全文获取类型
收费全文 | 2217篇 |
免费 | 239篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 34篇 |
儿科学 | 50篇 |
妇产科学 | 28篇 |
基础医学 | 293篇 |
口腔科学 | 117篇 |
临床医学 | 343篇 |
内科学 | 282篇 |
皮肤病学 | 8篇 |
神经病学 | 383篇 |
特种医学 | 86篇 |
外科学 | 310篇 |
综合类 | 36篇 |
一般理论 | 11篇 |
预防医学 | 223篇 |
眼科学 | 44篇 |
药学 | 151篇 |
中国医学 | 5篇 |
肿瘤学 | 56篇 |
出版年
2021年 | 19篇 |
2020年 | 28篇 |
2019年 | 43篇 |
2018年 | 49篇 |
2017年 | 30篇 |
2016年 | 26篇 |
2015年 | 29篇 |
2014年 | 48篇 |
2013年 | 123篇 |
2012年 | 82篇 |
2011年 | 111篇 |
2010年 | 58篇 |
2009年 | 70篇 |
2008年 | 92篇 |
2007年 | 99篇 |
2006年 | 104篇 |
2005年 | 110篇 |
2004年 | 84篇 |
2003年 | 104篇 |
2002年 | 89篇 |
2001年 | 88篇 |
2000年 | 86篇 |
1999年 | 74篇 |
1998年 | 21篇 |
1997年 | 20篇 |
1996年 | 23篇 |
1995年 | 23篇 |
1994年 | 21篇 |
1992年 | 27篇 |
1991年 | 45篇 |
1990年 | 31篇 |
1989年 | 35篇 |
1988年 | 36篇 |
1987年 | 46篇 |
1986年 | 29篇 |
1985年 | 20篇 |
1984年 | 24篇 |
1983年 | 27篇 |
1981年 | 18篇 |
1979年 | 25篇 |
1978年 | 27篇 |
1977年 | 16篇 |
1976年 | 18篇 |
1974年 | 24篇 |
1973年 | 21篇 |
1972年 | 24篇 |
1971年 | 18篇 |
1970年 | 23篇 |
1968年 | 18篇 |
1967年 | 21篇 |
排序方式: 共有2460条查询结果,搜索用时 0 毫秒
1.
2.
AIMS: Immunohistological and molecular characterisation of a case of peripheral T-cell lymphoma (PTCL) of angioimmunoblastic T-cell lymphoma (AILD) type. METHODS: Frozen and paraffin wax sections of the diagnostic lymph node were stained with a panel of T- and B-cell lineage monoclonal antibodies. DNA was isolated from the paraffin wax embedded biopsy material for T-cell receptor (TCR) and immunoglobulin (Ig) PCR amplification, and resultant PCR products were cloned and sequenced. RESULTS: Immunohistological analysis of the presenting lymph node was consistent with an extensive infiltrate of pleomorphic CD3+CD8+ lymphocytes. Most (>80%) of these infiltrating CD3+ cells were also positive for the TCR VB5.1 gene family product, and were shown to be oligoclonal by TCRB PCR amplification and sequencing. Three oligoclones of B cells were also demonstrable by PCR amplification with Ig heavy chain primers and sequencing, a finding at variance with the diagnosis of AILD. CONCLUSIONS: These data demonstrate the complexity and heterogeneity of PTCL which require extensive histological examination and molecular characterisation. 相似文献
3.
Hydroxyethyl methacrylate (HEMA) has been advocated as a polymerizing solution with which to prevent deflation of detachable balloons in interventional neuroradiology. It is pertinent to know if unpolymerized HEMA would have untoward effects if accidentally released into the carotid artery by balloon rupture or deflation. Seven mongrel dogs underwent transfemoral catheterization of the common carotid artery and subsequent injection of HEMA solution in volumes of 1 cc in five dogs, 2 cc in one, and 4 cc in one. Angiography performed at the time of injection revealed evidence of intravascular thrombosis as well as possible spasm. Three surviving animals were sacrificed at 48 hours; the brains were fixed and examined histopathologically. One brain was normal and one was autolyzed and could not be examined. Five of the seven animals had histopathologically documented cerebral infarctions of varying size. No foreign substance was seen within the blood vessels to suggest intravascular polymerization. The animals injected with 2 or 4 cc HEMA solution did not survive 48 hours. Literature review reveals little documentation of the toxicology of intravascular HEMA. With its increasing popularity as a compound for polymerization in detachable balloons introduced into the brain, further investigations are warranted to understand the physical properties of the compound and potential risks of its use. 相似文献
4.
Jeffrey A. Gray Stephen N. Mitchell Michael H. Joseph Grigory A. Grigoryan Sharon Dawe Helen Hodges 《Drug development research》1994,31(1):3-17
Data are reviewed, largely from experiments in the authors'laboratory, that suggest three modes of action of systemic nicotine in producing three different types of effect upon behavior and cognitive function. (1) Preexposure of a stimulus without consequence makes it harder subsequently to form associations to that stimulus, a form of selective attention known as latent inhibition. Latent inhibition is blocked by nicotine, an effect that is apparently mediated by a nicotine-induced increase in dopamine release in the nucleus accumbens. (2) A single dose of nicotine proactively increases the partial reinforcement extinction effect measured several weeks later: that is, resistance to extinction is decreased by nicotine in animals that have been trained on a continuous reinforcement schedule, and increased in animals trained on a partial reinforcement schedule. This effect appears to be due to increased synthesis of tyrosine hydroxylase in the cell bodies of noradrenergic neurons in the locus coeruleus, followed by axonal transport to the hippocampus and increased synthesis and release of noradrenaline in that structure. (3) Nicotine improves vigilance in animals with cognitive deficits due to destruction of the forebrain cholinergic projection system, either as a consequence of excitotoxic lesions of the nuclei of origin of this system or after prolonged alcohol consumption; and also in human subjects with Alzheimer's disease (in which this system undergoes degeneration). This effect is most likely due to an action at denervated cholinergic synapses in the hippocampus and neocortex. © 1994 Wiley-Liss, Inc. 相似文献
5.
躯干运动和负重时对足底支撑面侧向横移的姿势控制 总被引:3,自引:0,他引:3
目的:本研究假设自主运动命令和姿势控制信号间有冲突,因此设计在附加重物和不同自主任务的同时给予足底一个模拟受滑的干扰(横移)来观察姿势变化并分析其是否受冲突命令或者力学参数的影响.方法:受试者在执行各种不同的自主任务时,随机给予足底支撑面一个左侧或右侧的横移干扰.这些不同的自主任务包括不负重静止站立、静止站立单手负重5kg、负重5kg站立并躯干静止侧屈15°、负重5kg动态地提重物和放重物5项任务.测量和分析下列参数:中心压力的侧位移(COP)、躯干和股部在冠状面上的角位移和腹内压(IAP).结果:干扰离开质量(向右)、始反应超射的幅度、达到终平衡的时间和达到平衡前COP位移的次数都增加,这种情况可以看作是为了再获得平衡的姿势反应效率降低,因此,如果质量的重力效果能对抗干扰,则再获得平衡的反应效率甚至可以被增进.结论:提重和负重是危害姿势反应效率的因素,因为提重和负重改变了重力效果,加大了对躯干的干扰.在动态条件下躯干的运动不是被横移干扰增强就是被横移干扰抵消,并没有显著地影响改变最终平衡位置姿势校正的效应.因此附加任务的同时给一个支持面上的横移干扰,姿势控制的效应可以被抵消.这个减低的效应可以引起脊柱周围结构的负荷增加和增加受伤的危险性.但是,在恰当地放置负重的位置时,反而可以增进躯干控制和协助恢复姿势平衡. 相似文献
6.
P A Hodges 《Journal of the American Dietetic Association》1992,92(7):840-843
The history of the profession of dietetics is a history of caring, dedicated, and capable individuals. This article examines the experiences of three dietitians during World War II in the Philippines--their pre-war status and their changing environments as the Japanese invaded the Philippines in overwhelming numbers. It recounts the extreme hardships they endured for 3 years as prisoners of war of the Japanese at Santo Tomas Internment Camp (formerly Santo Tomas University) in Manila. The article covers the time before Army dietitians had military status and concludes shortly after the former prisoners returned to the United States, when they were commissioned and promoted to the rank of first lieutenant. 相似文献
7.
Current perspectives on childhood depression: an overview 总被引:2,自引:0,他引:2
J H Kashani A Husain W O Shekim K K Hodges L Cytryn D H McKnew 《The American journal of psychiatry》1981,138(2):143-153
The rapidly increasing research interest in childhood depression indicates that it has become a recognized disorder. The authors review the literature on depression in children, focusing on epidemiology, various diagnostic criteria, classification schemes, assessment instruments, and intervention studies that have been applied to childhood depression. Given that there are many etiological factors, it will be important to study the disorder from various conceptual frameworks, including biochemical, genetic learned helplessness, life stresses, cognitive distortion, behavioral reinforcement, and sociological models. 相似文献
8.
Publication in professional journals has become an expectation not only of neuroscience nurse educators but practitioners as well. Through publication, the neuroscience nurse demonstrates commitment to the profession and specialty area by sharing clinical insights and knowledge with colleagues practicing in the field. The publication process includes many steps beginning with the idea for publication to a careful review of the galley proofs. This article describes opportunities for journal publication and strategies for ensuring success in the publication process. 相似文献
9.
Semantic memory impairment in Alzheimer's disease: failure of access or degraded knowledge? 总被引:6,自引:0,他引:6
A battery of neuropsychological tests designed to assess semantic knowledge about the same items both within and across different modalities was administered to a group of 22 patients with dementia of the Alzheimer type (DAT) and 26 matched controls. The DAT patients were impaired on tests of category fluency, picture naming, spoken word-picture matching, picture sorting and generation of verbal definitions. A relative preservation of superordinate knowledge on the sorting and definition tests, as well as a disproportionate reduction in the generation of exemplars from lower order categories was noted. Analysis of the errors made by each patient across the different tests, revealed a significant correspondence between the individual items. These findings offer compelling evidence that the semantic breakdown in DAT is caused by storage degradation. 相似文献
10.
Nancy I Thomas Norman DePaul Brown Linda C Hodges Jay Gandy Louanne Lawson Janet E Lord David K Williams 《AAOHN journal》2006,54(1):24-31
The Central Arkansas Veterans Healthcare System (CAVHS) spends $1 million annually on occupational illnesses and injuries. To address the problem of injuries among hospital employees, a retrospective case-control study was conducted to examine select risk factors for work-related injuries (WRI) among CAVHS employees. Study methods included a review of employee health charts and computer and manual databases from 1997 to 2002 (N = 2,050). The researchers found that WRI increased with age; WRI occurred more often in women than in men; WRI was greater among maintenance and custodial staff compared to direct caregivers, and less among clerical staff; WRI occurred less often in part-time than full-time staff; and WRI increased with increasing body mass index. Developing standards, guidelines, and policies for preplacement screening, preventive measures, training, and education may help to minimize WRI and associated costs. 相似文献