全文获取类型
收费全文 | 657篇 |
免费 | 34篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 44篇 |
妇产科学 | 15篇 |
基础医学 | 70篇 |
口腔科学 | 27篇 |
临床医学 | 41篇 |
内科学 | 170篇 |
皮肤病学 | 10篇 |
神经病学 | 19篇 |
特种医学 | 10篇 |
外国民族医学 | 1篇 |
外科学 | 82篇 |
综合类 | 17篇 |
一般理论 | 7篇 |
预防医学 | 64篇 |
眼科学 | 23篇 |
药学 | 42篇 |
中国医学 | 10篇 |
肿瘤学 | 38篇 |
出版年
2023年 | 7篇 |
2022年 | 20篇 |
2021年 | 23篇 |
2020年 | 13篇 |
2019年 | 19篇 |
2018年 | 24篇 |
2017年 | 12篇 |
2016年 | 16篇 |
2015年 | 11篇 |
2014年 | 28篇 |
2013年 | 27篇 |
2012年 | 55篇 |
2011年 | 53篇 |
2010年 | 34篇 |
2009年 | 25篇 |
2008年 | 35篇 |
2007年 | 36篇 |
2006年 | 35篇 |
2005年 | 28篇 |
2004年 | 21篇 |
2003年 | 18篇 |
2002年 | 11篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 19篇 |
1992年 | 5篇 |
1991年 | 13篇 |
1990年 | 15篇 |
1989年 | 15篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1972年 | 1篇 |
1969年 | 2篇 |
1966年 | 2篇 |
1962年 | 2篇 |
排序方式: 共有694条查询结果,搜索用时 78 毫秒
101.
Mohammad M. Tavakol Flavio G. Vincenti Hamid Assadi Michael J. Frederick Stephen J. Tomlanovich John P. Roberts Andrew M. Posselt 《Clinical journal of the American Society of Nephrology》2009,4(7):1230-1238
Background and objectives: Increasing demand for live-donor kidneys has encouraged the use of obese donors despite the absence of long-term outcome data and evidence that obesity can adversely affect renal function. We wished to determine whether obesity increased the risk for renal dysfunction and other medical comorbidities in donors several years after donation.Design, setting, participants, & measurements: Ninety-eight patients who donated a kidney 5 to 40 years previously were stratified according to body mass index (BMI) at donation and evaluated for renal dysfunction and risk factors for cardiovascular disease. Patients who were from the 2005 through 2006 National Health and Nutrition Examination Survey database; did not have renal disease; and were matched for age, gender, race, and BMI served as two-kidney control subjects.Results: Renal function in obese (BMI ≥30) and nonobese (BMI <30) donors was similar, and both donor groups had reduced renal function compared with BMI-matched two-kidney control subjects. Obesity was associated with more hypertension and dyslipidemias in both donors and two-kidney control subjects; however, there were no significant differences between the two groups within each BMI category.Conclusions: These results indicate that obese donors are not at higher risk for long-term reduced renal function compared with nonobese donors and that the increased incidence of hypertension and other cardiovascular disease risk factors in obese donors is due to their obesity and is not further exacerbated by nephrectomy. These findings support the current practice of using otherwise healthy overweight and obese donors but emphasize the need for more intensive preoperative education and postoperative health care maintenance in this donor group.Live-donor kidney transplantation is generally considered the best choice for patients who have renal failure and are awaiting transplantation, because these kidneys function better than kidneys from deceased donors, and waiting times for deceased-donor transplants are long (1). Although several studies have shown that kidney donation has low short-term morbidity and mortality, the data on long-term outcomes are much less complete (2,3). This is particularly true of donor groups with medical comorbidities that are now being used with greater frequency. One such patient group is the obese donor. There is increasing evidence that obese patients are more susceptible to the development of renal disease either as a direct result of their weight or as a consequence of their obesity-related comorbidities, such as hypertension and diabetes. Conversely, even mild renal dysfunction is thought to increase the risk for developing cardiovascular disease (CVD), an important concern in overweight patients who are already prone to developing this complication (4–6). Despite these findings in the general population, little is known about the effects of obesity on long-term outcomes in kidney donors. This study addressed this issue by examining long-term outcomes in nonobese (body mass index [BMI] <30) and obese (BMI ≥30) patients who donated a kidney at the University of California, San Francisco (UCSF), between 1967 and 2003. 相似文献
102.
Jalil Nejati Hasan Vatandoost Mohammad Ali Oshghi Masud Salehi Ehssan Mozafari Seyed Hasan Moosa-Kazemi 《Asian Pacific Journal of Tropical Biomedicine》2013,3(12):1003-1008
Objective
To determine the bionomics and susceptibility status of the malarial vector Anopheles superpictus (An. superpictus) to different insecticides in the Sistan-Baluchestan province which has the highest malarial prevalence in Iran.Methods
Different sampling methods, in addition to scoring abdominal conditions, were used to define the seasonal activity and endo/exophilic behavior of this species. In addition, the standard WHO susceptibility tests were applied on adult field strains.Results
Most adult mosquitoes were collected from outdoor shelters. The peak of seasonal activity of An. superpictus occurred at the end of autumn. Most larvae were collected from natural and permanent breeding places with full sunlight and no vegetation. Blood feeding activities occurred around midnight. Compared with the abdominal conditions of adult mosquitoes collected indoors, the abdominal conditions of adult mosquitoes collected outdoors were gravid and semigravid. This species was suspected to be resistant to DDT, but was susceptible to other insecticides.Conclusions
An. superpictus was present in almost all outdoor shelters, and the ratios of gravid, semigravid/unfed, and freshly fed confirmed that this species had a higher tendency to rest outdoors than indoors. This behavior can protect An. superpictus from indoor residual spraying in this malarious area. To the best of our knowledge, this is the first report on the susceptibility status of An. superpictus in Southeastern Iran. We do not suggest the use of DDT for indoor residual spraying in southeast Iran. 相似文献103.
Juriyati Jalil Ibrahim Jantan Khozirah Shaari Iftikhar Ahmad Abdul Rafi 《Pharmaceutical biology》2013,51(6):457-461
In the course of our search for novel platelet-activating factor (PAF) antagonists from medicinal plants, the methanol extract of the leaves of Ardisia elliptica Thunb. was investigated for its inhibitory effects on PAF receptor binding to rabbit platelets using 3H-PAF as a ligand. The methanol extract showed inhibitory activity of 53.9% and its ethyl acetate, n-butanol, and methanol fractions exhibited 48.6%, 39.0%, and 22.0% inhibition, respectively. Bioassay-guided fractionation of the ethyl acetate fraction led to the isolation of a new alkenylresorcinol, 5-(Z-heptadec-4′-enyl)resorcinol, together with 5-pentadecylresorcinol. The alkenylresorcinol showed a strong inhibition with an IC50 value of 7.1 µM. The structures of the compounds were elucidated by spectroscopic techniques. 相似文献
104.
105.
Background
Patellar dislocations are a commonly treated injury in the Emergency Department (ED), with a majority of cases involving lateral subluxation of the patella outside of the joint space. Intra-condylar dislocations of the patella are rare. Of the two types of axis rotation, vertical and horizontal, the vertical occurs five times less frequently. These injuries most often undergo open reduction or, at best, closed reduction under general anesthesia.Objectives
To remind Emergency Physicians to consider this injury in any patient with severe knee pain and limited mobility, even with a history that is lacking significant trauma.Case Report
We present a case of intra-condylar patellar dislocation with vertical axis rotation.Conclusion
This injury is no longer primarily attributed to the young and, barring fracture, closed reduction in the ED should be considered. 相似文献106.
Background
Previous studies reported that, in non-degenerate discs, the nucleus pulposus migrates posteriorly during flexion and anteriorly during extension within the intervertebral disc. However, in these studies the differences between anterior and posterior distances have been regarded as an indicator of nucleus pulposus migration. This study investigated the reality of migration of the nucleus pulposus within the intervertebral disc with changing postures.Method
Magnetic resonance images were obtained of the lumbar spines of 25 asymptomatic volunteers in sitting, standing and supine postures. The anterior and posterior height of the intervertebral disc, the anterior -posterior length of the intervertebral disc and nucleus pulposus, and the positions of the anterior and posterior margins of the nucleus were measured from mid-line sagittal images.Findings
Changing postures altered the anterior and posterior height of the disc and three types of morphological changes, including changes in the anterior -posterior lengths of the intervertebral disc and nucleus pulposus, together with the position of the nucleus in the disc were found. The length of the intervertebral disc and nucleus pulposus changed under the variations in spinal loading caused by posture.Interpretation
The results of this study indicated that the apparent nucleus pulposus migration within intervertebral disc is actually deformation of the nucleus pulposus length which depends on posture and the magnitude of the load. In other words, adopting different postures deforms the nucleus pulposus and therefore, changes the position of the nucleus pulposus but there is no apparent nucleus pulposus migration within the intervertebral disc. 相似文献107.
108.
Abdul Razak HR Nordin AJ Ackerly T Van Every B Martin R Geso M 《Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine》2011,34(3):367-374
This study aimed to quantify the amount of change in Standardised Uptake Values (SUVs) of PET/CT images by simulating the
set-up as closely as possible to the actual patient scanning. The experiments were conducted using an anthropomorphic phantom,
which contained an amount of radioactivity in the form of Fluorodeoxyglucose (FDG) in a primary plastic test tube and one
litre saline bags, including the insertion of bony structures and another two test tubes containing different concentrations
of iodine contrast media. Standard scanning protocols were employed for the PET/CT image acquisition. The highest absolute
differences in the SUVmax and SUVmean values of the saline bags were found to be about 0.2 and 0.4, respectively. The primary
test tube showed the largest change of 1.5 in both SUVs; SUV max and SUVmean. However, none of these changes were found to
be statistically significant. The clinical literature also contains no evidence to suggest that the changes of this magnitude
would change the final diagnosis. Based on these preliminary data, we propose that iodine contrast media can be used during
the CT scan of PET/CT imaging, without significantly affecting the diagnostic quality of this integrated imaging modality. 相似文献
109.
One of the key goals of assessment in medical education is the minimisation of all errors influencing a test in order to produce an observed score which approaches a learner's 'true' score, as reliably and validly as possible. In order to achieve this, assessors need to be aware of the potential biases that can influence all components of the assessment cycle from question creation to the interpretation of exam scores. This Guide describes and explains the processes whereby objective examination results can be analysed to improve the validity and reliability of assessments in medical education. We cover the interpretation of measures of central tendency, measures of variability and standard scores. We describe how to calculate the item-difficulty index and item-discrimination index in examination tests using different statistical procedures. This is followed by an overview of reliability estimates. The post-examination analytical methods described in this guide enable medical educators to construct reliable and valid achievement tests. They also enable medical educators to develop question banks using the collection of appropriate questions from existing examination tests in order to use computerised adaptive testing. 相似文献
110.