全文获取类型
收费全文 | 18749篇 |
免费 | 1163篇 |
国内免费 | 181篇 |
专业分类
耳鼻咽喉 | 174篇 |
儿科学 | 427篇 |
妇产科学 | 449篇 |
基础医学 | 2743篇 |
口腔科学 | 708篇 |
临床医学 | 2246篇 |
内科学 | 3921篇 |
皮肤病学 | 374篇 |
神经病学 | 1745篇 |
特种医学 | 585篇 |
外科学 | 1870篇 |
综合类 | 153篇 |
一般理论 | 9篇 |
预防医学 | 1779篇 |
眼科学 | 274篇 |
药学 | 1461篇 |
中国医学 | 108篇 |
肿瘤学 | 1067篇 |
出版年
2024年 | 19篇 |
2023年 | 185篇 |
2022年 | 245篇 |
2021年 | 489篇 |
2020年 | 308篇 |
2019年 | 521篇 |
2018年 | 699篇 |
2017年 | 501篇 |
2016年 | 542篇 |
2015年 | 707篇 |
2014年 | 773篇 |
2013年 | 1097篇 |
2012年 | 1609篇 |
2011年 | 1642篇 |
2010年 | 791篇 |
2009年 | 671篇 |
2008年 | 1198篇 |
2007年 | 1259篇 |
2006年 | 1151篇 |
2005年 | 1072篇 |
2004年 | 1021篇 |
2003年 | 911篇 |
2002年 | 834篇 |
2001年 | 146篇 |
2000年 | 125篇 |
1999年 | 119篇 |
1998年 | 131篇 |
1997年 | 113篇 |
1996年 | 125篇 |
1995年 | 82篇 |
1994年 | 65篇 |
1993年 | 60篇 |
1992年 | 64篇 |
1991年 | 56篇 |
1990年 | 64篇 |
1989年 | 53篇 |
1988年 | 54篇 |
1987年 | 47篇 |
1986年 | 48篇 |
1985年 | 43篇 |
1984年 | 54篇 |
1983年 | 33篇 |
1982年 | 40篇 |
1981年 | 51篇 |
1980年 | 38篇 |
1979年 | 22篇 |
1978年 | 17篇 |
1977年 | 17篇 |
1976年 | 16篇 |
1975年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
Genetic relationship between Streptococcus pneumoniae isolates from nasopharyngeal and cerebrospinal fluid of two infants with Pneumococcal Meningitis
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
de Andrade AL Pimenta FC Brandileone MC Laval CA Guerra ML de Andrade JG Di Fabio JL 《Journal of clinical microbiology》2003,41(8):3970-3972
The molecular epidemiology of Streptococcus pneumoniae isolates from carriage and cerebrospinal fluid (CSF) concurrently recovered from the same individual has not yet been reported. By using pulsed-field gel electrophoresis, we demonstrated the genetic linkage among strains from CSF and nasopharynges of two children with pneumococcal meningitis. 相似文献
72.
Performance of a commercial, type-specific enzyme-linked immunosorbent assay for detection of herpes simplex virus type 2-specific antibodies in Ugandans
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Laeyendecker O Henson C Gray RH Nguyen RH Horne BJ Wawer MJ Serwadda D Kiwanuka N Morrow RA Hogrefe W Quinn TC 《Journal of clinical microbiology》2004,42(4):1794-1796
Two hundred forty-eight human immunodeficiency virus (HIV)-positive and 496 HIV-negative subjects in Uganda were tested by HerpeSelect herpes simplex virus type 2 enzyme-linked immunosorbent assay (ELISA) and Western blotting to optimize the ELISA for use in this population. A higher index cutoff value was required for optimal sensitivity and specificity, and overall performance of the assay was not affected by HIV status. 相似文献
73.
George Capone Mary Stephens Stephanie Santoro Brian Chicoine Peter Bulova Moya Peterson Joan Jasien Anna Jo Smith Down Syndrome Medical Interest Group Adult Health Workgroup 《American journal of medical genetics. Part A》2020,182(7):1832-1845
Adults with Down syndrome (DS) represent a unique population who are in need of clinical guidelines to address their medical care. Many of these conditions are of public health importance with the potential to develop screening recommendations to improve clinical care for this population. Our workgroup previously identified and prioritized co‐occurring medical conditions in adults with DS. In this study, we again performed detailed literature searches on an additional six medical conditions of clinical importance. A series of key questions (KQ) were formulated a priori to guide the literature search strategy. Our KQs focused on disease prevalence, severity, risk‐factors, methodologies for screening/evaluation, impact on morbidity, and potential costs/benefits. The available evidence was extracted, evaluated and graded on quality. The number of participants and the design of clinical studies varied by condition and were often inadequate for answering most of the KQ. Based upon our review, we provide a summary of the findings on hip dysplasia, menopause, acquired cardiac valve disease, type 2 diabetes mellitus, hematologic disorders, and dysphagia. Minimal evidence demonstrates significant gaps in our clinical knowledge that compromises clinical decision‐making and management of these medically complex individuals. The creation of evidence‐based clinical guidance for this population will not be possible until these gaps are addressed. 相似文献
74.
Van Roy N Van Gele M Vandesompele J Messiaen L Van Belle S Sciot R Mortéle K Gyselinck J Michiels E Forsyth R Van Marck E De Paepe A Speleman F 《Cancer Genetics and Cytogenetics》2003,143(2):120-124
Malignant peripheral nerve sheath tumors (MPNST) are rare soft-tissue malignancies. The genetic basis of these tumors is still poorly understood. Cytogenetic analyses predominantly revealed complex karyotypes, precluding the identification of recurrent chromosomal changes. We report loss of 1p material in a near-diploid karyotype with few or no additional structural chromosome changes in two sporadic cases of MPNST, indicating an important role of 1p loss in MPNST development. In one of these two tumors, a distal 1p deletion (1p31.2 approximately pter) was detected suggesting involvement of a tumor suppressor gene located within this distal region of 1p. Further evidence for recurrent 1p loss in MPNST was obtained by interphase fluorescence in situ hybridization, which showed loss of 1p material in 3 out of 13 tumors. These findings together with data from the literature suggest that loss of a tumor suppressor gene located within distal 1p is implicated in the pathogenesis of MPNST. 相似文献
75.
Regulation of gelatinase B in human monocytic and endothelial cells by PECAM-1 ligation and its modulation by interferon-beta. 总被引:1,自引:0,他引:1
Inge Nelissen Isabelle Ronsse Jo Van Damme Ghislain Opdenakker 《Journal of leukocyte biology》2002,71(1):89-98
Platelet endothelial cell adhesion molecule-1 (PECAM-1 or CD31) and gelatinase B are coexpressed at sites of inflammation, where an intense interaction occurs between leukocytes and endothelial cells. To investigate whether a functional link exists between PECAM-1 activation and gelatinase B production, the regulatory role of PECAM-1, IFN-gamma, IFN-beta, LPS, and PMA on the production of gelatinase B (MMP-9) was studied in vitro in normal human umbilical vein endothelial cells (HUVECs), human peripheral blood mononuclear cells (PBMCs), and in a human monocytic leukemia cell line. In THP-1 cells, progelatinase B levels were slightly up-regulated by immobilized PECAM-1-specific monoclonal antibody (mAb) and soluble recombinant PECAM-1 when compared with strong induction by LPS and PMA. IFN-beta inhibited the induced and basal gelatinase B production but had no modulating effect on the expression of PECAM-1. HUVECs mainly produced progelatinase A (proMMP-2). Treatment with LPS and triggering of the endothelial cells with PECAM-1 mAb or recombinant PECAM-1 had no effect on gelatinase A or B production, whereas PMA stimulated the production of progelatinase B. IFN-beta significantly up-regulated the expression of PECAM-1 in HUVECs but did not affect gelatinase secretion. Finally, in PBMCs, progelatinase B production was increased by soluble PECAM-1 mAb, recombinant PECAM-1, LPS, and PMA, whereas IFN-beta reduced gelatinase B secretion. IFN-beta did not alter PECAM-1 expression on PBMCs. Thus, PECAM-1 and gelatinase B are differently regulated in leukocytes and endothelial cells. 相似文献
76.
Pinheiro PS Rodrigues RJ Silva AP Cunha RA Oliveira CR Malva JO 《Neuroscience letters》2003,336(2):97-100
Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors have been identified mostly as postsynaptic receptors mediating fast glutamatergic synaptic transmission. However, neurochemical studies based on the modulation of neurotransmitter release have suggested the existence of presynaptic AMPA receptors. We have used a recently described technique that allows a high-purity fractionation of the pre- and postsynaptic proteins of synaptic junctions to evaluate the distribution of the different AMPA receptor subunits in rat hippocampal synapses. Surprisingly, we found very high levels of GluR1- and GluR2/3-like immunoreactivity in the presynaptic fraction, but also in the postsynaptic and extrasynaptic fractions. GluR4-like immunoreactivity was much less abundant but was still detected, predominantly in the postsynaptic fraction. This methodology appears to be far more sensitive than the classical immunogold electron microscopy to determine the localization of synaptic receptors. 相似文献
77.
Impairment of a cortical event-related desynchronisation during a bimanual load-lifting task in children with autistic disorder 总被引:1,自引:0,他引:1
In autism, the abilities of communication are affected, associated with abnormalities of cognitive, sensorial and motor development. In a previous study based on a load-lifting task, we showed impairment of anticipation in children with autism as evidenced by kinematics and eletromyographic recordings [Neurosci. Lett. 348 (2003) 17]. In the present study, we assessed the cortical counterparts of the use of anticipatory postural adjustments in a group of control children and in a group of children with autism. The tasks required maintaining a stable forearm position despite imposed or voluntary lifting of an object placed either on the controlateral forearm or on a support. We investigated the differences between the two groups of children on the Event-Related Desynchronisation (ERD) which precedes movement onset in adults [Electroencephalogr. Clin. Neurophysiol. 46 (1979) 138]. Electroencephalogram (EEG) power evolution of a 6-8-Hz frequency band was averaged before and after imposed or voluntary movement onset. EEG reactivity of control and autistic children did not differ during the imposed unloading condition, but significant differences appeared in the voluntary unloading situations. Before lifting the object, control children showed an ERD above the left motor areas. An ERD also occurred above the right motor areas when the object was placed on their forearm. This indicates that the ERD can also translate the use of anticipatory postural adjustments. By contrast, children with autism did not show an ERD in the two voluntary situations. This suggests a central deficit of anticipation in both postural and motor control in children with autism. 相似文献
78.
Inhibition of CDK activity and PCNA-dependent DNA replication by p21 is blocked by interaction with the HPV-16 E7 oncoprotein
下载免费PDF全文
![点击此处可从《Genes & development》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jens Oliver Funk Shou Waga Jo Beth Harry Erik Espling Bruce Stillman Denise A. Galloway 《Genes & development》1997,11(16):2090-2100
p21 inhibits cyclin-dependent kinase (CDK) activity and proliferating cell nuclear antigen (PCNA)-dependent DNA replication by binding to CDK/cyclin complexes and to PCNA through distinct domains. The human papillomavirus (HPV)-16 E7 oncoprotein (16E7) abrogated a DNA damage-induced cell cycle arrest in vivo, despite high levels of p21. Using cell lysates and purified proteins we show that 16E7 prevented p21 both from inhibiting CDK2/cyclin E activity and PCNA-dependent DNA replication, whereas the nononcogenic HPV-6 E7 had reduced effects. Inactivation of both inhibitory functions of p21 was attained through binding between 16E7 and sequences in the carboxy-terminal end of p21 that overlap with the PCNA-binding site and the second p21 cyclin-binding motif. These data imply that the carboxyl terminus of p21 simultaneously modulates both CDK activity and PCNA-dependent DNA replication and that a single protein, 16E7, can override this modulation to disrupt normal cell cycle control. 相似文献
79.
Objectives. The aims of the study were to examine the reliability of the Dutch and French versions of the Tampa scale kinesiophobia (TSK) version chronic fatigue syndrome (CFS), and to examine the reliability and validity of the Dutch and French versions of the CFS symptom list. Design. Repeated‐measures design. Methods. Native Dutch speakers (N=100) and native French (N=48) speakers fulfilling the diagnostic criteria for CFS were asked to list the five most important symptoms and to complete the TSK–CFS, the CFS symptom list, and the Short Form 36 Health Status Survey or SF‐36. A modified version of the TSK–CFS and the CFS symptom list was filled in within 24 hours of the first assessment. Results. The French and Dutch version of the TSK–CFS and CFS symptom lists displayed good reliability (ICC≥.83). The CFS symptom list was internally consistent (Cronbach's α≥.93) and concurrently valid with the SF‐36. For the native Dutch and French speakers, respectively, 82 and 78% of the self‐reported symptoms matched the content of CFS symptom list. Conclusions. The results are in support of the psychometric properties of the French and Dutch versions of both the TSK–CFS and the CFS symptom list for assessing kinesiophobia and symptom severity, respectively. 相似文献
80.
Faucherre A Desbois P Nagano F Satre V Lunardi J Gacon G Dorseuil O 《Human molecular genetics》2005,14(11):1441-1448
Oculocerebrorenal Lowe syndrome is a rare X-linked disorder characterized by bilateral cataract, mental retardation and renal Fanconi syndrome. The Lowe syndrome protein Ocrl1 is a PIP2 5-phosphatase, primarily localized to the trans-Golgi network (TGN), which 'loss of function' mutations result in PIP2 accumulation in patient's cells. Although PIP2 is involved in many cell functions including signalling, vesicle trafficking and actin polymerization, it has been difficult so far to decipher molecular/cellular mechanisms responsible for Lowe syndrome phenotype. We have recently shown that, through its C-terminal RhoGAP domain, Ocrl1 forms a stable complex with Rac GTPase within the cell. In line with this finding, we report here that upon epidermal growth factor induced Rac activation in COS-7 cells, a fraction of Ocrl1 translocates from TGN to plasma membrane and concentrates in membrane ruffles. In order to investigate the functionality of Ocrl1 in plasma membrane, we have analysed PIP2 distribution in human dermal fibroblasts (HDFs) from Lowe patients versus control HDFs. As revealed by both immunodetection and green fluorescent protein-PH binding, PIP2 was found strikingly to accumulate in PDGF induced ruffles in Lowe HDFs when compared with control. This suggests that Ocrl1 is active as a PIP2 5-phosphatase in Rac induced membrane ruffles. Cellular properties such as cell migration and establishment of cell-cell contacts, which depend on ruffling and lamellipodia formation, should be further investigated to understand the pathophysiology of Lowe syndrome. 相似文献