全文获取类型
收费全文 | 29517篇 |
免费 | 2261篇 |
国内免费 | 423篇 |
专业分类
耳鼻咽喉 | 63篇 |
儿科学 | 779篇 |
妇产科学 | 527篇 |
基础医学 | 4905篇 |
口腔科学 | 445篇 |
临床医学 | 2776篇 |
内科学 | 3119篇 |
皮肤病学 | 384篇 |
神经病学 | 4938篇 |
特种医学 | 289篇 |
外国民族医学 | 3篇 |
外科学 | 1149篇 |
综合类 | 2579篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 6381篇 |
眼科学 | 82篇 |
药学 | 2815篇 |
11篇 | |
中国医学 | 416篇 |
肿瘤学 | 538篇 |
出版年
2024年 | 108篇 |
2023年 | 515篇 |
2022年 | 976篇 |
2021年 | 1363篇 |
2020年 | 1157篇 |
2019年 | 1057篇 |
2018年 | 969篇 |
2017年 | 1056篇 |
2016年 | 1094篇 |
2015年 | 951篇 |
2014年 | 1629篇 |
2013年 | 2449篇 |
2012年 | 1366篇 |
2011年 | 1580篇 |
2010年 | 1189篇 |
2009年 | 1202篇 |
2008年 | 1264篇 |
2007年 | 1227篇 |
2006年 | 1157篇 |
2005年 | 910篇 |
2004年 | 805篇 |
2003年 | 732篇 |
2002年 | 638篇 |
2001年 | 525篇 |
2000年 | 413篇 |
1999年 | 375篇 |
1998年 | 313篇 |
1997年 | 312篇 |
1996年 | 269篇 |
1995年 | 259篇 |
1994年 | 235篇 |
1993年 | 213篇 |
1992年 | 203篇 |
1991年 | 208篇 |
1990年 | 172篇 |
1989年 | 177篇 |
1988年 | 169篇 |
1987年 | 157篇 |
1986年 | 206篇 |
1985年 | 303篇 |
1984年 | 302篇 |
1983年 | 192篇 |
1982年 | 258篇 |
1981年 | 254篇 |
1980年 | 249篇 |
1979年 | 219篇 |
1978年 | 160篇 |
1977年 | 174篇 |
1976年 | 160篇 |
1975年 | 111篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
《Nutrition, metabolism, and cardiovascular diseases : NMCD》2022,32(12):2883-2889
Background and aimsCoronary artery disease (CAD) is the principal cause of death in individuals with non-alcoholic fatty liver disease (NAFLD). The aim of this study was to use genetic epidemiology to study the association between de novo lipogenesis (DNL), one of the major pathways leading to NAFLD, and CAD risk.Methods and resultsDNL susceptibility genes were used as instruments and selected using three approaches: 1) genes that are associated with both high serum triglycerides and low sex hormone-binding globulin, both downstream consequences of DNL (unbiased approach), 2) genes that have a known role in DNL (biased approach), and 3) genes that have been associated with serum fatty acids, used as a proxy of DNL. Gene-CAD effect estimates were retrieved from the meta-analysis of CARDIoGRAM and the UK Biobank (~76014 cases and ~264785 controls). Effect estimates were clustered using a fixed-effects meta-analysis. Twenty-two DNL susceptibility genes were identified by the unbiased approach, nine genes by the biased approach and seven genes were associated with plasma fatty acids. Clustering of genes selected in the unbiased and biased approach showed a statistically significant association with CAD (OR:1.016, 95%CI:1.012; 1.020 and OR:1.013, 95%CI:1.007; 1.020, respectively), while clustering of fatty acid genes did not (OR:1.004, 95%CI:0.996–1.011). Subsequent exclusion of potential influential outliers did reveal a statistically significant association (OR:1.009, 95%CI:1.000; 1.018).ConclusionsDNL susceptibility genes are associated with an increased risk of CAD. These findings suggest that DNL may be involved in the pathogenesis of CAD and favor further development of strategies that target NAFLD through DNL. 相似文献
3.
Convergent Reliability and Validity of the Questions About Behavioral Function and the Motivation Assessment Scale: A Replication Study 总被引:1,自引:1,他引:0
Karrie A. Shogren Johannes Rojahn 《Journal of developmental and physical disabilities》2003,15(4):367-375
This study compared key psychometric properties of the Motivation Assessment Scale (MAS) and the Questions About Behavioral Function (QABF) and explored their convergent validity. Twenty adults with mental retardation and problem behaviors (aggression, self-injury, or property destruction) and 31 respondents participated. Test–retest reliability of the subscales in both scales was good to excellent (Cicchetti, D. V., 1994, Psychol. Assess. 6: 284–290), and—except for 1 QABF subscale—internal consistency was good considering the small number of items and the purpose of the scale. Consistent with some earlier studies, interrater reliability was less satisfactory with both scales falling only into the fair to good range.Correlations between functionally equivalent subscales were statistically significant and were generally higher than correlations between nonequivalent subscales. The QABF and the MAS were found to be comparable in terms of the assessed reliabilities, and both instruments appear to be measuring very similar constructs. 相似文献
4.
5.
Fos Expression in the Rat Brain Following Vaginal-Cervical Stimulation by Mating and Manual Probing 总被引:4,自引:2,他引:2
Marc J. Tetel Michael J. Getzinger Jeffrey D. Blaustein 《Journal of neuroendocrinology》1993,5(4):397-404
Vaginal-cervical stimulation (VCS), provided by mating or manual probing, induces many reproductive behavioral and endocrine changes in female rats. These changes include an increase in lordosis duration, heat termination and pseudopregnancy. Electro-physiological and [14C]2-deoxy-D-glucose studies collectively show that neurons in the medial preoptic area, ventromedial hypothalamus and midbrain central gray respond to manual VCS. In the present study we immunocytochemically labeled brain sections for Fos, the protein product of the immediate early gene c-fos, to detect VCS-responsive neurons in hormone-primed animals receiving VCS by mating or manual probing. In Experiment 1, females receiving mounts and intromissions were compared to: 1) vaginally-masked females receiving mounts but no VCS, 2) females exposed to an intact anesthetized male or 3) females not exposed to males or the testing arena. Those animals receiving VCS showed a dramatic increase in the number of Fos-immunoreactive cells in the medial preoptic area, posterodorsal portion of the medial amygdala and bed nucleus of the stria terminalis, as well as the dorsomedial hypothalamus, ventromedial hypothalamus and midbrain central gray. These effects of VCS were confirmed in Experiment 2 in animals receiving manual vaginal-cervical probing. These findings extend previous electrophysiological and [14C]2-deoxy-D-glucose studies by providing evidence that additional brain areas respond to VCS by mating, as well as manual probing. 相似文献
6.
Meir Steiner Richard J. Katz Giulio Baldrighi Bernard J. Carroll 《Psychoneuroendocrinology》1981,6(1):81-90
(1) The estrous cycle in the rat may be used to study recurrent changes in motor behaviors and motivation which are strongly related to cyclic hormonal and CNS changes. (2) The peak in motivated behaviors occurs during a sharply defined period on the night between proestrus and estrus and is evident in facilitated wheel-running, lordosis, and intracranial self-stimulation. (3) Behaviors without a clearly motivated character do not show an estrous cyclicity. (4) The estrous cyclic variation in intracranial self-stimulation was observed at a specific locus — the pars campacta of the substantia nigra. (5) A neurochemical link between sexually motivated behavior, wheel running and intracranial self-stimulation is suggested. This link is in part dopaminergic but is probably also activated by many other systems. 相似文献
7.
D. Caroline Blanchard Jon K. Shepherd Antonio De Padua Carobrez Robert J. Blanchard 《Neuroscience and biobehavioral reviews》1991,15(4):461-468
Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety. 相似文献
8.
9.
10.