全文获取类型
收费全文 | 1698篇 |
免费 | 112篇 |
国内免费 | 113篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 69篇 |
妇产科学 | 15篇 |
基础医学 | 172篇 |
口腔科学 | 75篇 |
临床医学 | 197篇 |
内科学 | 417篇 |
皮肤病学 | 42篇 |
神经病学 | 48篇 |
特种医学 | 371篇 |
外国民族医学 | 1篇 |
外科学 | 70篇 |
综合类 | 50篇 |
预防医学 | 164篇 |
眼科学 | 15篇 |
药学 | 147篇 |
中国医学 | 3篇 |
肿瘤学 | 66篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 10篇 |
2020年 | 8篇 |
2019年 | 13篇 |
2018年 | 21篇 |
2017年 | 9篇 |
2016年 | 25篇 |
2015年 | 30篇 |
2014年 | 30篇 |
2013年 | 46篇 |
2012年 | 29篇 |
2011年 | 39篇 |
2010年 | 61篇 |
2009年 | 63篇 |
2008年 | 40篇 |
2007年 | 80篇 |
2006年 | 55篇 |
2005年 | 67篇 |
2004年 | 26篇 |
2003年 | 25篇 |
2002年 | 36篇 |
2001年 | 31篇 |
2000年 | 41篇 |
1999年 | 30篇 |
1998年 | 97篇 |
1997年 | 98篇 |
1996年 | 108篇 |
1995年 | 66篇 |
1994年 | 62篇 |
1993年 | 66篇 |
1992年 | 24篇 |
1991年 | 44篇 |
1990年 | 29篇 |
1989年 | 57篇 |
1988年 | 48篇 |
1987年 | 57篇 |
1986年 | 38篇 |
1985年 | 55篇 |
1984年 | 24篇 |
1983年 | 22篇 |
1982年 | 28篇 |
1981年 | 24篇 |
1980年 | 32篇 |
1979年 | 14篇 |
1978年 | 15篇 |
1977年 | 19篇 |
1976年 | 28篇 |
1975年 | 16篇 |
1972年 | 4篇 |
排序方式: 共有1923条查询结果,搜索用时 15 毫秒
11.
新生期大白鼠皮下注射谷氨酸单钠对成年后下丘脑α-促黑素细胞激素神经元免疫反应性的影响 总被引:2,自引:0,他引:2
本文用免疫组化方法研究了新生期大白鼠注射谷氨酸单钠(MSG)对成年后下丘脑α-促黑素细胞激素(α-MSH)免疫反应神经元的影响,结果显示MSG处理以后下丘脑弓状核区α-MSII免疫反应神经元减少甚至完全消失,但不影响下丘脑背外侧区的α-MSH神经元群。文中还讨论了这两群α-MSH神经元的生理作用。 相似文献
12.
13.
D Chatel Y Martin-Bouyer C Acar H Bouchoucha JL Sableyrolles V Jebara JC Chachques A Carpentier 《Surgical and radiologic anatomy : SRA》1993,15(4):341-348
Summary The anatomic constraints imposed on a total artificial heart (TAH) require specific anatomic studies. A thoracic anatomic study was performed with a scanning device equipped with three-dimensional (3-D) reconstruction software on 15 male patients, between the ages of 41 to 63 years (52 ± 6 years). All were candidates for heart transplantation. The 3-D reconstructions of the cardiovascular structures obtained from surgical anatomy data specific to TAH implantation allowed a volumetric measurement of these structures. A modeling diagram of these structures permitted reproducible quantitative measurements of the 35 geometrical parameters which characterized shape, orientation, and position of these structures within the thorax. Most of the measured parameters were characterized by low variability (coefficient of variation from 10 to 25%).
Modélisation tridimensionnelle de l'anatomie du cur et des gros vaisseaux
Résumé Les contraintes anatomiques imposées au cur artificiel total (CAT) nécessitent des études anatomiques spécifiques. Une étude anatomique thoracique a été réalisée avec un scanner doté d'un logiciel de reconstruction tridimensionnelle (3-D) chez 15 patients, tous de sexe masculin, agés de 41 à 63 ans (52 ± 6 ans), et candidats à une transplantation cardiaque. Les reconstructions 3-D des structures cardio-vasculaires réalisées selon les données de l'anatomie chirurgicale propre à l'implantation du CAT ont permis la mesure volumétrique de ces structures. Un schéma de modélisation de ces structures a permis des mesures quantitatives reproductibles de 35 paramètres géométriques caractéristiques de la forme, de l'orientation, de la position de ces structures dans le thorax. Les résultats de ces mesures ont pu être exprimés en termes statistiques. La plupart des paramètres mesurés étaient caractérisés par une faible variabilité (coefficients de variations de 10 à 25%).相似文献
14.
Inhibitory effect of ethacrynic acid on chloride permeability 总被引:1,自引:0,他引:1
15.
Frataxin is reduced in Friedreich ataxia patients and is associated with mitochondrial membranes 总被引:17,自引:8,他引:17
Campuzano V; Montermini L; Lutz Y; Cova L; Hindelang C; Jiralerspong S; Trottier Y; Kish SJ; Faucheux B; Trouillas P; Authier FJ; Durr A; Mandel JL; Vescovi A; Pandolfo M; Koenig M 《Human molecular genetics》1997,6(11):1771-1780
Friedreich ataxia is a progressive neurodegenerative disorder caused by
loss of function mutations in the frataxin gene. In order to unravel
frataxin function we developed monoclonal antibodies raised against
different regions of the protein. These antibodies detect a processed 18
kDa protein in various human and mouse tissues and cell lines that is
severely reduced in Friedreich ataxia patients. By immunocytofluorescence
and immunocytoelectron microscopy we show that frataxin is located in
mitochondria, associated with the mitochondrial membranes and crests.
Analysis of cellular localization of various truncated forms of frataxin
expressed in cultured cells and evidence of removal of an N-terminal
epitope during protein maturation demonstrated that the mitochondrial
targetting sequence is encoded by the first 20 amino acids. Given the
shared clinical features between Friedreich ataxia, vitamin E deficiency
and some mitochondriopathies, our data suggest that a reduction in frataxin
results in oxidative damage.
相似文献
16.
How to use Chlamydia antibody testing in subfertility patients 总被引:1,自引:9,他引:1
Screening for tubal factor subfertility by means of Chlamydia antibody
testing (CAT) was introduced into the initial work-up of subfertile couples
several years ago. The results reported, however, are heterogeneous, and no
uniformity exists in cut-off levels of titres, or in definitions of tubal
factor subfertility. We performed a prospective cohort study to evaluate
the implications of varying the definitions of tubal pathology and of
modifying the cut-off levels on the clinical impact of CAT in predicting
tubal factor subfertility. In 227 consecutive patients who attended our
fertility clinic, the Chlamydia IgG antibody titre was determined and
related to tuboperitoneal abnormalities at laparoscopy as a reference
standard. According to received operating characteristic (ROC) curve
analysis, a titre of 16 is the optimum cut-off level. Increasing the
cut-off level improves specificity and positive likelihood ratio (LR+), at
the expense of sensitivity and negative LR (LR-). Changing the definition
of tubal factor subfertility from unspecified tuboperitoneal abnormalities
into extensive adhesions and/or bilateral distal tubal occlusion improves
LR+, LR- and kappa significantly. We conclude that CAT is more accurate in
predicting severe distal tubal pathology than unspecified tuboperitoneal
abnormalities. Although from a statistical point of view a titre of 16 is
the optimum cut-off level, from a clinical point of view 32 or 64 may be
preferable, depending on the aim of screening and the inception cohort.
相似文献
17.
Alternative splicing of exon 14 determines nuclear or cytoplasmic localisation of fmr1 protein isoforms 总被引:6,自引:9,他引:6
Impaired expression of the FMR1 gene is responsible for the fragile X
mental retardation syndrome. The FMR1 gene encodes a cytoplasmic protein
with RNA-binding properties. Its complex alternative splicing leads to
several isoforms, whose abundance and specific functions in the cell are
not known. We have cloned in expression vectors, cDNAs corresponding to
several isoforms. Western blot comparison of the pattern of endogenous FMR1
proteins with these transfected isoforms allowed the tentative
identification of the major endogenous isoform as ISO 7 and of a minor band
as an isoform lacking exon 14 sequences (ISO 6 or ISO 12), while some other
isoforms (ISO 4, ISO 5) were not expressed at detectable levels.
Surprisingly, in immunofluorescence studies, the transfected splice
variants that exclude exon 14 sequences (and have alternate C-terminal
regions) were shown to be nuclear. Such differential localisation was
however not seen in subcellular fractionation studies. Analysis of various
deletion mutants suggests the presence of a cytoplasmic retention domain
encoded in exon 14 and of a nuclear association domain encoded within the
first eight exons that appear however to lack a typical nuclear
localisation signal.
相似文献
18.
P L Toubas K A Abla W Cao L G Logan T W Seale 《Pharmacology, biochemistry, and behavior》1990,35(1):121-126
Many animal species exhibit approach-avoidance responses upon the novel placement of a mirror into an individual animal's environment. With a view toward identifying new behavioral measures with qualitatively or quantitatively different responses to anxiolytic agents, we developed a mirrored chamber apparatus for which adult male BALB/cByJ mice showed an extended latency to enter. Administration of diazepam significantly reduced this latency to enter a mirrored chamber in a dosage-dependent manner. The psychomotor stimulant, methylphenidate, had no effect on latency to enter the mirrored chamber at a dose which stimulated locomotor activity to the same extent as diazepam. Thus, the decreased latency to enter the mirrored chamber brought about by diazepam seems unlikely to reflect the motor effects of this benzodiazepine. The potency of diazepam was significantly lower in the mirrored chamber assay than it was on three other measures of exploratory activity--"head-dipping" performance, plus-maze performance and locomotor activity stimulation. The findings of our study indicate that the mirrored chamber method is simple to carry out, nonpunishing, rapid and quantitative and that it possesses pharmacological attributes which distinguish its response to anxiolytics from other assays of exploratory behavior. 相似文献
19.
0 引言 胰腺多房性潴留性囊肿极为罕见,我科收治1例,报道如下.1 病例报告 患者,男,29岁,因发现右上腹包块11d入院,缘于11d前无明显诱因感右上腹痛,仅局限于右上腹部,无肩背部放散痛,伴间歇性发热,体温最高达38.3℃,经抗炎,对症治疗无效.并逐渐可触及右上腹有一肿块,在当地医院行穿刺检查为脓血性液体.镜检发现炎性细胞,B超示:胆囊窝下方及右肾内侧及腹腔动脉,下腔静脉外前方可见异常区,大小约9.1cm×6.6cm×7.6cm,边界清楚,形态不规则,内呈蜂窝状,可见多个大小不等的液性暗区,CT示:右上腹部上腔静脉前方6.0cm×9.0cm肿块和周围组织粘… 相似文献
20.
A young boy presented with an uncommon finding of impaction of upper right central incisor and transposition of canine and lateral incisor on the same side. Esthetic management of his cosmetic problem which included fixed appliance therapy followed by light cure restorations is discussed.KEY WORDS: Impaction, Transposition 相似文献