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   1419篇
  免费   132篇
  国内免费   6篇
耳鼻咽喉   11篇
儿科学   75篇
妇产科学   15篇
基础医学   151篇
口腔科学   20篇
临床医学   267篇
内科学   312篇
皮肤病学   18篇
神经病学   57篇
特种医学   182篇
外科学   122篇
综合类   57篇
预防医学   102篇
眼科学   12篇
药学   63篇
中国医学   2篇
肿瘤学   91篇
  2022年   5篇
  2021年   15篇
  2020年   11篇
  2019年   19篇
  2018年   23篇
  2017年   20篇
  2016年   22篇
  2015年   33篇
  2014年   42篇
  2013年   58篇
  2012年   69篇
  2011年   64篇
  2010年   44篇
  2009年   34篇
  2008年   49篇
  2007年   53篇
  2006年   53篇
  2005年   53篇
  2004年   52篇
  2003年   52篇
  2002年   49篇
  2001年   50篇
  2000年   54篇
  1999年   55篇
  1998年   41篇
  1997年   44篇
  1996年   44篇
  1995年   41篇
  1994年   41篇
  1993年   26篇
  1992年   23篇
  1991年   31篇
  1990年   23篇
  1989年   25篇
  1988年   25篇
  1987年   24篇
  1986年   27篇
  1985年   27篇
  1984年   12篇
  1983年   15篇
  1982年   10篇
  1981年   11篇
  1980年   6篇
  1979年   6篇
  1977年   8篇
  1976年   10篇
  1975年   6篇
  1973年   8篇
  1970年   6篇
  1968年   5篇
排序方式: 共有1557条查询结果,搜索用时 15 毫秒
1.
2.
Primary tuberculous pathology in nasolpolypi is a rare condition. A case of bilateral ethmoidal polypi with tubercular lesion diagnosed on histopathologlcal examination is being reported and the available relevant literature has been reviewed.  相似文献   
3.
The prevalence of asthma and allergic disease has increased in many countries, and there has been speculation that immunization promotes allergic sensitization. Bordetella pertussis infection exacerbates allergic asthmatic responses. We investigated whether acellular pertussis vaccine (Pa) enhanced or prevented B. pertussis-induced exacerbation of allergic asthma. Groups of mice were immunized with Pa, infected with B. pertussis, and/or sensitized to ovalbumin. Immunological, pathological, and physiological changes were measured to assess the impact of immunization on immune deviation and airway function. We demonstrate that immunization did not enhance ovalbumin-specific serum immunoglobulin E production. Histopathological examination revealed that immunization reduced the severity of airway pathology associated with sensitization in the context of infection and decreased bronchial hyperreactivity upon methacholine exposure of infected and sensitized mice. These data demonstrate unequivocally the benefit of Pa immunization to health and justify selection of Pa in mass vaccination protocols. In the absence of infection, the Pa used in this study enhanced the interleukin-10 (IL-10) and IL-13 responses and influenced airway hyperresponsiveness to sensitizing antigen; however, these data do not suggest that Pa contributes to childhood asthma overall. On the contrary, wild-type virulent B. pertussis is still circulating in most countries, and our data suggest that the major influence of Pa is to protect against the powerful exacerbation of asthma-like pathology induced by B. pertussis.  相似文献   
4.
5.
目的:对临床确诊糖尿病患同时测定血清葡萄糖(Glu)及糖化血清蛋白(GSP)的含量,观察二的关系,以及糖化血清蛋白水平对于评价近期(2—3周)糖尿病患血糖在体内变化的临床意义进行了观察。方法:血清葡萄糖、糖化血清蛋白测定均采用酶法测定。结果:178例糖尿病患Glu、GSP均正常3l例占17.4%;Glu、GSP均增高107例占60.1%;Glu正常、GSP增高15例占8.43%;Glu增高、GSP正常25例占14%。结论:糖化血清蛋白的含量不受即时血糖的影响,二的变化不成比例性,对评价糖尿病患2~3周病情的控制是一项灵敏可靠的指标,尤其对于住院病人的治疗与监控有一定的意义。  相似文献   
6.
This study describes ultrastructural changes in the pigmented hooded Lister rat retina, 3–12 months following X-irradiation with single doses of between 200 and 2000 cGy. The extreme radiosensitivity of the photoreceptor cells was underlined by the continued manifestation of fine structural changes and cell death up to 6 months post-radiation in animals receiving doses above 500 cGy. The retinal pigment epithelial (RPE) cells were more radioresistant than photoreceptors and RPE cell loss was only observed at doses of more than 1500 cGy. One year after irradiation with 1500 cGy the retinal vasculature showed capillary occlusion with some evidence of recanalisation. Telangiectasia was observed in the large retinal veins. Although the inner retinal neurones and glia1 cells showed no evidence of direct radiation damage, the nerve fibre layer adjacent to occluded retinal vessels demonstrated ultrastructural evidence of ischaemic neuropathy and retinal oedema. At doses above 1500 cGy the choriocapillaris showed platelet aggregation and capillary loss.  相似文献   
7.
8.
9.
10.
Steroid 21-hydroxylase deficiency is among the most common inborn errors of metabolism in man. Characterization of mutations in the 21- hydroxylase gene (CYP21) has permitted genetic diagnosis, facilitated by the polymerase chain reaction (PCR). The most common mutation is conversion of an A or C at nt656 to a G in the second intron causing aberrant splicing of mRNA. Homozygosity for nt656G is associated with profoundly deficient adrenal cortisol and aldosterone synthesis, secondary hypersecretion of adrenal androgens, and a severe form of congenital adrenal hyperplasia (CAH) characterized by ambiguous genitalia and/or sodium wasting in newborns. During the course of genetic analysis of CYP21 mutations in CAH families, we and others have noticed a number of relatives genotyped as nt656G homozygotes, yet showing no clinical signs of disease. A number of lines of evidence have led us to propose that the putative asymptomatic nt656G/G individuals are incorrectly typed due to dropout of one haplotype during PCR amplification of CYP21. For prenatal diagnosis, we recommend that microsatellite typing be used as a supplement to CYP21 genotyping in order to resolve ambiguities at nt656.   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