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   217814篇
  免费   18749篇
  国内免费   4610篇
耳鼻咽喉   3351篇
儿科学   4183篇
妇产科学   3732篇
基础医学   17173篇
口腔科学   7526篇
临床医学   20116篇
内科学   21035篇
皮肤病学   2468篇
神经病学   10534篇
特种医学   6103篇
外国民族医学   11篇
外科学   22267篇
综合类   34254篇
现状与发展   9篇
一般理论   25篇
预防医学   29030篇
眼科学   2055篇
药学   21102篇
  349篇
中国医学   26632篇
肿瘤学   9218篇
  2024年   974篇
  2023年   4399篇
  2022年   8262篇
  2021年   10894篇
  2020年   10539篇
  2019年   11762篇
  2018年   10450篇
  2017年   8987篇
  2016年   8032篇
  2015年   7476篇
  2014年   14718篇
  2013年   15066篇
  2012年   13056篇
  2011年   14037篇
  2010年   11292篇
  2009年   9752篇
  2008年   9089篇
  2007年   9140篇
  2006年   7777篇
  2005年   6556篇
  2004年   5447篇
  2003年   4851篇
  2002年   3723篇
  2001年   3109篇
  2000年   2742篇
  1999年   2289篇
  1998年   1798篇
  1997年   1613篇
  1996年   1320篇
  1995年   1260篇
  1994年   1131篇
  1993年   1001篇
  1992年   901篇
  1991年   841篇
  1990年   734篇
  1989年   704篇
  1988年   657篇
  1987年   598篇
  1986年   543篇
  1985年   1796篇
  1984年   2077篇
  1983年   1301篇
  1982年   1731篇
  1981年   1193篇
  1980年   1024篇
  1979年   920篇
  1978年   744篇
  1977年   562篇
  1976年   700篇
  1975年   478篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Summary A case of Turner's syndrome with the typical marked webbing of the neck is presented. A posterior approach is preferred for correction of this webbed neck deformity. A butterfly shaped portion of excess skin is excised and the margins of the defect mobilised as four flaps. The flaps are sutured with a very short midline vertical component, resulting in an almost X-shaped scar. The first procedure resulted in only a partial correction of the deformity and an excess of hypertrophic scar tissue. This was treated with a repeat of the procedure but the midline wounds was repaired with mulitple small Z-plasties. The final appearance of the neck was satisfactory in the lateral profile, but there was still some excess tissue posteriorly.  相似文献   
103.
以23例肾功能不全与20例肾功正常患者的唾液尿素氮、钠、钾、舌面pH值和血液的相应生化检查作对照。结果唾液尿素氮、钾与血尿素氮、钾成正相关性。证实了中医“津血同源”“肾为唾”的理论。  相似文献   
104.
The mortality of cerebrovascular diseases in Denmark was analysed for men and women 15-44 years of age, in a 14-year period before and after the appearance of oral contraceptives (OC) in 1966. 1,670 deaths were registered over 28 years, during which the female incidence of cerebrovascular deaths increased by 19% (P less than 0.025), while the male mortality was unchanged. Women showed a percentage increase in deaths from cerebral thromboembolic attacks (CTA) of 33%, men a fall of 14%. The increase of female CTA deaths was most pronounced in the young fertile group, the age group with a high OC use. A relative risk of CTA of 3.3-4.5 for OC users compared with non-users could explain the CTA trend difference between women and men. No other single risk factor responsible for the observed trends could be identified. Both women and men had a significant increase in the mortality of subarachnoidal hemorrhages, and a significant fall in the mortality of intracerebral hemorrhages.  相似文献   
105.
对人胎儿前庭器超微结构的研究,国内外报道甚少。本文对18至36周人胎儿颞骨10具进行了扫描电镜和透射电镜的观察,并对应用Surface preparation法制做人胎儿前庭器标本的方法进行了探讨。本文观察所见:豚鼠平衡斑的生理状态与人胎儿很近似,体面积比人胎儿平衡斑小,感觉毛长,细胞排列更整齐。28周以后的胎儿因前庭周围骨质变硬,制做标本时可以分别取出两囊斑和壶腹嵴。  相似文献   
106.
Nerve growth factor-induced increase in calcium uptake by PC12 cells   总被引:1,自引:0,他引:1  
Treatment of PC12 cells with nerve growth factor (NGF) produces a rapid and transient increase in calcium uptake into the cells. The increased uptake is maximal after 5 minutes of NGF treatment, but after 15 minutes of NGF treatment, no such increase can be observed. The effect of NGF is partially inhibited by blockers of L-type calcium channels. K-252a, an alkaloid-like kinase inhibitor that usually is found to inhibit the actions of NGF on PC12 cells, produces an increase in calcium uptake similar to, but smaller than, that seen with NGF. NGF had no effect on calcium release under these conditions.  相似文献   
107.
d-Amphetamine, 4-OH amphetamine, and epinephrine have been shown in many behavioral studies to facilitate memory when given post-training. The effect of these drugs on the maintained discharge of cells in the locus coeruleus (LC) was investigated using a route of administration (intraperitoneal) and a log-dose range of these drugs comparable to those used in the behavioral experiments.d-Amphetamine profoundly suppressed maintained discharge: an inhibitory effect was observed at every dose (0.1, 1.0, 10.0 mg/kg). In contrast, only the highest dose of 4-OH amphetamine (8.2 mg/kg) inhibited activity in the LC, and this effect was a modest one. Unlike the amphetamines, epinephrine (500 μ/kg) elevated maintained discharge. These results are discussed in the contex of the hypothesized involvement of the LC in the enhancement of memory by these drugs.  相似文献   
108.
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   
109.
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   
110.
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   
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