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   2913篇
  免费   187篇
  国内免费   50篇
耳鼻咽喉   72篇
儿科学   28篇
妇产科学   27篇
基础医学   424篇
口腔科学   13篇
临床医学   141篇
内科学   499篇
皮肤病学   12篇
神经病学   322篇
特种医学   149篇
外科学   114篇
综合类   157篇
预防医学   265篇
眼科学   40篇
药学   453篇
中国医学   128篇
肿瘤学   306篇
  2023年   51篇
  2022年   90篇
  2021年   118篇
  2020年   150篇
  2019年   128篇
  2018年   112篇
  2017年   97篇
  2016年   100篇
  2015年   99篇
  2014年   221篇
  2013年   274篇
  2012年   157篇
  2011年   220篇
  2010年   133篇
  2009年   145篇
  2008年   142篇
  2007年   109篇
  2006年   87篇
  2005年   76篇
  2004年   57篇
  2003年   44篇
  2002年   48篇
  2001年   34篇
  2000年   29篇
  1999年   24篇
  1998年   21篇
  1997年   11篇
  1996年   15篇
  1994年   13篇
  1993年   12篇
  1992年   12篇
  1990年   9篇
  1989年   10篇
  1988年   11篇
  1987年   14篇
  1986年   10篇
  1985年   15篇
  1984年   16篇
  1983年   11篇
  1982年   18篇
  1981年   13篇
  1980年   13篇
  1979年   16篇
  1978年   14篇
  1976年   12篇
  1975年   18篇
  1974年   16篇
  1973年   29篇
  1972年   16篇
  1971年   11篇
排序方式: 共有3150条查询结果,搜索用时 15 毫秒
1.
2.
Objective: The objective of this study was to gain greater insight into individuals’ quality of life (QOL) definitions, appraisals, and adaptations following spinal cord injury (SCI).

Design: A mixed-methods design, applying the Schwartz and Sprangers response shift (RS) model. RS is a cognitive process wherein, in response to a change in health status, individuals change internal standards, values, or conceptualization of QOL

Setting: Community-dwelling participants who receive medical treatment at a major Midwestern medical system and nearby Veterans’ Affairs hospital.

Participants: A purposive sample of participants with SCI (N?=?40) completed semi-structured interviews and accompanying quantitative measures.

Interventions: Not applicable.

Outcome Measures: Qualitative data were analyzed using content analysis to identify themes. Analysis of variance were performed to detect differences based on themes and QOL, well-being, and demographic and injury characteristics.

Results: Four RS themes were identified, capturing the range of participant perceptions of QOL. The themes ranged from complete RS, indicating active engagement in maintaining QOL, to awareness and comparisons redefining QOL, to a relative lack of RS. Average QOL ratings differed as a function of response shift themes. PROMIS Global Health, Anxiety, and Depression also differed as a function of RS themes.

Conclusion: The RS model contextualizes differences in QOL definitions, appraisals, and adaptations in a way standardized QOL measures alone do not.  相似文献   

3.
医保对象对职工医疗保险制度反应性的分析   总被引:3,自引:0,他引:3  
该文对享受上海市城镇职工基本医疗保险的市民进行随机抽样调查,就其对医保政策的评价和就医行为反应性改变,分析医保改革的有效性和震荡度.提出加强医保法制建设,强化费用分担意识,完善医保政策,进一步体现福利性、公益性、公平性.  相似文献   
4.
青年男性MMPI-215F量表应答时间效应分析   总被引:1,自引:1,他引:0  
目的分析青年男性心理测评中F量表条目应答时间,研究其相关影响因素和变化规律,并对该测评计算机化过程中应答时间的设定提供一定的参考.方法使用MMPI-215对全国18个省市的青年男性进行测试,利用计算机对时间记录,汇总分析.结果青年男性在F量表各条目平均应答时间(以下简称F均时)为4.57s;低于总测试的各条目平均应答时间(6.34 s)(P<0.01);F均时与F分数、应答前后不一致的条目数以及漏答条目数有显著相关;F均时受文化程度、年龄、城乡结构多种因素影响;每个条目的应答时间主要取决于条目汉字的个数.结论 F均时在测评中表现出一定的变化规律,可以结合临床进一步深入研究,使其成为评价青年男性性格特征的客观性指标之一.  相似文献   
5.
Summary In the 4th International Workshop on Chronic Lymphocytic Leukaemia (CLL), staging and response criteria were proposed to help physicians make decisions on when and how to treat patients with CLL. The most important factor is prolonging survival. There are several promising new treatment approaches under investigation, and the criteria proposed should facilitate future therapy trials.Supported in part by grants 89-0353 (Fondo de Investigaciones Sanitarias de la Seguridad Social), PA 85-0234 and PB 86-0593 (Dirreción General de Investigación Científica y Técnica), Ministerio de Educación y Ciencia  相似文献   
6.
The hypothesis that responding contributes to the reward value of brain stimulation was tested in two novel experimental paradigms. In the first experiment rats lever-presssed for rewarding brain stimulation during 90 sec periods. After each period the lever automatically retracted and experimenter-administered stimulation (EAS) was presented at the same rate and current parameters as during the self-stimulation (SS). The rats could demonstrate a preference for SS (vs EAS) by pressing a reset lever on the opposite wall of the test chamber. This action terminated the EAS and reinstated the SS-lever for an additional 90 sec. Results showed that the rats preferred to respond for stimulation than to have that same stimulation administered by the experimenter. This was true even when a signal preceded each train of EAS or when subjects had a great deal of previous EAS experience. In the second experiment conditioned taste preferences were observed following novel taste/SS pairings but not following novel taste/EAS pairings. The data from these two experiments suggest that responding contributes to the rewarding value of brain stimulation.  相似文献   
7.
Work undertaken to investigate the effect on EEG responses of ocular artefact removal by proportional electro-oculogram subtraction using the least-squares method is reported. The ocular artefact model and the least-squares approach to estimation of the model parameters and hence of the EEG waveform, including the response, are described. Results are presented to show that the response shapes become modified if ocular artefact removal is implemented recursively. This happens because the response is incorrectly treated as part of the random background EEG. The solution is to incorporate a model of the response within the ocular artefact removal algorithm. The results of tests on simulated data confirm these conclusions. The results of the incorporation of response models in removing ocular artefacts from CNV recordings are presented. Even with modelling recursive ocular artefact removal is found to modify the shape of the CNV, and so reliable results can only be obtained if the removal is implemented nonrecursively. Evidence is given that it is advisable to remove DC levels from the recorded data.  相似文献   
8.
In decerebrate cats, rotation about the longitudinal axis of the animal, leading to sinusoidal stimulation of labyrinth receptors, produces a tonic contraction of limb extensors during side-down tilt ( responses) and of dorsal neck extensors during side-up tilt ( responses). These changes in posture are mediated, at least in part, by lateral vestibular nucleus (LVN) neurons, with response characteristics to stimulation of macular and/or canal receptors that have so far been evaluated at the level of either unidentified vestibulospinal (VS) neurons or vestibulo-collic neurons projecting to the upper cervical cord. In the present study we investigated the dynamics of the responses of VS neurons projecting to the lumbosacral segments of the spinal cord to increasing frequencies of tilt (from 0.026 to 0.32 Hz, ±10°). All the recorded units showed an average phase lead with respect to position of +25.6±5.5° (SE) at the tilt frequency of 0.026 Hz. Most of these neurons (n=32) were particularly activated during side-down tilt ( responses) and showed either a stable phase or an increase in phase lead of the responses with increasing frequency of tilt. At the tilt frequency of 0.026 Hz, the smaller the phase lead of the responses, the larger was the response gain. Moreover, the smaller the phase lead of the responses at that frequency of tilt, the smaller the increase in gain but the larger was the increase in lead of the responses obtained by increasing the stimulation frequency up to 0.32 Hz. Through this set of finely organized changes in unit response characteristics, the overall output of this population of neurons increased, while the phase angle of the responses reached the mean value of +64.9±2.6° (SE), thus becoming more related to the velocity than to the positional signal. The remaining units (n=7), which were mainly activated during side-up tilt ( responses), displayed an increase in phase lag of the responses to increasing frequency of stimulation, which reached the mean value of-118.9±14.5° (SE) at 0.32 Hz. The differences in the dynamic properties of these VS neurons projecting to the lumbosacral cord, with respect to those of previously recorded populations of VS neurons, are discussed.  相似文献   
9.
Prefrontocortical dopamine (DA) plays an essential role in the regulation of cognitive functions and behavior. The orbitofrontal cortex (OFC) receives a dopaminergic projection from the ventral tegmental area and is particularly important for goal-directed appetitive behaviors and for the neural representation of reward value. We here examined the effects of DA receptor blockers locally infused into the OFC, on instrumental behavior under a progressive schedule of reinforcement. After continuous reinforcement training (lever pressing for casein pellets) rats received bilateral intra-OFC-infusions of the DA D1-receptor antagonist SCH23390 (3 μg/0.5 μl), the DA D2-receptor antagonist sulpiride (3 μg/0.5 μl), or phosphate buffered saline through chronically indwelling cannulae. Immediately after infusion they were tested under a time-constrained progressive ratio schedule of reinforcement (3, 6, 9, 12, … lever presses for 1 casein pellet within 180 s). Both SCH23390 and sulpiride led to a significant reduction of the break point (cessation to respond to the increasing criterion of instrumental effort) compared to vehicle infusions. A food preference test revealed no drug effects on the amount of consumed pellets and on the preference of casein pellets over laboratory chow. Leftward shifts of the break point in progressive ratio tasks indicate a disturbance of the mechanisms that translate motivation into appetitive behavior under conditions of increasing instrumental effort. Therefore, our data indicate that orbitofrontal dopamine is necessary for reward-related instrumental behavior.  相似文献   
10.
The aim of the present research was to study individual response specificity in 22 male patients having essential hypertension (HT) and to compare these patients with age-matched male normotensive controls (NT). Four stimuli, letter identification, mental arithmetic, cold pressor and isometric exercise, were administered while recordings were made of: systolic and diastolic blood pressures, heart rate, respiration, forearm and hand blood flows, and skin conductance level and fluctuations. After each session urine samples were collected and epinephrine and norepinephrine levels were analyzed. Twelve subjects in the HT group were given beta-adrenergic blocking agents and retested 1 to 21 months (X?= 12 months) after the first session. Each response was standardized, using NT as the reference group. Intraclass correlations were computed to evaluate whether HT males reacted with a more consistent hierarchy of responses than did NT. Intraclass correlations were significantly higher among the patients than in the control group, regardless of whether the blood pressure response was included or excluded in the computation of the intraclass correlations. Thus, we conclude that male HT patients show more individual response specificity than NT controls. Beta-adrenergic receptor antagonists reduced levels of cardiovascular activity and attenuated reactivity but did not affect amount of specificity. Thus, intraclass correlations provide unique and useful information, since they are not related to blood pressure reactivity or to urinary catecholamine levels, nor affected by beta-adrenergic blockade.  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