18290篇
  2013年   25246篇
  2012年   34777篇
  2011年   36784篇
  2010年   21893篇
  2009年   20231篇
  2008年   33130篇
  2007年   35299篇
  2006年   35671篇
  2005年   33806篇
  2004年   31944篇
  2003年   30621篇
  2002年   29391篇
  2001年   61440篇
  2000年   62837篇
  1999年   52194篇
  1998年   13174篇
  1997年   11734篇
  1996年   11613篇
  1995年   10824篇
  1994年   9795篇
  1993年   9155篇
  1992年   38214篇
  1991年   36602篇
  1990年   36044篇
  1989年   34543篇
  1988年   31091篇
  1987年   30185篇
  1986年   28369篇
  1985年   26577篇
  1984年   19279篇
  1983年   16181篇
  1982年   8870篇
  1979年   17083篇
  1978年   11430篇
  1977年   10246篇
  1976年   8858篇
  1975年   10088篇
  1974年   11682篇
  1973年   11299篇
  1972年   10782篇
  1971年   10118篇
  1970年   9268篇
  1969年   8941篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Inflammatory bowel disease (IBD) is a chronic disease that requires chronic treatment throughout the evolution of the disease, with a complex physiopathology that entails great challenges for the development of new and specific treatments for ulcerative colitis and Crohn´s disease. The anti-tumor necrosis factor alpha therapy has impacted the clinical course of IBD in those patients who do not respond to conventional treatment, so there is a need to develop new therapies and markers of treatment response. Various pathways involved in the development of the disease are known and the new therapies have focused on blocking the inflammatory process at the gastrointestinal level by oral, intravenous, subcutaneous, and topical route. All these new therapies can lead to more personalized treatments with higher success rates and fewer relapses. These treatments have not only focused on clinical remission, but also on achieving macroscopic changes at the endoscopic level and microscopic changes by achieving mucosal healing. These treatments are mainly based on modifying signaling pathways, by blocking receptors or ligands, reducing cell migration and maintaining the integrity of the epithelial barrier. Therefore, this review presents the efficacy and safety of the new treatments that are currently under study and the advances that have been made in this area in recent years.  相似文献   
12.
13.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion.  相似文献   
14.
15.
Cantharidin (CTD) is an effective antitumor agent. However, it exhibits significant hepatotoxicity, the mechanism of which remains unclear. In this study, biochemical and histopathological analyses complemented with ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS)-based targeted metabolomic analysis of bile acids (BAs) were employed to investigate CTD-induced hepatotoxicity in rats. Sixteen male and female Sprague–Dawley rats were randomly divided into two groups: control and CTD (1.0 mg/kg) groups. Serum and liver samples were collected after 28 days of intervention. Biochemical, histopathological, and BA metabolomic analyses were performed for all samples. Further, the key biomarkers of CTD-induced hepatotoxicity were identified via multivariate and metabolic pathway analyses. In addition, metabolite–gene–enzyme network and Kyoto Encyclopedia of Genes and Genomes pathway analyses were used to identify the signaling pathways related to CTD-induced hepatotoxicity. The results revealed significantly increased levels of biochemical indices (alanine aminotransferase, aspartate aminotransferase, and total bile acid). Histopathological analysis revealed that the hepatocytes were damaged. Further, 20 endogenous BAs were quantitated via UHPLC-MS/MS, and multivariate and metabolic pathway analyses of BAs revealed that hyocholic acid, cholic acid, and chenodeoxycholic acid were the key biomarkers of CTD-induced hepatotoxicity. Meanwhile, primary and secondary BA biosynthesis and taurine and hypotaurine metabolism were found to be associated with the mechanism by which CTD induced hepatotoxicity in rats. This study provides useful insights for research on the mechanism of CTD-induced hepatotoxicity.  相似文献   
16.
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Heavy metal concentrations in surface soils of Reserved Forests (RFs) have a significant impact on...  相似文献   
17.
Colorectal cancer (CRC) is the third most diagnosed cancer and the second leading cause of cancer-related mortality in the United States. Across the globe, people in the age group older than 50 are at a higher risk of CRC. Genetic and environmental risk factors play a significant role in the development of CRC. If detected early, CRC is preventable and treatable. Currently, available screening methods and therapies for CRC treatment reduce the incidence rate among the population, but the micrometastasis of cancer may lead to recurrence. Therefore, the challenge is to develop an alternative therapy to overcome this complication. Nanotechnology plays a vital role in cancer treatment and offers targeted chemotherapies directly and selectively to cancer cells, with enhanced therapeutic efficacy. Additionally, nanotechnology elevates the chances of patient survival in comparison to traditional chemotherapies. The potential of nanoparticles includes that they may be used simultaneously for diagnosis and treatment. These exciting properties of nanoparticles have enticed researchers worldwide to unveil their use in early CRC detection and as effective treatment. This review discusses contemporary methods of CRC screening and therapies for CRC treatment, while the primary focus is on the theranostic approach of nanotechnology in CRC treatment and its prospects. In addition, this review aims to provide knowledge on the advancement of nanotechnology in CRC and as a starting point for researchers to think about new therapeutic approaches using nanotechnology.  相似文献   
18.
Maternal and Child Health Journal - Early life exposures can have an impact on a child’s developmental trajectory and children born late preterm (34–36&nbsp;weeks gestational age)...  相似文献   
19.
20.
夏靖  倪诚 《天津中医药》2019,36(12):1149-1152
中医对于脂溢性脱发,传统多按"血热风燥""血虚风燥""湿热""肝肾不足"等分型论治,虽能取得一定的临床疗效,暂时缓解病情,但难以根治,给患者带来困扰。倪诚教授根据国医大师王琦教授所提出的"肤-体相关论""体质可调论",认为湿热体质是脂溢性脱发发病的主要土壤,指出瘀浊蛀发是脂溢性脱发的病机要点,治疗上以清利湿热调体治本、凉血活血为主、佐以滋养肝肾,方用茵陈蒿汤合升降散加减配合外洗经验方,从标本兼顾、分期论治、内服外洗等方面治疗脂溢性脱发,在临床上取得良好的疗效。  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