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   927篇
  国内免费   11篇
  完全免费   57篇
  药学   995篇
  2019年   2篇
  2018年   11篇
  2017年   9篇
  2016年   12篇
  2015年   10篇
  2014年   21篇
  2013年   10篇
  2012年   55篇
  2011年   63篇
  2010年   44篇
  2009年   55篇
  2008年   87篇
  2007年   69篇
  2006年   42篇
  2005年   50篇
  2004年   58篇
  2003年   29篇
  2002年   37篇
  2001年   24篇
  1999年   22篇
  1998年   17篇
  1997年   26篇
  1996年   30篇
  1995年   23篇
  1994年   16篇
  1993年   16篇
  1992年   12篇
  1991年   9篇
  1990年   9篇
  1989年   4篇
  1988年   6篇
  1987年   8篇
  1986年   13篇
  1985年   18篇
  1984年   11篇
  1983年   6篇
  1982年   13篇
  1981年   4篇
  1980年   3篇
  1979年   12篇
  1978年   9篇
  1977年   2篇
  1976年   2篇
  1975年   1篇
  1974年   2篇
  1973年   4篇
  1972年   7篇
  1971年   1篇
  1970年   1篇
排序方式: 共有995条查询结果,搜索用时 35 毫秒
1.
Rationale Nicotine has been shown in a variety of studies in humans and experimental animals to improve cognitive function. Nicotinic treatments are being developed as therapeutic treatments for cognitive dysfunction. Objectives Critical for the development of nicotinic therapeutics is an understanding of the neurobehavioral bases for nicotinic involvement in cognitive function. Methods Specific and diverse cognitive functions affected by nicotinic treatments are reviewed, including attention, learning, and memory. The neural substrates for these behavioral actions involve the identification of the critical pharmacologic receptor targets, in particular brain locations, and how those incipient targets integrate with broader neural systems involved with cognitive function. Results Nicotine and nicotinic agonists can improve working memory function, learning, and attention. Both α4β2 and α7 nicotinic receptors appear to be critical for memory function. The hippocampus and the amygdala in particular have been found to be important for memory, with decreased nicotinic activity in these areas impairing memory. Nicotine and nicotinic analogs have shown promise for inducing cognitive improvement. Positive therapeutic effects have been seen in initial studies with a variety of cognitive dysfunctions, including Alzheimer's disease, age-associated memory impairment, schizophrenia, and attention deficit hyperactivity disorder. Conclusions Discovery of the behavioral, pharmacological, and anatomic specificity of nicotinic effects on learning, memory, and attention not only aids the understanding of nicotinic involvement in the basis of cognitive function, but also helps in the development of novel nicotinic treatments for cognitive dysfunction. Nicotinic treatments directed at specific receptor subtypes and nicotinic cotreatments with drugs affecting interacting transmitter systems may provide cognitive benefits most relevant to different syndromes of cognitive impairment such as Alzheimer's disease, schizophrenia, and attention deficit hyperactivity disorder. Further research is necessary in order to determine the efficacy and safety of nicotinic treatments of these cognitive disorders.  相似文献
2.
目的研究加味四逆散(JWSNS)抗应激性抑郁效应及其海马N-甲基-D-天冬氨酸(N-methyl-D-aspartate,NMDA)受体通道的机制。方法采用慢性轻度不可预计应激(chronicmild unpredictable stress,CMUS)制作大鼠抑郁症模型。在造模前后测量基础糖水消耗量和体重的变化;离体海马脑片TTC染色检测各组大鼠海马损伤情况以及JWSNS含药血清的保护作用;运用细胞贴附式膜片钳记录模式检测大鼠海马NMDA受体通道开放概率和平均开放时间的变化,Tillvision图像处理系统检测海马神经元细胞内游离Ca2+浓度。结果CMUS可引起大鼠糖水偏爱度下降(P<0.01),JWSNS和MK801可提高应激性抑郁症大鼠糖水偏爱度(P<0.01,P<0.05),但对大鼠的体重无影响。JWSNS、20%JWSNS含药血清和MK801均能明显升高应激性抑郁症大鼠海马光密度值,降低海马脑片损伤百分率(P<0.05,P<0.01)。模型组大鼠海马NMDA受体通道开放概率明显增高(P<0.05),而JWSNS、MK801能明显降低海马NMDA受体通道开放概率(P<0.05,P<0.01);对NMDA受体通道平均开放时间无明显影响。JWSNS、MK801能明显降低应激性抑郁症大鼠海马神经元内升高的游离Ca2+浓度(P<0.01)。结论JWSNS具有抗抑郁作用,NMDA受体可能是其药理学作用靶点之一,调控海马神经元NMDA受体的功能状态可能是JWSNS发挥抗抑郁效应的直接作用机制之一。  相似文献
3.
目的观察知母皂苷(SAaB)是否对脂多糖(LPS)引起的大鼠学习记忆障碍和炎症反应有改善作用。方法大鼠随机分为对照组、LPS损伤组、LPS+SAaB(20、40mg·kg-1)组。对照组和LPS损伤组大鼠灌胃给予0.2%的二甲基亚砜,SAaB组大鼠灌胃给予SAaB。连续给药7d后,左侧脑室内单次注射LPS30μg/只大鼠,注射量为5μl,正常对照组大鼠注射等量的生理盐水。脑室注射后d2进行大鼠Morris水迷宫实验,连续6d,训练期间继续给药。水迷宫实验结束后,Nissl染色观察海马CA1区锥体神经元改变;白细胞介素-1β(IL-1β)分别与integrinαM和胶质原纤维酸性蛋白(GFAP)双重免疫荧光染色观察IL-1β表达部位;Westernblot检测海马IL-1β、诱导型一氧化氮合酶(iNOS)的表达水平。结果 SAaB(40mg·kg-1·d-1)能明显改善LPS所致大鼠学习记忆能力损伤,表现在明显缩短大鼠的逃避潜伏期,增加大鼠在原平台象限的游泳时间占总游泳时间的百分比;海马CA1区锥体神经元损伤较LPS组明显减轻,对抗LPS引起的IL-1β及iNOS的蛋白表达水平增加;激光共聚焦实验结果显示IL-1β主要在小胶质细胞表达,少量在星形胶质细胞表达。结论 SAaB能改善LPS引起的大鼠学习记忆障碍,抑制其海马的炎症反应。  相似文献
4.
地黄寡糖对谷氨酸诱导海马神经元损伤的影响   总被引:6,自引:1,他引:5  
目的观察地黄寡糖对谷氨酸诱导海马神经元损伤的影响。方法将培养7~9d的SD大鼠海马细胞进行NSE鉴定,然后随机分为:正常组(control);单纯地黄寡糖用药组(ROS);谷氨酸损伤组(Glu);谷氨酸损伤前地黄寡糖预处理组(ROS+Glu)。采用倒置显微镜观察细胞形态学变化,噻唑蓝(MTT)法测定细胞存活率,比色法测定培养液中的乳酸脱氢酶(LDH)含量,流式细胞术测定细胞凋亡率。结果0.1mmol·L-1谷氨酸作用于海马神经元24h,出现明显细胞损伤,细胞存活率下降,培养液中LDH含量明显增加,细胞凋亡率增高(P<0.01);4、20、100mg·L-1的地黄寡糖可不同程度的改善谷氨酸损伤引起的神经细胞形态的改变,提高细胞存活力,减少LDH的漏出,降低细胞凋亡率,并呈一定的剂量依赖性。4、20、100mg·L-1单纯地黄寡糖组与正常组间各指标差异没有显著性(P>0.05)。结论谷氨酸能诱导海马原代细胞的凋亡,地黄寡糖能有效保护海马神经细胞免受谷氨酸诱导的细胞损伤。  相似文献
5.
目的观察吡格列酮(Pio)是否对学习记忆障碍有治疗改善作用。方法大鼠随机分为正常对照组,淀粉样β蛋白片段1-42(Aβ1-42)损伤组,Aβ1-42+Pio20,40及80mg·kg-1组。于d1和2,Pio处理组大鼠灌胃给予Pio,正常对照组和Aβ1-42损伤组灌胃给予0.2%二甲亚砜。d2给药处理后,Aβ1-42损伤组及Pio处理组大鼠左侧脑室内单次注射Aβ1-425μL(2.0mmol·L-1)制备大鼠痴呆动物模型,正常对照组注射等量生理盐水。同时,d2开始进行Morris水迷宫实验,连续6d;水迷宫实验结束后,Nissl染色观察海马CA1区锥体神经元改变和免疫组织化学法观察星形胶质细胞改变;Western蛋白印迹法检测白细胞介素(IL)-1β和诱导型一氧化氮合酶(iNOS)的表达水平。结果脑室注射Aβ1-42可引起大鼠学习记忆能力明显降低,表现为逃避潜伏期延长,原平台象限游泳时间占总时间的比例降低;形态学上表现为海马CA1区锥体神经元的损伤和星形胶质细胞的激活和浸润;同时海马IL-1β和iNOS蛋白表达也显著增加。Pio(40和80mg·kg-1)能明显改善大鼠学习记忆能力,减轻海马CA1区锥体神经元损伤和星形胶质细胞激活与浸润,抑制Aβ1-42引起的IL-1β及iNOS蛋白表达增加。结论Pio能改善Aβ1-42损伤大鼠学习记忆障碍,抑制海马炎症反应可能是其机制之一。  相似文献
6.
Neonatal excitotoxic hippocampal damage in the rat results in postpubertal onset of a variety of abnormal behaviors related to excessive dopaminergic transmission in the mesolimbic/nigrostriatal system, and thus may be considered an animal model of some aspects of schizophrenia. Because sensorimotor gating is impaired in adult patients with schizophrenia and in rats with experimentally induced mesolimbic dopamine hyperactivity, the present experiments investigated the effects of neonatal (postnatal day 7, PD7) ibotenic acid (3 µg) lesions of the ventral hippocampus (VH) on the amplitude and prepulse inhibition (PPI) of acoustic startle in prepubertal (PD35) and postpubertal (PD56) rats. Startle was elicited using 105 and 118-dB pulses alone or preceded by 4, 8, or 16 dB above-background prepulses in rats treated with vehicle or apomorphine (APO; 0.025 or 0.1 mg/kg SC). At PD35, PPI in VH-lesioned rats did not differ significantly from these measures in sham operated rats. Apomorphine significantly increased startle amplitude and reduced PPI in both sham operated and VH-lesioned rats at PD35. At PD56, startle amplitude in VH-lesioned rats was not significantly different from controls, but PPI was reduced significantly compared to controls. Ventral hippocampus lesioned rats also exhibited an exaggerated reduction in PPI after treatment with APO. These findings provide further evidence of postpubertal impairments that may be related to increased mesolimbic dopamine transmission and receptor sensitivity in rats with neonatal hippocampal damage, and provide further support for the fidelity of this animal model of schizophrenia.  相似文献
7.
日本海马温肾壮阳相关活性的实验研究   总被引:4,自引:4,他引:6  
对日本海马进行了温肾壮阳相关活性的实验研究,实验证实,口服日本海马能明显提高氢化可的松所致“阳虚”小鼠的抗疲劳能力,提高小鼠碳粒廓清速率,促进小鼠外周血液溶血素的生成,增加幼鼠前列腺,精囊,睾丸的重量,并且能提高小鼠血清睾酮的含量及睾丸组织中cAMP水平,为其临床应用提供了实验依据。  相似文献
8.
Rationale: The elevated plus-maze provides a test situation in which distinctive states of anxiety are elicited on trials 1 and 2 and the dorsal hippocampus has previously been shown to mediate the anxiogenic effects of (–)-nicotine in the social interaction test. Objective: To determine the effects of a wide dose range of (–)-nicotine on trial 1 and 2 in the plus-maze after systemic administration and whether the dorsal hippocampus is a site mediating the anxiogenic effect of nicotine. Methods: (–)-Nicotine (0.001, 0.005, 0.01, 0.05, 0.1, 0.5 and 1 mg/kg) was injected IP 30 min before testing for 5 min in the plus-maze. Rats receiving dorsal hippocampal infusions received bilateral infusions of 0.5 μl of artificial CSF or (–)-nicotine (0.1, 1, 4 or 8 μg). The needle was left in place for 50 s after injection and testing took place 3 min later. Rats tested on trial 1 were naive to the plus-maze, those tested on trial 2 had received a previous 5-min undrugged exposure to the maze 48 h earlier. Results: Low doses of (–)-nicotine (0.001, 0.005, 0.01, 0.05 and 0.1 mg/kg, IP) were without effect on either trial, but higher doses (0.5 and 1 mg/kg, IP) had anxiogenic effects on both trials, as shown by decreases in percentage time spent and percentage entries onto the open arms. Infusion of (–)-nicotine (0.1, 1, 4 and 8 μg) bilaterally into the dorsal hippocampus was without effect on trial 1, but 1 μg had an anxiolytic effect on trial 2, shown by an increased percentage time spent on the open arms. Conclusions: The results on both trials in the plus-maze after systemic administration of nicotine add to previous reports from the social interaction test that high doses of nicotine have anxiogenic effects. However, the effects of nicotine in the dorsal hippocampus are different in all three anxiety tests (anxiogenic in social interaction, ineffective on trial 1, anxiolytic on trial 2) showing that nicotinic cholinergic control in this brain region may vary depending on the state and/or type of anxiety generated by the test. The brain region(s) underlying the anxiogenic effects of IP nicotine on both trials in the plus-maze remain to be identified. Received: 16 August 1998 / Final version: 10 December 1998  相似文献
9.
目的 探讨氯胺酮(Ket)对未成年大鼠记忆维持能力及海马磷酸化环腺苷酸应答元件结合蛋白(p-CREB)、c-fos表达的影响及其相关性.方法 筛选合格21日龄SD大鼠72只分为正常对照组、生理盐水组、假训练组、氯胺酮组(根据时间与剂量不同分为四个亚组:Ket1a、Ket1b:分别给与氯胺酮50 mg/kg、100 mg/kg腹腔注射后3 d进行训练).生理盐水组腹腔注射等体积的生理盐水.采用Y型迷宫进行学习记忆能力测试,应用免疫组化法检测海马p-CREB、c-fos的表达.结果 与生理盐水组相比,Ket1a、Ket1b组大鼠记忆维持能力下降(P<0.05),同时海马神经元p-CREB、c-fos的表达减少(P<0.05);而Ket3a组、Ket3b组差异无统计学意义(P>0.05).与正常对照组相比,其余各组海马神经元p-CREB、c-fos表达均增多(P<0.05).而Ket1a和Ket1b或Ket3a和Ket3b组之间的行为学指标与免疫组化指标差异均无统计学意义(P>0.05).结论 氯胺酮可能通过抑制未成年大鼠海马p-CREB、c-fos的表达短期影响其记忆维持能力.  相似文献
10.
本文旨在观察丹酚酸B对脑缺血再灌注大鼠神经发生和神经细胞损伤的影响,探讨丹酚酸B促进机体功能恢复的作用环节。研究采用大鼠局灶性脑缺血再灌注模型,治疗给药,用BrdU法观察海马齿状回颗粒下层(sub-granular zone,SGZ)和侧脑室下层(sub-ventricular zone,SVZ)神经发生的变化;尼氏体染色观察神经细胞损伤;平衡杆法观察肢体功能恢复。结果显示,缺血后再灌注7 d,模型组SGZ和SVZ的BrdU细胞明显多于假手术组(P<0.05),丹酚酸B(10 mg·kg-1)显著增加SGZ和SVZ的BrdU细胞数目(P<0.01 vs模型组);缺血再灌注14 d,模型动物缺血侧海马CA1区和皮层神经细胞明显减少,丹酚酸B(10 mg·kg-1)明显改善神经细胞损伤(P<0.01 vs模型组);同时,丹酚酸B(10 mg·kg-1)明显促进缺血动物肢体功能恢复。以上结果表明,丹酚酸B能够增加脑缺血大鼠SVZ和SGZ的BrdU细胞数目,改善缺血区神经细胞损伤,促进肢体功能恢复,提示促进神经发生是丹酚酸B改善脑功能的重要环节。  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