全文获取类型
收费全文 | 12886篇 |
免费 | 765篇 |
国内免费 | 86篇 |
专业分类
耳鼻咽喉 | 93篇 |
儿科学 | 326篇 |
妇产科学 | 321篇 |
基础医学 | 1821篇 |
口腔科学 | 277篇 |
临床医学 | 1005篇 |
内科学 | 3178篇 |
皮肤病学 | 160篇 |
神经病学 | 1741篇 |
特种医学 | 458篇 |
外科学 | 1169篇 |
综合类 | 24篇 |
一般理论 | 4篇 |
预防医学 | 691篇 |
眼科学 | 249篇 |
药学 | 998篇 |
中国医学 | 33篇 |
肿瘤学 | 1189篇 |
出版年
2024年 | 29篇 |
2023年 | 185篇 |
2022年 | 329篇 |
2021年 | 558篇 |
2020年 | 319篇 |
2019年 | 444篇 |
2018年 | 492篇 |
2017年 | 377篇 |
2016年 | 446篇 |
2015年 | 457篇 |
2014年 | 659篇 |
2013年 | 781篇 |
2012年 | 1064篇 |
2011年 | 1140篇 |
2010年 | 637篇 |
2009年 | 558篇 |
2008年 | 814篇 |
2007年 | 779篇 |
2006年 | 773篇 |
2005年 | 702篇 |
2004年 | 553篇 |
2003年 | 473篇 |
2002年 | 417篇 |
2001年 | 54篇 |
2000年 | 50篇 |
1999年 | 75篇 |
1998年 | 64篇 |
1997年 | 55篇 |
1996年 | 51篇 |
1995年 | 38篇 |
1994年 | 39篇 |
1993年 | 27篇 |
1992年 | 29篇 |
1991年 | 31篇 |
1990年 | 33篇 |
1989年 | 29篇 |
1988年 | 28篇 |
1987年 | 22篇 |
1986年 | 22篇 |
1985年 | 11篇 |
1984年 | 15篇 |
1983年 | 15篇 |
1982年 | 6篇 |
1981年 | 14篇 |
1980年 | 6篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1967年 | 2篇 |
1966年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Stefania Barozzi Daniela Soi Elisabetta Intieri Marisa Giani Mirko Aldè Eleonora Tonon Lia Signorini Alessandra Renieri Chiara Fallerini Paola Perin Giovanni Montini Umberto Ambrosetti 《American journal of medical genetics. Part A》2020,182(10):2345-2358
Alport syndrome (AS) is caused by mutations in collagen IV, which is widespread in the basement membranes of many organs, including the kidneys, eyes, and ears. Whereas the effects of collagen IV changes in the cochlea are well known, no changes have been described in the posterior labyrinth. The aim of this study was to investigate both the auditory and the vestibular function of a group of individuals with AS. Seventeen patients, aged 9–52, underwent audiological tests including pure‐tone and speech audiometry, immittance test and otoacoustic emissions and vestibular tests including video head impulse test, rotatory test, and vestibular evoked myogenic potentials. Hearing loss affected 25% of the males and 27.3% of the females with X‐linked AS. It was sensorineural with a cochlear localization and a variable severity. 50% of the males and 45.4% of the females had a hearing impairment in the high‐frequency range. Otoacoustic emissions were absent in about one‐third of the individuals. A peripheral vestibular dysfunction was present in 75% of the males and 45.4% of the females, with no complaints of vertigo or dizziness. The vestibular impairment was compensated and the vestibulo‐ocular reflex asymmetry was more evident in rotatory tests carried out at lower than higher speeds; a vestibular hypofunction was present in all hearing impaired ears although it was also found in subjects with normal hearing. A posterior labyrinth injury should be hypothesized in AS even when the patient does not manifest hearing disorders or evident signs of renal failure. 相似文献
82.
83.
Mario Cocco Cristiana Bellan Roxane Tussiwand Davide Corti Elisabetta Traggiai Stefano Lazzi Susanna Mannucci Lucio Bronz Nazzareno Palummo Chiara Ginanneschi Piero Tosi Antonio Lanzavecchia Markus G. Manz Lorenzo Leoncini 《The American journal of pathology》2008,173(5):1369-1378
Recent studies suggest that Epstein-Barr virus (EBV) can infect naïve B cells, driving them to differentiate into resting memory B cells via the germinal center reaction. This hypothesis has been inferred from parallels with the biology of normal B cells but has never been proven experimentally. Rag2−/− γc−/− mice that were transplanted with human CD34+ cord blood cells as newborns were recently shown to develop human B, T, and dendritic cells, constituting lymphoid organs in situ. Here we used this model to better define the strategy of EBV infection of human B cells in vivo and to compare this model system with different conditions of EBV infection in humans. Our results support the model of EBV persistence in vivo in cases that were characterized by follicular hyperplasia and a relatively normal CD4+ and CD8+ T-cell distribution. Intriguingly, in cases that were characterized by nodular and diffuse proliferation with a preponderance of CD8+ T cells, similar to infectious mononucleosis, EBV still infects naïve B cells but also induces clonal expansion and ongoing somatic mutations without germinal center reactions. Our results reveal different strategies of EBV infection in B cells that possibly result from variations in the host immune response. Future experiments might allow understanding of the mechanisms responsible for persistent EBV infection and provide targets for more highly tailored therapeutic interventions. 相似文献
84.
Selected pool of peptides from ESAT-6 and CFP-10 proteins for detection of Mycobacterium tuberculosis infection 总被引:6,自引:0,他引:6
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)
Scarpellini P Tasca S Galli L Beretta A Lazzarin A Fortis C 《Journal of clinical microbiology》2004,42(8):3469-3474
We have validated a new test for detecting Mycobacterium tuberculosis infection. A pool of synthetic peptides derived from ESAT-6 and CFP-10 proteins was used to detect the number of specific gamma interferon-producing T cells by means of an enzyme-linked immunospot assay. Sixty-eight individuals positive for M. tuberculosis infection, either human immunodeficiency virus-seropositive or -seronegative, were studied. The test results were highly specific (87.5%) and sensitive (93.1%), more so than a classical lymphoproliferative assay (specificity and sensitivity of 77.27%), opening new possibilities for diagnosis and screening of tuberculosis. Moreover, the test allowed us to distinguish individuals infected with M. tuberculosis from those vaccinated with BCG. 相似文献
85.
Evaluation of the VITEK 2 System for Rapid Identification of Medically Relevant Gram-Negative Rods 总被引:2,自引:12,他引:2
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)
Guido Funke Dominique Monnet Chiara deBernardis Alexander von Graevenitz Jean Freney 《Journal of clinical microbiology》1998,36(7):1948-1952
The new VITEK 2 system (bioMérieux) was evaluated at two independent sites with the identification card for gram-negative bacilli (ID-GNB card). Of the 845 strains tested, which represented 70 different taxa belonging to either the family Enterobacteriaceae or the nonenteric bacilli, 716 (84.7%) were correctly identified at the species level. Thirty-two (3.8%) additional strains were identified to the species level after the performance of simple, rapid manual tests (oxidase, hemolysis, indole reaction, motility, and pigmentation). For 80 (9.5%) strains, these additional tests did not lead to an identification at the species level but the correct species identification was given among the organisms listed. Only 7 (0.8%) strains were misidentified, and 10 (1.2%) were not identified. Mistakes were randomly distributed over different taxa. Due to the new, more sensitive fluorescence-based technology of the VITEK 2 system, final results were available after 3 h. Since our evaluation was mainly a stress test, it is predicted that the VITEK 2 system in conjunction with the ID-GNB card would perform well under conditions of a routine clinical laboratory in identifying members of the family Enterobacteriaceae and selected species of nonenteric bacteria. This system is a promising, highly automated new tool for the rapid identification of gram-negative bacilli from human clinical specimens. 相似文献
86.
87.
Silvana Lindgren 《Journal of neural transmission (Vienna, Austria : 1996)》1987,69(1-2):33-46
Summary Changes in the endogenous GABA concentration and in GABA turnover following GABA receptor stimulation or blockade were studied in the substantia nigra and the corpus striatum of the rat. The GABA agonists, muscimol, baclofen and THIP decreased the accumulation of GABA following inhibition of GABA--ketoglutaric acid aminotransferase by-acetylenic GABA (GAG) in both structures investigated. Only the effect of muscimol in the substantia nigra was inhibited by the GABA antagonist, bicuculline. Muscimol, baclofen and progabide reduced the disappearance rate of GABA in the substantia nigra following inhibition of the glutamate decarboxylase by 4-deoxypyridoxine. The endogenous GABA concentration was decreased in the corpus striatum following muscimol, THIP or baclofen, probably due to a decreased synthesis of GABA. Smaller effects were seen on the endogenous GABA concentration in the substantia nigra, since both the synthesis and the utilization of GABA were decreased by muscimol and baclofen. Thus, the turnover of brain GABA might be regulated by changes in receptor activity. 相似文献
88.
Journal of Public Health - This study aimed at assessing emergency medical service (EMS) use by patients with acute myocardial infarction (AMI), factors associated with EMS use, and outcomes in the... 相似文献
89.
Davide Serrano Chiara Pozzi Silvia Guglietta Bruno Fosso Mariano Suppa Patrizia Gnagnarella Federica Corso Federica Bellerba Debora Macis Valentina Aristarco Paolo Manghi Nicola Segata Cristina Trovato Maria Giulia Zampino Marinella Marzano Bernardo Bonanni Maria Rescigno Sara Gandini 《Nutrients》2021,13(2)
Obesity and diet are associated with colorectal cancer (CRC) risk, and microbiome could mediate this risk factor. To investigate this interaction, we performed a case–control study (34 CRC cases and 32 controls) and analyzed fecal microbiota composition using 16S rRNA metabarcoding and sub-sequential shotgun analyses of genomic bacterial DNA to evaluate the role of microbiome and diet in CRC etiology, taking into account vitamin D and other risk biomarkers. Dietary habits were evaluated using a short questionnaire. Multivariate methods for data integration and mediation analysis models were used to investigate causal relationships. CRC cases were significantly more often deficient in vitamin D than controls (p = 0.04); FokI and CYP24A1 polymorphism frequency were different between cases and controls (p = 0.03 and p = 0.02, respectively). A diet poor in fatty fish and rich in carbohydrates was found to be significantly associated with CRC risk (p = 0.011). The mediation analysis confirmed the significant role of the microbiome in mediating CRC risk—increasing levels of Bifidobacteria/Escherichia genera ratio, an indicator of “healthy” intestinal microbiome, can overcome the effect of diet on CRC risk (p = 0.03). This study suggests that microbiome mediates the diet effect on CRC risk, and that vitamin D, markers of inflammation, and adipokines are other factors to consider in order to achieve a better knowledge of the whole carcinogenic process. 相似文献
90.
Adele Romano Marzia Friuli Laura Del Coco Serena Longo Daniele Vergara Piero Del Boccio Silvia Valentinuzzi Ilaria Cicalini Francesco P. Fanizzi Silvana Gaetani Anna M. Giudetti 《Nutrients》2021,13(2)
Oleoylethanolamide (OEA) is a naturally occurring bioactive lipid belonging to the family of N-acylethanolamides. A variety of beneficial effects have been attributed to OEA, although the greater interest is due to its potential role in the treatment of obesity, fatty liver, and eating-related disorders. To better clarify the mechanism of the antiadipogenic effect of OEA in the liver, using a lipidomic study performed by 1H-NMR, LC-MS/MS and thin-layer chromatography analyses we evaluated the whole lipid composition of rat liver, following a two-week daily treatment of OEA (10 mg kg−1 i.p.). We found that OEA induced a significant reduction in hepatic triacylglycerol (TAG) content and significant changes in sphingolipid composition and ceramidase activity. We associated the antiadipogenic effect of OEA to decreased activity and expression of key enzymes involved in fatty acid and TAG syntheses, such as acetyl-CoA carboxylase, fatty acid synthase, diacylglycerol acyltransferase, and stearoyl-CoA desaturase 1. Moreover, we found that both SREBP-1 and PPARγ protein expression were significantly reduced in the liver of OEA-treated rats. Our findings add significant and important insights into the molecular mechanism of OEA on hepatic adipogenesis, and suggest a possible link between the OEA-induced changes in sphingolipid metabolism and suppression of hepatic TAG level. 相似文献