全文获取类型
收费全文 | 20178篇 |
免费 | 1352篇 |
国内免费 | 283篇 |
专业分类
耳鼻咽喉 | 41篇 |
儿科学 | 512篇 |
妇产科学 | 203篇 |
基础医学 | 3628篇 |
口腔科学 | 368篇 |
临床医学 | 2060篇 |
内科学 | 1520篇 |
皮肤病学 | 149篇 |
神经病学 | 3936篇 |
特种医学 | 181篇 |
外国民族医学 | 1篇 |
外科学 | 496篇 |
综合类 | 1794篇 |
一般理论 | 1篇 |
预防医学 | 4048篇 |
眼科学 | 37篇 |
药学 | 2301篇 |
8篇 | |
中国医学 | 223篇 |
肿瘤学 | 306篇 |
出版年
2023年 | 273篇 |
2022年 | 464篇 |
2021年 | 950篇 |
2020年 | 715篇 |
2019年 | 585篇 |
2018年 | 531篇 |
2017年 | 624篇 |
2016年 | 673篇 |
2015年 | 645篇 |
2014年 | 1157篇 |
2013年 | 1587篇 |
2012年 | 1001篇 |
2011年 | 1165篇 |
2010年 | 828篇 |
2009年 | 872篇 |
2008年 | 912篇 |
2007年 | 878篇 |
2006年 | 827篇 |
2005年 | 662篇 |
2004年 | 542篇 |
2003年 | 517篇 |
2002年 | 450篇 |
2001年 | 348篇 |
2000年 | 273篇 |
1999年 | 260篇 |
1998年 | 213篇 |
1997年 | 201篇 |
1996年 | 170篇 |
1995年 | 162篇 |
1994年 | 147篇 |
1993年 | 127篇 |
1992年 | 138篇 |
1991年 | 131篇 |
1990年 | 114篇 |
1989年 | 119篇 |
1988年 | 121篇 |
1987年 | 99篇 |
1986年 | 148篇 |
1985年 | 247篇 |
1984年 | 242篇 |
1983年 | 174篇 |
1982年 | 213篇 |
1981年 | 200篇 |
1980年 | 195篇 |
1979年 | 181篇 |
1978年 | 127篇 |
1977年 | 139篇 |
1976年 | 130篇 |
1975年 | 92篇 |
1973年 | 73篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
101.
Buprenorphine, a partial mu-opioid receptor agonist, has been proposed as a treatment for cocaine abuse. However, studies
in animals have produced conflicting results on the nature of the interaction between buprenorphine and cocaine. In some studies,
buprenorphine attenuated the effects of cocaine and in others it enhanced them. The purpose of the present study was to evaluate
the interaction of buprenorphine and cocaine on the rotational behavior of the nigrally-lesioned rat. Both buprenorphine (0.003–0.1
mg/kg) and cocaine (1.0– 30 mg/kg) alone produced dose-dependent increases in rotational behavior. Buprenorphine produced
long-lasting turning with a peak at 60 min after administration, while cocaine produced turning that peaked immediately after
administration and lasted for about 2 h. To distinguish simple additivity from other possible outcomes, we determined the
relative potency of each drug alone, using a defined level of effect: 150 turns above the saline control in 4 h. This effect
was produced by 10.0 mg/kg cocaine alone and by 0.0175 mg/kg buprenorphine alone. Based on these results, fixed ratio combinations
were tested and the experimentally derived effects were compared to the theoretically additive values, using an isobolographic
analysis. The fixed ratio combinations of the two drugs tested produced turning greater than predicted from simple additivity.
This finding provides statistically-supported evidence for synergism between the actions of buprenorphine and cocaine.
Received: 28 January 1997 / Final version: 7 June 1997 相似文献
102.
ITSUGI NAGATOMO MD SYUNJI IWAGAWA MD MORIKUNI TAKIGAWA MD 《Psychiatry and clinical neurosciences》1997,51(2):53-56
Abstract We investigated factors correlated with abnormal behavior in the elderly residing in a special nursing home (group A) and a psychiatric hospital (group B) using the dementia behavior disturbance scale, the mini mental state examination, the Japanese version of the Philadelphia Geriatric Center morale scale, and the ADL assessment scale. The cognitive function of group B was decreased compared with that of group A, but most activities of daily living (ADL) in the latter group were disrupted compared with those in the former. Only a few categories of ADL correlated with abnormal behavior in group A, whereas cognitive function, quality of life, and most categories of ADL correlated with abnormal behavior in group B. These results suggest that factors correlated with abnormal behavior in the elderly differ within institutions of medical and social welfare systems. 相似文献
103.
104.
临床护理本科生对教师行为评价的调查与分析 总被引:3,自引:0,他引:3
目的 了解护理本科生对临床带教教师的教学行为评价,找出存在问题,提高教学质量.方法 采用问卷调查法,对教师自身行为(7项)教师教学行为(8项),对学生态度行为(7项)三个方面进行调查.结果 对教师自身行为,教师教学行为,对学生的态度行为进行方差分析,F=0.021,说明三者之间存在差异.进一步用LSD法作两两分析发现教师的教学行为与教师自身行为和对学生的态度行为之间的差异显著(P《0.05).对教师教学行为中表明组内实习内容安排有计划,并能按时完成内容;每次教学活动有准备,按程序进行;能充分利用医疗资源供学生学习;有启发式、引导式提问.与其余四项进行比较差异显著(P《0.05),说明二者之间存在一定的差异.结论 临床教师的教学行为是学生关注的重点,教师应加强这方面的培养,以保证教学质量. 相似文献
105.
Two surveys of a Northern Ireland student sample were conducted in 1987 and 1988. A total of 419 female and 201 male subjects completed self-administered anonymous questionnaires concerning their behavior, knowledge, and attitudes towards sex, AIDS, homosexuality, contraception, and relationships. Results indicated a relatively low level of sexual experience, and for those with experience, relatively few partners. The possible influences of gender and religiosity on sexual behavior and attitudes, in the context of Northern Ireland, are discussed. Subjects reported considerable variation in the amount of sex education, but the majority received little or none. This student sample held relatively conservative attitudes towards love, sex, and marriage and this was particularly true for females and for regular churchgoers. In addition, attitudes towards homosexuality were negative (particularly among regular churchgoers). Attitudes towards contraception were more positive than expected among Catholic subjects, and few indicated that they would refuse to use contraceptives on principle. Responses to items about AIDS were highly uniform, suggesting that much of the information made available to the public has been absorbed. However, the lack of uniformity of response to more general items about sex, relationships, and contraception may indicate that fundamental changes in sexual behavior are unlikely to be brought about by influencing a rather narrowly defined set of attitudes about AIDS. 相似文献
106.
During reproductive maturation of female insects, the acquisition of sexual receptivity is coordinated with ovarian development. Juvenile homone regulates vitellogenesis in the ovaries, but the action of this hormone in the development of sexual behavior is less well-understood. A strain ofDrosophila melanogaster carrying a mutation in theapterous gene(ap
4) was known to exhibit arrested vitellogenesis (rescuable by applying exogenous juvenile hormone), sterility of both sexes, and a deficiency of juvenile hormone. In this study, we examined the effects of mutations ofap on female receptivity and its relationship to juvenile hormone. We observed abnormally low female receptivity in homozygousap strains, and heteroallelic combinations ofap mutations exhibited low receptivity. For female receptivity,ap showed no dominance (i.e.,ap/ap
+ was intermediate betweenap/ap andap
+/ap
+). Low receptivity mapped genetically to theap locus. The reduction in female receptivity in these mutants is positively correlated with levels of juvenile hormone synthesized by their corpora allata.This work was supported in part by The Scheinfeld Center for Humans Genetics in the Social Sciences (J.R.), The National Science Foundation (BNS-882 1339 to J.R.), BARD (No. IS-1664-89R to D.S.), The Israel Cancer Research Fund (grant to D.S.), The Rekanati Foundation of Tel Aviv University (grant to D.S.), and The Israeli Fruit Council (award to M.A.) 相似文献
107.
Katherine A. Vittes Ph.D. Susan B. Sorenson Ph.D. 《The Journal of adolescent health》2006,39(6):929-932
In a survey of 5657 community-residing adolescents, those who said they could get a handgun in two days reported similar and those who said they could not get a handgun reported fewer risk behaviors and less violence perpetration and victimization than adolescents who have their own handgun. Adolescents who said they could get a handgun reported more exposure to and experience with firearms than those who said they could not get a handgun. Risk reduction efforts regarding adolescents should be expanded to include adolescents who say they can get a handgun. 相似文献
108.
Kelvin L Chou Maria L Moro-De-Casillas Melissa M Amick Leora L Borek Joseph H Friedman 《Movement disorders》2007,22(3):411-414
We examined the relationship between testosterone levels, violent dreams, and REM sleep behavior disorder (RBD) in 31 men with Parkinson's disease (PD): 12 with clinical RBD and 19 without. All PD patients with clinical RBD experienced violent dreams, but none of the 19 non-RBD patients reported violent dreams. While dream content appears to be more aggressive in PD patients with clinical RBD, the presence of violent dreams or clinical RBD is not associated with testosterone levels in men with PD. 相似文献
109.
BCPT对慢性应激抑郁大鼠行为及体重的影响 总被引:7,自引:0,他引:7
目的:研究一种拟青霉代谢物提取物(BCPT)对慢性轻度不可预见性应激(CUMS)大鼠行为及体重的影响.方法:采用CUMS法,造成大鼠抑郁模型,定期测量BCPT对该模型大鼠的体重及糖水消耗量,以开野实验的方法测定大鼠水平及垂直活动.结果:与正常组相比,模型组大鼠体重增长缓慢,糖水消耗量明显下降,水平活动和垂直活动均明显下降.与模型组大鼠相比,BCPT组大鼠体重增长略有提高,糖水消耗量明显增加,水平活动和垂直活动均明显增加.结论:本模型为较理想的抑郁模型,BCPT能明显改善抑郁大鼠的行为活动及体重,提示BCPT具有一定的抗抑郁作用. 相似文献
110.
Josefa Vega-Matuszczyk Viveka Hillegaart Knut Larsson Sven Ahlenius 《Brain research》1993,630(1-2):82-87
Regional changes in the rate of brain monoamine synthesis were monitored in male rats exposed to, but prevented from physical contact with, an estrous or an ovariectomized female. The in vivo rate of tyrosine and tryptophan hydroxylase activities were estimated by measuring the accumulation of DOPA and 5-HTP following inhibition of cerebral aromatic l-amino acid decarboxylase by means of 3-hydroxybenzylhydrazine (NSD-1015) treatment (100 mg/kg i.p.) 5 min upon NSD-1015 treatment, the males were exposed to an intact estrous female or an ovariectomized female for 20 min before decapitation and brain dissections. Exposure to an estrous female produced an increased rate of tyrosine and tryptophan hydroxylase activity in the medial prefrontal cortex, the dorso-lateral neostriatum and in the ventral neostriatum, in comparison with home-cage controls. By the same comparison, exposure to an ovariectomized female resulted in an increased rate of tyrosine hydroxylase activity in the medial prefrontal cortex, byt not in the neostriatal areas, whereas tryptophan hydroxylase activity was unaffected. Finally, exposure to the empty test cage, with no stimulus females present, did not produce any statistically significant changes in the rate of tyrosine or tryptophan hydroxylase activity in any of the brain areas sampled. Taken together with recent findings from this laboratory, the present results demonstrate that the level of sexual motivation brought about by the olfactory, auditory and/or visual stimulation of a receptive female is associated with an increased demand on catecholamine and 5-hydroxytryptamine synthesis in the limbic forebrain of the male rat. The finding that the presence of an unestrous female produced an enhanced demand on tyrosine hydroxylase activity in the medial prefrontal neocortex demonstrates that the sexual incentive provided by the estrous female may not be the only factor responsible for all the effects observed in the present study. In fact, there is a distinct possibility that the intense challenge produced by sexually significant stimuli is but an endpoint, and that the changes found in forebrain monoamine synthesis is a reflection of an environmental challenge not necessarily specifically linked to the sexual behavior. 相似文献