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   25349篇
  免费   2637篇
  国内免费   1536篇
耳鼻咽喉   170篇
儿科学   425篇
妇产科学   286篇
基础医学   3244篇
口腔科学   434篇
临床医学   3313篇
内科学   3840篇
皮肤病学   261篇
神经病学   1869篇
特种医学   1120篇
外国民族医学   20篇
外科学   2578篇
综合类   3571篇
现状与发展   5篇
一般理论   7篇
预防医学   1500篇
眼科学   859篇
药学   2706篇
  33篇
中国医学   1402篇
肿瘤学   1879篇
  2024年   77篇
  2023年   363篇
  2022年   929篇
  2021年   1380篇
  2020年   1012篇
  2019年   907篇
  2018年   964篇
  2017年   787篇
  2016年   793篇
  2015年   1056篇
  2014年   1470篇
  2013年   1206篇
  2012年   1807篇
  2011年   1882篇
  2010年   1145篇
  2009年   989篇
  2008年   1248篇
  2007年   1214篇
  2006年   1322篇
  2005年   1211篇
  2004年   795篇
  2003年   844篇
  2002年   757篇
  2001年   506篇
  2000年   615篇
  1999年   596篇
  1998年   398篇
  1997年   405篇
  1996年   291篇
  1995年   273篇
  1994年   224篇
  1993年   142篇
  1992年   227篇
  1991年   187篇
  1990年   150篇
  1989年   126篇
  1988年   137篇
  1987年   122篇
  1986年   105篇
  1985年   108篇
  1984年   50篇
  1983年   41篇
  1979年   46篇
  1974年   45篇
  1973年   43篇
  1972年   37篇
  1970年   39篇
  1969年   42篇
  1968年   36篇
  1966年   37篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
101.
In this study the endocrine function following intraperitoneal hetero- and orthotopic pancreatico-duodenal-splenic allotransplantation (PDS) in hemipancreatectomized, non-immune-suppressed chacma baboons was assessed. Significantly reduced K-values and insulin release together with glucose intolerance during IVGTT were observed in hemipancreatectomized recipients (HPS) without grafts. Orthotopic and heterotopic PDS transplantation improved the glucose intolerance of HPS recipients; orthotopically sited grafts rendering the best curves. Normal glucose tolerance was not achieved. Both orthotopic and heterotopic PDS transplantation rendered suboptimal insulin release during IVGTT; heterotopically draining grafts released significantly more insulin than orthotopic grafts. Hyperglucagonaemia during IVGTT was a constant feature in both groups, heterotopic grafts releasing the most glucagon during stimulation. C-peptide release was significantly lower in orthotopic grafts compared to normal animals or heterotopically drained insulin. It is concluded that glucose tolerance was not directly related to insulin or glucagon release in this study as orthotopic grafts rendered near-normal IVGTT curves in the presence of hypoinsulinaemia, hyperglucagonaemia, and reduced C-peptide values. The hormonal response after PDS transplantation was variable and the advantages of portal vs systemic insulin drainage remain to be defined.  相似文献   
102.
R波相关振动法血压测量   总被引:1,自引:0,他引:1  
为了提高振地血压测量的准确性,提出了一咱基于心电R波与血压振动波之间相关性,识别振动信号的一种抗干扰方法=-R波相关法,结合振动波形特征识别,该方法可有效地提取信号,消除干扰影响,该算法已在16位8098单片机上实现,本文同时给出了程序的详细流程图。  相似文献   
103.
Summary: The most common human viruses have different abilities to establish persistent chronic infection. Virus‐specific T‐cell responses are critical in the control of virus replication and in the prevention of disease in chronic infection. A large number of phenotypic markers and a series of functions have been used to characterize virus‐specific CD4+ and CD8+ T‐cell responses, and these studies have shown great phenotypic and functional heterogeneity of the T‐cell responses against different viruses. The heterogeneity of the T‐cell response has been proposed to be specific to each virus. However, over the past 2 years, several studies have provided evidence that the phenotypic and functional heterogeneity of CD4+ and CD8+ T‐cell responses is predominantly regulated by the levels of antigen load. The levels of antigen load modulate the phenotypic and functional patterns of the T‐cell response within the same virus infection. Furthermore, the functional characterization of virus‐specific CD4+ and CD8+ T‐cell responses has identified signatures of protective antiviral immunity. Polyfunctional, i.e. interleukin‐2 and interferon‐γ (IFN‐γ) secretion and proliferation, and not monofunctional, i.e. IFN‐γ secretion, CD4+ and CD8+ T‐cell responses represent correlates of protective antiviral immunity in chronic virus infections.  相似文献   
104.
Voors  A.  A.  Petrie  C.  J.  Petrie  M.  C.  任付先 《世界核心医学期刊文摘》2006,2(1):44-44
目的:脉压(PP)升高一贯用来预测有心血管疾病危险患者和轻度慢性心衰(CH F)患者的心血管疾病发生率和死亡率增高。相反,PP降低与急性失代偿性心衰患者死亡率升高相关。然而,尚不清楚PP对于晚期CH F患者的预测价值。方法和结果:采用Cox比例风险回归分析研究了1901例N YH A III或IV级CH F患者(平均年龄65岁,平均射血分数26%)的资料,经校正其他危险因素后,分析PP对死亡率的影响。检测了1个亚组患者的利钠肽水平。多元Cox回归分析表明,PP降低与死亡率增高相关(每增加10m m H g的H R为0.91,95%CI0.93~0.99),这一相关性独立于平均…  相似文献   
105.
报告1100名35岁以上农民冠心病患病率及易患因素的调查结果。全组中检出冠心病15例,其中陈旧心肌梗塞3例、心绞痛7例、心律失常及不典型心绞痛伴有心电图缺血型改变者5例,冠心病现患率为1.36%。另有单纯ST-T 缺血型改变84例,各种严重心律失常36例,未计入冠心病现患率之内.经单变量线性相关及多变量Logistic 函数分析结果,选出有意义的冠心病易患因素有甘油三酯、年龄及收缩期血压增高,以及血浆高密度脂蛋白胆固醇的降低。  相似文献   
106.
作者采用正文试验法,以水提醇沉法提取和分离酚戒类有效成分,并以苯乙醇成含量作为含量测定指标,考察了乙醇浓度、提取温度及煎煮时间三个因素对有效成分提取量的影响,从而筛选出芸杞补肾口服液的是佳生产工艺。  相似文献   
107.
运用巢式聚合酶链反应(PCR)等方法检测了5例丙型肝炎病毒核糖核酸(HCV—RNA)阳性患者的肝癌、癌旁组织和周围血清中HCV—RNA正链和负链,其中男4例,女1例。结果,正链检测:血清及癌旁组织全部阳性,癌组织中3例阳性。负链检测:血清中均阴性,癌组织3例阳性,癌旁组织5例均阳性。本组5例患者肝脏HCV—RNA负链阳性,推测HCV以HCV—RNA负链作为模板在感染的肝脏组织中复制,HCV持续存在于肝脏组织中对肝癌的发生起了一定的作用。  相似文献   
108.
Abruptio placentae occurred in 16 of 132 patients with severe pre-eclampsia who were admitted to an obstetric high-risk ward before 34 weeks' gestation. These 16 patients were compared with those who did not develop abruptio placentae. Systolic and diastolic blood pressure levels, proteinuria and birth weights did not differ significantly between the two groups. Apgar scores were significantly lower in the abruptio placentae group. There were 6 intra-uterine and 2 neonatal deaths in the abruptio placentae group (50% perinatal mortality (PNM] and 3 intra-uterine and 16 neonatal deaths in the other group (18% PNM). Four patients with abruptio placentae presented with abnormal fetal heart-rate patterns and 8 with abdominal pain. No warning signs were present in 3 patients and the fetal heart-rate pattern before delivery was not available in 1 patient. Abnormal fetal heart-rate patterns were present in 5 of the 8 patients who presented with pain. Abruptio placentae occurring in patients with severe proteinuric hypertension carries a high PNM. Frequent monitoring of the fetal heart rate sometimes helps to diagnose fetal distress before the clinical signs of abruption become apparent.  相似文献   
109.
110.
The effects of cigarette smoking on the activity of pulmonary macrophage   总被引:3,自引:0,他引:3  
  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