全文获取类型
收费全文 | 13005篇 |
免费 | 719篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 142篇 |
儿科学 | 391篇 |
妇产科学 | 250篇 |
基础医学 | 1632篇 |
口腔科学 | 323篇 |
临床医学 | 1253篇 |
内科学 | 2537篇 |
皮肤病学 | 136篇 |
神经病学 | 1428篇 |
特种医学 | 468篇 |
外科学 | 1716篇 |
综合类 | 81篇 |
一般理论 | 7篇 |
预防医学 | 1042篇 |
眼科学 | 410篇 |
药学 | 920篇 |
中国医学 | 20篇 |
肿瘤学 | 1002篇 |
出版年
2023年 | 49篇 |
2021年 | 155篇 |
2020年 | 174篇 |
2019年 | 216篇 |
2018年 | 283篇 |
2017年 | 233篇 |
2016年 | 271篇 |
2015年 | 287篇 |
2014年 | 367篇 |
2013年 | 640篇 |
2012年 | 816篇 |
2011年 | 837篇 |
2010年 | 477篇 |
2009年 | 455篇 |
2008年 | 759篇 |
2007年 | 741篇 |
2006年 | 777篇 |
2005年 | 718篇 |
2004年 | 649篇 |
2003年 | 653篇 |
2002年 | 646篇 |
2001年 | 213篇 |
2000年 | 159篇 |
1999年 | 171篇 |
1998年 | 131篇 |
1997年 | 126篇 |
1996年 | 104篇 |
1995年 | 127篇 |
1994年 | 111篇 |
1993年 | 116篇 |
1992年 | 121篇 |
1991年 | 138篇 |
1990年 | 116篇 |
1989年 | 121篇 |
1988年 | 95篇 |
1987年 | 91篇 |
1986年 | 104篇 |
1985年 | 108篇 |
1984年 | 114篇 |
1983年 | 79篇 |
1982年 | 110篇 |
1981年 | 88篇 |
1980年 | 54篇 |
1979年 | 48篇 |
1977年 | 71篇 |
1976年 | 53篇 |
1975年 | 57篇 |
1973年 | 65篇 |
1971年 | 51篇 |
1967年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Ruby Del Risco Kollerud Hege S. Haugnes Bjørgulf Claussen Magne Thoresen Per Nafstad James M. Farnham Karl G. Blaasaas Øyvind Næss Lisa A. Cannon-Albright 《International journal of cancer. Journal international du cancer》2020,147(6):1604-1611
Similar family-based cancer and genealogy data from Norway and Utah allowed comparisons of the incidence of testicular cancer (TC), and exploration of the role of Scandinavian ancestry and family history of TC in TC risk. Our study utilizes data from the Utah Population Database and Norwegian Population Registers. All males born during 1951–2015 were followed for TC until the age of 29 years. A total of 1,974,287 and 832,836 males were born in Norway and Utah, respectively, of whom 2,686 individuals were diagnosed with TC in Norway and 531 in Utah. The incidence per year of TC in Norway (10.6) was twice that observed in Utah (5.1) for males born in the last period (1980–1984). The incidence rates of TC in Utah did not differ according to the presence or absence of Scandinavian ancestry (p = 0.669). Having a brother diagnosed with TC was a strong risk factor for TC among children born in Norway and Utah, with HR = 9.87 (95% CI 5.68–17.16) and 6.02 (95% CI 4.80–7.55), respectively; with even higher HR observed among the subset of children in Utah with Scandinavian ancestry (HR = 12.30, 95% CI 6.78–22.31). A clear difference in TC incidence among individuals born in Norway and descendants of Scandinavian people born in Utah was observed. These differences in TC rates point to the possibility of environmental influence. Family history of TC is a strong risk factor for developing TC in both populations. 相似文献
2.
Hypomineralized enamel may be found in connection with the condition molar incisor hypomineralization (MIH), which has a prevalence of around 15% in most parts of the world. Molar incisor hypomineralization is associated with extensive objective and subjective problems, such as hypersensitivity of the affected teeth, enamel breakdown, and problems with retention of restorations. The etiology behind MIH has not yet been elucidated, but a number of possible factors, which affect the same or different functions of ameloblasts during their different stages of maturation, have been suggested. The aim of this study was to utilize multi‐nuclear, solid‐state nuclear magnetic resonance (ss‐NMR) and time‐of‐flight secondary ion mass spectroscopy (ToF‐SIMS) to elucidate any differences, at a molecular level, between enamel powder prepared from normal, healthy teeth and enamel powder prepared from teeth diagnosed with MIH. 31P and 23Na ss‐NMR confirmed the presence of and two different Na+ sites in hypomineralized enamel, suggesting a heterogeneous chemical composition. The content of organic components was higher in hypomineralized enamel, as shown by both 13C ss‐NMR and ToF‐SIMS, indicating the presence of higher numbers of proteins and phospholipids. The interplay between both is necessary for the formation and mineralization of enamel, which might be disturbed or halted in hypomineralized enamel. 相似文献
3.
Joakim Nordanstig Odd Bech-Hanssen Per Skoog Lennart Jivegård 《Scandinavian cardiovascular journal : SCJ》2019,53(3):153-161
Objective. Skeletal muscle perfusion during walking relies on complex interactions between cardiac activity and vascular control mechanisms, why cardiac dysfunction may contribute to intermittent claudication (IC) symptoms. The study aims were to describe cardiac function at rest and during stress in consecutive IC patients, to explore the relations between cardiac function parameters and treadmill performance, and to test the hypothesis that clinically silent myocardial ischemia during stress may contribute to IC limb symptomatology. Design. Patients with mild to severe IC (n?=?111, mean age 67 y, 52% females, mean treadmill distance 195 m) underwent standard echocardiography, dobutamine stress echocardiography (SE) and treadmill testing. The patient cohort was separated in two groups based on treadmill performance (HIGH and LOW performance). Results. Ten patients (9%) had regional wall motion abnormalities of which three had left ventricular ejection fraction <50% at standard echocardiography. A majority had lower than expected systolic- and diastolic ventricular volumes. LOW performers had smaller diastolic left ventricular volumes and lower global peak systolic velocity during dobutamine stress. No patient demonstrated significant cardiac dysfunction during dobutamine provocation that was not also evident at standard echocardiography. Conclusions. Most IC patients were without signs of ischemic heart disease or cardiac failure. The majority had small left ventricular volumes. The hypothesis that clinically silent myocardial ischemia impairing left ventricular function during stress may contribute to IC limb symptomatology was not supported.Trial registration: ClinicalTrials.gov identifier: NCT01219842. 相似文献
4.
5.
Qianlai Luo Jonathan N. Hofmann Ruth M. Pfeiffer Cari M. Kitahara Minkyo Song Meredith S. Shiels 《International journal of cancer. Journal international du cancer》2023,153(1):64-72
In the United States, renal cell carcinoma (RCC) incidence and the prevalence of obesity, an established risk factor for RCC, have been increasing for several decades. RCC is more common among older individuals. We sought to quantify the contribution of excess adiposity to the rising incidence of RCC among individuals 60 years or older. National Institutes of Health-American Association of Retired Persons Diet and Health Study data (n = 453 859 participants, enrolled in 1995-1996, age at enrollment 50-71 years) were used to estimate multivariable-adjusted hazard ratios (HRs) for RCC across body mass index categories and HRs associated with smoking. Population attributable fractions (PAFs) were calculated using estimated HRs and annual overweight/obesity prevalence from the National Health Interview Survey (1985-2008). PAF estimates were combined with RCC incidence from Surveillance, Epidemiology and End Results-13 to calculate annual percent changes in RCC incidence attributable (and unrelated) to overweight/obesity. We found that between 1995 and 2018, among individuals aged 60 years and older, PAF for overweight/obesity increased from 18% to 29% for all RCCs. In comparison, the PAF for smoking declined from 12% to 9%. RCC incidence increased 1.8% per year (95% confidence interval [CI] 1.5%-2.1%) overall, while RCC incidence attributable to overweight/obesity increased 3.8% per year (95%CI 3.5%-4.2%) and RCC incidence unrelated to overweight/obesity increased 1.2% per year (95% CI 0.9%-1.4%). In conclusion, overweight/obesity appears to have contributed importantly to the rising incidence of RCC in the United States since the mid-1990s. Public health interventions focused on reducing overweight and obesity could help substantially in curbing this trend. 相似文献
6.
7.
Ronald F. Pfeiffer 《Neurotherapeutics》2020,17(4):1464
Recognition of the importance of nonmotor dysfunction as a component of Parkinson’s disease has exploded over the past three decades. Autonomic dysfunction is a frequent and particularly important nonmotor feature because of the broad clinical spectrum it covers. Cardiovascular, gastrointestinal, urinary, sexual, and thermoregulatory abnormalities all can appear in the setting of Parkinson’s disease. Cardiovascular dysfunction is characterized most prominently by orthostatic hypotension. Gastrointestinal dysfunction can involve virtually all levels of the gastrointestinal tract. Urinary dysfunction can entail either too frequent voiding or difficulty voiding. Sexual dysfunction is frequent and frustrating for both patient and partner. Alterations in sweating and body temperature are not widely recognized but often are present. Autonomic dysfunction can significantly and deleteriously impact quality of life for individuals with Parkinson’s disease. Because effective treatment for many aspects of autonomic dysfunction is available, it is vitally important that assessment of autonomic dysfunction be a regular component of the neurologic history and exam and that appropriate treatment be initiated and maintained.Electronic supplementary materialThe online version of this article (10.1007/s13311-020-00897-4) contains supplementary material, which is available to authorized users.Key Words: Autonomic, gastrointestinal, orthostatic hypotension, urinary, erectile dysfunction, thermoregulatory 相似文献
8.
9.
Sevilla-Cermeño Laura Rautio Daniel Andrén Per Hillborg Maria Silverberg-Morse Maria Lahera Guillermo Mataix-Cols David Fernández de la Cruz Lorena 《European child & adolescent psychiatry》2020,29(9):1289-1299
European Child & Adolescent Psychiatry - Pediatric body dysmorphic disorder (BDD) is challenging to treat. This study aimed to establish the prevalence of insomnia in youth with BDD and explore... 相似文献
10.
Alessandro Mega Mette Hartmark Nilsen Lina Wik Leiss Nicholas P. Tobin Hrvoje Miletic Linda Sleire Carina Strell Sven Nelander Cecilia Krona Daniel Hägerstrand Per Ø. Enger Monica Nistér Arne Östman 《Glia》2020,68(2):316-327
Glioblastoma (GBM) is a deadly disease with a need for deeper understanding and new therapeutic approaches. The microenvironment of glioblastoma has previously been shown to guide glioblastoma progression. In this study, astrocytes were investigated with regard to their effect on glioblastoma proliferation through correlative analyses of clinical samples and experimental in vitro and in vivo studies. Co-culture techniques were used to investigate the GBM growth enhancing potential of astrocytes. Cell sorting and RNA sequencing were used to generate a GBM-associated astrocyte signature and to investigate astrocyte-induced GBM genes. A NOD scid GBM mouse model was used for in vivo studies. A gene signature reflecting GBM-activated astrocytes was associated with poor prognosis in the TCGA GBM dataset. Two genes, periostin and serglycin, induced in GBM cells upon exposure to astrocytes were expressed at higher levels in cases with high “astrocyte signature score”. Astrocytes were shown to enhance glioblastoma cell growth in cell lines and in a patient-derived culture, in a manner dependent on cell–cell contact and involving increased cell proliferation. Furthermore, co-injection of astrocytes with glioblastoma cells reduced survival in an orthotopic GBM model in NOD scid mice. In conclusion, this study suggests that astrocytes contribute to glioblastoma growth and implies this crosstalk as a candidate target for novel therapies. 相似文献