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   776篇
  免费   9篇
  国内免费   1篇
耳鼻咽喉   10篇
儿科学   16篇
妇产科学   5篇
基础医学   229篇
口腔科学   23篇
临床医学   152篇
内科学   106篇
皮肤病学   14篇
神经病学   47篇
特种医学   14篇
外科学   35篇
综合类   2篇
预防医学   41篇
眼科学   13篇
药学   56篇
肿瘤学   23篇
  2018年   5篇
  2016年   5篇
  2013年   12篇
  2012年   11篇
  2011年   21篇
  2010年   14篇
  2009年   15篇
  2008年   19篇
  2007年   18篇
  2006年   23篇
  2005年   15篇
  2004年   13篇
  2003年   20篇
  2002年   18篇
  2001年   12篇
  2000年   13篇
  1999年   12篇
  1998年   7篇
  1997年   9篇
  1996年   7篇
  1995年   11篇
  1993年   5篇
  1992年   15篇
  1991年   20篇
  1990年   24篇
  1989年   24篇
  1988年   30篇
  1987年   27篇
  1986年   20篇
  1985年   24篇
  1984年   16篇
  1983年   20篇
  1982年   10篇
  1981年   12篇
  1980年   8篇
  1979年   22篇
  1978年   15篇
  1977年   15篇
  1976年   12篇
  1975年   25篇
  1974年   16篇
  1973年   15篇
  1972年   12篇
  1971年   20篇
  1970年   8篇
  1969年   15篇
  1968年   17篇
  1967年   15篇
  1966年   9篇
  1965年   5篇
排序方式: 共有786条查询结果,搜索用时 15 毫秒
1.
BACKGROUND: On December 26, 2004, the biggest earthquake for 40 years, measuring 9.0 on the Richter scale, triggered a tsunami that pounded the coastal areas of South Asia and East Africa. The effects of the tsunami on skin conditions have not been evaluated. OBJECTIVE: To determine the influence of the tsunami on skin conditions by evaluating the skin problems of patients presenting at hospitals after the tsunami. METHODS: Between 5 and 25 January 2005, two dermatologists evaluated patients who complained of skin problems at an outpatient clinic and emergency room of a general hospital in Banda Aceh, Aceh Province, Indonesia. RESULTS: The total number of patients that presented during the study period was 235 (131 males and 104 females), and they had a total of 265 skin problems. In terms of age distribution, most subjects were in their fourth decade (23.0%), followed by the third (22.6%) and fifth decade (16.6%). The most prevalent skin problems were infections-infestations (32.5%), followed by eczemas (29.8%) and traumatic skin disorders (29.4%). In males, traumatic skin disorders were most common. The great majority of infection-infestation cases involved superficial fungal infections. Contact dermatitis accounted for three-quarters of eczema cases, and mainly involved the arms (40.0%) and legs (27.1%). The majority of traumatic skin disorders were lacerations, punctures and penetrations, and the feet (44.7%) and hands (18.8%) were most frequently affected. CONCLUSIONS: Unhygienic conditions, exposure to a hazardous environment and contact with various objects during and after the tsunami probably increased the prevalence of infections-infestations, traumatic skin disorders and contact dermatitis. To prevent these problems and associated secondary bacterial infections, health-related education and early medical management are required.  相似文献   
2.
It is suggested that the numerous variants of diverticula occurring in the region of the major duodenal papilla should be grouped into four types. Type I--the major duodenal papilla (MDP) is on the floor of the diverticulum; type II--the MDP is in the region of the lower ++semi-circumference of the diverticular orifice while the longitudinal fold runs radially on the wall of the diverticulum; type III--the MDP is in the region of the orifice of the diverticulum while the longitudinal fold does not pass on its wall; type IV--two diverticula located above the MDP to both sides of the longitudinal fold. Endoscopic papillosphincterotomy is considered contraindicated in patients with type I diverticulum. When indicated, the intervention was carried out in patients with types III and IV diverticula. Endoscopic papillosphincterotomy can be conducted in patients with type II diverticulum measuring more than 2 cm.  相似文献   
3.
Exploratory activity in the open field and noradrenaline concentration in the neocortex and brain stem were investigated in intact rats (n = 10) and in the following groups of rats with early postnatal neurotoxic (6-hydroxydopamine) lesion of the catecholaminergic system: (i) rats with embryonal locus coeruleus grafts in the frontal neocortex (n = 5); (ii) rats with the same grafts in lateral ventricles (n = 4); (iii) a control group with intracortical hippocampal tissue grafts (n = 3); (iv) sham-operated rats (n = 3). Experiments were performed by four independent groups of investigators using a double-blind method. In sham-operated rats as well as in rats with hippocampal grafts, and with locus coeruleus grafts in the ventricles, both exploratory activity and noradrenaline content of the forebrain were significantly lowered. In the rats with intracortical locus coeruleus grafts the level of exploratory activity was much higher (almost as in intact controls). This improvement of exploratory behaviour correlated highly with increased noradrenaline concentration in the forebrain. In all animals with locus coeruleus in lateral ventricles a significant increase in noradrenaline level of the brain stem was present, but no change of exploratory behaviour was observed. The grafts with the 3-mm-thick slabs of the adjacent tissue were dissected from the brain and used for histological analysis. The presence of typical locus coeruleus cells was shown in neocortex of all animals which received the grafts of corresponding tissue. The data show the possibility of stable compensation of the forebrain noradrenaline level and exploratory behaviour by embryonic noradrenergic neurons grafted into the neocortex, but not into lateral ventricles.  相似文献   
4.
5.
SUMMARY The study explored the incidence of clinical feminisation and the sex hormone levels of 18 Nigerian patients with liver cirrhosis (LC) alone and 18 patients with LC and hepatocellular carcinoma (HCC). The incidence (11%) of clinical feminisation in Nigerian patients was lower than values reported from other countries and there was no association between feminising signs and the sex hormone levels of the patients. Plasma oestradiol and sex hormone-binding globulin (SHBG) levels were significantly higher and testosterone lower in patients with liver diseases than in 18 age-matched normal controls. Serum concentrations of oestradiol were also found to be significantly higher in patients with LC alone than in those with LC and HCC. A possible promotive role for oestrogens in the development of HCC from the cirrhotic liver is discussed.  相似文献   
6.
A decrease in the amplitude of miniature and evoked end-plate potentials (MEPPs and EPPs) as well as changes in EPP facilitation and depression during frequency stimulation were observed in psychosine-treated m. cutaneous-pectoris of the frog. Electron-microscopic investigation demonstrated severe changes in synaptic Schwann cells embracing motor terminals and disturbances in the inner mesaxon structure of the myelinated parts of motor terminals.  相似文献   
7.
8.
9.
Fiala  ES; Sohn  OS; Li  H; El-Bayoumy  K; Sodum  RS 《Carcinogenesis》1997,18(9):1809-1815
We observed that pretreatment of male F344 rats with benzyl selenocyanate, a versatile organoselenium chemopreventive agent in several animal model systems, decreases the levels of DNA and RNA modifications produced in the liver by the hepatocarcinogen 2- nitropropane. To clarify the mechanisms involved, we pretreated male F344 rats with either benzyl selenocyanate, its sulfur analog benzyl thiocyanate, phenobarbital or cobalt protoporphyrin IX; the latter is a depletor of P450. We then determined (1) the ability of liver microsomes to denitrify 2-nitropropane, (2) effects on 2-nitropropane- induced liver DNA and RNA modifications and (3) amount of nitrate excreted in rat urine following administration of the carcinogen. Pretreatment with benzyl selenocyanate or phenobarbital increased the denitrification activity of liver microsomes by 217 and 765%, respectively, increased liver P4502B1 by 31- and 435-fold, respectively, decreased the levels of 2-nitropropane-induced modifications in liver DNA (29-70% and 17-30%, respectively) and RNA (67-85% and 30-50%, respectively), and increased the 24-h urinary excretion of nitrate by 157 and 209%, respectively. Pretreatment with benzyl thiocyanate had no significant effect on any of these parameters. Pretreatment with cobalt protoporphyrin IX decreased liver P4502B 1 by 87%, decreased the denitrification activity of liver microsomes by 76%, decreased the 24 h urinary excretion of nitrate by 88.5%, but increased the extent of 2-nitropropane-induced liver nucleic acid modifications by 17-67%. These results indicate that the metabolic sequence from 2-nitropropane to the reactive species causing DNA and RNA modifications does not involve the removal of the nitro group. Moreover, they suggest that benzyl selenocyanate inhibits 2-NP-induced liver nucleic acid modifications in part by increasing its detoxication through induction of denitrification, although it is evident that other mechanisms must also be involved.   相似文献   
10.
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