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   34634篇
  免费   3831篇
  国内免费   2344篇
耳鼻咽喉   271篇
儿科学   370篇
妇产科学   268篇
基础医学   3066篇
口腔科学   830篇
临床医学   4715篇
内科学   3645篇
皮肤病学   385篇
神经病学   1328篇
特种医学   1346篇
外国民族医学   13篇
外科学   3265篇
综合类   7566篇
现状与发展   10篇
一般理论   3篇
预防医学   3343篇
眼科学   764篇
药学   4154篇
  37篇
中国医学   3282篇
肿瘤学   2148篇
  2024年   226篇
  2023年   728篇
  2022年   1762篇
  2021年   2184篇
  2020年   1691篇
  2019年   1183篇
  2018年   1205篇
  2017年   1238篇
  2016年   1069篇
  2015年   1657篇
  2014年   1942篇
  2013年   2019篇
  2012年   2961篇
  2011年   3136篇
  2010年   2362篇
  2009年   1884篇
  2008年   2184篇
  2007年   2032篇
  2006年   1957篇
  2005年   1567篇
  2004年   1031篇
  2003年   1113篇
  2002年   793篇
  2001年   704篇
  2000年   492篇
  1999年   356篇
  1998年   199篇
  1997年   180篇
  1996年   140篇
  1995年   118篇
  1994年   100篇
  1993年   65篇
  1992年   97篇
  1991年   64篇
  1990年   84篇
  1989年   49篇
  1988年   53篇
  1987年   44篇
  1986年   31篇
  1985年   20篇
  1984年   18篇
  1983年   11篇
  1982年   6篇
  1981年   5篇
  1979年   16篇
  1978年   6篇
  1977年   4篇
  1976年   3篇
  1974年   5篇
  1966年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Diabetes is the seventh leading cause of death in United States. Dietary intake and behaviors are essential components of diabetes management. Growing evidence suggests dietary components beyond carbohydrates may critically impact glycemic control. Assessment tools on mobile platforms have the ability to capture multiple aspects of dietary behavior in real-time throughout the day to inform and improve diabetes management and insulin dosing. The objective of this narrative review was to summarize evidence related to dietary behaviors and composition to inform a mobile image-based dietary assessment tool for managing glycemic control of both diabetes types (type 1 and type 2 diabetes). This review investigated the following topics amongst those with diabetes: (1) the role of time of eating occasion on indicators of glycemic control; and (2) the role of macronutrient composition of meals on indicators of glycemic control. A search for articles published after 2000 was completed in PubMed with the following sets of keywords “diabetes/diabetes management/diabetes prevention/diabetes risk”, “dietary behavior/eating patterns/temporal/meal timing/meal frequency”, and “macronutrient composition/glycemic index”. Results showed eating behaviors and meal macronutrient composition may affect glycemic control. Specifically, breakfast skipping, late eating and frequent meal consumption might be associated with poor glycemic control while macronutrient composition and order of the meal could also affect glycemic control. These factors should be considered in designing a dietary assessment tool, which may optimize diabetes management to reduce the burden of this disease.  相似文献   
43.
目的:认识多发伤中骨折的主要特点,探讨内固定在救治中的意义。方法:回顾1994-08~1999-08间手术救治多发伤66例,对其161处骨折中的98处进行了“仿AO技术”有关方法内固定。结果:骨折均满意愈合;涉及骨折关节51个,功能恢复满意率为96.08%。结论:在多发伤中,骨折、合并伤与并发症远较“一般骨折”复杂、严重;有效固定骨折是一种重要的救命措施;内固定手术应争取在伤后24h进行,但如受条件制约,伤后1-3wk内手术也可获得满意效果;仿AO技术中的某些方法,如拉力螺钉、张力带钢丝及自动加压钢板等,用于内固定可使骨折获得卓有成效的稳定性。  相似文献   
44.
糖尿病患者膳食营养分析   总被引:5,自引:0,他引:5  
目的 :探讨糖尿病患者膳食营养状况 ,提出改善糖尿病患者膳食结构的策略。方法 :对 2 2 5例糖尿病患者连续调查 3天膳食供给情况 ,建立数据库输入计算机 ,用SPSS软件进行分析。结果 :热能摄入量不符合要求者占77 3% ;蛋白质供给量不足者占患者总数的 75 6% ;47 6%的糖尿病患者脂肪摄入量超过标准 ;5 5 1%的糖尿病患者碳水化合物的摄入量不符合要求 ;膳食纤维摄入不足者占患者总数的 94 2 % ;维生素和无机盐中 ,除铁、核黄素和抗坏血酸供给量尚可 ,其余均不足。结论 :糖尿病患者膳食是不合理的 ,必须按照膳食治疗方案调节膳食  相似文献   
45.
目的探讨肾病综合征患者焦虑的影响因素及对策.方法应用状态-特质焦虑问卷(STAI)、社会支持评定量表(SSRS)、生活事件量表(LES)等对80例肾病综合征患者进行测查.结果肾病综合征患者状态焦虑问卷(SAI)分值明显高于正常人群(49.55±8.18Vs39.31±8.66)(P<0.01).逐步回归分析发现,患者焦虑的主要因素为性格内向、社会支持状况差、负性生活事件多、担心治疗效果不好、担心医生治疗水平不高等.结论肾病综合征患者有明显的焦虑情绪,受多种因素影响,加强心理干预,配合药物治疗,能收到较好效果.  相似文献   
46.
目的 :探讨导电聚吡咯膜技术对大鼠肺Ⅱ型细胞体外生长的作用。方法 :采用四甲基偶氮唑盐比色法测定比较导电聚吡咯膜组和常规培养组大鼠肺Ⅱ型细胞的生长和增殖情况。结果 :培养 3~ 5d后两组OD值有显著差异 (P <0 .0 5 )。结论 :常规培养条件下的大鼠肺Ⅱ型细胞在体外生长时间约 2~ 3d ,导电聚吡咯膜可以将肺Ⅱ型细胞体外生长时间延长至 5d。  相似文献   
47.
The blood–testis barrier (BTB) of Sertoli cells (SCs) is an important biological barrier that maintains spermatogenesis and provides a favourable microenvironment for spermatogenesis. However, heat stress can directly damage the BTB structural proteins of testicular SCs, leading to dyszoospermia. Wuzi Yanzong Pills (WYP) is a traditional Chinese medicine formula used to treat male reproductive diseases. However, whether WYP could ameliorate heat stress injury in primary SCs extracted from rat testes and BTB proteins remains unknown. Here, treatment with WYP (low, medium and high dose) increased the SC viability and the proliferation of cell antigen Ki67 significantly. Additionally, it promoted SC maturation, which presented in the form of increased androgen receptors (ARs) and decreased cytokeratin 18 (CK-18) in three WYP dose groups. WYP upregulated BTB proteins such as zonula occludens 1 (ZO-1) and occludin across all WYP groups and decreased phosphorylated Akt (p-Akt) in the middle and high-dose groups; however, ZO-1 and occludin recovery were reduced with the presence of Akt inhibitor in WYP groups. WYP improved SC viability and proliferation, and ameliorated dedifferentiation and BTB-proteins damaged by heat stress via Akt signalling. The findings present theoretical support for the effects of WYP in the management of dyszoospermia and male infertility.  相似文献   
48.
BackgroundBariatric surgery is effective for polycystic ovary syndrome (PCOS), while the exact mechanism remains unclear.ObjectivesTo assess the impact of bariatric surgery on PCOS patients and further explore the possible mechanism.SettingA meta-analysis.MethodsWe searched PubMed, Web of Science, The Cochrane Library, and Embase to identify relevant studies published before November 2020.ResultsTwenty-one studies met our inclusion criteria, and we identified 552 patients with PCOS study. Results showed that the prevalence of preoperative PCOS, menstrual irregularity, hirsutism, type 2 diabetes (T2D), hypertension, infertility, and depression significantly decreased after bariatric surgery. Levels of total testosterone, fasting insulin, and luteinizing hormone (LH) decreased and estradiol increased, while levels of follicle-stimulating hormone (FSH) and LH/FSH did not show significant changes during the 3-month follow-up. There were decreases in testosterone and fasting insulin levels when the postoperative follow-up time was 6 months or ≥12 months. Levels of fasting blood glucose and triglycerides were significantly reduced after 6 months or ≥12 months of bariatric surgery. High-density lipoprotein (HDL) and sex hormone-binding globulin (SHBG) significantly improved ≥12 months after bariatric surgery.ConclusionSymptoms of PCOS and related complications are significantly alleviated after bariatric surgery. In addition, we found a significant improvement on anomalous secretion of gonadotropins, glucose metabolism, and lipid metabolism in patients with PCOS after bariatric surgery.  相似文献   
49.
Bulletin of Environmental Contamination and Toxicology - An effective method of iron extraction from bauxite residue was explored, and iron was used to prepare iron carbon composite material, which...  相似文献   
50.
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