全文获取类型
收费全文 | 29528篇 |
免费 | 2912篇 |
国内免费 | 2735篇 |
专业分类
耳鼻咽喉 | 106篇 |
儿科学 | 247篇 |
妇产科学 | 261篇 |
基础医学 | 3809篇 |
口腔科学 | 490篇 |
临床医学 | 1721篇 |
内科学 | 3105篇 |
皮肤病学 | 382篇 |
神经病学 | 1907篇 |
特种医学 | 578篇 |
外国民族医学 | 47篇 |
外科学 | 1756篇 |
综合类 | 7341篇 |
现状与发展 | 5篇 |
预防医学 | 877篇 |
眼科学 | 758篇 |
药学 | 4554篇 |
中国医学 | 2447篇 |
肿瘤学 | 4784篇 |
出版年
2024年 | 107篇 |
2023年 | 356篇 |
2022年 | 684篇 |
2021年 | 1004篇 |
2020年 | 882篇 |
2019年 | 790篇 |
2018年 | 713篇 |
2017年 | 1002篇 |
2016年 | 1075篇 |
2015年 | 1368篇 |
2014年 | 1575篇 |
2013年 | 2118篇 |
2012年 | 1893篇 |
2011年 | 2135篇 |
2010年 | 1868篇 |
2009年 | 1747篇 |
2008年 | 1921篇 |
2007年 | 2003篇 |
2006年 | 1893篇 |
2005年 | 1825篇 |
2004年 | 1648篇 |
2003年 | 1492篇 |
2002年 | 1223篇 |
2001年 | 1192篇 |
2000年 | 905篇 |
1999年 | 580篇 |
1998年 | 469篇 |
1997年 | 307篇 |
1996年 | 179篇 |
1995年 | 107篇 |
1994年 | 47篇 |
1993年 | 12篇 |
1992年 | 15篇 |
1991年 | 11篇 |
1990年 | 3篇 |
1989年 | 10篇 |
1988年 | 1篇 |
1987年 | 6篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
ThecoronaryarterycomplicationcouldbefoundinalmostalcasesofKawasakidisease[1].Ithasrecentlybeenshownthatplatelet-derivedgrowth... 相似文献
52.
53.
van den Eijnde SM Lips J Boshart L Vermeij-Keers C Marani E Reutelingsperger CP De Zeeuw CI 《The European journal of neuroscience》1999,11(2):712-724
Apoptosis is a critical cellular event during several stages of neuronal development. Recently, we have shown that biotinylated annexin V detects apoptosis in vivo in various cell lineages of a wide range of species by binding to phosphatidylserines that are exposed at the outer leaflet of the plasma membrane. In the present study, we tested the specificity by which annexin V binds apoptotic neurons, and subsequently investigated developmental cell death in the central and peripheral nervous system of early mouse embryos at both the cellular and histological level, and compared the phagocytic clearance of apoptotic neurons with that of apoptotic mesodermal cells. Our data indicate: (i) that biotinylated annexin V can be used as a sensitive marker that detects apoptotic neurons, including their extensions at an early stage during development; (ii) that apoptosis plays an important part during early morphogenesis of the central nervous system, and during early quantitative matching of brain-derived neurotrophic factor and neurotrophic factor 3 responsive postmitotic large clear neurons in the peripheral ganglia with their projection areas; and (iii) that apoptotic neurons are removed by a process that differs from classical phagocytosis of non-neuronal tissues. 相似文献
54.
55.
56.
Detection of drug-induced apoptosis by flow cytometry after alkaline extraction of ethanol fixed cells 总被引:5,自引:0,他引:5
Mihalik R Uher F Pocsik É Berczi L Benczur M Kopper L 《Pathology oncology research : POR》1996,2(1-2):78-83
A new flow cytometric method was developed to detect apoptotic cells with fragmented DNA and to determine cell cycle distribution
of viable cells, in the same sample, by propidium iodide staining. Apoptosis, in HT58 human B lymphoma cells, was induced
by etoposide and/or by staurosporine. Using appropriate alkaline solutions (between 1-10 mN NaOH in 150 mM saline) followed
by neutralization with buffer solution, the fragmented DNA can be extracted quantitatively from ethanol fixed cells. Further,
good resolution of the cell cycle distribution can be obtained in unimpaired cells without RNase treatment. Furthermore, unlike
the widely used hypotonic-detergent extraction of unfixed cells, the suggested extraction method can prevent drug-induced
disintegration of dead cells when karyorrhexis occurs.
This work was supported by Hungarian National Research Foundation (OTKA I/352 and OTKA II/2622). 相似文献
57.
Pellet JB Haefliger JA Staple JK Widmann C Welker E Hirling H Bonny C Nicod P Catsicas S Waeber G Riederer BM 《The European journal of neuroscience》2000,12(2):621-632
Islet-brain 1 (IB1) was recently identified as a DNA-binding protein of the GLUT2 gene promoter. The mouse IB1 is the rat and human homologue of the Jun-interacting protein 1 (JIP-1) which has been recognized as a key player in the regulation of c-Jun amino-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways. JIP-1 is involved in the control of apoptosis and may play a role in brain development and aging. Here, IB1 was studied in adult and developing mouse brain tissue by in situ hybridization, Northern and Western blot analysis at cellular and subcellular levels, as well as by immunocytochemistry in brain sections and cell cultures. IB1 expression was localized in the synaptic regions of the olfactory bulb, retina, cerebral and cerebellar cortex and hippocampus in the adult mouse brain. IB1 was also detected in a restricted number of axons, as in the mossy fibres from dentate gyrus in the hippocampus, and was found in soma, dendrites and axons of cerebellar Purkinje cells. After birth, IB1 expression peaks at postnatal day 15. IB1 was located in axonal and dendritic growth cones in primary telencephalon cells. By biochemical and subcellular fractionation of neuronal cells, IB1 was detected both in the cytosolic and membrane fractions. Taken together with previous data, the restricted neuronal expression of IB1 in developing and adult brain and its prominent localization in synapses suggest that the protein may be critical for cell signalling in developing and mature nerve terminals. 相似文献
58.
Induction of neuronal death by alpha-synuclein 总被引:9,自引:0,他引:9
Saha AR Ninkina NN Hanger DP Anderton BH Davies AM Buchman VL 《The European journal of neuroscience》2000,12(8):3073-3077
The molecular and cellular mechanisms underlying neuronal loss in neurodegenerative diseases are unclear. It is generally thought that aggregation of mutated, abnormally modified or abnormally folded proteins leads to the accumulation of extracellular, intracellular or intranuclear deposits that severely compromise cell physiology, leading to the death of the affected neurons. However, there is growing evidence that neuronal apoptosis in the absence of obvious pathological deposits could have a serious impact on the pathogenesis of neurodegenerative diseases. alpha-Synuclein has been implicated in aetiology and pathogenesis of certain neurodegenerative diseases, although the precise role of this protein in neurodegeneration is uncertain. The normal functions of alpha-synuclein and other members of the synuclein family in the development and function of the nervous system also remain elusive. Here we show that overexpression of wild-type and mutant forms of alpha-synuclein in cultured neurons, but not the closely related persyn (gamma-synuclein), causes apoptosis. These findings suggest that abnormalities of alpha-synuclein metabolism could lead to the neuronal loss occurring in certain forms of neurodegeneration before the formation of characteristic pathological lesions. 相似文献
59.
目的 :探讨雄激素对阴茎海绵体结构和功能的影响以及细胞凋亡与 NOS活性在阴茎勃起中的关系。方法 :将 30只成年雄性大白鼠随机分为 3组 ,阉割组、替代组及假手术组 ,阉割组与替代组分别切除双侧睾丸 ,其中替代组在切除睾丸后给予睾酮替代。于 1周后取阴茎海绵体 ,用紫外分光光度计测定其一氧化氮合酶 (NOS)活性 ,同时用 ISEL 法检测其细胞凋亡情况。结果 :阉割组海绵体 NOS活性下降 70 % ,并出现细胞凋亡 (P <0 .0 1) ,睾酮替代组和对照组 NOS活性及细胞凋亡差异无显著性 (P >0 .0 5 ) .结论 :雄激素可通过调节 NOS活性及细胞的增殖与凋亡而维持阴茎海绵体的结构与功能。 相似文献
60.
Salicylate enhances necrosis and apoptosis mediated by the mitochondrial permeability transition. 总被引:1,自引:0,他引:1
Onset of the mitochondrial permeability transition (MPT) causes both necrotic and apoptotic cell death in cultured hepatocytes. Salicylate lowers the threshold for onset of the MPT. In this study, our aim was to determine whether nontoxic concentrations of salicylate potentiate MPT-mediated cell killing. In necrotic killing models to rat hepatocytes, salicylate (1 mM) enhanced calcium ionophore (Br-A23187)- and tert-butylhydroperoxide (t-BuOOH)-induced cell death, which was blocked or delayed by cyclosporin A (CsA, 2 microM), a specific inhibitor of the MPT. In hepatocyte apoptosis induced by tumor necrosis factor-alpha (TNF-alpha), salicylate accelerated cell killing after low-dose TNF-alpha (1 ng/ml), which by itself induced little apoptosis. Salicylate enhancement of apoptosis was associated with onset of the MPT and accelerated caspase 3 activation. Salicylate also augmented killing of MCF-7 human breast tumor cells by etoposide and PLC/PRF/5 human hepatoma cells by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). In conclusion, salicylate potentiates both necrotic and apoptotic cell killing by promoting onset of the MPT. Enhancement by salicylate of MPT-dependent apoptosis may play a role in protection by aspirin and other nonsteroidal anti-inflammatory drugs against colon, lung, and breast cancer. 相似文献