全文获取类型
收费全文 | 208841篇 |
免费 | 17959篇 |
国内免费 | 7333篇 |
专业分类
耳鼻咽喉 | 1734篇 |
儿科学 | 3056篇 |
妇产科学 | 2415篇 |
基础医学 | 32631篇 |
口腔科学 | 3418篇 |
临床医学 | 15021篇 |
内科学 | 36734篇 |
皮肤病学 | 2926篇 |
神经病学 | 15781篇 |
特种医学 | 4738篇 |
外国民族医学 | 55篇 |
外科学 | 14512篇 |
综合类 | 27304篇 |
现状与发展 | 20篇 |
一般理论 | 6篇 |
预防医学 | 11148篇 |
眼科学 | 2080篇 |
药学 | 33578篇 |
44篇 | |
中国医学 | 8811篇 |
肿瘤学 | 18121篇 |
出版年
2023年 | 3615篇 |
2022年 | 4754篇 |
2021年 | 9280篇 |
2020年 | 7762篇 |
2019年 | 7153篇 |
2018年 | 6904篇 |
2017年 | 6665篇 |
2016年 | 6668篇 |
2015年 | 7898篇 |
2014年 | 12265篇 |
2013年 | 13742篇 |
2012年 | 12220篇 |
2011年 | 14505篇 |
2010年 | 12170篇 |
2009年 | 11823篇 |
2008年 | 11274篇 |
2007年 | 10347篇 |
2006年 | 9246篇 |
2005年 | 8097篇 |
2004年 | 6738篇 |
2003年 | 6045篇 |
2002年 | 4858篇 |
2001年 | 4023篇 |
2000年 | 3340篇 |
1999年 | 2925篇 |
1998年 | 2424篇 |
1997年 | 2386篇 |
1996年 | 2062篇 |
1995年 | 2094篇 |
1994年 | 1880篇 |
1993年 | 1636篇 |
1992年 | 1381篇 |
1991年 | 1284篇 |
1990年 | 1070篇 |
1989年 | 903篇 |
1988年 | 865篇 |
1987年 | 730篇 |
1986年 | 666篇 |
1985年 | 1409篇 |
1984年 | 1551篇 |
1983年 | 1129篇 |
1982年 | 1120篇 |
1981年 | 991篇 |
1980年 | 854篇 |
1979年 | 741篇 |
1978年 | 520篇 |
1977年 | 421篇 |
1976年 | 487篇 |
1975年 | 365篇 |
1974年 | 274篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Clémence Briand MD Louise Galmiche-Rolland MD Pierre Vabres MD PHD Vincent Couloigner MD PHD Severine Audebert MD Laurent Misery MD PHD Claire Abasq-Thomas MD 《Pediatric dermatology》2020,37(6):1128-1130
We report the case of a 5-year-old girl with congenital right-sided facial hemihypertrophy and right hemi-macroglossia with lingual mucosal neuromas. The segmental presentation of findings suggested the diagnosis of congenital infiltrating lipomatosis of the face (CILF), which belongs within the PIK3CA-related overgrowth spectrum (PROS). This was confirmed by genetic analysis showing a mosaic mutation in PIK3CA H1047R. CILF/PROS should be considered in the differential diagnosis of mucosal neuromas. 相似文献
992.
Viktória Koroknai István Szász Hector Hernandez-Vargas Nora Fernandez-Jimenez Cyrille Cuenin Zdenko Herceg Laura Vízkeleti Róza Ádány Szilvia Ecsedi Margit Balázs 《Experimental dermatology》2020,29(1):39-50
Tumor cell invasion is one of the key processes during cancer progression, leading to life-threatening metastatic lesions in melanoma. As methylation of cancer-related genes plays a fundamental role during tumorigenesis and may lead to cellular plasticity which promotes invasion, our aim was to identify novel epigenetic markers on selected invasive melanoma cells. Using Illumina BeadChip assays and Affymetrix Human Gene 1.0 microarrays, we explored the DNA methylation landscape of selected invasive melanoma cells and examined the impact of DNA methylation on gene expression patterns. Our data revealed predominantly hypermethylated genes in the invasive cells affecting the neural crest differentiation pathway and regulation of the actin cytoskeleton. Integrative analysis of the methylation and gene expression profiles resulted in a cohort of hypermethylated genes (IL12RB2, LYPD6B, CHL1, SLC9A3, BAALC, FAM213A, SORCS1, GPR158, FBN1 and ADORA2B) with decreased expression. On the other hand, hypermethylation in the gene body of the EGFR and RBP4 genes was positively correlated with overexpression of the genes. We identified several methylation changes that can have role during melanoma progression, including hypermethylation of the promoter regions of the ARHGAP22 and NAV2 genes that are commonly altered in locally invasive primary melanomas as well as during metastasis. Interestingly, the down-regulation of the methylcytosine dioxygenase TET2 gene, which regulates DNA methylation, was associated with hypermethylated promoter region of the gene. This can probably lead to the observed global hypermethylation pattern of invasive cells and might be one of the key changes during the development of malignant melanoma cells. 相似文献
993.
Coronavirus disease 2019 (COVID‐19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has become a global pandemic. Therefore, convenient, timely and accurate detection of SARS‐CoV‐2 is urgently needed. Here, we review the types, characteristics and shortcomings of various detection methods, as well as perspectives for the SARS‐CoV‐2 diagnosis. Clinically, nucleic acid‐based methods are sensitive but prone to false‐positive. The antibody‐based method has slightly lower sensitivity but higher accuracy. Therefore, it is suggested to combine the two methods to improve the detection accuracy of COVID‐19. 相似文献
994.
《Annales médico-psychologiques》2020,178(7):695-698
At the beginning of March 2020, South Africa (59 million inhabitants) was hit by the pandemic of COVID-19 and soon became the most affected country in Africa by the SARS-CoV-2 virus. From one single case on March 5th, the number of cases increased rapidly, forcing the South-African Government to swiftly react and place the country under strict lockdown for six weeks. The strategy of the South African Government bore fruits with a contained spread of the virus. If the number of positive cases at the end of the lockdown reached 5647, the number of fatal casualties was limited to 103 deaths. The lockdown was overall well respected, even if serious problems of food supply soon occurred in informal settlements, leading to riots and confrontation with security forces. Indeed, populations were obedient, but not being able to practice sport or outdoors activities appeared heavy. The constant fear of the poorest not to have enough money to pay rent and buy food (even if the Government organised food parcels’ distributions), and to find less and less work was echoed by the fear of losing jobs among those more privileged. Despite the risk of an economic crisis, the South African Government has continued on the reasonable path of containing the pandemic with ending the lockdown at a slow pace, in five phases. 相似文献
995.
996.
997.
Olfaction is critical for survival in neonatal mammals. However, little is known about the neural substrate for this ability as few studies of synaptic development in several olfactory processing regions have been reported. Odor information detected in the nasal cavity is first processed by the olfactory bulb and then sent via the lateral olfactory tract to a series of olfactory cortical areas. The first of these, the anterior olfactory nucleus pars principalis (AONpP), is a simple, two layered cortex with an outer plexiform and inner cell zone (Layers 1 and 2, respectively). Five sets of studies examined age-related changes in the AONpP. First, immunocytochemistry for glutamatergic (VGlut1 and VGlut2) and GABAergic (VGAT) synapses demonstrated that overall synaptic patterns remained uniform with age. The second set quantified synaptic development with electron microscopy and found different developmental patterns between Layers 1 and 2. As many of the interhemispheric connections in the olfactory system arise from AONpP, the third set examined the development of crossed projections using anterograde tracers and electron microscopy to explore the maturation of this pathway. A fourth study examined ontogenetic changes in immunostaining for the proteoglycans aggrecan and brevican, markers of mesh-like extracellular structures known as perineuronal nets whose maturation is associated with the end of early critical periods of synaptogenesis. A final study found no age-related changes in the density of vasculature in the peduncle from P5 to P30. This work is among the first to examine early postnatal changes in this initial cortical region of the olfactory system. 相似文献
998.
《Neurología (Barcelona, Spain)》2020,35(4):233-237
IntroductionThe COVID-19 epidemic has led to the need for unprecedented decisions to be made to maintain the provision of neurological care. This article addresses operational decision-making during the epidemic.DevelopmentWe report the measures taken, including the preparation of a functional reorganisation plan, strategies for hospitalisation and emergency management, the use of telephone consultations to maintain neurological care, provision of care at a unit outside the hospital for priority patients, decisions about complementary testing and periodic in-hospital treatments, and the use of a specific telephone service to prioritise patients with epileptic seizures.ConclusionDespite the situation of confinement, neurology departments must continue to provide patient care through different means of operation. Like all elements of management, these must be evaluated. 相似文献
999.
《Neurología (Barcelona, Spain)》2020,35(5):295-302
IntroductionIschaemic stroke has been reported in patients with COVID-19, particularly in more severe cases. However, it is unclear to what extent this is linked to systemic inflammation and hypercoagulability secondary to the infection.MethodsWe describe the cases of 4 patients with ischaemic stroke and COVID-19 who were attended at our hospital. Patients are classified according to the likelihood of a causal relationship between the hypercoagulable state and ischaemic stroke. We also conducted a review of studies addressing the possible mechanisms involved in the aetiopathogenesis of ischaemic stroke in these patients.ResultsThe association between COVID-19 and stroke was probably causal in 2 patients, who presented cortical infarcts and had no relevant arterial or cardioembolic disease, but did show signs of hypercoagulability and systemic inflammation in laboratory analyses. The other 2 patients were of advanced age and presented cardioembolic ischaemic stroke; the association in these patients was probably incidental.ConclusionsSystemic inflammation and the potential direct action of the virus may cause endothelial dysfunction, resulting in a hypercoagulable state that could be considered a potential cause of ischaemic stroke. However, stroke involves multiple pathophysiological mechanisms; studies with larger samples are therefore needed to confirm our hypothesis. The management protocol for patients with stroke and COVID-19 should include a complete aetiological study, with the appropriate safety precautions always being observed. 相似文献
1000.
Pinar Eser Ocak Umut Ocak Prativa Sherchan John H. Zhang Jiping Tang 《Journal of neuroscience research》2020,98(1):29-41
Major facilitator superfamily domain-containing protein-2a (Mfsd2a) which was considered as an orphan transporter has recently gained attention for its regulatory role in the maintenance of proper functioning of the blood–brain barrier. Besides the major role of Mfsd2a in maintaining the barrier function, increasing evidence has emerged with regard to the contributions of Mfsd2a to various biological processes such as transport, cell fusion, cell cycle, inflammation and regeneration, managing tumor growth, functioning of other organs with barrier functions or responses to injury. The purpose of this article is to review the different roles of Mfsd2a and its involvement in the physiological and pathophysiological processes primarily in the central nervous system and throughout the mammalian body under the lights of the current literature. 相似文献