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   235165篇
  免费   19608篇
  国内免费   4964篇
耳鼻咽喉   3700篇
儿科学   4633篇
妇产科学   4270篇
基础医学   18098篇
口腔科学   10164篇
临床医学   21234篇
内科学   23421篇
皮肤病学   2857篇
神经病学   11286篇
特种医学   6262篇
外国民族医学   11篇
外科学   22373篇
综合类   36507篇
现状与发展   9篇
一般理论   24篇
预防医学   30201篇
眼科学   2227篇
药学   22487篇
  354篇
中国医学   28862篇
肿瘤学   10757篇
  2024年   1040篇
  2023年   4632篇
  2022年   8728篇
  2021年   11366篇
  2020年   10959篇
  2019年   12375篇
  2018年   10927篇
  2017年   9438篇
  2016年   8592篇
  2015年   7978篇
  2014年   15800篇
  2013年   16166篇
  2012年   14337篇
  2011年   15554篇
  2010年   12453篇
  2009年   11062篇
  2008年   10141篇
  2007年   10224篇
  2006年   8535篇
  2005年   7243篇
  2004年   6015篇
  2003年   5404篇
  2002年   4077篇
  2001年   3439篇
  2000年   2972篇
  1999年   2453篇
  1998年   1952篇
  1997年   1723篇
  1996年   1410篇
  1995年   1338篇
  1994年   1215篇
  1993年   1043篇
  1992年   974篇
  1991年   873篇
  1990年   765篇
  1989年   737篇
  1988年   680篇
  1987年   625篇
  1986年   562篇
  1985年   1836篇
  1984年   2103篇
  1983年   1308篇
  1982年   1742篇
  1981年   1210篇
  1980年   1046篇
  1979年   934篇
  1978年   767篇
  1977年   573篇
  1976年   710篇
  1975年   498篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
基于无线网络及条形码技术的图书排架、定位系统   总被引:3,自引:2,他引:1  
利用无线网络与条形码技术,建立起图书排架、定位系统,可实现图书排架和图书的准确定位.该系统可有效地解决传统管理方法易产生的乱架和死书问题,提高图书借阅效率并降低管理人员的工作强度.  相似文献   
82.
The aetiology of Klinefelter's Syndrome is not known. The causative factor(s) must explain the hypogonadism, low androgen levels, the disordered carbohydrate metabolism and the commonly associated psychiatric conditions. A biotin deficient/dependent state can account for the above. A biotin deficient Klinefelter's Syndrome patients with the above is described. The possible role of biotin in the primary, secondary and tertiary prevention of Klinefelter's Syndrome needs further research.  相似文献   
83.
The effects of haloperidol on motor and functioning and cognitive functioning were studied in young (3-5 months old) and aged (20-22 months old) male mice by examining haloperidol-induced catalepsy and haloperidol-induced decrements in performance on a radial arm maze. The aged mice were much more sensitive to these adverse effects of haloperidol than were the young mice. Studies of the distribution of radioactivity from [3H]haloperidol to the brain indicated that the differences in sensitivity to this drug were not due to pharmacokinetic differences. The results demonstrate that mice are suitable for studies of aging-induced changes in the behavioral effects of neuroleptic agents.  相似文献   
84.
85.
高等医学院校医学化学教材改革的几点思考   总被引:2,自引:1,他引:1  
医学的发展已进入分子水平,医学生必须具有扎实的化学基础才能适应专业学习及临床、科研工作的需要。现行医学化学教材大多沿用几十年前的模式,部分内容陈旧滞后,实用性不强。面对现实,改革势在必行。我们认为,突出重点、注重实用、体现医学特色应作为改革的方向。  相似文献   
86.
生物医学测量及控制技术新进展   总被引:2,自引:0,他引:2  
介绍生物医学测量及控制技术领域中的一些研究进展。  相似文献   
87.
The immunohistochemical occurrence of the high affinity neurotrophin (NT) receptors trkA, trkB, and trkC is shown in the pre-term newborn, infant, and adult human post-mortem cerebellum. Immunoreactive neuronal perikarya and processes were observed in all specimens examined, where they appeared unevenly distributed in the cerebellar cortical layers and deep nuclei, and showed regional differences among cerebellar lobules and folia. The trk receptor-antibodies, tested by Western blot on human cerebellum homogenates, revealed multiple immunoreactive bands for trkA and single bands for trkB and trkC. The results obtained show the tissue localization of the trk receptor-like immunoreactivity in the human cerebellum from prenatal to adult age. The analysis for codistribution of the receptors with the relevant ligand and among the receptors in discrete cortical and deep nuclei tissue fields shows a wide variety of conditions, from a good similarity in terms of type and density of labeled structures, to a lack of correspondence, and suggests the possibility of colocalization of trk receptors with the relevant neurotrophin and among them in the cerebellar cortex. These results sustain the concept that the neurotrophin trophic system participates in the development, differentiation, and maintenance of the human cerebellar connectivity and support the possibility of a multifactorial trophic support for the neurotrophins through target-derived and local mechanisms.  相似文献   
88.
89.
A lymph node metastasis in the neck or parotid region from an unknown primary melanoma is an uncommon occurrence. Out of a total of 300 patients with head and neck melanoma treated at the Netherlands Cancer Institute between 1976 and 1992, 17 (5.7%) presented in this way. The most common site for metastatic lymph nodes (18 nodes in 17 patients) was level V (n= 7), followed by the parotid region (n= 4), level II (n= 4), level III (n= 2), and level IV (n= 7). Two patients had local excision of the neck node metastasis only, while the remaining 15 patients underwent more extensive surgical treatment. The 5-year disease-specific survival rate in this group was 48%, with a median survival of 36 months, which is more or less similar to the prognosis of stage II melanoma of the head and neck with a known, surgically treated primary tumour. No relation was found between disease-free interval and sex, the number of positive lymph nodes or the duration of symptoms.  相似文献   
90.
Abstract The major reason for late graft losses is chronic rejection. Recently, a large number of studies have indicated that proteolytic enzymes play an important role as mediators of glomerular injury. The cysteine proteinases cathepsins B and L degrade structural matrix proteins such as type I collagen and laminin. We investigated intraglomerular protease activities in 12 patients after kidney graftectomy because of end-tage renal disease following chronic rejection. A group of 12 patients undergoing nephrectomy because of cancer served as controls using only non-involved parts of the kidney. The activities of cathepsins B and L in homogenates of isolated glomeruli were measured fluorometrically methylcoumarylamidc substrates and related to DNA content. In rejected kidney allografts we observed significantly enhanced intraglomerular cathepsin B activity and cathepsin B + L activity.  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