全文获取类型
收费全文 | 22490篇 |
免费 | 1777篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 172篇 |
儿科学 | 747篇 |
妇产科学 | 682篇 |
基础医学 | 2963篇 |
口腔科学 | 239篇 |
临床医学 | 2904篇 |
内科学 | 4115篇 |
皮肤病学 | 277篇 |
神经病学 | 2230篇 |
特种医学 | 435篇 |
外科学 | 2255篇 |
综合类 | 377篇 |
一般理论 | 81篇 |
预防医学 | 3369篇 |
眼科学 | 240篇 |
药学 | 1299篇 |
中国医学 | 19篇 |
肿瘤学 | 1895篇 |
出版年
2024年 | 32篇 |
2023年 | 276篇 |
2022年 | 305篇 |
2021年 | 969篇 |
2020年 | 608篇 |
2019年 | 927篇 |
2018年 | 931篇 |
2017年 | 697篇 |
2016年 | 741篇 |
2015年 | 768篇 |
2014年 | 999篇 |
2013年 | 1360篇 |
2012年 | 2089篇 |
2011年 | 2021篇 |
2010年 | 1055篇 |
2009年 | 851篇 |
2008年 | 1497篇 |
2007年 | 1413篇 |
2006年 | 1401篇 |
2005年 | 1276篇 |
2004年 | 1108篇 |
2003年 | 911篇 |
2002年 | 799篇 |
2001年 | 115篇 |
2000年 | 102篇 |
1999年 | 121篇 |
1998年 | 173篇 |
1997年 | 100篇 |
1996年 | 72篇 |
1995年 | 60篇 |
1994年 | 41篇 |
1993年 | 49篇 |
1992年 | 33篇 |
1991年 | 25篇 |
1990年 | 34篇 |
1989年 | 20篇 |
1988年 | 20篇 |
1987年 | 18篇 |
1986年 | 17篇 |
1985年 | 28篇 |
1984年 | 29篇 |
1983年 | 24篇 |
1982年 | 29篇 |
1981年 | 38篇 |
1980年 | 17篇 |
1979年 | 11篇 |
1978年 | 14篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1975年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
51.
52.
PURPOSE: In children with intractable, surgically approachable epilepsy, the ketogenic diet is often perceived as less efficacious than surgery. METHODS: A retrospective chart review was performed of 554 children started on the ketogenic diet since 1994. Forty-five children were identified as surgical candidates, with at least 2 focal routine EEGs, ictal video-EEG, and corresponding focal neuroimaging findings, of whom 24 eventually had resective surgery and were followed subsequently. A comparison cohort group was also created of 45 children matched for age and seizure frequency that received the diet but were not surgical candidates (multifocal or generalized seizures). RESULTS: Of the 24 children who received both dietary and surgical therapies, there was a higher likelihood after 6 months of both >90% seizure reduction (71% versus 17%) and seizure freedom (63% versus 0%) following surgery, both p < 0.0001. Similarly, the 45 cohort children who were not surgical candidates were more likely to be seizure-free (29% versus 13%, p = 0.041) and remained on the diet for shorter duration (10 months versus 18 months, p = 0.035) compared to the surgical group. CONCLUSION: Children with surgically approachable epilepsy do respond to the diet, but are more likely to be seizure-free following surgery. 相似文献
53.
54.
55.
56.
57.
Rebecca Knight MD Erick R Ratzer MD FACS Michael E Fenoglio MD FACS John T Moore MD 《Journal of the American College of Surgeons》1997,185(5):481-485
Background:Most abnormal parathyroid glands can be removed through a standard cervical incision; even those in the superior mediastinum. Those located in certain areas of the mediastinum, for example posteriorly or in the aortopulmonic window, historically have required excision through a median sternotomy or thoracotomy. Angioablation is a nonsurgical alternative to management of these lesions.Study Design:We present two case reports of mediastinal parathyroid adenomas that were excised thoracoscopically, and review the literature regarding the management of mediastinal parathyroid adenomas.Results:Both patients who underwent precise localization and thoracoscopic excision of their mediastinal parathyroid adenomas had resolution of their hypercalcemia with minimal associated morbidity and shortened recovery periods.Conclusions:We suggest that thoracoscopic excision of mediastinal parathyroid adenomas is the better means of controlling hypercalcemia secondary to parathyroid adenoma in those patients considered for either median sternotomy, thoracotomy or angiographic ablation where the exact location of the lesion can be established preoperatively. 相似文献
58.
Rebecca Setliff Janet E Porter Michael Malison Steve Frederick Thomas R Balderson 《JPHMP》2003,9(2):91-102
To address the need for management development in public health, the Centers for Disease Control and Prevention (CDC) established three independent workforce development initiatives aimed primarily at strengthening management and leadership capacity: the Sustainable Management Development Program, the Management Academy for Public Health, and the CDC Leadership and Management Institute. Though independently designed and implemented, the programs share similar guiding principles in their approach to management development: interactive (adult) learning, management tools that reinforce evidence-based decision making, individual feedback, continuous improvement of the learning process, posttraining support for networking and life-long learning, and teamwork. This article will discuss important lessons learned regarding best practices in management and leadership development. 相似文献
59.
Quan-Yang Duh M.D. Allan E. Siperstein M.D. Rebecca A. Miller B.A. Joan J. Sancho M.D. Michael J. Demeure M.D. Orlo H. Clark M.D. 《World journal of surgery》1990,14(3):410-417
Thyroid stimulating hormone (TSH) and epidermal growth factor (EGF) are growth factors for some thyroid cells in cultures. We have previously found more EGF receptors in neoplastic human thyroid tissues than in normal thyroid tissues. We have also found a higher TSH-stimulated adenylate cyclase (AC) activity in neoplastic human thyroid tissues than in normal thyroid tissues. To clarify the relationship between the effect of EGF and TSH on thyroid tissue, we measured the binding of EGF and TSH and the basal, TSH-stimulated and forskolin-stimulated adenylate cyclase activity in 49 normal, hyperplastic and neoplastic human thyroid tissues (5 normal, 2 Hashimoto thyroiditis, 5 Graves' disease, 14 multinodular goiters, 9 follicular adenomas, S follicular carcinomas, 8 papillary carcinomas, and 1 undifferentiated carcinoma). Specific binding of EGF and TSH were measured by radioreceptor assays using competitive inhibition of radio-labeled ligand by unlabeled ligand. Basal, maximally (300 mU/ml) TSH-stimulated, and maximally (100 mM) forskolin-stimulated adenylate cyclase activities were also measured in the same membrane particulate fractions from the thyroid tissues. We found: neoplastic thyroid tissues bind more labeled EGF than nonneoplastic thyroid tissues; follicular adenomas and carcinomas have higher EGF binding than other thyroid tissues; a weak but significant correlation between specific EGF binding and specific TSH binding, and between specific EGF binding and TSH-stimulated adenylate cyclase activity of the thyroid membrane preparations. These findings are consistent with the hypothesis that TSH stimulates an increase in thyroid EGF receptors by increasing intracellular cAMP. The higher binding of EGF and the higher TSH-stimulated AC activity may explain why thyroid neoplasms grow to a larger size than normal thyroid tissues.
Presented at the International Association of Endocrine Surgeons in Toronto, Ontario, Canada, September, 1989.
Supported in part by the Medical Research Service of the Veterans Administration Medical Center, San Francisco, California and the Affirmative Action Faculty Development Grant of the University of California, San Francisco, California. 相似文献
Resumen La hormona estimuladora de tiroides (TSH) y el factor de crecimiento epidermal (EGF) son factores de crecimiento para algunas células tiroideas en cultivo tisular. Previamente hemos informado el hallazgo de más receptores de EGF en tejidos tiroideos neoplásicos humanos que en tejidos tiroideos normales. Con el objeto de clarificar la relación entre el efecto del EGF y de la TSH sobre el tejido tiroideo, realizamos la determinacion de la ligación del EGF y de la TSH y de la actividad basai y de la actividad estimulada por TSH y forskolina de la adenilato-ciclasa (AC) en 49 especímenes de tejido tiroideo humano (5 normales, 2 tiroiditis de Hashimoto, 5 enfermedad de Graves, 14 bocios multinodulares, 9 adenomas foliculares, 5 carcinomas foliculares, 8 carcinomas papilares, y 1 carcinoma indiferenciado). La ligadura especifica del EGF y de la TSH fue medida mediante determinaciones de receptores utilizando inhibición competitiva radiomarcada. También se determinó la actividad basai y la actividad estimulada por forskolina de la adenilato-ciclasa en las mismas fracciones de tejidos tiroideos. Se registraron los siguientes hallazgos: los tejidos neoplásicos ligan más EGF marcado que los tejidos tiroideos no neoplásicos; los adenomas foliculares y los carcinomas poseen una capacidad de ligación del EGF mayor que los otros tejidos tiroideos; hay una débil pero significativa correlación entre la ligación especifíca del TGF y la de la TSH, y entre la ligación específica del EGF y la actividad estimulada por TSH de la adenilato-ciclasa en las preparaciones de membrana tiroidea. Estos hallazgos aparecen consistentes con la hipótesis de que la TSH estimula un aumento en los receptores de EGF mediante el incremento de la cAMP intracelular. La aumentada ligación de EGF y la incrementada actividad estimulada de TSH pueden explicar el por qué los neoplasmas tiroideos crecen hasta un tamaño mayor que los tejidos tiroideos normales.
Résumé La thyroid stimulating hormone (TSH) et l'epidermal growth factor (EGF) sont des facteurs de croissance agissant sur certaines cellules thyroïdes en culture. Nous avons trouvé qu'il y avait plus de récepteurs EGF dans le tissu thyroïde humain néoplasique que dans le tissu thyroïdien normal. Nous avons également montré qu'il y avait plus d'activité d'adenylate cyclase stimulée par la TSH dans le tissu thyroïden néoplasique par rapport au tissu normal. Pour clarifier le rapport entre les effets de l'E.GF et la TSH sur le tissu thyroïden, nous avons mesuré l'activité de liaison d'EGF, de TSH et l'activité adénulate cyclase de base, stimulée par la TSH, et par la forskoline chez 49 patients ayant du tissu normal, hyperplasique ou néoplasique (5 normaux, 2 thyroïdites de Hashimoto, 5 maladies de Basedow, 14 goîtres multinodulaires, 9 adénomes folliculaires, 5 cancers folliculaires, 8 cancers papillaires, et 1 cancer indifférencié). Les liaisons spécifiques d'EGF et de TSH ont été mesurées par le dosage des récepteurs nucléaires par la méthode de déplacement des ligands marqués par des ligands froids (non marquées). Les activités adénylate cyclase de base, maximale (300 mU/mL), stimulée par la TSH (300 mU/mL) et la forskoline (100 mM) ont été également mesurées dans les mêmes fractions de particules membranaires provenant des tissus thyroïdens. Nous avons trouvé que: les tissus néoplasiques se liaient davantage avec l'EGF que les tissus non néoplasiques; les adénomes folliculaires et les cancers avaient un index de liaison plus élevé que les autres tissus thyroïdens; et il y avait une corrélation faible mais significative entre la liaison spécifique EGF et TSH, et entre la liaison spécifique EGF et l'activité adénylate cyclase des préparations de membrane thyroïdienne. Ces résultats sont en faveur de l'hypothèse selon laquelle la TSH provoque une augmentation des récepteurs EGH de la thyroïde en augmentant la concentration intracellulaire d'AMP cyclique. Le degré de liaison d'EGF élevé, et l'augmentation de l'activité stimulée par la TSH peuvent expliquer la croissance accélérée des tissus néoplasiques par rapport à celle des tissus normaux.
Presented at the International Association of Endocrine Surgeons in Toronto, Ontario, Canada, September, 1989.
Supported in part by the Medical Research Service of the Veterans Administration Medical Center, San Francisco, California and the Affirmative Action Faculty Development Grant of the University of California, San Francisco, California. 相似文献
60.
Christine N Vidal Rob Nicolson Timothy J DeVito Kiralee M Hayashi Jennifer A Geaga Dick J Drost Peter C Williamson Nagalingam Rajakumar Yihong Sui Rebecca A Dutton Arthur W Toga Paul M Thompson 《Neuropsychopharmacology》2006,60(3):218-225
BACKGROUND: Volumetric studies have reported reductions in the size of the corpus callosum (CC) in autism, but the callosal regions contributing to this deficit have differed among studies. In this study, a computational method was used to detect and map the spatial pattern of CC abnormalities in male patients with autism. METHODS: Twenty-four boys with autism (aged 10.0 +/- 3.3 years) and 26 control boys (aged 11.0 +/- 2.5 years) underwent a magnetic resonance imaging (MRI) scan at 3 Tesla. Total and regional areas of the CC were determined using traditional morphometric methods. Three-dimensional (3D) surface models of the CC were also created from the MRI scans. Statistical maps were created to visualize morphologic variability of the CC and to localize regions of callosal thinning in autism. RESULTS: Traditional morphometric methods detected a significant reduction in the total callosal area and in the anterior third of the CC in patients with autism; however, 3D maps revealed significant reductions in both the splenium and genu of the CC in patients. CONCLUSIONS: Statistical maps of the CC revealed callosal deficits in autism with greater precision than traditional morphometric methods. These abnormalities suggest aberrant connections between cortical regions, which is consistent with the hypothesis of abnormal cortical connectivity in autism. 相似文献