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   29995篇
  免费   1378篇
  国内免费   200篇
耳鼻咽喉   326篇
儿科学   549篇
妇产科学   717篇
基础医学   3457篇
口腔科学   1554篇
临床医学   2286篇
内科学   8116篇
皮肤病学   443篇
神经病学   2813篇
特种医学   1149篇
外科学   4301篇
综合类   115篇
一般理论   8篇
预防医学   1567篇
眼科学   438篇
药学   1650篇
中国医学   120篇
肿瘤学   1964篇
  2023年   177篇
  2022年   427篇
  2021年   810篇
  2020年   461篇
  2019年   642篇
  2018年   831篇
  2017年   586篇
  2016年   708篇
  2015年   813篇
  2014年   1123篇
  2013年   1518篇
  2012年   2311篇
  2011年   2479篇
  2010年   1420篇
  2009年   1262篇
  2008年   2152篇
  2007年   2201篇
  2006年   2042篇
  2005年   2048篇
  2004年   1821篇
  2003年   1578篇
  2002年   1452篇
  2001年   200篇
  2000年   128篇
  1999年   188篇
  1998年   245篇
  1997年   196篇
  1996年   191篇
  1995年   149篇
  1994年   138篇
  1993年   93篇
  1992年   104篇
  1991年   98篇
  1990年   82篇
  1989年   88篇
  1988年   87篇
  1987年   62篇
  1986年   56篇
  1985年   47篇
  1984年   88篇
  1983年   55篇
  1982年   74篇
  1981年   48篇
  1980年   27篇
  1979年   26篇
  1978年   30篇
  1977年   31篇
  1976年   24篇
  1974年   17篇
  1973年   23篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
1996年我们在意大利全国范围内开展了一次关于急性胰腺炎的调查,并对研究结果进行了计算机统计分析.  相似文献   
73.
74.
75.
The mesoaccumbens dopamine system has been hypothesized to be a common neural substrate mediating the actions of various drugs of abuse, including ethanol. However, the involvement of the mesopallidal dopamine system has received very little attention. The present study examined the effects of intraperitoneal (IP) ethanol administration on the extracellular levels of dopamine in the ventral pallidum (VP) and globus pallidus (GP) of Wistar rats. Rats were bilaterally implanted with microdialysis probes aimed at the VP and GP or nucleus accumbens (NAc) and dorsal striatum (dSTR). During microdialysis testing, rats with probes located in the VP and GP were injected IP with sterile saline or 15% (v/v) ethanol in saline at doses of 0.75, 1.5, or 2.25 g/kg. Rats with NAc and dSTR probes were injected with saline or 2.25 g/kg ethanol. The IP administration of 1.5 and 2.25 g/kg ethanol significantly (p <0.05) elevated the extracellular levels of dopamine in the VP (maximal increase: 136 and 182% of baseline, respectively) but not in the GP. No effects on extracellular dopamine levels were observed following the IP injections of 0.75 g/kg ethanol or saline. The IP administration of 2.25 g/kg ethanol significantly (p <0.05) elevated the extracellular levels of dopamine in the NAc (maximal increase: 198% of baseline) and dSTR (maximal increase: 155% of baseline). Analysis of the effects of 2.25 g/kg ethanol on dopamine release revealed greater increases in the VP, NAc, and dSTR compared to the GP. The data suggest that the mesopallidal, mesoaccumbens, and nigrostriatal dopamine systems are more sensitive to the effects of ethanol than the nigropallidal dopamine system.  相似文献   
76.
PURPOSE: Postoperative variables such as pain, swelling, and trismus after surgery of the impacted lower third molars are the main concerns of dental clinicians and surgeons. Many authors claim that the use of a drain could help control these variables. The purpose of this study was to evaluate the effect of the use of a tube drain in impacted lower third molar surgery. MATERIALS AND METHODS: Fifty-three patients of both genders with bilateral impacted lower third molars comprised our comparative study. The patients were divided into 2 groups: in the first the suture procedure was accomplished using a drain, and in the second the suture procedure was accomplished without a drain. The postoperative pain, swelling, and trismus were evaluated at 24 hours, 72 hours, 7 days, and 15 days. RESULTS: In the group in which the drain was used, the control of the swelling variable was statistically significant at 24 and 72 hours (P <.001) in comparison with the group in which the drain was not used. However, pain and trismus were not statistically significant at the evaluation period. CONCLUSION: The use of the drain helps to control swelling. However, it had no effect on pain or trismus.  相似文献   
77.
The features of enamel hypoplasia in a small group of patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) are described. Using a recently developed method, the authors evaluated quantitatively the amount of defect in each tooth by measuring the width of the hypoplastic lesions and dividing the value by the crown height. They then assessed the degree of damage in each tooth type (from central incisors to second premolars) and patient. Canines were the most severely affected among maxillary and mandibular teeth, but all tooth types were involved. Analysing both the differences between patients and their age at the beginning of the defect, the authors observe that hypoparathyroidism is not responsible for the onset of enamel hypoplasia in APECED, although it may contribute to the damage.  相似文献   
78.
79.
80.
Twenty patients with AIDS who had intracranial lesions underwent both brain biopsy and cerebro-spinal fluid (CSF) examination to compare histological diagnosis with the polymerase chain reaction (CSF-PCR) for the identification of infectious agents. CSF-PCR was performed for herpes simplex virus, varicella zoster virus, cytomegalovirus (CMV), JC virus (JCV), Epstein-Barr virus (EBV), Toxoplasma gondii and Mycobacterium tuberculosis. A definitive diagnosis was obtained by brain biopsy in 14 patients (2 with astrocytoma, 12 with brain infection). CSF-PCR was positive for EBV DNA in 3 of 3 cases of primary cerebral lymphoma, positive for JCV DNA in 6 of 7 biopsy-proven (and one autopsy-proven) cases of progressive multifocal leukoencephalopathy (PML). CSF-PCR was positive for CMV DNA in one biopsy-proven and one autopsy-proven case of CMV encephalitis (the former also had PML) and positive for M. tuberculosis DNA in one case of tuberculous encephalitis. None of the five toxoplasmic encephalitis cases (one definite, four presumptive) were T. gondii DNA positive. There was close correlation between histology and CSF-PCR for CMV encephalitis, PML and PCL. Antitoxoplasma therapy affected the sensitivity of both histological and CSF-PCR methods. Received: 8 November 1995 Received in revised form: 9 July 1996 Accepted: 19 July 1996  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