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   100982篇
  免费   10085篇
  国内免费   5141篇
耳鼻咽喉   992篇
儿科学   2152篇
妇产科学   1335篇
基础医学   9579篇
口腔科学   1768篇
临床医学   13775篇
内科学   12540篇
皮肤病学   1172篇
神经病学   4475篇
特种医学   3271篇
外国民族医学   17篇
外科学   7819篇
综合类   19489篇
现状与发展   23篇
一般理论   54篇
预防医学   10215篇
眼科学   2444篇
药学   11497篇
  157篇
中国医学   7351篇
肿瘤学   6083篇
  2024年   398篇
  2023年   1378篇
  2022年   3385篇
  2021年   4450篇
  2020年   3606篇
  2019年   2833篇
  2018年   2854篇
  2017年   3114篇
  2016年   2793篇
  2015年   4173篇
  2014年   5285篇
  2013年   6168篇
  2012年   8519篇
  2011年   9094篇
  2010年   6793篇
  2009年   5790篇
  2008年   6746篇
  2007年   6561篇
  2006年   5909篇
  2005年   5008篇
  2004年   3828篇
  2003年   3417篇
  2002年   2947篇
  2001年   1715篇
  2000年   1333篇
  1999年   990篇
  1998年   637篇
  1997年   602篇
  1996年   507篇
  1995年   429篇
  1994年   429篇
  1993年   293篇
  1992年   201篇
  1991年   193篇
  1990年   176篇
  1989年   170篇
  1988年   156篇
  1987年   144篇
  1986年   115篇
  1985年   127篇
  1984年   129篇
  1983年   94篇
  1982年   166篇
  1981年   140篇
  1980年   135篇
  1979年   76篇
  1978年   86篇
  1977年   83篇
  1976年   69篇
  1974年   79篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
长期以来的研究只能用结合试验来证明核基质结合区(MARs)的存在,对其真正的功能了解甚少.直到最近,人们才发现了MARs的一些生物学活性,MARs参与襻环的形成和染色体的高级包装,在真核生物的转录调控和凋亡方面起到了重要作用.对MARs的生物学功能仍在进一步的研究中,本文主要就MARs的结构、在转录调控中的作用及其它一些研究进展作一综述.  相似文献   
42.
The Childrens Cancer Study Group evaluated daily oral 13-cis-retinoic acid to determine its therapeutic efficacy in 28 children with advanced neuroblastoma refractory to conventional therapy. Cheilitis and fissured lips were the most common side effects; however, fewer than 50% of the patients experienced any toxicity. Two of twenty-two evaluable children demonstrated positive response to therapy. In one case, a child received the drug for 11 months. Seventeen patients demonstrated progressive disease within 28 days of the start of treatment. Three other patients with stable disease, or removed from study at day 28, were considered nonresponsive. Our data demonstrate that, when given as a single daily oral dose of 100 mg/m2, 13-cis-retinoic acid does not have significant activity in children with advanced neuroblastoma. © 1992 Wiley-Liss, Inc.  相似文献   
43.
44.
45.
46.
糖皮质激素依赖性皮炎的治疗进展   总被引:8,自引:0,他引:8  
糖皮质激素依赖性皮炎临床报道中,中医、中西医结合的治疗方法最多,显示出了其优势所在,其中中药疗效优于西药,且在改善和治愈面部潮红、毛细血管扩张、色素变化、病情反跳等症状方面优势明显,对于面部痤疮样皮疹、痒及不适等症状,中、西药治疗疗效相近。目前糖皮质激素依赖性皮炎最好的治疗方法应该是中西医结合疗法。  相似文献   
47.
Rotigotine is a new, non-ergot dopamine agonist formulated in a transdermal delivery system. The present study was to investigate the efficacy and safety of the rotigotine transdermal patch in the treatment of early Parkinson's disease. Patients (n = 561) were randomized to rotigotine, ropinirole, or placebo. The titration period was up to 13 weeks, and there was a minimum dose-maintenance period of 24 weeks for ropinirole and 33 weeks for rotigotine. The primary endpoint was the proportion of patients with a minimum of 20% decrease in the combined Unified Parkinson's Disease Rating Scale Part II and Part III scores. The responder rate in the rotigotine group was significantly higher than in the placebo group (52% vs. 30%, P < 0.0001). Transdermal rotigotine at doses < or =8 mg/24 h did not show noninferiority to ropinirole at doses < or =24 mg/day. In a post-hoc subgroup analysis, rotigotine < or =8 mg/24 hours had a similar efficacy to ropinirole at doses < or =12 mg/day. The rotigotine transdermal patch was well tolerated. The most common adverse events were application-site reactions, nausea, and somnolence. Application-site reactions were predominantly mild or moderate in intensity. In conclusion, the rotigotine transdermal patch represents an effective and safe option for the treatment of patients with early Parkinson's disease.  相似文献   
48.
肺血管扩张在肝肺综合征发病机制中作用的研究进展   总被引:3,自引:0,他引:3  
肺血管扩张是肝肺综合征的主要发病机制,然而导致HPS肺血管扩张的机制相当复杂,至今仍不清楚.目前认为肺血管内巨噬细胞聚积和雌激素升高导致的血管活性因子增多和活性增强可能与此有关,近年来这方面的研究很多,本文对此作一综述.  相似文献   
49.
OBJECTIVE: To study the expression of neuron-specific enolase (NSE) and olfactory marker protein (OMP) in the developing olfactory mucosa of human fetuses. METHOD: The expression of NSE and OMP in the olfactory mucosa of 6 human fetuses (12, 16, 20, 24, 28 and 34 weeks) was studied using the technique of immunohistochemistry. RESULTS: NSE immunological positive reactions were seen in all 6 fetal mucosa from gestational 12 (G12) to G34, with plenty of positive-stained dual-pole neuron cells. At G12, the positive cells aligned tightly, the cell bodies were localized in the lower portion of olfactory epithelium and the positive-stained area occupied upper 2/3 of fetal nasal mucosa. With the development, the positive cells gradually became multilayer, but the density and the relative area of positive-cells reduced. At G34, the positive cells were located only in upper 1/3 of nasal mucosa. OMP-positive reactions were localized in a few dual-pole neurons at G12, the number was much less than NSE-positive cells in the same fetus. With the development, the OMP-positive cells gradually increased with most of the cell bodies located in the upper portion of epithelium, but number still relatively less than the NSE-positive cells at the same age. CONCLUSION: At G12, there were lots of olfactory neuron in the olfactory mucosa and only a few olfactory neurons had became mature. With the development, the olfactory epithelial area reduced but the number of mature olfactory neurons increased. At the last trimester, fetal olfactory sensor was almost matured.  相似文献   
50.
RATIONALE: Holocaust survivors, who experienced trauma 60 years ago, provide an opportunity to explore the impact of early lifetime trauma in later life and, in particular, the interplay of depression and posttraumatic stress disorder (PTSD). In this study, the authors contrast depressed Holocaust survivors (HD), nondepressed Holocaust survivors (HND), and older depressed persons (CD). METHODS: The sample consisted of 36 consecutive Holocaust survivors (mean age: 79 years) treated in a primary care practice, among whom 20 (56%) were diagnosed as having a major depressive disorder and 16 as nondepressed; 18 depressed non-Holocaust Jewish primary care patients served as controls (mean age: 84 years). The authors examined nine clinical and social variables. The Kruskal-Wallis, Mann-Whitney U, and chi(2) tests were used to contrast the groups. The authors used a conservative significance level of .01. RESULTS: In contrast to the CD group, the HD group was significantly older, more likely to report PTSD and guilt symptoms, to have higher Beck Anxiety Inventory (BAI) and Brief Psychiatric Rating Scale (BPRS) scores, and to have more impaired social functioning. In contrast to the HND group, the HD group was significantly more likely to report PTSD and guilt feelings, to have higher Hamilton Depression Scale (HAM-D), BAI, and BPRS scores, and to have more impaired social functioning. In contrast to the CD group, the HND group was significantly more likely to have PTSD symptoms and to have lower HAM-D and BPRS scores. CONCLUSIONS: The prevalence of depression and PTSD symptoms were very high among survivors. Depressed survivors had significantly worse psychologic and social functioning than depressed controls. Depressed survivors had more PTSD symptoms than nondepressed survivors, although it is unclear as to the causal direction of the relationship between depression and PTSD.  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