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   4911篇
  免费   386篇
  国内免费   41篇
耳鼻咽喉   37篇
儿科学   219篇
妇产科学   184篇
基础医学   616篇
口腔科学   185篇
临床医学   542篇
内科学   936篇
皮肤病学   105篇
神经病学   341篇
特种医学   116篇
外国民族医学   1篇
外科学   547篇
综合类   116篇
现状与发展   1篇
一般理论   1篇
预防医学   415篇
眼科学   110篇
药学   524篇
中国医学   59篇
肿瘤学   283篇
  2024年   9篇
  2023年   83篇
  2022年   141篇
  2021年   255篇
  2020年   178篇
  2019年   231篇
  2018年   281篇
  2017年   220篇
  2016年   222篇
  2015年   201篇
  2014年   218篇
  2013年   328篇
  2012年   404篇
  2011年   368篇
  2010年   221篇
  2009年   148篇
  2008年   219篇
  2007年   217篇
  2006年   169篇
  2005年   175篇
  2004年   140篇
  2003年   134篇
  2002年   106篇
  2001年   64篇
  2000年   68篇
  1999年   60篇
  1998年   26篇
  1997年   18篇
  1996年   13篇
  1995年   11篇
  1994年   12篇
  1993年   15篇
  1992年   27篇
  1991年   42篇
  1990年   34篇
  1989年   24篇
  1988年   22篇
  1987年   25篇
  1986年   28篇
  1985年   22篇
  1984年   14篇
  1982年   14篇
  1979年   11篇
  1977年   8篇
  1975年   7篇
  1974年   14篇
  1972年   9篇
  1971年   8篇
  1970年   11篇
  1969年   13篇
排序方式: 共有5338条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Diabetes, as a low‐grade chronic inflammatory disease, causes disruption in proper function of immune and metabolic system. Chromium is an important element required for normal lipid and glucose metabolism. Chromium deficiency is correlated with elevation in cardiometabolic risk, which results from increased inflammation. This systematic review was conducted to discover the potential roles of chromium on inflammatory biomarkers. Eligible studies were all in vitro, animal and human studies published in English‐language journals from inception until October 2018. PubMed, Scopus, Embase, ProQuest and Google Scholar databases were searched to fined interventional studies from the effects of chromium on inflammatory biomarkers such as tumour necrosis factor a (TNF‐a), C‐reactive protein (CRP), interleukins, monocyte chemoattractant protein–1 (MCP‐1), intercellular adhesion molecule‐1 (ICAM‐1) and adipocytokines in hyperglycaemia and diabetes. Out of 647 articles found in the search, only 14 articles were eligible for analysis, three in vitro studies, eight animal studies and three human studies. Twelve of the 14 studies included in this review, chromium significantly decreased inflammatory factors. The findings of this review indicate, based on in vitro and in vivo studies, that chromium might have potential anti‐inflammatory properties, but some of the studies did not show anti‐inflammatory effects for chromium (two studies). There are only three studies in humans with controversial results. Therefore, more consistent randomized double‐blind controlled trials are needed to reach relevant clinical recommendations, as well as to determine the precise mechanism, of chromium on inflammation in diabetes.  相似文献   
5.
6.
Costimulatory signals regulate T-cell activation. To investigate the role of costimulation in autoimmunity and transplantation, we studied the BB rat model of type 1 diabetes. Diabetes-prone BB (BBDP) rats spontaneously develop disease when 55–120 days of age. We observed that two anti-CD28 monoclonal antibodies (mAb) with different functional activities completely prevented diabetes in BBDP rats. Anti-CD154 mAb delayed diabetes, whereas treatment with CTLA4-Ig or anti-CD80 mAb accelerated disease. Anti-CD86 or anti-CD134L mAbs had no effect. Diabetes resistant BB (BBDR) rats are disease-free, but >95% of them develop diabetes after treatment with polyinosinic-polycytidylic acid and an mAb that depletes Treg cells. In the induced BBDR model, anti-CD154 mAb delayed onset of diabetes, whereas CTLA4-Ig, anti-CD134L or either of the anti-CD28 mAbs had little or no effect. In contrast, blockade of the CD134-CD134L pathway was highly effective for preventing autoimmune recurrence against syngeneic islet grafts in diabetic BBDR hosts. Blockade of the CD40-CD154 pathway was also effective, but less so. These data suggest that the effectiveness of costimulation blockade in the treatment of type 1 diabetes is dependent on both the costimulatory pathway targeted and the mechanism of induction, stage, intensity and duration of the pathogenic process.  相似文献   
7.
Forty-seven patients with oesophageal carcinoma were managed in 6 years' time. Average duration of illness was 5.5 months. History of chronic smoking and/or tobacco chewing was present in 80.85% of patients. Carcinoma included squamous cell variety (80.85%) and adenocarcinoma (19.15%). Thirty-one patients were in stage III while 16 patients were in stage II. Surgery included oesophagogastrectomy/oesophagogastrostomy (16 patients), feeding gastrostomy (11 patients), Mousseau-Barbin tube insertion (10 patients), only 10 patients were subjected to palliative radiotherapy. All patients after palliative treatment died within one year whereas 3-year and 5-year survivals after oesophagogastrectomy/oesophagogastrostomy were 68.75% and 31.25% respectively. Local lymph node metastasis adversely affected the 5-year survival rate.  相似文献   
8.
This is the first study to examine the hypothesis that prolonged sitting is associated with procoagulant changes in the local lower-limb venous system. A comparison was made with upper-limb venous changes. Changes in markers of thrombin generation, fibrinolysis, endothelial perturbation and haemoconcentration were analysed as 10 healthy adult male participants sat for 8 h. The change in foot volume was estimated. Subjective venous thromboembolism assessment was undertaken hourly, along with 2-week and 4-week safety follow-up for clinical events.Expected increases in median prothrombin fragments 1 and 2, thrombin-antithrombin complex and D-dimer were not observed in either limb. An increase greater than 45% in the median tissue plasminogen activator and plasminogen activator-1 molar ratio (t-PA/PAI-1), and a decrease greater than 15% in median soluble thrombomodulin were noted in both limbs. Median haematocrit decreased minimally (1%) in the lower limbs, while the foot volume increased by 4%. Subjects experienced vague symptoms after 6 h of sitting, but none developed symptomatic venous thromboembolism. Upper and lower-limb changes in biomarkers did not correlate, except those in t-PA/PAI-1 ratio and plasminogen activator-1. Significant correlation was found between changes in the lower-limb t-PA/PAI-1 ratio and right foot volume.This study originally reveals that even in the lower limbs, prolonged daytime cramped sitting is not associated with significant procoagulant changes in healthy adult male volunteers, and confirms a previous observation that local lower-limb venous changes are not identically reflected in the upper limbs.  相似文献   
9.
Graded pneumatic dilatation (PD) is an appropriate long-term therapy and botulinum toxin injection (BT) is a relatively short-term therapy in idiopathic achalasia. Their combination has not been previously scrutinized. This study aimed to evaluate the role of BT in enhancing the efficacy of PD with 30 mm balloons. Patients who underwent PD with 30 mm balloons after botulinum toxin injections and a group of age- and sex-matched controls who were treated only with PD were enrolled in the study. Symptom scores were taken before, 1 month after and then every 3 months after PD. There were no significant differences between the two groups in gender, duration or severity of symptoms. One of the 12 patients in the case group relapsed 30 months after PD but the others were in remission for an average of 25.6 months. In the control group, all the patients relapsed after a mean of 12.6 months and needed a 35-mm PD. The cumulative remission rate was significantly higher in the case group compared with the control group (P < 0.01). The mean symptom score decreased by 76% in the case group (P < 0.001) and 53% in the controls (P < 0.01) at the end of the first month. Neither age, sex, nor duration or severity of symptoms were predictive of patients' responses to treatment. It seems that BT may be a meaningful enhancing factor in long-term efficacy of PD. PD with a 30 mm balloon after a BT session may resolve the need for the future higher grade PD.  相似文献   
10.
Preimplantation genetic diagnosis (PGD) has been vigorously debated in Germany ever since the Bundesärztekammer (BÄK) published a draft of guidelines for PGD in March 2000. Many stakeholders such as churches, medical societies, and diverse associations have participated in the discussion. However, little is known about the attitudes of experts, directly affected patient groups, and the public in Germany. In several studies that are part of the German research program on ethical implications of the Human Genome Project, representative surveys were undertaken to assess the attitudes of the general population (n=1017), five relevant expert groups (n=879), and couples at high risk for genetic disorders(n=324) towards PGD and prenatal diagnosis (PD). All groups favor legislation for PGD. Differences exist in regard to the extent of their approval. For 17% of the high-risk couples with a persisting desire for a child, PGD performed in a neighboring country is the most probable reproductive option. These results should be carefully considered in the ongoing legislation process on human reproduction in our country.  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