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   750411篇
  免费   52070篇
  国内免费   1485篇
耳鼻咽喉   9689篇
儿科学   24210篇
妇产科学   18493篇
基础医学   116487篇
口腔科学   20911篇
临床医学   68143篇
内科学   143508篇
皮肤病学   17191篇
神经病学   53789篇
特种医学   27599篇
外国民族医学   78篇
外科学   112584篇
综合类   15276篇
现状与发展   2篇
一般理论   234篇
预防医学   53886篇
眼科学   17190篇
药学   56556篇
  3篇
中国医学   2423篇
肿瘤学   45714篇
  2021年   7010篇
  2019年   6681篇
  2018年   9280篇
  2017年   7072篇
  2016年   7925篇
  2015年   8836篇
  2014年   12001篇
  2013年   17437篇
  2012年   23838篇
  2011年   24766篇
  2010年   14568篇
  2009年   13546篇
  2008年   22580篇
  2007年   24116篇
  2006年   24337篇
  2005年   22701篇
  2004年   22073篇
  2003年   20856篇
  2002年   20203篇
  2001年   36789篇
  2000年   37356篇
  1999年   30866篇
  1998年   8280篇
  1997年   6987篇
  1996年   7207篇
  1995年   6862篇
  1994年   6295篇
  1992年   23292篇
  1991年   23221篇
  1990年   22576篇
  1989年   22323篇
  1988年   20266篇
  1987年   19642篇
  1986年   18670篇
  1985年   17549篇
  1984年   12887篇
  1983年   10923篇
  1982年   6076篇
  1979年   11678篇
  1978年   8267篇
  1977年   6957篇
  1976年   6713篇
  1975年   7375篇
  1974年   8631篇
  1973年   8250篇
  1972年   7772篇
  1971年   7235篇
  1970年   6971篇
  1969年   6399篇
  1968年   5863篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A 40-year-old man presented a painful haemorrhagic plaque on his chest in the same location where a nodular lesion had been presented for many years. After 2 months, the plaque was replaced by a depressed lesion. The lesion diagnosed as an anetoderma was excised and the biopsy showed an atrophic dermatofibroma accompanied by aneurysmatic characteristics.  相似文献   
992.
Positron emission tomography was performed on six patients with Rett syndrome to investigate cerebral blood flow and oxygen metabolism, and the results were compared with the concurrent clinical status of the patients. The cerebral metabolic rate of oxygen (CMRO2) was low in five patients, and oxygen extraction fraction was low in four patients; both had a tendency to decline with advancing age. Although the cause is unknown, it is suggested that impaired oxidative metabolism exists in Rett syndrome. An analysis of the distribution among brain regions showed that the ratios of values for the frontal cortex to those for the temporal cortex for both cerebral blood flow and CMRO2 were lower than those for the controls, which may indicate the loss of hyperfrontality in Rett syndrome.  相似文献   
993.
994.
995.
996.
4-(1H-Benzimidazol-1-ylmethyl)-and 4-(2-methyl-1H-benzimidazol-1-ylmethyl)phenyl-β-D-glucopyranosides have been synthesized by glycosylation of the corresponding phenols. The hemolytic activity of the synthesized compounds was studied on whole venous human donor blood at concentrations of 100, 200, and 300 μg/mL. It was established that the glycosides exhibit high biological activity and enter erythrocytes faster than do the initial phenols, which suggests that they are promising for the development of new drugs. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 41, No. 12, pp. 16–17, December, 2007.  相似文献   
997.
998.
The gamma-irradiation of adult rats with a semi-lethal dose (6 Gy) suppressed the posttraumatic regeneration of skeletal muscles and brought about considerable destructive changes in the thymus. The effect of He-Ne laser radiation at a total dose 4.5-5.4 J/cm2 at each operated leg in irradiated rats stimulated the regenerative capacity of skeletal muscle tissue, the healing of skin-muscle wound, and the processes of postradiation recovery in thymus cells (a decrease of chromosome aberrations). The histological structure of regenerates had more muscle pattern. At the same time, the positive dynamics of regenerative processes in muscles was achieved by an increased functional load on the thymus. To stimulate the regeneration of irradiated muscles on the background of a more moderate load on the thymus, the prolonged period of laser therapy and fragmentary distribution of laser exposures during muscle regeneration were preferable. Wound healing improved visibly. Nor formation of chronic radiation ulcers on operated shins was observed.  相似文献   
999.
1000.
A case of radiologically occult lung cancer is presented in which 201TI SPECT of the chest clearly delineated the involved area. A 66-yr-old man underwent chest screening examinations for asymptomatic smokers and presented a positive sputum cytology for lung cancer. Conventional chest x-ray, tomography of computed radiography, and a CT scan failed to locate the lesion in the lung. Thallium-201 SPECT, however, was successful in depicting the area of the involvement.  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