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   524595篇
  免费   33920篇
  国内免费   21531篇
耳鼻咽喉   5731篇
儿科学   11337篇
妇产科学   11429篇
基础医学   62709篇
口腔科学   11780篇
临床医学   59802篇
内科学   84423篇
皮肤病学   8099篇
神经病学   29231篇
特种医学   22418篇
外国民族医学   267篇
外科学   62224篇
综合类   54033篇
现状与发展   74篇
一般理论   37篇
预防医学   37783篇
眼科学   13820篇
药学   48074篇
  300篇
中国医学   18417篇
肿瘤学   38058篇
  2023年   4975篇
  2022年   12509篇
  2021年   15989篇
  2020年   12078篇
  2019年   10591篇
  2018年   14670篇
  2017年   13964篇
  2016年   12507篇
  2015年   19389篇
  2014年   22421篇
  2013年   20038篇
  2012年   34349篇
  2011年   31960篇
  2010年   19272篇
  2009年   17522篇
  2008年   19979篇
  2007年   20707篇
  2006年   20703篇
  2005年   28185篇
  2004年   23738篇
  2003年   18597篇
  2002年   12166篇
  2001年   12076篇
  2000年   9607篇
  1999年   13877篇
  1998年   5187篇
  1997年   4848篇
  1996年   4063篇
  1995年   3826篇
  1994年   3267篇
  1992年   9550篇
  1991年   9421篇
  1990年   9238篇
  1989年   8541篇
  1988年   7966篇
  1987年   7528篇
  1986年   7001篇
  1985年   6031篇
  1984年   4097篇
  1983年   3309篇
  1979年   4108篇
  1978年   2519篇
  1975年   2578篇
  1974年   3252篇
  1973年   2854篇
  1972年   2884篇
  1971年   2817篇
  1970年   2620篇
  1969年   2525篇
  1968年   2284篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
131.
The lack of estrogen during menopause is associated with various symptoms including osteoporosis, cardiovascular diseases, and menopausal symptoms. For many years, conventional hormone replacement therapy has been successfully used to treat these conditions. However, in light of recent studies that draw attention to potential hazards of conventional HRT, various attempts were undertaken to search for alternatives of classical HRT. Phytoestrogens are supposed to ameliorate various discomforts associated with menopause. Resveratrol (RES) is present in red wine, grapes and peanuts and has been implicated in cardioprotection and prevention of adverse side effects observed after regular HRT. As the pituitary-thyroid axis is a target of estrogen action, we first assessed the effects of E2 administration on thyroid hormone stimulating hormone releasing hormone (TRH)-induced thyroid stimulating hormone (TSH) secretion from pituitary cell cultures in vitro. Our data reveal that E2 treatment augments the TRH-induced TSH secretion. We furthermore designed a long-term study of three months to assess the effects of subcutaneous and oral administration of 17beta-estradiol (E2), as well as the actions of RES on the pituitary-thyroid axis in ovariectomized (OVX) female rats. Our results demonstrate that serum levels of 1.0 and 8.1 microM RES lead to a significant increase in total serum triiodthyronine (T3) levels. OVX induces TSHbeta mRNA in the adenohypohysis and E2 treatment attenuates this effect. Treatment of rats with subcutaneous implants of E2 does not affect the pituitary-thyroid axis, whereas orally applied E2 benzoate (E2B) increases plasma TSH and total thyroxine (T4) in OVX rats. In all animals, we could not detect changes in thyroid morphology as assessed by hematoxylin-eosin (HE) and Perjod-Acid Schiff's (PAS) staining.  相似文献   
132.
本文报告了暗纹节菱孢[Arthinium phaeospemum(Corda)Ellis]所致皮肤真菌病的组织病理学及超微结构观察。HE、PAS、镀银染色(Szatri)法及铅铀染色,对皮损的组织病理改变,进行了光镜及透射电镜观察。光镜下发现暗纹节菱孢引起真皮及皮下脂肪组织广泛性病理浸润,由多种细胞构成的肉芽肿,尤其对皮肤附属器严重破坏。在病理浸润中可见球形、卵圆形、菱形及晶体形,玫瑰红色、棕色及褐色孢子。透射电镜下见真皮成纤维细胞胞浆内吞噬多数界线清楚的圆形小体,空泡内也有相同的小体,胞浆空泡甚多,胞核完整。同时见到破坏的溶酶体。病理浸润内形态各异的孢子及不同颜色,是孢子生长的不同阶段。  相似文献   
133.
The objective of this study is to assess the efficacy and safety of herbal medicines (HMs), as a monotherapy or adjunct therapy, compared to placebo or conventional approaches in the treatment of idiopathic Parkinson's disease (PD). We conducted a systematic review of randomized controlled trials from both conventional and alternative medicine sources. Outcome measures were overall improvement, quality of life, reduction of levodopa dose, and adverse events. Nine studies were included, each testing a different HM. Six of the trials had limited internal validity due to major flaws in design, including the lack of proper randomization; insufficient blinding; unclear inclusive criteria in terms of diagnostic criteria, baseline staging, and duration of disease; lack of proper sample size calculation; and insufficient data analysis. Imbalances in gender and ethnicity among the patients in the included trials were observed. No major adverse events emerged, and no specific pattern was detected from the trials describing such data. In addition to major methodological defects, heterogeneity in (1) HM tested, (2) control treatment, and (3) outcome measure hindered in-depth data analysis and synthesis. Current evidence is insufficient to evaluate the efficacy and safety of various HMs. Further studies with improved trial design and reporting, with assessment on cost-effectiveness, quality of life, and qualitative data are warranted.  相似文献   
134.
目的探讨老年原发性高血压(ET)患者脉压与急性心肌梗塞(AMI)的关系。方法观测45例老年高血压病合并急性心肌梗塞患者的收缩压(SBP)、舒张压(DBP)及脉压(PP),以31例老年单纯高血压患者(冠脉造影排除冠心病)作对照组,进行比较。结果并发急性心肌梗塞组,其脉压较单纯高血压组明显增高。结论脉压与老年人急性心肌梗塞密切相关,对老年人高血压的治疗更要注重控制脉压。  相似文献   
135.
分析近年来国内高校教育形式的变化,肯定扎实学生基础、培养创新型人才的重要性,结合多年来在工科物理教改中的探索经验和初步成果,提出了深化工科物理教学改革、培养创新型人才的思路和实现途径。  相似文献   
136.
体重指数分级标准应用方法的探讨   总被引:1,自引:0,他引:1  
目的探讨按照体重指数分级标准计算出的体重值应用表的实用价值。方法将身高作为选定变量,其变量值间距为1 cm,按照体重指数分级标准上、下限值,分别乘以身高2(m2),即求出相对应的体重(kg),依此制成应用表。判定时依据身高和实测的体重,对照应用表得出其体重指数分级范围。结果制成并列出以体重值查对其相对应危险值应用表。结论本查对表适用于大规模的预防性健康体检。在人体生长发育阶段能做到自身动态监测,对早期预防肥胖症具有积极作用。  相似文献   
137.
138.
139.
3种霍乱弧菌检测方法在外环境标本中的应用研究   总被引:2,自引:1,他引:1  
目的:通过改进霍乱弧菌检测的技术手段,提高外环境标本中霍乱弧菌的检出率。方法:将常规分离鉴定法、PCR检测法和胶体金免疫层析试验法同时用于检测霍乱流行期间的外环境标本,并对其现场应用结果进行比较分析。结果:3种方法检测80份外环境标本霍乱弧菌的结果显示:它们均未出现假阳性,3种方法各有优势,且结果相互符合性好,但也存在各自弱点。结论:只用单一种方法来检测外环境标本霍乱弧菌存在明显不足。建议在外环境霍乱监测中选用胶体金法进行初筛,再用常规法和PCR法检测。最大限度减少漏检的可能性。  相似文献   
140.
AIM: To compare the effects of 17beta-estradiol given intranasally (intranasal E2) and raloxifene on serum lipid profile and fibrinogen in hypercholesterolemic postmenopausal women. METHODS: The study population consisted of 46 women after menopause. The placebo group (n = 11) was given calcium, while the intervention groups were given intranasal E2 (Aerodiol; Servier, Chambray-les-Tours, France) (n = 16) or raloxifene (Evista; Lilly SA, Madrid, Spain) (n = 19). Blood lipids and fibrinogen were compared between groups at baseline and after 3 months of treatment. RESULTS: The group receiving intranasal E2 showed a significant decrease in triglyceride levels (p<0.05) and a marked increase in high-density lipoprotein cholesterol levels (p<0.05). No changes in lipid profile were observed in the raloxifene and placebo groups. Raloxifene caused a significant decrease in fibrinogen levels (p<0.05). CONCLUSION: Intranasal E2 exerts significant effects on lipid profile in hypercholesterolemic postmenopausal women. Raloxifene has a greater impact on fibrinogen than intranasal E2 application.  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