全文获取类型
收费全文 | 790篇 |
免费 | 57篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 47篇 |
妇产科学 | 11篇 |
基础医学 | 115篇 |
口腔科学 | 31篇 |
临床医学 | 89篇 |
内科学 | 163篇 |
皮肤病学 | 34篇 |
神经病学 | 64篇 |
特种医学 | 130篇 |
外科学 | 52篇 |
综合类 | 37篇 |
预防医学 | 23篇 |
眼科学 | 5篇 |
药学 | 40篇 |
中国医学 | 2篇 |
肿瘤学 | 16篇 |
出版年
2023年 | 4篇 |
2021年 | 12篇 |
2020年 | 12篇 |
2019年 | 17篇 |
2018年 | 11篇 |
2017年 | 17篇 |
2016年 | 17篇 |
2015年 | 23篇 |
2014年 | 25篇 |
2013年 | 32篇 |
2012年 | 14篇 |
2011年 | 9篇 |
2010年 | 46篇 |
2009年 | 36篇 |
2008年 | 16篇 |
2007年 | 23篇 |
2006年 | 19篇 |
2005年 | 19篇 |
2004年 | 8篇 |
2003年 | 14篇 |
2002年 | 10篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 10篇 |
1998年 | 45篇 |
1997年 | 38篇 |
1996年 | 39篇 |
1995年 | 24篇 |
1994年 | 37篇 |
1993年 | 29篇 |
1992年 | 16篇 |
1991年 | 8篇 |
1990年 | 13篇 |
1989年 | 22篇 |
1988年 | 18篇 |
1987年 | 16篇 |
1986年 | 17篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 15篇 |
1979年 | 4篇 |
1978年 | 9篇 |
1977年 | 13篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1956年 | 3篇 |
1955年 | 2篇 |
排序方式: 共有864条查询结果,搜索用时 31 毫秒
1.
In the present study, we examined the ultrastructure of striatal neurons containing neuropeptide Y (NPY) which were labeled by an immunohistochemical method using peroxidase-conjugated F(ab) fragments in the rat. Each of the 26 neurons identified had a deeply indented oval nucleus. The cytoplasm, which was mainly concentrated at the emergence of the dendrites, contained an abundant Golgi apparatus and a well-developed granular endoplasmic reticulum. Dendrites were poorly branched and rarely exhibited varicosities or dendritic spines. NPY-immunoreactive (Ir) axons were small in diameter and unmyelinated. These features corresponded to a subpopulation of striatal neurons classified as aspiny type IV in previous Golgi studies. Axon terminals forming symmetrical synapses were numerous on the NPY-Ir perikarya and proximal dendrites. On distal NPY-Ir dendrites, synaptic contacts were mainly of the asymmetrical type, suggesting that NPY neurons are contacted by at least 2 categories of afferent fibers. Several NPY-Ir axonal processes and boutons were found to form symmetrical synapses with dendrites, dendritic spines and perikarya belonging to spiny type neurons. These data were consistent with the view that NPY may act as a neurotransmitter of striatal interneurons. Moreover, the frequent observation of NPY axonal processes in the close vicinity of striatal vessels suggested that NPY might also play a role in the control of cerebral vasomotricity. Thirty hours after intranigral injection of 6-hydroxydopamine to induce a degeneration of nigrostriatal dopamine terminals, some characteristic degenerative boutons were observed in close apposition to NPY-Ir cell bodies, suggesting that NPY neurons are under a direct nigrostriatal dopaminergic influence. 相似文献
2.
3.
GP SCHWAB AL BLUM E BODNER B DALLEMAGNE K GLASER H KOOP F PACE W RÖSCH JR SIEWERT G WETSCHER 《Journal of gastroenterology and hepatology》1997,12(12):785-789
Gastroesophageal reflux disease (GERD) is the most common disease of the upper gastrointestinal tract. With the introduction of proton pump inhibitors medical treatment of GERD has been significantly improved. However, the development of laparoscopic antireflux surgery resulted in an increasing interest of surgeons in this disease. An interactive meeting was organized in order to develop an agreement between gastoenterologists and surgeons regarding therapeutic decisions and this is the main topic of this paper. 相似文献
4.
5.
6.
Edward?J?HolloxEmail author Jane?Davies Uta?Griesenbach Juliana?Burgess Eric?WFW?Alton John?AL?Armour 《Journal of negative results in biomedicine》2005,4(1):9
Human beta-defensin 2 (DEFB4, also known as DEFB2 or hBD-2) is a salt-sensitive antimicrobial protein that is expressed in
lung epithelia. Previous work has shown that it is encoded in a cluster of beta-defensin genes at 8p23.1, which varies in
copy number between 2 and 12 in different individuals. We determined the copy number of this locus in 355 patients with cystic
fibrosis (CF), and tested for correlation between beta-defensin cluster genomic copy number and lung disease associated with
CF. No significant association was found. 相似文献
7.
Missense FGFR3 mutations create cysteine residues in thanatophoric dwarfism type I (TD1) 总被引:10,自引:1,他引:10
Rousseau F; el Ghouzzi V; Delezoide AL; Legeai-Mallet L; Le Merrer M; Munnich A; Bonaventure J 《Human molecular genetics》1996,5(4):509-512
Thanatophoric dwarfism (TD) is a sporadic lethal skeletal dysplasia with
micromelic shortening of the limbs, macrocephaly, platyspondyly and reduced
thoracic cavity. In the most common subtype (TD1), femurs are curved, while
in TD2, straight femurs are associated with cloverleaf skull. Mutations in
the fibroblast growth factor receptor 3 (FGFR3) gene were identified in
both subtypes. While TD2 was accounted for by a single recurrent mutation
in the tyrosine kinase 2 domain, TD1 resulted from either stop codon
mutations or missense mutations in the extracellular domain of the gene.
Here, we report the identification of FGFR3 mutations in 25/26 TD cases.
Two novel missense mutations (Y373C and G370C) were detected in 8/26 and
1/26 TD1 cases respectively. Both mutations created cysteine residues in
the juxta extramembrane domain of the receptor. Sixteen cases carried the
previously reported R248C (9/26 cases), S249C (2/26 cases) or stop codon
FGFR3 mutations (5/26 cases). Our results suggest that TD1 is a genetically
homogeneous condition and give additional support to the view that newly
created cysteine residues in the extracellular domain of the protein play a
key role in the severity of the disease.
相似文献
8.
B Conte-Devolx M Grino A Nieoullon F Javoy-Agid E Castanas V Guillaume M C Tonon H Vaudry C Oliver 《Neuroscience letters》1985,56(2):217-222
We have compared hypothalamic contents of various neurotransmitters (dopamine (DA), norepinephrine and serotonin) and their metabolites (dihydroxyphenyl acetic acid, homovanilic acid, 5-hydroxyindoleacetic acid) in post-mortem human controls and parkinsonian hypothalami. Neurotransmitters and their metabolites were measured in 0.1 N HCl hypothalami extracts using electrochemical detection after high performance liquid chromatography. Using specific radioimmunoassays we have also measured corticoliberin and somatocrinin contents in these hypothalami. Despite a 50% decrease of DA contents in parkinsonian hypothalami, no variations of corticoliberin and somatocrinin contents were found: 16.6 +/- 1.78 pg/mg tissue in Parkinson disease vs 16.71 +/- 1.89 in controls for human corticotropin-releasing factor (hCRF 1-41) and 37.38 +/- 11 vs 45.16 for human growth-hormone-releasing factor (hGRF 1-44). 相似文献
9.
Morphological analysis of degeneration and regeneration of syncytiotrophoblast in first trimester placental villi during organ culture 总被引:3,自引:1,他引:3
We have recently shown using dansyl-L-lysine exclusion studies that the
release of human chorionic gonadotrophin (HCG) in conjunction with L-
lactate dehydrogenase (LDH) from first trimester villi during organ culture
is symptomatic of syncytiotrophoblast degeneration. The purpose of this
study was to examine chorionic villi at the ultrastructural level in order
to determine events occurring during organ culture. The tissue was sampled
after 0, 24, 48 and 120 h in culture and processed for electron microscopy.
In addition to confirming the previously recorded syncytial degeneration,
the electron micrographs showed clearly the generation of a new
syncytiotrophoblast layer. The new layer, derived from differentiating
cytotrophoblast cells, was largely formed by 48 h and was maintained for at
least 120 h in culture. This study demonstrates a model which provides an
opportunity to study the differentiation of cytotrophoblast cells whilst
they retain their anatomical relationships within the villous structure.
相似文献
10.