全文获取类型
收费全文 | 17886篇 |
免费 | 1392篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 199篇 |
儿科学 | 464篇 |
妇产科学 | 282篇 |
基础医学 | 2241篇 |
口腔科学 | 247篇 |
临床医学 | 1907篇 |
内科学 | 4259篇 |
皮肤病学 | 289篇 |
神经病学 | 1555篇 |
特种医学 | 585篇 |
外科学 | 3266篇 |
综合类 | 213篇 |
一般理论 | 16篇 |
预防医学 | 1374篇 |
眼科学 | 345篇 |
药学 | 1002篇 |
中国医学 | 41篇 |
肿瘤学 | 1050篇 |
出版年
2024年 | 24篇 |
2023年 | 203篇 |
2022年 | 434篇 |
2021年 | 888篇 |
2020年 | 459篇 |
2019年 | 714篇 |
2018年 | 805篇 |
2017年 | 551篇 |
2016年 | 550篇 |
2015年 | 639篇 |
2014年 | 896篇 |
2013年 | 1007篇 |
2012年 | 1540篇 |
2011年 | 1520篇 |
2010年 | 800篇 |
2009年 | 663篇 |
2008年 | 1088篇 |
2007年 | 1035篇 |
2006年 | 918篇 |
2005年 | 808篇 |
2004年 | 700篇 |
2003年 | 618篇 |
2002年 | 486篇 |
2001年 | 157篇 |
2000年 | 173篇 |
1999年 | 152篇 |
1998年 | 90篇 |
1997年 | 66篇 |
1996年 | 58篇 |
1995年 | 46篇 |
1994年 | 37篇 |
1993年 | 57篇 |
1992年 | 100篇 |
1991年 | 82篇 |
1990年 | 79篇 |
1989年 | 80篇 |
1988年 | 70篇 |
1987年 | 76篇 |
1986年 | 56篇 |
1985年 | 69篇 |
1984年 | 51篇 |
1983年 | 56篇 |
1982年 | 41篇 |
1981年 | 42篇 |
1980年 | 32篇 |
1979年 | 50篇 |
1978年 | 37篇 |
1976年 | 37篇 |
1974年 | 27篇 |
1971年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Amy Hammerich Julie Whitman Paul Mintken Thomas Denninger Venu Akuthota Eric E. Sawyer Melissa Hofmann John D. Childs Joshua Cleland 《Archives of physical medicine and rehabilitation》2019,100(5):797-810
Objective
To examine the effectiveness of epidural steroid injection (ESI) and back education with and without physical therapy (PT) in individuals with lumbar spinal stenosis (LSS).Design
Randomized clinical trial.Setting
Orthopedic spine clinics.Participants
A total of 390 individuals were screened with 60 eligible and randomly selected to receive ESI and education with or without PT (N=54).Interventions
A total of 54 individuals received 1-3 injections and education in a 10-week intervention period, with 31 receiving injections and education only (ESI) and 23 additionally receiving 8-10 sessions of multimodal PT (ESI+PT).Main Outcome Measures
Disability, pain, quality of life, and global rating of change were collected at 10 weeks, 6 months, and 1 year and analyzed using linear mixed model analysis.Results
No significant difference was found between ESI and ESI+PT in the Oswestry Disability Index at any time point, although the sample had significant improvements at 10 weeks (P<.001; 95% confidence interval [CI], ?18.01 to ?5.51) and 1 year (P=.01; 95% CI, ?14.57 to ?2.03) above minimal clinically important difference. Significant differences in the RAND 36-Item Short Form Health Survey 1.0 were found for ESI+PT at 10 weeks with higher emotional role function (P=.03; 95% CI, ?49.05 to ?8.01), emotional well-being (P=.02; 95% CI, ?19.52 to -2.99), and general health perception (P=.05; 95% CI, ?17.20 to ?.78).Conclusions
Epidural steroid injection plus PT was not superior to ESI alone for reducing disability in individuals with LSS. Significant benefit was found for the addition of PT related to quality of life factors of emotional function, emotional well-being, and perception of general health. 相似文献992.
Joshua M Schrock Lawrence S Sugiyama Nirmala Naidoo Paul Kowal J Josh Snodgrass 《Evolution, Medicine, and Public Health》2022,10(1):156
Background and objectivesHuman susceptibility to chronic non-communicable disease may be explained, in part, by mismatches between our evolved biology and contemporary environmental conditions. Disease-induced fatigue may function to reduce physical activity during acute infection, thereby making more energy available to mount an effective immune response. However, fatigue in the context of chronic disease may be maladaptive because long-term reductions in physical activity increase risks of disease progression and the acquisition of additional morbidities. Here, we test whether cumulative chronic morbidity is associated with subjective fatigue.MethodologyWe constructed a cumulative chronic morbidity score using self-reported diagnoses and algorithm-based assessments, and a subjective fatigue score based on four questionnaire items using cross-sectional survey data from the Study on global AGEing and adult health, which features large samples of adults from six countries (China, Ghana, India, Mexico, Russia and South Africa).ResultsIn a mixed-effects linear model with participants nested in countries (N = 32 455), greater cumulative chronic morbidity is associated with greater subjective fatigue (β = 0.34, SE = 0.005, P < 2e−16). This association replicates within each country and is robust to adjustment for key sociodemographic and physical covariates (sex, age, household wealth, physical function score, habitual physical activity, BMI and BMI2).Conclusions and implicationsFatigue is a common but perhaps maladaptive neuropsychological response to chronic morbidity. Disease-induced fatigue may mediate a self-perpetuating cycle, in which chronic morbidity reduces physical activity, and less physical activity increases cumulative chronic morbidity. Longitudinal research is needed to test whether chronic morbidity, fatigue and physical activity form a cyclical feedback loop. Lay Summary: Fatigue during acute illness may promote recovery, but persistent fatigue in the context of chronic disease may make matters worse. We present evidence from six countries that more chronic disease is associated with more fatigue. This fatigue may reduce physical activity, which increases risks of acquiring additional chronic health problems. 相似文献
993.
Susceptibility weighted imaging: neuropsychologic outcome and pediatric head injury 总被引:10,自引:0,他引:10
Babikian T Freier MC Tong KA Nickerson JP Wall CJ Holshouser BA Burley T Riggs ML Ashwal S 《Pediatric neurology》2005,33(3):184-194
Traumatic brain injury is among the most frequent pediatric neurologic disorders in the United States, affecting multiple aspects of neuropsychologic functioning. This study assessed the efficacy of susceptibility weighted imaging as a predictor of long-term neuropsychologic functioning after pediatric brain injury compared with magnetic resonance spectroscopic imaging. Susceptibility weighted imaging is a relatively new method that is considered superior to traditional magnetic resonance imaging sequences for detecting hemorrhagic diffuse axonal injury. In this study, imaging and spectroscopy were acquired 6 +/- 4 days after injury. Measures of neuropsychologic functioning were administered to 18 children and adolescents 1-4 years post injury. Negative correlations between lesion number and volume with neuropsychologic functioning were demonstrated. Lesion volume explained over 32% of the variance in cognitive performance, explaining at least an additional 20% beyond injury severity and age at injury alone and 19% beyond magnetic resonance spectroscopic metabolite variables. Exploratory analyses resulted in notable trends, with lesions in deeper brain regions more strongly associated with poorer neuropsychologic performance. Improved detection of the extent of diffuse axonal injury following a brain injury will allow for a better understanding of its association with long-term outcome, which in turn can improve prognostic efficacy for effective treatment planning. 相似文献
994.
Jennifer R. Marin Karen E. Thomas Angela M. Mills Joshua S. Broder Kathy Boutis 《Emergency radiology》2017,24(5):479-486
Purpose
The purposes of this study were to evaluate the frequency with which emergency physicians involved in residency leadership disclose potential malignancy risks from computed tomography (CT), assess comfort with these discussions, and evaluate factors influencing risk disclosure.Methods
We surveyed emergency medicine residency program directors and associate/assistant directors. Primary outcome was the proportion who “almost always” or “most of the time” discussed potential risks.Results
Two hundred and seventy-four (50.6%) of 542 eligible physicians responded. There were 82.1% (95% CI 76.8%, 86.6%) who reported almost always or most of the time discussing potential risks for patients ≤18 years; proportions for adults 19–40, 41–65, and >65 years were 50.6% (95% CI 44.4, 56.7%), 20.7% (95% CI 16.0, 26.0%), and 5.2% (95% CI 2.9, 8.5%), respectively (test for trend, p < 0.001). The proportion reporting being “extremely” or “very” comfortable discussing risks was 57.1% (95% CI 51.1, 63.2%). Patient/family CT request that the physician felt was not indicated was of “very high” or “high” importance for driving risk discussions in 86.4% of respondents. For 75.5%, patient/family query about radiation risks was of “high” or “very high” importance. Among 57.4% of respondents, the patient being elderly and/or having a reduced life expectancy was of “high” or “very high” importance in the decision not to discuss risk.Conclusions
Emergency physicians involved in residency leadership report frequently disclosing potential malignancy risks from CT at frequencies inversely proportional to patient age. About half are comfortable with discussions, and many discussions are driven by patient requests. Opportunities exist to optimize and standardize emergency department CT radiation risk disclosure practices.995.
Reyes de la Cuesta Benjumea Manuel Tasende AreosaM. Ángeles Martos Cano Enrique Iglesias Goy 《Progresos de Obstetricia y Ginecología》2008
Objective
To evaluate the results and analyse different factors influencing pregnancy rate using homologous intrauterine insemination.Subjects and methods
Retrospective analysis of 500 homologous intrauterine insemination cycles in 183 infertile couples. Only one insemination per stimulated ovarian cycle was performed in patients with: mild endometriosis, ovulatory factor, male subfertility or unexplained infertility. We studied female age, duration of infertility, stimulation protocol, number of cycle, number of preovulatory follicles, motile sperm count and endometrial thickness related to pregnancy rate.Results
Pregnancy rate per couple was 24% and per intrauterine insemination 9%, 11% was multiple pregnancies. Best outcome has been got in women younger than 37 years (P=.048) and in cycles with more than one preovulatory follicle. Other studied factors did not have influence in homologous intrauterine insemination outcome.Conclusions
Female age is a prognostic factor for homologous intrauterine insemination with poor outcome in women older than 38 years. Cycles with more than one preovolatory follicle have better outcome. No differences in pregnancy rate have been achieved with motile sperm count over 1.5 millions/0.3 ml. 相似文献996.
Metabolic assessment of the brain using proton magnetic resonance spectroscopy in a growth-restricted human fetus: case report 总被引:1,自引:0,他引:1
Azpurua H Alvarado A Mayobre F Salom T Copel JA Guevara-Zuloaga F 《American journal of perinatology》2008,25(5):305-309
Proton magnetic resonance spectroscopy (MRS) is a noninvasive method to assess concentrations of different metabolites in tissues, including the brain. We evaluated a fetus with growth restriction using Doppler ultrasound and proton MRS. Doppler assessment revealed absent end diastolic flow in the umbilical artery. Diastolic flow was increased in the middle cerebral artery. Proton MRS of the fetal brain showed lactate and a low N-acetylaspartate/choline index, metabolic markers of starvation/hypoxia. Proton MRS gave us in vivo metabolic information of the brain of a fetus under starvation/hypoxic conditions. It is potentially a new tool for fetal surveillance. To our knowledge, this is the first report of cerebral lactate detection using proton MRS in a growth-restricted human fetus with no associated malformations in the English literature. Further experimental and clinical longitudinal investigations are needed to evaluate its efficacy in the clinical setting. 相似文献
997.
Gutiérrez M Suyama TL Engene N Wingerd JS Matainaho T Gerwick WH 《Journal of natural products》2008,71(6):1099-1103
Cancer cell toxicity-guided fractionation of extracts of the Papua New Guinea marine cyanobacteria Lyngbya majuscula and Lyngbya sordida led to the isolation of apratoxin D (1). Compound 1 contains the same macrocycle as apratoxins A and C but possesses the novel 3,7-dihydroxy-2,5,8,10,10-pentamethylundecanoic acid as the polyketide moiety. The planar structures and stereostructures of compound 1 were determined by extensive 1D and 2D NMR and MS data analyses and by comparison with the spectroscopic data of apratoxins A and C. Apratoxin D (1) showed potent in vitro cytotoxicity against H-460 human lung cancer cells with an IC 50 value of 2.6 nM. 相似文献
998.
Buhimschi CS Turan OM Funai EF Azpurua H Bahtiyar MO Turan S Zhao G Dulay A Bhandari V Copel JA Buhimschi IA 《Obstetrics and gynecology》2008,111(3):715-722
OBJECTIVE: Fetal adaptation to stress is regulated in part by the pituitary-adrenocortical system. The stress hormones dehydroepiandrosterone sulfate (DHEAS) and cortisol have opposing effects: cortisol suppresses while DHEAS enhances immune functions. We sought to estimate the impact of intraamniotic inflammation on fetal adrenal gland volume and cortisol-to-dehydroepiandrosterone sulfate ratio (fetal stress ratio) in pregnancies complicated by preterm birth. METHODS: Fifty-one consecutive singleton fetuses of mothers who had an indicated amniocentesis to rule out infection were analyzed. Intraamniotic inflammation was assessed by proteomic profiling of amniotic fluid for the biomarkers of the Mass Restricted score. The Mass Restricted score ranges from 0 (biomarkers absent) to 4 (all biomarkers present), with Mass Restricted scores of 3 or 4 indicating severe intraamniotic inflammation. Fetal adrenal gland volume was assessed by three-dimensional ultrasonography and corrected for estimated fetal weight. Interleukin-6 (IL-6), cortisol, and DHEAS were measured by immunoassay. RESULTS: Women with intraamniotic inflammation delivered earlier (27.8+/-3.4 weeks, n=16, compared with 32.3+/-3.0 weeks, n=35, P<.001), and their fetuses had higher cord blood IL-6 (P=.011) and higher corrected adrenal gland volumes (P=.027). Cord blood IL-6 levels were in direct relationship with corrected adrenal volume (r=0.372, P=.019), fetal cortisol (r=0.428, P=.010), and DHEAS (r=0.521, P<.001). However, fetuses exposed to intraamniotic inflammation had an overall lower fetal stress ratio (P=.034). These results maintained after adjusting for gestational age, uterine contractions, and steroid exposure. CONCLUSION: Fetuses exposed to intraamniotic inflammation have higher adrenal gland volumes and lower cortisol-to-DHEAS ratios, suggesting that the fetal adrenocortical axis plays a role in the intrauterine adaptation to inflammation. 相似文献
999.
Press JZ Kenyon JA Xue H Miller MA De Luca A Miller DM Huntsman DG Gilks CB McAlpine JN Wang YZ 《Gynecologic oncology》2008,110(2):256-264
1000.
Joshua G. Travers Charles A. Tharp Marcello Rubino Timothy A. McKinsey 《The Journal of clinical investigation》2022,132(5)
Cardiovascular diseases remain the leading cause of death worldwide, with pathological fibrotic remodeling mediated by activated cardiac myofibroblasts representing a unifying theme across etiologies. Despite the profound contributions of myocardial fibrosis to cardiac dysfunction and heart failure, there currently exist limited clinical interventions that effectively target the cardiac fibroblast and its role in fibrotic tissue deposition. Exploration of novel strategies designed to mitigate or reverse myofibroblast activation and cardiac fibrosis will likely yield powerful therapeutic approaches for the treatment of multiple diseases of the heart, including heart failure with preserved or reduced ejection fraction, acute coronary syndrome, and cardiovascular disease linked to type 2 diabetes. In this Review, we provide an overview of classical regulators of cardiac fibrosis and highlight emerging, next-generation epigenetic regulatory targets that have the potential to revolutionize treatment of the expanding cardiovascular disease patient population. 相似文献