全文获取类型
收费全文 | 4520篇 |
免费 | 487篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 266篇 |
妇产科学 | 159篇 |
基础医学 | 773篇 |
口腔科学 | 82篇 |
临床医学 | 554篇 |
内科学 | 1074篇 |
皮肤病学 | 56篇 |
神经病学 | 218篇 |
特种医学 | 276篇 |
外科学 | 469篇 |
综合类 | 101篇 |
一般理论 | 3篇 |
预防医学 | 424篇 |
眼科学 | 38篇 |
药学 | 283篇 |
中国医学 | 1篇 |
肿瘤学 | 215篇 |
出版年
2021年 | 51篇 |
2018年 | 71篇 |
2017年 | 37篇 |
2015年 | 49篇 |
2014年 | 65篇 |
2013年 | 102篇 |
2012年 | 153篇 |
2011年 | 166篇 |
2010年 | 131篇 |
2009年 | 121篇 |
2008年 | 169篇 |
2007年 | 189篇 |
2006年 | 173篇 |
2005年 | 155篇 |
2004年 | 132篇 |
2003年 | 176篇 |
2002年 | 129篇 |
2001年 | 116篇 |
2000年 | 137篇 |
1999年 | 143篇 |
1998年 | 100篇 |
1997年 | 96篇 |
1996年 | 104篇 |
1995年 | 84篇 |
1994年 | 81篇 |
1993年 | 74篇 |
1992年 | 115篇 |
1991年 | 119篇 |
1990年 | 112篇 |
1989年 | 130篇 |
1988年 | 122篇 |
1987年 | 121篇 |
1986年 | 108篇 |
1985年 | 100篇 |
1984年 | 57篇 |
1983年 | 52篇 |
1982年 | 40篇 |
1981年 | 48篇 |
1980年 | 39篇 |
1979年 | 86篇 |
1978年 | 61篇 |
1977年 | 45篇 |
1976年 | 47篇 |
1975年 | 46篇 |
1974年 | 55篇 |
1973年 | 36篇 |
1972年 | 40篇 |
1971年 | 44篇 |
1970年 | 44篇 |
1967年 | 35篇 |
排序方式: 共有5011条查询结果,搜索用时 15 毫秒
41.
In vitro regulation of thyroglobulin (Tg) autoantibody production by Tg-specific T-cell lines and hybridomas. 下载免费PDF全文
To define the interactions between self thyroglobulin (Tg)-reactive T and B we co-cultured enriched B cells taken from rat or mouse Tg-primed mice with major histocompatibility complex (MHC) class II-restricted T-cell lines specific for iodinated determinants on self-Tg, or hybridomas derived from those lines. Using two clonally distinct T-cell hybridomas, ADA2 and CH9, in vitro help for Tg autoantibody responses was observed using mouse (M)Tg-primed B cells and a 100 ng/ml MTg challenge. Using rat Tg-primed B cells and the same conditions, only CH9 provided help, indicating that the fine specificity of B cells influences their ability to interact with specific anti-Tg T-cell clones. In contrast to T-cell hybridomas, their parent T-cell lines MTg9B3 and MTg12B suppressed Tg autoantibody responses in vitro, although they augmented bystander proliferation of unprimed B cells. The MTg12B cells also (i) diminished the survival of Tg-primed B cells, and (ii) inhibited the proliferation of an antigen-presenting B-cell hybridoma (LK35.2) in a cytostasis assay. These findings together support the view that their suppressive activity is mediated through cytotoxicity. While the role of class II-restricted cytotoxic cells in thyroid autoimmunity is unknown, the results suggest that such cells may act to suppress autoantibody responses as well as to mediate tissue damage to class II-expressing thyroid cells. 相似文献
42.
Satoshi Yoshihara Gregory Yanik Kenneth R Cooke Shin Mineishi 《Biology of blood and marrow transplantation》2007,13(7):749-759
Pulmonary dysfunction is a significant complication following allogeneic hematopoietic stem cell transplantation (HSCT), and is associated with significant morbidity and mortality. Effective antimicrobial prophylaxis and treatment strategies have increased the incidence of noninfectious lung injury, which can occur in the early posttransplant period or in the months and years that follow. Late-onset noninfectious pulmonary complications are frequently encountered, but diagnostic criteria and terminology for these disorders can be confusing and therapeutic approaches are suboptimal. As a consequence, inaccurate diagnosis of these conditions may hamper the appropriate data collection, enrollment into clinical trials, and appropriate patient care. The purpose of this review is to clarify the pathogenesis and diagnostic criteria of representative conditions, such as bronchiolitis obliterans syndrome and bronchiolitis obliterans organizing pneumonia, and to discuss the appropriate diagnostic strategies and treatment options. 相似文献
43.
P Hutchings D C Rayner B R Champion S Marshall-Clarke S Macatonia I Roitt A Cooke 《European journal of immunology》1987,17(3):393-398
B cells primed in vivo with mouse or rat thyroglobulin present these antigens at very low concentrations to CH9, an Ly 1+2- T cell hybridoma specific for mouse and rat thyroglobulin. Presentation measured by interleukin 2 release from CH9 is sensitive to treatment with a monoclonal antibody eliminating splenic B cells but is unaffected by anti-Thy-1.2 or 33D1 (which destroy T cells and dendritic cells, respectively). Presentation is specific for the priming antigen and is blocked by preincubation of the B cells with sheep anti-mouse F(ab')2. We suggest that in this system, primed B cells present thyroglobulin and that this may represent a means by which an initial triggering event priming both B and T cells could allow maintenance of autoreactive responses in vivo in the presence of low concentrations of circulating antigen. 相似文献
44.
Detection of a 15q deletion in a child with Angelman syndrome by cytogenetic analysis and flow cytometry 总被引:1,自引:0,他引:1
A Cooke J L Tolmie F J Glencross E Boyd M M Clarke R Day J B Stephenson J M Connor 《American journal of medical genetics》1989,32(4):545-549
A proximal 15q deletion, del(15) (q11:q13), was detected in a child with Angelman syndrome by cytogenetic analysis of peripheral lymphocytes. The chromosomes of both parents appeared normal. Flow karyotype analysis carried out on lymphoblastoid cell lines derived from the child and her parents confirmed the presence of a de novo 15 deletion. The estimated size of the deleted segment ranged from 6.1-9.5% of chromosome 15 (approximately 6-9.3 million base pairs). The parental origin of the deleted chromosome could not be resolved by flow cytometry, but cytogenetic evidence suggested that it was derived from the smaller chromosome 15 homologue in the mother. 相似文献
45.
Human muscle sympathetic neural and haemodynamic responses to tilt following spaceflight 总被引:6,自引:5,他引:6
Benjamin D. Levine James A. Pawelczyk rew C. Ertl James F. Cox Julie H. Zuckerman ré Diedrich Italo Biaggioni Chester A. Ray Michael L. Smith Satoshi Iwase Mitsuru Saito Yoshiki Sugiyama Tadaaki Mano Rong Zhang Kenichi Iwasaki Lynda D. Lane Jay C. Buckey Jr William H. Cooke Friedhelm J. Baisch David Robertson Dwain L. Eckberg C. Gunnar Blomqvist 《The Journal of physiology》2002,538(1):331-340
46.
Partial rescue of the Dazl knockout mouse by the human DAZL gene 总被引:11,自引:0,他引:11
Y-chromosomal DAZ (deleted in azoospermia) and autosomal DAZ-like (DAZL) comprise a gene family involved in gametogenesis. Y-chromosomal and autosomal genes only co-exist in humans and old world monkeys, indicating that DAZ genes are a recent acquisition of the Y chromosome. In most mammals, the ancestral Dazl alone is sufficient to complete gametogenesis. It is not yet understood why humans and old world monkeys have a second set of genes that are apparently necessary for spermatogenesis, since deletions removing the Y-chromosomal DAZ are often associated with azoo- or oligospermia. We used transgenic mice carrying either human DAZL or human DAZ on a mouse Dazl null background to investigate the functions of the human homologues. Both transgenes enabled prophase spermatocytes to be produced, mainly of the leptonema/zygonema stage, but failed to promote differentiation into mid- to late pachytenes. The presence of human DAZL resulted in a larger amount of early germ cells compared with that observed in DAZ. The degree of rescue was independent of copy number, integration site or presence of the DAZ repeat region for the DAZ transgenes. These findings confirm that DAZL and DAZ can only substitute for early functions of the murine homologue resulting in the establishment of the germ cell population and partial progression into meiosis. 相似文献
47.
Cooke MN Fisher JP Dean D Rimnac C Mikos AG 《Journal of biomedical materials research. Part B, Applied biomaterials》2003,64(2):65-69
A novel approach to the manufacture of biodegradable polymeric scaffolds for tissue-engineering utilizing stereolithography (SLA) is presented. SLA is a three-dimensional (3D) printing method that uses an ultraviolet laser to photo-crosslink a liquid polymer substrate. The current generation of SLA devices provide a 3D printing resolution of 0.1 mm. The experiments utilized a biodegradable resin mixture of diethyl fumarate (DEF), poly(propylene fumarate) (PPF), and a photoinitiator, bisacylphosphine oxide (BAPO). The PPF is crosslinked with the use of the SLA's UV laser (325-nm wavelength). An SLA device was retrofitted with a custom fixture build tank enclosing an elevator-driven build table. A 3D prototype model testing the manufacturing control this device provides was created in a computer-aided-design package. The resulting geometric data were used to drive the SLA process, and a DEF/PPF prototype part was successfully manufactured. These scaffolds have application in the tissue engineering of bony substrates. 相似文献
48.
J-L Stievenart EA Cabanis P Menard J Knoplioch A Lopez J Tamraz M-T Iba-Zizen B Philippe G Prevost J-C Bertrand 《Surgical and radiologic anatomy : SRA》1993,15(1):47-54
Summary In view of the variety of 3D representation techniques, a clinical study was carried out in order to evaluate their respective usefulness. It appears that a single technique cannot be claimed to be valid for all clinical situations and that a combination of representations brings more relevant information. Among the different techniques a clear delineation must be established between those which allow the accurate definition of landmarks (multiplanar reformation, surface representation), and those which do not (integral shading, reconstructed radiology). The main point is the possibility to recognize anatomical landmarks on these latter modes and to choose oblique cut planes in relation to them. Visualization quality is strongly dependent upon the acquisition protocol which must provide a spatial resolution as isotropic as possible.
Une revue de différents modes de visualisation en haute résolution d'un objet volumique avec des applications
Résumé Face à la variété des techniques de représentation 3D une étude clinique a été conduite pour évaluer leurs utilités respectives. Il apparait qu'une technique unique ne peut pas convenir à toutes les situations cliniques et qu'une combinaison de différents modes de présentation apporte une information plus pertinente. Parmi les différentes techniques une distinction claire doit être établie entre celles qui autorisent la prise de repères précis (reformatage multiplanaire, représentation de surface), et celles qui ne le permettent pas (ombrage intégral, radiologie reconstruite). Le point principal est la possibilité de reconnaître des repères anatomiques sur ces derniers modes et de choisir des plans de coupe en relation avec eux. La qualité de la visualisation dépend étroitement du protocole d'acquisition qui doit fournir une résolution aussi isotrope que possible.相似文献
49.
Thyroid autoimmunity 总被引:1,自引:0,他引:1
Antigenic structure remains a major focus in thyroid immunology. The genes for three major thyroid antigens--thyroglobulin, thyroid peroxidase and the thyrotropin receptor--were sequenced in the late 1980's, and epitopes for antibody and T cells have been reported within the last year. In addition, new evidence for selective use of T-cell receptor V gene segments in human thyroid infiltrates may point the way to specific immunotherapy. 相似文献
50.
Igarashi S; Takiyama Y; Cancel G; Rogaeva EA; Sasaki H; Wakisaka A; Zhou YX; Takano H; Endo K; Sanpei K; Oyake M; Tanaka H; Stevanin G; Abbas N; Durr A; Rogaev EI; Sherrington R; Tsuda T; Ikeda M; Cassa E; Nishizawa M; Benomar A; Julien J; Weissenbach J; Tsuji S 《Human molecular genetics》1996,5(7):923-932
Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative
disorder caused by unstable expansion of a CAG repeat in the MJD1 gene at
14q32.1. To identify elements affecting the intergenerational instability
of the CAG repeat, we investigated whether the CGG/GGG polymorphism at the
3' end of the CAG repeat affects intergenerational instability of the CAG
repeat. The [expanded (CAG)n-CGG]/[normal (CAG)n- GGG] haplotypes were
found to result in significantly greater instability of the CAG repeat
compared to the [expanded (CAG)n- CGG]/[normal (CAG)n-CGG] or [expanded
(CAG)nGGG]/[normal (CAG)n-GGG] haplotypes. Multiple stepwise logistic
regression analysis revealed that the relative risk for a large
intergenerational change in the number of CAG repeat units (< -2 or >
2) is 7.7-fold (95% CI: 2.5-23.9) higher in the case of paternal
transmission than in that of maternal transmission and 7.4-fold (95% CI:
2.4-23.3) higher in the case of transmission from a parent with the
[expanded (CAG)n-CGG]/[normal (CAG)n-GGG] haplotypes than in that of
transmission from a parent with the [expanded (CAG)n-CGG]/[normal
(CAG)n-CGG] or [expanded (CAG)n- GGG]/[normal (CAG)n-GGG] haplotypes. The
combination of paternal transmission and the [expanded (CAG)n-CGG]/[normal
(CAG)n-GGG] haplotypes resulted in a 75.2-fold (95% CI: 9.0-625.0) increase
in the relative risk compared with that of maternal transmission and the
[expanded (CAG)n-CGG]/[normal (CAG)n-CGG] or [expanded (CAG)n- GGG]/[normal
(CAG)n-GGG] haplotypes. The results suggest that an inter- allelic
interaction is involved in the intergenerational instability of the
expanded CAG repeat.
相似文献