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   4181篇
  免费   192篇
  国内免费   28篇
耳鼻咽喉   51篇
儿科学   43篇
妇产科学   56篇
基础医学   560篇
口腔科学   107篇
临床医学   284篇
内科学   1356篇
皮肤病学   83篇
神经病学   252篇
特种医学   126篇
外科学   691篇
综合类   14篇
一般理论   1篇
预防医学   107篇
眼科学   79篇
药学   214篇
中国医学   5篇
肿瘤学   372篇
  2022年   32篇
  2021年   89篇
  2020年   41篇
  2019年   41篇
  2018年   56篇
  2017年   40篇
  2016年   59篇
  2015年   46篇
  2014年   69篇
  2013年   93篇
  2012年   176篇
  2011年   188篇
  2010年   103篇
  2009年   80篇
  2008年   179篇
  2007年   194篇
  2006年   197篇
  2005年   253篇
  2004年   228篇
  2003年   226篇
  2002年   222篇
  2001年   140篇
  2000年   126篇
  1999年   118篇
  1998年   60篇
  1997年   54篇
  1996年   51篇
  1995年   36篇
  1994年   26篇
  1993年   32篇
  1992年   63篇
  1991年   64篇
  1990年   69篇
  1989年   82篇
  1988年   89篇
  1987年   71篇
  1986年   80篇
  1985年   76篇
  1984年   35篇
  1983年   38篇
  1979年   54篇
  1978年   31篇
  1977年   41篇
  1976年   25篇
  1975年   23篇
  1974年   33篇
  1972年   26篇
  1971年   27篇
  1970年   27篇
  1969年   26篇
排序方式: 共有4401条查询结果,搜索用时 15 毫秒
81.
Colonoscopy has been shown to reduce the risk of colon cancer by enabling the removal of precancerous lesions. Although cold snare and hot snare polypectomy have similar retrieval rates and complete resection rates, rates of delayed bleeding tend to be lower with cold snare polypectomy than with hot snare polypectomy, especially for patients taking antithrombotic agents. However, among cold snares there may be differences in terms of the completeness of polyp excision, as complete removal appears more likely with thin‐wire dedicated cold snares compared to the traditional, thick‐wire cold snares. Cold snare polypectomy may be especially well suited for use in patients taking antithrombotic agents, due to its minimal risk of delayed bleeding. Histological analyses suggest that cold snare polypectomy causes less damage to blood vessels in the submucosal layers, which results in a reduced incidence of hemorrhage compared to hot snare polypectomy. However, cold snare removal of small polyps may result in fragmentation of small specimens during collection and concerns as to whether the resection is complete. An endoscopy biomarker of effective cold snare polypectomy technique is needed to ensure complete removal of non‐pedunculated colorectal polyps ≤10 mm. Future uses of cold snare polypectomy may include piecemeal removal of sessile serrated adenoma/polyp lesions >10 mm. Currently, cold snare polypectomy should be considered a primary method for colorectal polyps of less than 10 mm, especially those in the 4‐ to 10‐mm range.  相似文献   
82.
Aggregatibacter actinomycetemcomitans is well-known as the pathogen of gingivitis or periodontitis, and discitis or vertebral osteomyelitis cases caused by this organism have rarely been reported. Ampicillin or amoxicillin has been used in the previously reported discitis cases; however, no cases have been reported that is treated with levofloxacin. We report the first published case we chose levofloxacin to treat. We failed to perform the susceptibility testing because of the poor growth and fastidious nature of the organism, and the result of susceptibility of amoxicillin was unclear. Levofloxacin, which A. actinomycetemcomitans is usually susceptible to, can be an effective alternative oral antimicrobial agent in such cases.  相似文献   
83.
84.
85.
86.
87.
88.
Nonspecific vasodilatation during iontophoresis is an important confounding factor in experimental pharmacology. In this investigation, we studied the involvement of sensory nerves and histamine-related reactions in causing nonspecific vasodilatation in a model of anodal and cathodal iontophoresis of sodium chloride. Firstly, we applied a mixture of local anesthetic (EMLA) cream to confirm its suppressive effect on nonspecific vasodilatation and to measure its efficacy in three different dosages (duration: 1, 2, and 3 h). We then investigated the role of histamine in nonspecific vasodilatation by giving an oral antihistamine drug (cetirizine) to subjects who had and had not been given EMLA. We found substantial suppression of the nonspecific vasodilatation in all EMLA-treated groups (all dosages) compared with untreated controls (with suppression rates of 60-65%). Dosage had no significant effect. A further suppression of nonspecific vasodilatation was seen after oral cetirizine during anodal and cathodal iontophoresis in both EMLA-treated and untreated groups. The antihistamine effect was most pronounced during anodal iontophoresis. These results suggest a histaminergic increase in perfusion that may be independent of neurogenic mechanisms and depend on polarity (anode or cathode). Local nerve blocks (EMLA) together with cetirizine may therefore be used to reduce nonspecific vasodilatation in both anodal and cathodal iontophoresis.  相似文献   
89.
90.
BACKGROUND: There are few monitoring systems widely used in clinical practice for evaluating the effectiveness of aspirin therapy, so in the present study aspirin's antiplatelet effects we investigated with a whole blood aggregometer using a screen filtration pressure (SFP) method. METHODS AND RESULTS: Thirty-five healthy male volunteers took 100 mg/day aspirin for 14 days. Whole-blood aggregation was analyzed at baseline and on days 7 and 14, using collagen and adenosine diphosphate as the stimuli, and compared with the platelet-rich plasma (PRP) aggregation measured by optical aggregometer. The platelet-aggregation threshold index (PATI) for both methods, which was defined as the putative agonist-concentration giving half-maximal aggregation, and the PRP-maximal aggregation rate were analyzed. The maximal aggregation rate induced by 1.6 mg/L collagen decreased from 85.5% (80.8-92.8) [median (interquartile range)] at baseline to 51.5% (39-63.8) on day 14 (p<0.0001). The PRP-PATI and whole-blood PATI for collagen increased from 0.32 (0.28-0.70) to 1.82 mg/L (1.25-2.89) (p<0.0001) and from 0.28 (0.22-0.3) to 1.06 mg/L (1.01-1.29) (p<0.0001) respectively. CONCLUSIONS: The whole-blood PATI and PRP-PATI for collagen, as well as the maximal PRP aggregation rate, clearly distinguish platelet aggregability before and after aspirin intake. However, whole-blood analysis by the SFP-method is easier to perform, and is a promising method of monitoring aspirin's effects.  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