全文获取类型
收费全文 | 119091篇 |
免费 | 8639篇 |
国内免费 | 1181篇 |
专业分类
耳鼻咽喉 | 982篇 |
儿科学 | 1454篇 |
妇产科学 | 442篇 |
基础医学 | 5400篇 |
口腔科学 | 587篇 |
临床医学 | 3516篇 |
内科学 | 3918篇 |
皮肤病学 | 641篇 |
神经病学 | 3950篇 |
特种医学 | 1213篇 |
外国民族医学 | 2篇 |
外科学 | 3394篇 |
综合类 | 4912篇 |
现状与发展 | 8篇 |
一般理论 | 4篇 |
预防医学 | 1191篇 |
眼科学 | 93284篇 |
药学 | 2362篇 |
43篇 | |
中国医学 | 506篇 |
肿瘤学 | 1102篇 |
出版年
2024年 | 246篇 |
2023年 | 1843篇 |
2022年 | 4057篇 |
2021年 | 4349篇 |
2020年 | 3488篇 |
2019年 | 2916篇 |
2018年 | 3587篇 |
2017年 | 2775篇 |
2016年 | 3149篇 |
2015年 | 3632篇 |
2014年 | 6146篇 |
2013年 | 5859篇 |
2012年 | 6633篇 |
2011年 | 6952篇 |
2010年 | 5335篇 |
2009年 | 4770篇 |
2008年 | 5427篇 |
2007年 | 5607篇 |
2006年 | 5027篇 |
2005年 | 4647篇 |
2004年 | 4336篇 |
2003年 | 4157篇 |
2002年 | 3787篇 |
2001年 | 3796篇 |
2000年 | 3371篇 |
1999年 | 3044篇 |
1998年 | 1029篇 |
1997年 | 966篇 |
1996年 | 797篇 |
1995年 | 795篇 |
1994年 | 598篇 |
1993年 | 614篇 |
1992年 | 2064篇 |
1991年 | 1919篇 |
1990年 | 1759篇 |
1989年 | 1558篇 |
1988年 | 1482篇 |
1987年 | 818篇 |
1986年 | 287篇 |
1985年 | 402篇 |
1984年 | 490篇 |
1983年 | 490篇 |
1982年 | 459篇 |
1981年 | 452篇 |
1980年 | 465篇 |
1979年 | 411篇 |
1978年 | 362篇 |
1977年 | 244篇 |
1976年 | 276篇 |
1973年 | 258篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Summary Putative dopaminergic neurons in theXenopus retina were identified using an immunoreaction against tyrosine hydroxylase. A single class of cell was stained whose perikaryon (12–15 m in diameter) was located at the border of the inner nuclear and inner plexiform layers. About 2% of the stained cell bodies were located in the ganglion cell layer, but the distribution of the processes of displaced cells had the same geometry as for the majority of stained cells. Tyrosine hydroxylase-like immunoreactive perikarya gave rise to one to four stout processes that descended to the most proximal level of the inner plexiform layer, within which they branched repeatedly to generate a diffuse network of fine processes. Secondary branches ascended to the most distal sublayer of the inner plexiform layer where they ramified into fine processes that joined other fibres arising horizontally from the cell body and confined to the distal inner plexiform layer throughout their course. The diameter of the dendritic arbor of stained cells was in the range of 350–600 m. The dense network of fine fibres within the distal inner plexiform layer was arrayed in rings that surrounded other amacrine cells; using an antiserum against glycine we found that at least some of these were glycinergic neurons. Most tyrosine hydroxylase-positive neurons emitted one or two fine ascending processes that arose from the perikaryon, traversed the inner plexiform layer and arborized within the outer plexiform layer. Additionally, fine varicose fibres arising from the sublayer 1 of the inner plexiform layer and running to the outer retina were observed. Thus, based on light microscopic criteria, dopaminergic neurons in theXenopus retina appeared to be interplexiform cells. A few tyrosine hydroxylase-immunoreactive fibres were observed in the optic nerve, some of which entered the inner retina where they ramified, thus indicating that they were centrifugal axons. In addition, a small number of stout smooth processes were observed to traverse the entire inner nuclear layer and course laterally at the level of the photoreceptor bases. Whether this second class of ascending process arises from the tyrosine hydroxylase-like immunoreactive efferents remains to be determined. The total number of dopaminergic neurons per retina was 750–800, equivalent to an average density of 30 cells mm–2. The dendritic fields of adjacent cells strongly overlapped, with an estimated coverage factor of 4.8. 相似文献
992.
993.
994.
Constitutive retinal CD200 expression regulates resident microglia and activation state of inflammatory cells during experimental autoimmune uveoretinitis 总被引:6,自引:0,他引:6
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Broderick C Hoek RM Forrester JV Liversidge J Sedgwick JD Dick AD 《The American journal of pathology》2002,161(5):1669-1677
Recent evidence supports the notion that tissue OX2 (CD200) constitutively provides down-regulatory signals to myeloid-lineage cells via CD200-receptor (CD200R). Thus, mice lacking CD200 (CD200(-/-)) show increased susceptibility to and accelerated onset of tissue-specific autoimmunity. In the retina there is extensive expression of CD200 on neurons and retinal vascular endothelium. We show here that retinal microglia in CD200(-/-) mice display normal morphology, but unlike microglia from wild-type CD200(+/+) mice are present in increased numbers and most significantly, express inducible nitric oxide synthase (NOS2), a macrophage activation marker. Onset and severity of uveitogenic peptide (1-20) of interphotoreceptor retinoid-binding protein-induced experimental autoimmune uveoretinitis is accelerated in CD200(-/-) mice and although tissue destruction appears no greater than seen in CD200(+/+) mice, there is continued increased ganglion and photoreceptor cell apoptosis. Myeloid cell infiltrate was increased in CD200(-/-) mice during experimental autoimmune uveoretinitis, although NOS2 expression was not heightened. The results indicate that the CD200:CD200R axis regulates retinal microglial activation. In CD200(-/-) mice the release of suppression of tonic macrophage activation, supported by increased NOS2 expression in the CD200(-/-) steady state accelerates disease onset but without any demonstration of increased target organ/tissue destruction. 相似文献
995.
Brémond-Gignac D Gérard-Blanluet M Copin H Bitoun P Baumann C Crolla JA Benzacken B Verloes A 《American journal of medical genetics. Part A》2005,134(4):422-425
The WAGR contiguous gene deletion syndrome is a combination of Wilms tumor, Aniridia, Genito-urinary abnormalities, and growth and mental retardation which is invariably associated with an 11p13 deletion. We report two monozygotic twins and a third, unrelated patient with WAGR syndrome and additional clinical features not usually associated with WAGR. Both twins had developmental delay, growth deficiency, severe ocular involvement (nystagmus, aniridia, cataracts), atrial septal defect and two uncommon findings: agenesis of the corpus callosum and duplication of the halluces. One twin developed Wilms tumors aged 19 months while her sister remained tumor free by the age of 6.5 years. The singleton patient showed typical WAGR syndrome and preaxial hallucal polydactyly. Molecular cytogenetic studies refined the identification of the extent of the deleted segments, which were not identical in the two families. The two deletions included the PAX6 and WT1 genes as previously reported in typical WAGR patients. The unusual anomalies described in this report, may represent the expression of low penetrant traits associated with haploinsufficency of one or more of the genes present in the deletion (PAX6 is expressed in CNS) or may indicate epistatic influences of modifier genes on the expression of gene(s) present in the WAGR region. 相似文献
996.
Dinu Stanescu-Segall Thomas Sales de Gauzy Rhianon Reynolds Livia Faes Dominika Pohlmann Kaivon Pakzad-Vaezi 《Expert Review of Clinical Immunology》2020,16(7):651-657
ABSTRACT
Introduction
Routine medical and ophthalmic care is being drastically curtailed in the context of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Uveitis patients require particular attention because of their theoretical risk of viral infection, in the context of therapeutic immunosuppression. 相似文献997.
Xiao Liu Xiaohong Meng Lizhu Yang Yanling Long Yu Fujinami‐Yokokawa Jiayun Ren Toshihide Kurihara Kazuo Tsubota Kazushige Tsunoda Kaoru Fujinami Shiying Li East Asia Inherited Retinal Disease Society Study Group 《American journal of medical genetics. Part C, Seminars in medical genetics》2020,184(3):694-707
Stargardt disease 1 (STGD1) is the most prevalent retinal dystrophy caused by pathogenic biallelic ABCA4 variants. Forty‐two unrelated patients mostly originating from Western China were recruited. Comprehensive ophthalmological examinations, including visual acuity measurements (subjective function), fundus autofluorescence (retinal imaging), and full‐field electroretinography (objective function), were performed. Next‐generation sequencing (target/whole exome) and direct sequencing were conducted. Genotype grouping was performed based on the presence of deleterious variants. The median age of onset/age was 10.0 (5–52)/29.5 (12–72) years, and the median visual acuity in the right/left eye was 1.30 (0.15–2.28)/1.30 (0.15–2.28) in the logarithm of the minimum angle of resolution unit. Ten patients (10/38, 27.0%) showed confined macular dysfunction, and 27 (27/37, 73.7%) had generalized retinal dysfunction. Fifty‐eight pathogenic/likely pathogenic ABCA4 variants, including 14 novel variants, were identified. Eight patients (8/35, 22.8%) harbored multiple deleterious variants, and 17 (17/35, 48.6%) had a single deleterious variant. Significant associations were revealed between subjective functional, retinal imaging, and objective functional groups, identifying a significant genotype–phenotype association. This study illustrates a large phenotypic/genotypic spectrum in a large well‐characterized STGD1 cohort. A distinct genetic background of the Chinese population from the Caucasian population was identified; meanwhile, a genotype–phenotype association was similarly represented. 相似文献
998.
Illigens BM Yamada A Fedoseyeva EV Anosova N Boisgerault F Valujskikh A Heeger PS Sayegh MH Boehm B Benichou G 《Human immunology》2002,63(10):912-925
In this study, we measured direct and indirect T-cell alloresponses mediated by CD4(+) and CD8(+) T cells in three mouse transplantation models: skin, cornea, and retina. We show that the contribution of direct and indirect antigen recognition pathways to the alloresponse to fully allogeneic grafts varies depending upon the nature of the tissue/organ transplanted. The implications of this finding for understanding the cellular mechanisms by which rejection is mediated in different transplant models are discussed. 相似文献
999.
Localization of a novel X-linked congenital stationary night blindness locus: close linkage to the RP3 type retinitis pigmentosa gene region 总被引:1,自引:0,他引:1
Bergen Arthur A.B.; Brink Jacoline B.ten; Riemslag Frans; Schuurman Ellen J.M.; Tijmes Nel 《Human molecular genetics》1995,4(5):931-935
X-linked congenital stationary night blindness (CSNBX) is anon-progressive retinal disorder characterized by decreasedvisual acuity and loss of night vision. CSNBX Is clinicallyheterogeneous with respect to the involvement of retinal rodsand/or cones in the disease. in this study, we localize a newlocus for CSNBX to Xp21.1, thus providing evidence that CSNBXis also genetically heterogeneous. A clear correlation betweendifferent genotypes and phenotypes cannot be found yet. Thenew CSNBX gene described here is closely linked to the X-linkedretinitis pigmentosa type 3 gene region, which supports thehypothesis that there may be a functional relationship betweencongenital stationary night blindness and retinitis pigmentosa. 相似文献
1000.
G. A. Lamaris B. Esmaeli G. Chamilos A. Desai R. F. Chemaly I. I. Raad A. Safdar R. E. Lewis D. P. Kontoyiannis 《European journal of clinical microbiology & infectious diseases》2008,27(5):343-347
Few data exist on the etiology, presentation, prognosis, and management of fungal endophthalmitis (FE) in cancer patients.
FE cases were identified by reviewing the ophthalmology reports and microbiology cultures of patients at The University of
Texas M. D. Anderson Cancer Center. We retrospectively reviewed the medical records and obtained information related to malignancy,
fungal infection and its management, visual outcome, and mortality. We compared FE caused by Candida spp. (CE) to FE caused by molds (ME). Of the 102 cancer patients with a fungal infection for whom an ophthalmology consult
was requested, 23 met the criteria for definite (N = 6) or probable (N = 17) FE (8 with CE, 15 with ME). All of the patients with ME had hematologic malignancies, whereas half of the patients
with CE had solid tumor (P = .008). Only patients with CE had a history of surgery within 30 days of FE diagnosis (38%, P = .03). Fungal pneumonia [17 (74%)] and disseminated infection [14, (61%)] were common. The most common presenting symptoms
were decreased vision [16 (70%)] and ocular pain [14 (61%)]. All treated patients received systemic antifungals (combination
therapy in 72% of the cases). Seven patients (30%) underwent vitrectomy. Only one patient received intraocular injection of
amphotericin B along with systemic antifungals. Four-week mortality was high [13 (57%)], especially in ME (73%, P = .04). Among the eight surviving patients where visual acuity could be assessed, visual outcome improved or remained stable
in five (63%). FE in cancer patients occurs in the setting of severe, frequently disseminated opportunistic mycoses, is caused
predominantly by hyalohyphomycetes, and is a marker for high 4-week mortality. 相似文献