全文获取类型
收费全文 | 344篇 |
免费 | 14篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 8篇 |
妇产科学 | 11篇 |
基础医学 | 42篇 |
口腔科学 | 10篇 |
临床医学 | 22篇 |
内科学 | 115篇 |
皮肤病学 | 13篇 |
神经病学 | 23篇 |
特种医学 | 4篇 |
外科学 | 40篇 |
预防医学 | 21篇 |
眼科学 | 8篇 |
药学 | 30篇 |
中国医学 | 3篇 |
肿瘤学 | 6篇 |
出版年
2023年 | 4篇 |
2022年 | 9篇 |
2021年 | 18篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2018年 | 11篇 |
2017年 | 8篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 12篇 |
2013年 | 15篇 |
2012年 | 23篇 |
2011年 | 24篇 |
2010年 | 15篇 |
2009年 | 10篇 |
2008年 | 13篇 |
2007年 | 23篇 |
2006年 | 27篇 |
2005年 | 32篇 |
2004年 | 22篇 |
2003年 | 15篇 |
2002年 | 16篇 |
2001年 | 1篇 |
2000年 | 4篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1965年 | 3篇 |
排序方式: 共有360条查询结果,搜索用时 46 毫秒
11.
12.
Anaglyph of Retinal Stem Cells And Developing Axons: Selective Volume Enhancement In Microscopy Images 下载免费PDF全文
Néstor Gabriel Carri Sebastián Noo Bermúdez Luciano Fiore Jennifer Di Napoli Gabriel Scicolone 《Anatomical record (Hoboken, N.J. : 2007)》2014,297(4):770-780
Retinal stem cell culture has become a powerful research tool, but it requires reliable methods to obtain high‐quality images of living and fixed cells. This study describes a procedure for using phase contrast microscopy to obtain three‐dimensional (3‐D) images for the study of living cells by photographing a living cell in a culture dish from bottom to top, as well as a procedure to increase the quality of scanning electron micrographs and laser confocal images. The procedure may also be used to photograph clusters of neural stem cells, and retinal explants with vigorous axonal growth. In the case of scanning electron microscopy and laser confocal images, a Gaussian procedure is applied to the original images. The methodology allows for the creation of anaglyphs and video reconstructions, and provides high‐quality images for characterizing living cells or tissues, fixed cells or tissues, or organs observed with scanning electron and laser confocal microscopy. Its greatest advantage is that it is easy to obtain good results without expensive equipment. The procedure is fast, precise, simple, and offers a strategic tool for obtaining 3‐D reconstructions of cells and axons suitable for easily determining the orientation and polarity of a specimen. It also enables video reconstructions to be created, even of specimens parallel to the plastic base of a tissue culture dish, It is also helpful for studying the distribution and organization of living cells in a culture, as it provides the same powerful information as optical tomography, which most confocal microscopes cannot do on sterile living cells. Anat Rec, 297:770–780, 2014. © 2014 Wiley Periodicals, Inc. 相似文献
13.
Medina Castro N Moreno Alvarez O Guzmán Huerta M Hernández Andrade E 《Ginecología y obstetricia de México》2007,75(10):621-629
Introduction of Doppler ultrasound in obstetrical practice has changed both management and understanding of several diseases that put at risk women and them fetuses. To establish necessary basics and correctly apply this technique, this review will focus in physical principles, acquisition methods, consistency, and safety issues of Doppler ultrasound, in order to improve precision, accuracy and interpretation of this methodology. 相似文献
14.
Pedro González Ramos Nadia Nassar MelicNéstor Herráiz Esteban María José Boíllos CalvoPilar Pérez Hiraldo Patricia Ibáñez Burillo 《Progresos de Obstetricia y Ginecología》2011,54(6):325-329
We describe a new animal model for training resident physicians in gynecological endoscopy. The surgery and training exercises are performed in live, anesthetized, Wistar rats in a pelvitrainer for gynecological endoscopy. The pelvitrainer is used to practice dissection, cutting, electrocoagulation, mobilization of structures in the abdominal cavity, subtotal hysterectomy with double anexectomy, extraction of the surgical specimen in a bag, and knotting to close the surgical wound. Twelve hours of training are sufficient for third-year resident surgeons to master the movements required to perform these techniques in humans. 相似文献
15.
Bofill-Mas S Clemente-Casares P Albińana-Giménez N de Motes Porta CM Hundesa Gonfa A Girones Llop R 《Revista espa?ola de salud pública》2005,79(2):253-269
The development of molecular technologies applied to environmental studies has shown that even in highly industrialized countries there is a high prevalence of viruses in the environment that represents an important impact on public health and substantial economic losses mainly related to the transmission of viruses through water and food. Significant concentrations of viruses are detected in the water flowed to the environment and in the biosolids generated in wastewater treatment plants. This work describes the general characteristics of the environmental contamination by viruses principally by emergent viruses, with a special emphasis on the hepatitis E virus (HEV) and the human polyomaviruses as the environmental contaminants more recently identified in industrialized countries. It has been shown that there is a high prevalence of the human polyomaviruses BKV and JCV in urban sewage in all studied countries, implying a potential transmission of these viruses and their potential oncogenic genes through the oral route. Recent studies have shown that the epidemiological pattern of the HEV infection in industrialized countries is complex and that a diversity of HEV strains simultaneously infects the population. The control of the viral contamination requires the standardization of molecular techniques and the development of a surveillance program for the evaluation of the viral parameters and to reduce the dissemination of already established diseases and emergent viral infections. 相似文献
16.
Molfino NA 《Respiration; international review of thoracic diseases》2005,72(1):105-112
Many drugs may be potentially useful in the treatment of chronic obstructive pulmonary disease (COPD), but relatively few become available for human use due to lack of safety, lack of efficacy, or both. This is an inherent risk in the drug development process, which coupled with the limited understanding of the molecular pathogenesis of COPD, has produced a trend toward improving existing compounds rather than to develop new compounds. This review focuses on improved existing compounds and newly discovered compounds that are in clinical trials, but not yet marketed. The improved existing compounds include: isomers of the long-acting bronchodilators, once-daily beta2-adrenoceptor agonists, anticholinergics and corticosteroids. The pool of novel compounds is in constant fluctuation and comprises anti-inflammatory drugs, antioxidants, leukotriene modifiers and a number of compounds aimed at treating different aspects of COPD such as pulmonary hypertension and hypophosphatemia. 相似文献
17.
18.
19.
In vivo tissue-specific regulation of the human papillomavirus type 18 early promoter by estrogen, progesterone, and their antagonists 总被引:4,自引:0,他引:4
Human papillomavirus type 18 is a causative agent of epithelial cancers in the uterine cervix. We show here that estrogen and progesterone activate beta-galactosidase expression from the early promoter of this virus in the genital epithelia of transgenic mice. Ovariectomy caused suppression of transgene expression exclusively in vagina and cervix epithelia. Beta-galactosidase expression could be restored in ovariectomized females by administration of estrogen, alone or in combination with progesterone. Further, rescue of transgene expression was inhibited by the estrogen antagonist tamoxifen and the anti-progesterone RU486, suggesting that this was a specific effect. 相似文献
20.
The aim of the present work was to study the nephrotoxicity of aluminum lactate administered for 3 months (0.57 mg/100 g bodyweight aluminum, i.p., three times per week) to male Wistar rats. Renal function was studied after 6 weeks of treatment (urine was obtained from rats in metabolic cages) and at the end of the treatment using clearance techniques. Another group of rats was used as kidneys donors at the end of treatment. The renal cortex was separated and homogenized to determine glutathione (GSH) level, glutathione S-transferase (GST) activity and lipid peroxidation (LPO) level. Renal cortex slices were also used to study the p-aminohippuric acid (PAH) accumulation during steady-state conditions and the kinetics of uptake process. Clearance results, at the end of the treatment, indicated that renal functions in treated-rats were not different from those measured in control rats, although the renal concentration parameters differ when they were measured in treated rats after 24 h of food and water deprivation. Balances of water and sodium were also modified at both 1.5 and 3 months of treatment. The activity of alkaline phosphatase (AP) relative to inulin excreted in urine was significantly impaired: controls 2.2±0.6 IUI/mg, Al-treated 5.1±0.5 IU/mg, P<0.05. These data indicated that proximal tubular cells were loosing apical brush border membranes. Data obtained in cortex homogenates indicated that both GSH and GST activity were significantly decreased, and a significant increase of LPO was noted simultaneously in Al-treated rats. Renal accumulation of PAH, estimated as slice-to-medium ratio, decreased significantly in the Al-treated rats: control rats 3.06±0.02 (n=12), Al-treated rats 2.26±0.04 (n=12), P<0.0001. The maximal rate of uptake was also diminished in treated rats, while the apparent affinity remained unchanged. All these results indicate that aluminum accumulation in renal tissue affects cellular metabolism, promotes oxidative stress and induces alterations in renal tubular PAH transport, together with an impairment in sodium and water balance only detected under conditions of water deprivation, without other evident changes in glomerular filtration rate or other global functions measured by clearance techniques at least at this time of chronic toxicity. 相似文献