全文获取类型
收费全文 | 579795篇 |
免费 | 301569篇 |
国内免费 | 57266篇 |
专业分类
耳鼻咽喉 | 5657篇 |
儿科学 | 7760篇 |
妇产科学 | 7234篇 |
基础医学 | 129808篇 |
口腔科学 | 8021篇 |
临床医学 | 105123篇 |
内科学 | 144393篇 |
皮肤病学 | 8347篇 |
神经病学 | 39501篇 |
特种医学 | 20899篇 |
外国民族医学 | 218篇 |
外科学 | 75861篇 |
综合类 | 102692篇 |
现状与发展 | 79篇 |
一般理论 | 25篇 |
预防医学 | 60754篇 |
眼科学 | 25778篇 |
药学 | 90178篇 |
352篇 | |
中国医学 | 62650篇 |
肿瘤学 | 43300篇 |
出版年
2023年 | 7345篇 |
2022年 | 16696篇 |
2021年 | 20289篇 |
2020年 | 18091篇 |
2019年 | 23807篇 |
2018年 | 24950篇 |
2017年 | 24101篇 |
2016年 | 22256篇 |
2015年 | 27288篇 |
2014年 | 30399篇 |
2013年 | 28438篇 |
2012年 | 36460篇 |
2011年 | 40806篇 |
2010年 | 32719篇 |
2009年 | 36646篇 |
2008年 | 29314篇 |
2007年 | 26278篇 |
2006年 | 25719篇 |
2005年 | 25471篇 |
2004年 | 20967篇 |
2003年 | 19415篇 |
2002年 | 18311篇 |
2001年 | 19125篇 |
2000年 | 15354篇 |
1999年 | 21062篇 |
1998年 | 18942篇 |
1997年 | 18851篇 |
1996年 | 18668篇 |
1995年 | 18497篇 |
1994年 | 17664篇 |
1993年 | 15317篇 |
1992年 | 15390篇 |
1991年 | 14347篇 |
1990年 | 13074篇 |
1989年 | 12637篇 |
1988年 | 11875篇 |
1987年 | 11095篇 |
1986年 | 10413篇 |
1985年 | 9320篇 |
1984年 | 7029篇 |
1983年 | 6883篇 |
1982年 | 7816篇 |
1981年 | 7316篇 |
1980年 | 6950篇 |
1979年 | 6838篇 |
1978年 | 5891篇 |
1977年 | 6199篇 |
1976年 | 5806篇 |
1975年 | 5537篇 |
1974年 | 5131篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
31.
Access to good-quality health services is crucial for the improvement of many health outcomes, such as those targeted by the
Millennium Development Goals (MDGs) adopted by the international community in 2000. The health-related MDGs cannot be achieved
if vulnerable populations do not have access to skilled personnel and to other necessary inputs. This paper focuses on the
geographical dimension of access and on one of its critical determinants: the availability of qualified personnel. The objective
of this paper is to offer a better understanding of the determinants of geographical imbalances in the distribution of health
personnel, and to identify and assess the strategies developed to correct them. It reviews the recent literature on determinants,
barriers and the effects of strategies that attempted to correct geographical imbalances, with a focus on empirical studies
from developing and developed countries. An analysis of determinants of success and failures of strategies implemented, and
a summary of lessons learnt, is included. 相似文献
32.
L. Dvorakova J. Sikora M. Hrebicek H. Hulkova M. Bouckova L. Stolnaja M. Elleder 《Journal of inherited metabolic disease》2006,29(4):591
Summary We present the third case of Niemann–Pick disease type C without neurological symptoms. The patient was a 53-year-old woman
without significant prior health problems who died of acute pulmonary embolism. Autopsy findings of hepatosplenomegaly, lymphadenopathy
and ceroid-rich foam cells raised the suspicion of the visceral form of acid sphingomyelinase deficiency (Niemann–Pick disease
type B; NPB) or a much rarer disorder, variant adult visceral form of Niemann–Pick disease type C (NPC). To verify the histopathological
findings, SMPD1, NPC1 and NPC2 genes were analysed. Two novel sequence variants, c.1997G>A (S666N) and c.2882A>G (N961S) were detected in the NPC1 gene. No pathogenic sequence variants were found either in the SMPD1 gene mutated in NPB or in NPC2 gene. The pathogenicity of both NPC1 variants was supported by their location in regions important for the protein function. Both variations were not found in
more than 300 control alleles. Identified sequence variations confirm the diagnosis of the extremely rare adult visceral form
of Niemann–Pick disease type C, which is otherwise dominated by neurovisceral symptoms. Although only three patients have
been reported, this (most probably underdiagnosed) form of NPC should be considered in differential diagnosis of isolated
hepatosplenomegaly with foam cells in adulthood.
Electronic supplementary material Supplementary material is available for this article at 相似文献
33.
Background
In meningitis, the cerebrospinal fluid contains high levels of innate immune molecules (e.g. complement) which are essential to ward off the infectious challenge and to promote the infiltration of phagocytes (neutrophils, monocytes). However, epithelial cells of either the ependymal layer, one of the established niche for adult neural stem cells, or of the choroid plexus may be extremely vulnerable to bystander attack by cytotoxic and cytolytic complement components. 相似文献34.
35.
Harvey A. Siegal PhD ; Paul J. Draus PhD ; Robert G. Carlson PhD ; Russel S. Falck MA ; Jichuan Wang PhD 《The Journal of rural health》2006,22(2):169-173
CONTEXT: Although the nonmedical use of stimulant drugs such as cocaine and methamphetamine is increasingly common in many rural areas of the United States, little is known about the health beliefs of people who use these drugs. PURPOSE: This research describes illicit stimulant drug users' views on health and health-related concepts that may affect their utilization of health care services. METHODS: A respondent-driven sampling plan was used to recruit 249 not-in-treatment, nonmedical stimulant drug users who were residing in 3 rural counties in west central Ohio. A structured questionnaire administered by trained interviewers was used to collect information on a range of topics, including current drug use, self-reported health status, perceived need for substance abuse treatment, and beliefs about health and health services. FINDINGS: Participants reported using a wide variety of drugs nonmedically, some by injection. Alcohol and marijuana were the most commonly used drugs in the 30 days prior to the interview. Powder cocaine was used by 72.3% of the sample, crack by 68.3%, and methamphetamine by 29.7%. Fair or poor health status was reported by 41.3% of the participants. Only 20.9% of the sample felt they needed drug abuse treatment. Less than one third of the sample reported that they would feel comfortable talking to a physician about their drug use, and 65.1% said they preferred taking care of their problems without getting professional help. CONCLUSIONS: Stimulant drug users in rural Ohio are involved with a range of substances and hold health beliefs that may impede health services utilization. 相似文献
36.
We report clinical, neuroradiologic features, and neuropathologic findings of a 76‐year‐old man with coexistent Pick’s disease and progressive supranuclear palsy. The patient presented with loss of recent memory, abnormal behavior and change in personality at the age of 60. The symptoms were progressive. Three years later, repetitive or compulsive behavior became prominent. About 9 years after onset, he had difficulty moving and became bed‐ridden because of a fracture of his left leg. His condition gradually deteriorated and he developed mutism and became vegetative. The patient died from pneumonia 16 years after the onset of symptoms. Serial MRI scans showed progressive cortex atrophy, especially in the bilateral frontal and temporal lobes. Macroscopic inspection showed severe atrophy of the whole brain, including cerebrum, brainstem and cerebellum. Microscopic observations showed extensive superficial spongiosis and severe neuronal loss with gliosis in the second and third cortical layers in the frontal, temporal and parietal cortex. There were Pick cells and argyrophilic Pick bodies, which were tau‐ and ubiquitin‐positive in neurons of layers II–III of the above‐mentioned cortex. Numerous argyrophilic Pick bodies were observed in the hippocampus, especially in the dentate fascia. In addition, moderate to severe loss of neurons was found with gliosis and a lot of Gallyas/tau‐positive globus neurofibrillary tangles in the caudate nucleus, globus pallidus, thalamus, substantia nigra, locus coeruleus and dentate nucleus. Numerous thorned‐astrocytes and coiled bodies but no‐tuft shaped astrocytes were noted in the basal ganglion, brainstem and cerebellar white matter. In conclusion, these histopathological features were compatible with classical Pick’s disease and coexistence with progressive supranuclear palsy without tuft‐shaped astrocytes. 相似文献
37.
38.
A Trakic F Liu H Sanchez Lopez H Wang S Crozier 《Magnetic resonance in medicine》2007,57(6):1119-1130
The switching of magnetic field gradient coils in magnetic resonance imaging (MRI) inevitably induces transient eddy currents in conducting system components, such as the cryostat vessel. These secondary currents degrade the spatial and temporal performance of the gradient coils, and compensation methods are commonly employed to correct for these distortions. This theoretical study shows that by incorporating the eddy currents into the coil optimization process, it is possible to modify a gradient coil design so that the fields created by the coil and the eddy currents combine together to generate a spatially homogeneous gradient that follows the input pulse. Shielded and unshielded longitudinal gradient coils are used to exemplify this novel approach. To assist in the evaluation of transient eddy currents induced within a realistic cryostat vessel, a low-frequency finite-difference time-domain (FDTD) method using the total-field scattered-field (TFSF) scheme was performed. The simulations demonstrate the effectiveness of the proposed method for optimizing longitudinal gradient fields while taking into account the spatial and temporal behavior of the eddy currents. 相似文献
39.
Pulmonary Lophomonas blattarum infection in patients with kidney allograft transplantation 总被引:3,自引:0,他引:3
Yong Wang Zheng Tang Shuming Ji Zhen Zhang Jinsong Chen Zhen Cheng Dongrui Cheng Zhihong Liu Leishi Li 《Transplant international》2006,19(12):1006-1013
The aim of the study was to analyse the clinical manifestation and management of pulmonary Lophomonas blattarum infection in four allograft transplantation recipients retrospectively. Four patients with pulmonary L. blattarum infection were diagnosed by using Fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) examination. Their clinical manifestation and management are summarized. Four cases of pulmonary L. blattarum were found during the period from the second month to the third month after transplantation. Concurring infection by other pathogens was found in three of them. Common initial symptoms included fever (>38 degrees C) without cough and breathlessness. Lower lobe shadowing could be found on chest X-ray. Body temperature decreased to the normal range in three patients and to 37.5 degrees C in the other one, after intravenous injection of metronidazole and tapering immunosuppressant. Radiological examination confirmed improved health condition of the patients afterwards. Two patients received repeated FOB and only dead L. blattarum was found. Pulmonary L. blattarum infection in allograft transplant recipients carry relatively obscure initial symptoms. Possible L. blattarum infection needs to be screened in post-transplantation pulmonary infection patients with similar symptoms, especially in those who respond poorly to anti-infection treatment. Microscopic examination of BAL fluid can help to identify pulmonary L. blattarum infection and metronidazole is an ideal treatment choice. 相似文献
40.