全文获取类型
收费全文 | 6862篇 |
免费 | 358篇 |
国内免费 | 59篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 60篇 |
妇产科学 | 55篇 |
基础医学 | 763篇 |
口腔科学 | 214篇 |
临床医学 | 458篇 |
内科学 | 1930篇 |
皮肤病学 | 100篇 |
神经病学 | 497篇 |
特种医学 | 415篇 |
外科学 | 1318篇 |
综合类 | 41篇 |
预防医学 | 163篇 |
眼科学 | 162篇 |
药学 | 420篇 |
中国医学 | 6篇 |
肿瘤学 | 581篇 |
出版年
2023年 | 35篇 |
2022年 | 110篇 |
2021年 | 165篇 |
2020年 | 74篇 |
2019年 | 141篇 |
2018年 | 141篇 |
2017年 | 125篇 |
2016年 | 126篇 |
2015年 | 131篇 |
2014年 | 166篇 |
2013年 | 254篇 |
2012年 | 392篇 |
2011年 | 415篇 |
2010年 | 246篇 |
2009年 | 218篇 |
2008年 | 378篇 |
2007年 | 362篇 |
2006年 | 341篇 |
2005年 | 378篇 |
2004年 | 310篇 |
2003年 | 343篇 |
2002年 | 310篇 |
2001年 | 161篇 |
2000年 | 163篇 |
1999年 | 176篇 |
1998年 | 68篇 |
1997年 | 43篇 |
1996年 | 46篇 |
1995年 | 40篇 |
1994年 | 45篇 |
1993年 | 35篇 |
1992年 | 112篇 |
1991年 | 115篇 |
1990年 | 121篇 |
1989年 | 111篇 |
1988年 | 103篇 |
1987年 | 118篇 |
1986年 | 97篇 |
1985年 | 107篇 |
1984年 | 45篇 |
1983年 | 44篇 |
1982年 | 23篇 |
1981年 | 24篇 |
1979年 | 44篇 |
1978年 | 22篇 |
1977年 | 36篇 |
1974年 | 24篇 |
1971年 | 20篇 |
1970年 | 19篇 |
1969年 | 19篇 |
排序方式: 共有7279条查询结果,搜索用时 15 毫秒
71.
Tetsuichiro Inai Akihito Sengoku Eiji Hirose Hiroshi Iida Yosaburo Shibata 《Anatomical record (Hoboken, N.J. : 2007)》2007,290(11):1431-1438
Claudins are integral membrane proteins at tight junctions (TJs) and form TJ strands. In the present study, we found that claudin‐7 was localized along the entire lateral membranes of epididymal epithelium, including the apical junctional region throughout the epididymis, but claudin‐8 was restricted to the apical junctional region. This finding raises the possibility that aberrant TJ strands may be formed on lateral membranes. Thus, we focused on examining whether TJ strands exist on lateral membranes of epididymal epithelium. Freeze‐fracture electron microscopy showed that aberrant TJ strands were observed in only a few principal cells in all segments of the epididymis except for the initial segment, indicating that the occurrence of aberrant strands is very rare. Aberrant TJ strands were smooth and not subdivided into individual particles in the protoplasmic face, and complementary grooves in the extracellular face were almost free of particles. Aberrant TJ strands in the distal caput and corpus epididymis were accompanied by many vesicle‐like structures but those in the proximal caput and cauda epididymis were not. These results suggest that most of claudin‐7 in lateral membranes may exist in a nonpolymerized form and may play some different roles other than the formation of TJ strands, for example, in the formation of a pool of claudin proteins or in the reinforcement of cell adhesion. Anat Rec, 1431‐1438, 2007. © 2007 Wiley‐Liss, Inc. 相似文献
72.
73.
Masuda Y Kim SK Kato T Iida S Yoshida A Tachibana Y Morimoto T 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2005,161(3):397-404
The cortical masticatory area (CMA) elicits rhythmic jaw movements in response to repetitive stimulation and is involved in the control of mastication. Based on jaw movement patterns, the CMA is divided into two parts. One is the part of the CMA in which a T-pattern similar to jaw movements during food transport in natural mastication is evoked by electrical stimulation. The other is more dorsomedially located, and during chewing a C-pattern similar to jaw movements can be induced. However, it is still not known which region of the putamen receives projections from the CMA and whether projections originate from both parts of the CMA. In this study, electrophysiological and histological experiments were undertaken in rabbits to investigate projections from the CMA to the putamen. Both experiments showed that the ventral region of the putamen received projections from the CMA. The density of the projections from the CMA area inducing the T-pattern seemed to be higher than that from the area inducing the C-pattern. Furthermore, the peak latency of the evoked potentials from stimulation of the CMA area inducing the T-pattern was shorter than that from stimulation of the area inducing the C-pattern. The data obtained from the present study indicate the functional role of the ventral region of the putamen in the regulation of mastication, and further suggest that the corticostriatal pathway is involved in the transition between behavioral jaw movement patterns. 相似文献
74.
Crucial role of donor-derived stromal cells in successful treatment for intractable autoimmune diseases in mrl/lpr mice by bmt via portal vein 总被引:8,自引:0,他引:8
Kushida T Inaba M Hisha H Ichioka N Esumi T Ogawa R Iida H Ikehara S 《Stem cells (Dayton, Ohio)》2001,19(3):226-235
We have recently established a new bone marrow transplantation (BMT) method for the treatment of intractable autoimmune diseases in MRL/lpr mice; the method consists of fractionated irradiation (5.5 Gy x 2), followed by BMT of whole bone marrow cells (BMCs) from allogeneic C57BL/6 mice via the portal vein (abbreviated as 5.5 Gy x 2 + PV). In the present study, we investigate the mechanisms underlying the early engraftment of donor-derived cells in MRL/lpr mice by this method. In the mice treated with this method, the number of donor-derived cells possessing the mature lineage (Lin) markers rapidly increased in the BM, spleen, and liver; almost 100% were donor-derived cells by 14 days after the treatment. The number of donor-derived hemopoietic progenitor cells (defined as c-kit(+)/Lin(-) cells) increased in the BMCs, hepatic mononuclear cells, and especially spleen cells by 14 days after the treatment. Simultaneously, hemopoietic foci adjoining donor-derived stromal cells were observed in the liver when injected via the PV, but not via the peripheral vein (i.v.). When adherent cell-depleted BMCs were injected via the PV, recipients showed a marked reduction in the survival rate. However, when mice were transplanted with adherent cell-depleted BMCs with cultured stromal cells, all the recipients survived. These findings suggest that not only donor hematopoietic stem cells (HSCs) but also donor stromal cells administered via the PV were trapped in the liver, resulting in the early engraftment of donor HSCs in cooperation with donor-derived stromal cells. This new strategy to facilitate the early recovery of hemopoiesis would therefore be of great advantage in human application. 相似文献
75.
Assarsson E Kambayashi T Persson CM Ljunggren HG Chambers BJ 《Molecular immunology》2005,42(4):419-423
NK cells have primarily been defined by their ability to kill infected cells, tumor cells and some normal cells expressing low levels of MHC class I molecules. NK cells have also been shown to affect adaptive immune responses by their production of both pro- and anti-inflammatory cytokines. Recently it has been shown that adaptive immune responses can be enhanced or maintained also through direct lymphocyte-lymphocyte interactions. One of these interactions was identified to occur between 2B4 and CD48, where 2B4 acted as a co-stimulatory ligand for both NK cells and T cells. In the current article, we discuss the role of 2B4 in the development of adaptive immune responses and the role of NK-T cell interactions in these responses. 相似文献
76.
Unique properties of fetal lymphoid progenitors identified according to RAG1 gene expression 总被引:3,自引:0,他引:3
Yokota T Kouro T Hirose J Igarashi H Garrett KP Gregory SC Sakaguchi N Owen JJ Kincade PW 《Immunity》2003,19(3):365-375
RAG1/GFP knockin mice were exploited to isolate and characterize fetal lymphoid progenitors. CD11b and IL-7Ralpha are expressed in a developmental stage-dependent fashion, revealing how substantial numbers of early lymphoid progenitors were discarded or neglected in previous studies. The myeloerythroid potential of fetal progenitors in clonal assays declined in synchrony with activation of the RAG1 locus but was not completely extinguished. Lymphoid differentiation corresponded to patterns of gene expression previously found for adult marrow, but no fraction of fetal liver was enriched with respect to B + T progenitors. Also, unlike adults, fetal lymphoid progenitors transiently expressed endothelial cell markers. These findings help to reconcile discrepancies in previous reports and suggest that the fetal immune system arises via unique mechanisms. 相似文献
77.
Shikata K Kukita Y Matsumoto T Esaki M Yao T Mochizuki Y Hayashi K Iida M 《American journal of medical genetics. Part A》2005,134(3):326-329
We treated a 39-year-old woman with hypoproteinemia and anemia who had profuse gastric polyposis. Radiographic and endoscopic examination showed numerous polyps restricted to the stomach. The patient had pulmonary arteriovenous malformations in the left lung. Histological examination of the resected stomach revealed the gastric polyposis to be composed of cystic dilatation of the glands with small areas of adenocarcinoma. These findings were compatible with gastric juvenile polyposis (GJP) accompanied by gastric cancer. Analysis of genomic DNA revealed that the patient had truncating mutation of SMAD4, a responsible gene for juvenile polyposis (JP). Our case suggests that SMAD4 is possibly a responsible gene for GJP. 相似文献
78.
Sekigawa I Matsushita M Lee S Maeda N Ogasawara H Kaneko H Iida N Hashimoto H 《Autoimmunity》2000,33(1):37-44
Current investigations into the role of CD8+ T cells and their derived cytokine, interleukin (IL)-16, in the induction of CD4+ T cell abnormalities in systemic lupus erythematosus (SLE) were reviewed and discussed on the basis of results mainly obtained in our laboratory. 相似文献
79.
80.
Masahiro Kamouchi Takanari KitazonoTetsuro Ago Masanori WakisakaJunya Kuroda Kuniyuki NakamuraNoriko Hagiwara Hiroaki OoboshiSetsuro Ibayashi Mitsuo Iida 《Neuroscience letters》2007
Objective: The aims of the present study were to elucidate the interaction of reactive oxygen species (ROS) and Ca2+ response in central nervous system (CNS) pericytes. Methods: The intracellular Ca2+ concentration was measured using fluorescent Ca2+ indicator, fura-2, in cultured CNS pericytes. Results: Hydrogen peroxide evoked a dose-dependent increase in cytosolic Ca2+, which was completely inhibited by catalase. Removal of external Ca2+ or addition of nicardipine (1 μM) during application of hydrogen peroxide did not affect Ca2+ response. Incubation of the cells in Ca2+ free solution did not abolish but slightly reduced Ca2+ response by hydrogen peroxide. Ca2+ response to hydrogen peroxide was not altered by the depletion of intracellular Ca2+ by thapsigargin (1 μM). Pretreatment of the cells with tyrosine kinase inhibitor genistein (100 μM) or tyrphostin A47 (30 μM) significantly reduced Ca2+ increase by hydrogen peroxide. Conclusions: These results indicate that hydrogen peroxide evokes Ca2+ increase predominantly by release from intracellular Ca2+ store, which may be regulated by tyrosine kinases. 相似文献