全文获取类型
收费全文 | 3488128篇 |
免费 | 282928篇 |
国内免费 | 14599篇 |
专业分类
耳鼻咽喉 | 48462篇 |
儿科学 | 106940篇 |
妇产科学 | 91282篇 |
基础医学 | 546990篇 |
口腔科学 | 96880篇 |
临床医学 | 308390篇 |
内科学 | 618231篇 |
皮肤病学 | 93045篇 |
神经病学 | 297937篇 |
特种医学 | 138875篇 |
外国民族医学 | 453篇 |
外科学 | 543371篇 |
综合类 | 107087篇 |
现状与发展 | 24篇 |
一般理论 | 2262篇 |
预防医学 | 284329篇 |
眼科学 | 79698篇 |
药学 | 242993篇 |
23篇 | |
中国医学 | 10348篇 |
肿瘤学 | 168035篇 |
出版年
2021年 | 54914篇 |
2020年 | 35043篇 |
2019年 | 58027篇 |
2018年 | 70835篇 |
2017年 | 54091篇 |
2016年 | 59847篇 |
2015年 | 73986篇 |
2014年 | 108172篇 |
2013年 | 173361篇 |
2012年 | 90094篇 |
2011年 | 89167篇 |
2010年 | 115516篇 |
2009年 | 120727篇 |
2008年 | 77098篇 |
2007年 | 80629篇 |
2006年 | 91478篇 |
2005年 | 86799篇 |
2004年 | 89033篇 |
2003年 | 80391篇 |
2002年 | 70706篇 |
2001年 | 109278篇 |
2000年 | 102391篇 |
1999年 | 101325篇 |
1998年 | 65234篇 |
1997年 | 63135篇 |
1996年 | 60648篇 |
1995年 | 56093篇 |
1994年 | 50329篇 |
1993年 | 47019篇 |
1992年 | 71714篇 |
1991年 | 68015篇 |
1990年 | 64995篇 |
1989年 | 64338篇 |
1988年 | 60217篇 |
1987年 | 58843篇 |
1986年 | 56330篇 |
1985年 | 55967篇 |
1984年 | 50483篇 |
1983年 | 45770篇 |
1982年 | 42318篇 |
1981年 | 39785篇 |
1980年 | 37627篇 |
1979年 | 42937篇 |
1978年 | 37353篇 |
1977年 | 34267篇 |
1976年 | 31033篇 |
1975年 | 30688篇 |
1974年 | 32404篇 |
1973年 | 31077篇 |
1972年 | 29503篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Endogenous opioids are present in neurons of the vagus and the intrinsic nervous system and they are colocalized with gastrin in antral G-cells. This raises the possibility that endogenous opioids modulate gastrin release. Stimulation of both cervical vagi (10V, 5Hz, 5ms) elicited an increase of arterial plasma gastrin levels at intragastric pH7 or pH2. The response at pH2 was 30% of that at luminal pH7. Atropine reduced vagally stimulated gastrin levels substantially. At luminal pH2 the small residual noncholinergic response was mediated neither by adrenergic mechanisms nor by endogenous opioids. At luminal pH 7 adrenergic blockade with phentolamine and propranolol reduced vagally stimulated gastrin by 60%. In the presence of atropine adrenergic blockade elicited only a small inhibitory effect suggesting that vagal activation of adrenergic mechanisms depends on atropine-sensitive cholinergic pathways. Blockade of opiate receptors by naloxone had no effect on vagal gastrin release, however, the noncholinergic gastrin response was reduced significantly by naloxone, suggesting that cholinergic mechanisms normally restrain activation of endogenous opioids during vagal stimulation. Naloxone had no effect on the noncholinergic, nonadrenergic stimulation of gastrin levels. These data suggest that endogenous opioids can contribute to vagal gastrin release provided the cholinergic restraint is blocked and adrenergic mechanisms stimulate endogenous opioids. In conclusion a major role of endogenous opioids in the regulation of vagal gastrin release can not be detected. 相似文献
992.
993.
H Holzmann S Sollberg P Altmeyer 《Der Hautarzt; Zeitschrift für Dermatologie, Venerologie, und verwandte Gebiete》1987,38(5):253-257
A new classification of forms of progressive systemic scleroderma (PSS) is presented. Compared with previous classifications, it includes not only frequent, typical forms of PSS, but also rarer manifestations. For the first time, it considers pathogenetic factors, such as the phenomena which have become known concerning the immunological system, and distinguishes between noninflammatory and inflammatory subtypes. Etiological (in this case, immunogenetic) criteria are also considered. This classification is open to further differentiation and development. 相似文献
994.
(E)-5-(2-Bromovinyl)-2'-deoxyuridine (1; BrVUdR) inhibits the replication of herpes simplex virus type 1 (HSV-1) and of varicella-zoster virus (VZV) in vitro at concentrations of 0.01 to 0.23 mumol/l, whereas herpes simplex virus type 2 (HSV-2) is influenced only at 5.5 to 27 mumol/l. In comparison to some classical and newly developed antiherpetics, i. e. 5-iodo-2'-desoxyuridine (2; idoxuridine, IDU), 9-beta-D-arabinofuranosyladenine (4; vidarabine Ara-A), 9-(2-hydroxyethoxymethyl) guanine (5; acyclovir, ACV) and 2'-fluoro-5-iodo-1-beta-D-aracytosine (6;FIAC) the following order of decreasing activity was found:1 greater than 6 greater than 5 greater than 2 greater than 4 (against HSV-1) and 6 greater than 2 greater than 5 greater than 1 greater than 4 (against HSV-2). The high selectivity of the antiviral effect of BrVUdR towards HSV-1 and TZV is based on the fact, that proliferation of different mammalian cell lines is inhibited by 50% only at concentrations as high as 90 to 170 mumol/l, resulting in a therapeutical index of 1000 to 10,000. Successful treatment of an HSV-1 encephalitis in mice as well as an HSV-1 keratitis of rabbits confirmed the efficiency of 1 in experimental animal infections. No toxic side effects in both local and systemic applications were observed. Promising data from cell culture and animal experiments recommend 1 as a potential candidate for the local and systemic treatment of HSV-1 and VZV infections in man. 相似文献
995.
996.
A HIGH FREQUENCY OF INHERITED DEFICIENCY OF COMPLEMENT COMPONENT C4 IN DARWIN ABORIGINES 总被引:2,自引:0,他引:2
Abstract A high frequency of serum complement component C4A deficiency may explain the higher prevalence and greater severity of systemic lupus erythematosus reported in Australian Aborigines. Inherited deficiencies of serum complement components C4A, C4B, and C2 were examined in two Australian Aboriginal populations from Darwin and Alice Springs and compared with the prevalence of complement deficiencies in white Australian blood donors. The frequency of C4A deficiency alleles was 29% in Darwin Aborigines compared with 12% in Alice Springs and 17% in Canberra blood donors. Partial C4B deficiency was also higher in Darwin Aborigines than in the other populations. Inherited deficiency of serum complement component C2 was not observed. 相似文献
997.
998.
999.
T. A. Mustoe M.D. L. B. Kaban J. B. Mulliken 《European journal of plastic surgery》1987,10(4):135-138
Summary A group of thirty children with nasal fractures was evaluated retrospectively by means of a questionnaire and hospital records. Age at the time of injury ranged from age 3 to 12 (mean = 8.6) years and mean follow-up period was 9 years. Eight patients reported some degree of nasal obstruction post reduction, but only one patient required submucous resection and two patients underwent septorhinoplasty for appearance. No patients reported class III malocclusion, or required orthodontic treatment or maxillofacial corrective surgery for maxillary hypoplasia. We concluded that a childhood nasal fracture treated by closed reduction does not have deleterious effects on facial or nasal growth.This work was supported in part by the Brigham Surgical Group Foundation, Inc., Boston, Massachusetts, USA 相似文献
1000.
Summary A new modification of microvenous anastomosis, which has increased patency rates while simultaneously decreasing the difficulty of the procedure, is presented in this paper. The primary purpose of this study was to compare the classical and the temporary stent techniques of microvenous anastomosis. Because of problems such as mixing and tangling of strings during insertion and tying of the last four sutures while applying the temporary stent technique, we decided to modify the procedure. The silastic tube was removed through an incision (venotomy), distant from the actual suture line. This modified technique and the other above mentioned techniques were carried out on rat femoral veins. The results indicate that this modification has increased patency rates, shortened the time of anastomosis and facilitated the procedure. 相似文献