首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8148篇
  免费   441篇
  国内免费   65篇
耳鼻咽喉   109篇
儿科学   1876篇
妇产科学   506篇
基础医学   573篇
口腔科学   8篇
临床医学   1371篇
内科学   319篇
皮肤病学   32篇
神经病学   419篇
特种医学   83篇
外科学   361篇
综合类   1125篇
一般理论   1篇
预防医学   966篇
眼科学   36篇
药学   736篇
  9篇
中国医学   108篇
肿瘤学   16篇
  2023年   142篇
  2022年   231篇
  2021年   365篇
  2020年   301篇
  2019年   282篇
  2018年   276篇
  2017年   237篇
  2016年   264篇
  2015年   315篇
  2014年   628篇
  2013年   620篇
  2012年   553篇
  2011年   589篇
  2010年   453篇
  2009年   405篇
  2008年   364篇
  2007年   324篇
  2006年   345篇
  2005年   253篇
  2004年   190篇
  2003年   155篇
  2002年   125篇
  2001年   131篇
  2000年   92篇
  1999年   71篇
  1998年   61篇
  1997年   68篇
  1996年   75篇
  1995年   52篇
  1994年   49篇
  1993年   54篇
  1992年   45篇
  1991年   36篇
  1990年   34篇
  1989年   28篇
  1988年   36篇
  1987年   35篇
  1986年   36篇
  1985年   47篇
  1984年   45篇
  1983年   18篇
  1982年   38篇
  1981年   39篇
  1980年   25篇
  1979年   22篇
  1978年   18篇
  1977年   12篇
  1976年   13篇
  1975年   15篇
  1973年   11篇
排序方式: 共有8654条查询结果,搜索用时 343 毫秒
31.
A technique for temporary ventricular drainage using a subcutaneous pouch is described for use in neonatal hydrocephalus after intraventricular hemorrhage. The advantages include continuous, valve-regulated ventricular decompression, no exposed tubing, avoidance of electrolyte imbalance and of the loss of CSF, obviation of the need for repeated tapping, and the ability to convert to a peritoneal shunt on an elective basis.  相似文献   
32.
新生儿窒息合并心肌损害血清心肌酶变化(附12例分析)   总被引:1,自引:0,他引:1  
目的探讨心肌酶水平对窒息新生儿心肌损害的诊断价值。方法将12例窒息新生儿为实验组,另外收集10例同期正常新生儿作为对照组。两组新生儿经股静脉穿刺采血2 ml,分离血清,在24 h内测定心肌酶活性,同时做心电图检查,统计学处理采用t检验。结果两组血清心肌酶测定结果比较显示两组血清心肌酶均值间的差别有显著性意义。窒息组均出现心电图改变。结论血清心肌酶活性测定及心电图检测可作为新生儿窒息后心肌损害的早期监测和诊断的指标,为早期治疗提供依据。  相似文献   
33.
AIM: The aim of this study was to investigate the nature and organization of maternal needs and priorities in a neonatal unit. BACKGROUND: The relationship between maternal needs and priorities appears to be an under studied area in neonatal nursing. METHODS: A quantitative survey was carried out based on 209 mothers with premature infants. Two self-assessment schedules were used: critical care maternal needs inventory (J. Leske, Heart and Lung 15, 27-42) and a ranking scale. The data were analysed with multivariate analysis. FINDINGS: Data analysis revealed clear priorities in maternal needs. In particular the need for accurate infant related information was a priority for 93% of the mothers. Good communication practices with professionals were also valued. The mothers displayed altruistic behaviour, and self-related needs took second place. It is proposed that maternal needs demonstrate a hierarchical organization. CONCLUSION: It is important for nurses to consider the individual needs of the mothers, simply because the satisfaction of these needs is essential for maternal well-being.  相似文献   
34.
Background: In Japan a new long‐term care insurance (LTCI) system, the so‐called ‘Kaigo‐Hoken’, was started in April 2000. The present study analyzes the change in the type of destination after discharge from a senile dementia therapy ward before and after the implementation of LTCI at Fukuoka Prefectural Onga Hospital, Japan. Methods: The present study examines data from 199 inpatients discharged from the Fukuoka Prefectural Onga Hospital that had been diagnosed with dementia and met the DSM IV criteria for Alzheimer's type, vascular dementia or other type of dementia. For the purposes of comparison two periods were defined, ‘the first period’ was defined as the period from 1 April 1999 to 31 March 2000, before LTCI was implemented, while ‘the second period’ was defined as the period from 1 April 2000 to 31 March 2001, after LTCI had started. Subject data was analyzed on the basis of where the subject had resided pre‐admission and their destination after discharge using the following classifications: nursing home or geriatric care facility, hospitalization, home and death. Results: While the certification rate of inpatients regarding long‐term care increased slightly in the second period, no significant change was observed based on where the subject had resided pre‐admission and their destination after discharge between the first and second periods. Conclusions: While LTCI is essential for Japan, it is necessary that people with dementia in senile dementia therapy wards are encouraged to return to their homes under the care and support of LTCI.  相似文献   
35.
目的研究重庆市新生儿黄疸儿G6PD三种常见基因突变与其临床表现特点之间的关系。初步估计其基因突变频率并探讨其临床意义和遗传学特征。方法应用突变特异性扩增系统(ARMS)法,检测54例重庆市新生儿黄疸儿的G6PD基因突变类型。结果检出G1388A突变39例(72%),G1376T突变8例(15%),未定型者7例(13%)。未检出G95A。结论本研究首次对重庆市新生儿黄疸儿进行G1388A、G1376T和A95G突变检测。提示G1388A和G1376T为重庆市新生儿黄疸儿G6PD缺乏症基因突变的主要类型。ARMS法是一种简便、快速、经济的检测G6PD已知基因突变的方法。本研究发现这两种突变类型仅见于中国人和华裔人群,具有遗传学及临床意义。  相似文献   
36.
3,4-Methylenedioxymethamphetamine damages fine serotonergic fibers and nerve terminals in adult organisms. Developing animals seem to be less susceptible to this effect, possibly due to a lack of drug-induced hyperthermia. We tested this hypothesis by producing hyperthermia in neonatal rats for 2 h after each of twice-daily MDMA (10 mg/kg s.c.) or saline injections administered from postnatal days 1–4. Other drug-treated and control litters were maintained at normothermic temperatures following injection. Changes in forebrain serotonergic innervation were assessed at postnatal day 25 (serotonin transporter binding and serotonin levels), postnatal day 60 (serotonin transporter binding), and 9 months of age (serotonin transporter immunohistochemistry). We also determined the influence of MDMA treatment on apoptotic activity by means of immunohistochemistry for cleaved caspase-3 at postnatal day 5. The hippocampus showed significant MDMA-related reductions in serotonergic markers at postnatal day 25 and postnatal day 60. At 9 months, there was no effect of prior MDMA exposure on serotonin transporter-immunoreactive fiber density in the hippocampus; however, significant reductions in fiber density were observed in two neocortical areas and a hyperinnervation was found in the caudate-putamen and nucleus accumbens shell. MDMA treatment also produced a two-fold increase in the number of cleaved caspase-3-immunoreactive cells in the rostral forebrain and hippocampus. All of these effects were completely independent of pup body temperature. These findings demonstrate that neonatal MDMA administration exposure stimulates apoptotic cell death in various forebrain areas and also leads to a long-term reorganization of the forebrain serotonergic innervation. Consequently, offspring of MDMA-using women may be at heightened risk for abnormal neural and behavioral development.  相似文献   
37.
In order to evaluate in vivo single-photon emission tomography (SPET) method of assessing cerebral function after hypoxic-ischemic injury in human neonates, we studied D1 and D2 dopamine receptors in a rat model. Seven-day-old rats underwent permanent unilateral common carotid ligation followed by exposure to 8% O2. Two weeks later, in brains with no visible loss of hemispheric volume, striatal dopaminergic receptors were studied, with [125I]TISCH and [1251]IBZM for the D1 and D2 dopamine receptors, respectively. Using [125I]TISCH, we observed no modifications of D1 receptors, but in contrast, ex vivo and in vitro autoradiographic experiments showed a 40% decrease in the striatal binding of [125I]IBZM on both the ipsilateral and the contralateral side to the carotid ligation. These alterations were detected with IBZM, a D2 dopamine receptor ligand usable for SPET imaging. Therefore, exploration of D2 receptors by SPET in human neonates suffering from perinatal hypoxia-ischemia may be valuable for the diagnosis and follow-up of cerebral function damages. Correspondence to: D. Guilloteau  相似文献   
38.
A newborn with rhizomelic bone dysplasia with club-like femora is reported. This is the fourth case Of this easily recognizable, recently reported, congenital bone disease. Maroteaux et al recently reported two patients with rhizomelic bone dysplasia and club-like femora as a distinctive new bone dysplasia. Their observation was confirmed by Gugliantini et al (2) who reported another case. This paper reports a fourth patient with this easily recognisable disorder.  相似文献   
39.
新生大鼠反复惊厥对NMDA受体表达的长期影响   总被引:6,自引:0,他引:6  
目的:研究反复惊厥对大鼠脑内N-甲基-D-天门冬氨酸(NMDA)受体表达,以及成年期认知功能和惊厥阈的长期影响。方法:生后6d(用P6表示,下同)的Wistar大鼠随机分成两组,每组6只,惊厥组每日吸入三氟乙醚诱导惊厥发作1次,每次持续30min,连续6d;对照组同样操作但不吸入三氟乙醚。两组大鼠于P60-P65行Morris水迷宫实验,检测大鼠的学习记忆功能。于P75时给予大鼠腹腔注射戊四唑(PTZ)测定大鼠的惊厥阈。随即断头处死大鼠,分离大脑皮质和海马,匀浆提取细胞膜蛋白,应用免疫印记法测定NMDA受体亚基l(NRl)和NR2A-2D表达的变化。结果:从P6l至P65,两组大鼠寻找平台时间均逐渐缩短,惊厥组大鼠在P65的平均寻找平台时间较对照组显著延长。惊厥组大鼠注射PTZ后发生惊厥的潜伏期与对照组比较差异无显著性。在大脑皮层,惊厥组大鼠较对照组NRl和NR2B表达水平明显下调,在海马这两种亚基表达水平无明显改变,在大脑皮层和海马区,惊厥组较对照组NR2A表达水平明显下调,NR2C表达水平明显上调。两组在皮层和海马均无NR2D表达。结论;新生大鼠反复惊厥可导致远期认知障碍,同时伴有NMDA受体的数量和结构上的长期改变,NMDA受体表达的这种改变可能在发育期惊厥导致的脑长期认知功能损害中起重要作用。  相似文献   
40.
Summary:  Naturally occurring mutants and genetically manipulated strains of mice are widely used to model a variety of human diseases. Atlases are an invaluable aid in understanding the impact of such manipulations by providing a standard for comparison and to facilitate the integration of anatomic, genetic, and physiologic observations from multiple subjects and experiments. We have developed digital atlases of the C57BL/6J mouse brain (adult and neonate) as comprehensive frameworks for storing and accessing the myriad types of information about the mouse brain. Along with raw and annotated images, these contain database management systems and a set of tools for comparing information from different techniques and different animals. Each atlas establishes a canonical representation of the mouse brain and provides the tools for the manipulation and analysis of new data. We describe both these atlases and discuss how they may be put to use in organizing and analyzing data from mouse models of epilepsy.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号