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   1604篇
  免费   68篇
  国内免费   11篇
耳鼻咽喉   54篇
儿科学   127篇
妇产科学   57篇
基础医学   133篇
口腔科学   100篇
临床医学   174篇
内科学   315篇
皮肤病学   69篇
神经病学   97篇
特种医学   77篇
外科学   237篇
综合类   24篇
预防医学   30篇
眼科学   33篇
药学   80篇
中国医学   3篇
肿瘤学   73篇
  2024年   2篇
  2023年   19篇
  2022年   25篇
  2021年   44篇
  2020年   21篇
  2019年   51篇
  2018年   36篇
  2017年   32篇
  2016年   56篇
  2015年   67篇
  2014年   90篇
  2013年   98篇
  2012年   122篇
  2011年   130篇
  2010年   75篇
  2009年   61篇
  2008年   125篇
  2007年   141篇
  2006年   130篇
  2005年   108篇
  2004年   95篇
  2003年   85篇
  2002年   35篇
  2001年   14篇
  2000年   6篇
  1999年   5篇
  1998年   4篇
  1997年   3篇
  1996年   1篇
  1995年   1篇
  1993年   1篇
排序方式: 共有1683条查询结果,搜索用时 15 毫秒
71.
72.
The seroprevalence of Helicobacter pylori and nitric oxide in acne rosacea   总被引:5,自引:0,他引:5  
BACKGROUND: Acne rosacea is a dermatosis with unknown etiology. Some studies have reported a high prevalence of Helicobacter pylori infection in acne rosacea. Other studies have reported a decrease in the severity of the lesions of acne rosacea after eradication of H. pylori. H. pylori is a Gram-negative bacterium which colonizes the gastric mucosa and increases the synthesis of oxygen radicals, such as superoxide and proinflammatory cytokines. These cytokines have been demonstrated to stimulate the synthesis of the inflammatory species nitric oxide (NO). In this study, we examined the role of NO in the possible effect of H. pylori in acne rosacea. METHODS: Thirty-three acne rosacea patients were included in the study and the control group comprised 20 healthy individuals. The levels of immunoglobulin G antibodies against H. pylori in the serum samples were measured using the enzyme-linked immunoabsorbent assay method. Measurement of nitrate was performed using chemiluminescence in accordance with the method described by Braman and Hendrix (Braman RS, Hendrix SA. Nanogram nitrite and nitrate determination in environmental and biological materials by vanadium(iii) reduction with chemiluminescence detection. Anal Chem 1989; 61: 2715-2718). For statistical analysis, the t-test was used. RESULTS: The seropositivity of H. pylori in acne rosacea patients was found to be high; however, the serum nitrate levels were found to be normal. CONCLUSIONS: The results of the study indicate that the inflammatory species NO, which has been hypothesized to be associated with H. pylori, has no role in the inflammatory mechanism of acne rosacea.  相似文献   
73.
The authors report a case of alveolar soft-part sarcoma with lung metastases demonstrated by "double imaging" with Tc-99m HDP and Tc-99m MIBI. The tumor originated in the soft tissue with direct invasion to the right scapula, which was hypoactive on bone scan and hyperactive on Tc-99m MIBI images. A focus of dense accumulation of Tc-99m MIBI in the lungs, suggesting metastasis was also demonstrated.  相似文献   
74.
Serological markers for Chlamydia pneumoniae were investigated by using the microimmunofluorescence (MIF) test in various age and patient groups in a specific area in Turkey. IgG seropositivity to C. pneumoniae was 64.3% and 18.7% in healthy adults and children, respectively. The highest positivity rate (77%) was in the 15–19 age group. Among the groups investigated, serological findings revealed a possible etiological association between C. pneumoniae and the clinical condition in the groups with acute myocardial infarction, atypical pneumoniae and chronic obstructive pulmonary disease.  相似文献   
75.
Mitomycin C prevents strictures in caustic esophageal burns in rats   总被引:2,自引:0,他引:2  
BACKGROUND: Caustic esophageal injuries lead to stricture formation. Although a number of agents have been tried experimentally to prevent strictures, few have gained clinical application. The purpose of this study was to investigate the effectiveness of Mitomycin C (MMC), which inhibits fibroblastic proliferation in preventing caustic esophageal strictures. MATERIAL AND METHODS: Fifty-six rats were allocated into four groups. Caustic esophageal burns were created as described by Gehanno. Group A was instilled only with saline. Group B was injured and untreated. Groups C and D were injured and received topical MMC at 0.02 and 0.04% concentrations, respectively. At 28 days, stenosis index (SI), collagen deposition, and hydroxyproline content (HP) were determined in distal esophageal segments. Statistical analyses were done. RESULTS: Mean SI in Group B was significantly higher than others (P < 0.05). Mean SI was statistically higher in Group C than A and D and similar between groups A and D. The greatest accumulation of collagen was found in Group B, followed by Group C, D, and A, respectively. Collagen deposition in Group D was statistically lower than Group B (P < 0.01) and similar to Group C. Mean HP in Group B was statistically higher than others (P < 0.05), significantly higher in Group C than Group D (P = 0.047), and similar between Groups A and D (P = 0.73). CONCLUSION: MMC was effective in preventing strictures following experimental caustic esophageal injury, in a dose-dependent manner. We consider that it can gain clinical utilization with the establishment of effective mode, dose, and timing of therapy.  相似文献   
76.
BACKGROUND: Translocating enteric bacteria have been suggested as playing a major role in the development of infections after partial hepatectomy. We investigated the effect of N-acetylcysteine (NAC) on bacterial translocation (BT) and intestinal mucosa as the first line of defense against BT. MATERIALS AND METHODS: We compared four groups of eight Sprague-Dawley male rats each: sham, control (partially hepatectomized), partial hepatectomy plus preoperative single-dose NAC, and a fourth that received partial hepatectomy with a preoperative single-dose NAC plus treatment with NAC for 2 days. Microorganism counts of tissues, lung injury score, lung tissue glutathione, and malondialdehyde levels and microscopy of intestinal mucosa were studied at the end of 48 h. RESULTS: Microorganism count in the lung and mesenteric lymph node cultures and lung injury score were significantly higher in the control group when compared with the sham, third, and fourth groups (lung: 9919.6 versus 0.0, 2912.9, 1550.0 cfu/g tissue; mesenteric lymph nodes: 8458.3 versus 0.0, 89.0, 88.9 cfu/g tissue; lung injury score: 3.25 versus 0.5, 1.13, 1.75). In the control group, the villous height of the distal ileal mucosa was significantly shorter than the sham group (65.25 versus 75.25 microm) and the difference from groups 3 and 4 was not statistically significant. Neutrophil infiltration in the distal ileal mucosa of the control group was significantly higher than the sham, third and fourth groups (3.13 versus 0.25, 0.38 and 1.0). CONCLUSIONS: The parenteral use of NAC attenuates bacterial translocation after partial hepatectomy in rats. Attenuation of the lung injury after partial hepatectomy in NAC-treated groups might be attributable to both anti-inflammatory effect and the effect on BT.  相似文献   
77.
78.
79.
80.
OBJECTIVE: The purpose of this study was to determine the levels of adrenomedullin (AdM) in amniotic fluid (AF) and maternal serum of misoprostol (PGE1)-induced pregnant women. MATERIALS AND METHODS: A total of 40 women were included in the study: 20 were in active labor and were delivered vaginally and a further 20 were not in labor and misoprostol induction was performed. Women who were undergoing labor induction received 50 microg of misoprostol, which was placed in the posterior fornix of the vagina every 4 hrs until the onset of labor. In each patient, maternal plasma and AF samples were collected. Samples of AF were collected by transvaginal route at the time of rupture of the membranes. The labor was at the same stage in both the groups during the sample collection. In all pregnant subjects, maternal blood samples were drawn from the cubital vein at the time of AF sampling. Amniotic fluid and serum AdM concentration was measured by using reverse-phase high-performance liquid chromatography. RESULTS: Misoprostol-induced pregnant women showed significantly higher AdM concentrations than control pregnant women in AF (79.48 +/- 6.14 pmol/ml versus 21.28 +/- 0.90 pmol/ml, P = 0.000) and maternal serum (88.20 +/- 4.34 pmol/ml versus 29.78 +/- 4.51 pmol/ml, P = 0.000). There was no significant difference between maternal serum and AF-AdM concentrations in misoprostol and control subjects. CONCLUSION: Increased serum and AF-AdM concentrations may be necessary to initiate cervical ripening in misoprostol-induced pregnant women.  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