全文获取类型
收费全文 | 1766篇 |
免费 | 251篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 2篇 |
妇产科学 | 2篇 |
基础医学 | 74篇 |
临床医学 | 22篇 |
内科学 | 70篇 |
皮肤病学 | 10篇 |
神经病学 | 103篇 |
特种医学 | 13篇 |
外科学 | 24篇 |
综合类 | 496篇 |
预防医学 | 13篇 |
眼科学 | 4篇 |
药学 | 266篇 |
中国医学 | 976篇 |
肿瘤学 | 1篇 |
出版年
2024年 | 11篇 |
2023年 | 23篇 |
2022年 | 37篇 |
2021年 | 45篇 |
2020年 | 55篇 |
2019年 | 45篇 |
2018年 | 31篇 |
2017年 | 55篇 |
2016年 | 60篇 |
2015年 | 53篇 |
2014年 | 122篇 |
2013年 | 128篇 |
2012年 | 150篇 |
2011年 | 133篇 |
2010年 | 113篇 |
2009年 | 111篇 |
2008年 | 125篇 |
2007年 | 106篇 |
2006年 | 93篇 |
2005年 | 94篇 |
2004年 | 70篇 |
2003年 | 85篇 |
2002年 | 64篇 |
2001年 | 53篇 |
2000年 | 42篇 |
1999年 | 27篇 |
1998年 | 26篇 |
1997年 | 21篇 |
1996年 | 18篇 |
1995年 | 14篇 |
1994年 | 11篇 |
1993年 | 12篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1973年 | 1篇 |
1971年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有2083条查询结果,搜索用时 0 毫秒
1.
益气复智颗粒对多发脑梗死性痴呆模型大鼠脑组织细胞凋亡的影响 总被引:1,自引:0,他引:1
目的 观察益气复智颗粒对多发脑梗死性痴呆模型大鼠脑皮质形态学、细胞凋亡的影响。方法 采用颈内动脉注射血栓的方法,复制多发梗死性痴呆大鼠模型,观察益气复智颗粒12.42g/kg分别于手术前、手术前后、手术后灌胃对实验动物脑皮质形态学、细胞凋亡的影响。结果 益气复智颗粒能使脑缺血后脑内神经细胞凋亡数目下降。结论 益气复智颗粒具有较好的保护脑神经元,阻断脑缺血致神经细胞死亡病理过程的作用。 相似文献
2.
目的建立滑膜炎颗粒剂中原儿茶醛的含量测定方法质量。方法采用高效液相色谱法对方中原儿茶醛进行含量测定。结果高效液相色谱法测定结果表明原儿茶醛在0.1005~1.005μg范围内呈线性关系,平均加样回收率为99.22%;RSD为0.72%。结论本法简便,重现性好、结果可靠,可作为控制滑膜炎颗粒剂的质量方法。 相似文献
3.
The cellular and regional distribution of glutathione (GSH) and GSH-related enzyme systems involved in cellular defense against reactive oxygen species and electrophilic xenobiotics in the nervous system has been extensively studied. However, little is known about the subcellular distribution of GSH systems in brain tissue and cultured neural cells. The present study investigates the distribution of mitochondrial and cytosolic GSH and GSH-related enzymes in cultured cerebellar astrocytes and granule cells, and compares them with levels in the adult rat cerebellum. Cytosolic GSH levels and cytosolic activities of glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) in astrocytes were 57, 153, 245, and 92% higher than those found in granule cells, respectively. In contrast, granule cells contained significantly higher mitochondrial GSH levels than astrocytes. Granule cells also demonstrated comparable mitochondria/cytosolic concentrations of GSH and GR, GPX and GST activities to those observed in the cerebellar tissue, whereas ratios in astrocytes were markedly lower. Although in vitro treatments with 100 μM ethacrynic acid depleted both cytosolic and mitochondrial GSH in cultured astrocytes and granule cells in a time-dependent fashion, cellular GSH in granule cells was more resistant to the GSH-depleting agent than astrocytes. These results suggest that although GSH and GSH-related enzymes are abundant in cytosolic compartments of astrocytes, mitochondrial pools are relatively small. Since brain mitochondria are sites of significant hydrogen peroxide generation, the mitochondrial localization of GSH and its associated enzymes in neural cells provide important defenses against toxic oxygen species in the nervous system. Differences in subcellular distribution of GSH systems in individual neural cell types may provide a basis for selective cellular and/or subcellular expression of neurotoxicity. 相似文献
4.
H. B. Jones C. R. Jenkins A. L. Bowdler M. G. Simpson E. A. Lock 《Acta neuropathologica》1997,93(3):241-251
The objectives of the studies described were to assess the ultrastructural neuropathology, blood-brain barrier (BBB) integrity
and calcium status of the cerebellum of rats following a single dose of 750 mg · kg–1
l-2-chloropropionic acid (l-2-CPA). The first indications of intoxication appeared at 36 h when condensation of many granule cells associated with Purkinje
cell degeneration and marked astroglial swelling were observed. Some electron-lucent granule cells were also noted lying amongst
these condensed forms. Condensed granule cells had swollen, electron-lucent mitochondria, dilated Golgi apparatus and nuclear
crenation. Occasionally, areas of granule cell necrosis were also present at this time. Granule cell condensation probably
represents a preliminary and irreversible stage in an excitotoxic process that leads to necrosis. At 48 and 72 h, most granule
cells were necrotic, and occasionally, extravasation of both erythrocytes and leucocytes into the expanded extravascular space
was observed. Evaluation of the BBB by ultrastructural cytochemical visualisation of horseradish peroxidase injected i.v.
2 min before killing by perfusion fixation showed substantial leakage. At 36 h post-dose, ultrastructural calcium localisation
using oxalate/pyroantimonate precipitation demonstrated a substantial increase in calcium pyroantimonate precipitate in mitochondria
and other membranous cytoplasmic organelles (especially the Golgi apparatus) in condensed granule cells, but with little in
their nuclei. However, their immediate neighbours (of ostensibly normal ultrastructural appearances) contained greater amounts
of intranuclear precipitate. Swollen astroglial cells (especially the Bergmann glia) contained considerable quantities of
precipitate. A possible excitotoxic mechanism via l-2-CPA-induced NMDA receptor agonism leading to overwhelming calcium influx and disruption of cellular calcium homeostasis
is proposed.
Received: 8 May 1996 / Revised: 1 September 1996 / Accepted: 11 September 1996 相似文献
5.
大鼠创伤性肠粘连模型的制备及黄厚排气颗粒对其粘连程度的影响 总被引:5,自引:0,他引:5
为筛选出操作方法简便,结果稳定可控的大鼠创伤性肠粘连模型,观察中药复方黄厚排气颗粒对其粘连程度的影响,选用SD大鼠,手术造成肠粘连模型,用中药复方2.5、5.0、10.0g/kg连续治疗7d后观察肠粘连程度。结果表明,以盲肠型动物模型的制备较为理想,手术易于操作,结果稳定可控。用中药复方治疗后模型动物的肠粘连程度得到明显改善。提示黄厚排气颗粒对术后肠粘连有一定的预防作用。 相似文献
6.
养阴清热、宣痹通络法治疗类风湿性关节炎的临床研究 总被引:5,自引:0,他引:5
目的 观察清络通痹颗粒治疗类风湿性关节炎阴虚络热证的临床疗效。方法 将118例患者随机分为清络通痹颗粒治疗组63例和雷公藤多甙片对照组55例,观察用药前后主要症状、体征和实验室检测指标的变化。结果 治疗组的临床治愈率为9.52%,临床治愈显效率为38.10%,总有效率为90.48%,疗效明显优于对照组的0%、20%、83.64%(P<0.05);治疗组的类风湿因子滴度、血沉、C反应蛋白、免疫球蛋白也明显降低,与对照组相比差异显著(P<0.05或P<0.01)。结论 清络通痹颗粒具有抗炎镇痛、调节免疫紊乱等作用,从而达到控制病情的治疗效果。 相似文献
7.
目的:研究中药生精冲剂对大鼠精索静脉曲张的影响及疗效。方法:从80只SD雄性大鼠中随机抽出20只作为假手术组,余60只均建立精索静脉曲张病理模型后随机均分为模型组、生精冲剂组和克罗米芬组。造模后15d生精冲剂组和克罗米酚组分别给予生精冲剂4g/(kg·d)和克罗米芬20mg/(kg·d)灌胃,模型组和假手术组正常喂食。造模后45d放免法测定血清性激素(FSH、LH和T)及观察各组大鼠睾丸组织结构。结果:生精冲剂组大鼠光镜下睾丸组织结构优于模型组和克罗米芬组;血清FSH、LH生精冲剂组显著低于模型组和克罗米芬组(P〈0.05),而克罗米芬组显著高于其他3组。T在生精冲剂组、克罗米芬组和假手术组之间无显著差异,但均显著高于模型组(P〈0.05)。结论:中药生精冲剂对精索静脉曲张引起的睾丸损害有保护及修复作用,且可能优于克罗米芬。 相似文献
8.
Dr. M. Ito Dr. N. Sato J. I. Simpson M. Udo 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1971,12(3):223-237
Summary In anaesthetized cats, electric pulse stimuli were applied at various lateralities to the anterior lobe of the cerebellum. In dorsal Deiters neurones delayed IPSPs with latencies of 3–6 msec were evoked from the entire area of the culmen including the paravermis bilaterally. The delayed IPSPs had a summit time of about 2 msec and a duration of about 7 msec. They showed a marked temporal facilitation and subsequent depression with double shock stimulation. Corticovestibular fibers were penetrated within the nucleus of Deiters and showed delayed, labile responses to cortical stimulation, corresponding to the delayed IPSPs in Deiters neurones. During stimulation of the anterior lobe at any laterality, field potentials recorded in the cerebellar cortex further revealed that there was activation, presumably through axon collaterals of mossy fibers, of granule cells and subsequently of Purkinje cells in the vermal cortex. Cortical events exhibited a prominent temporal facilitation and subsequent depression, in parallel with that observed for the delayed IPSPs in Deiters neurones. The delayed IPSPs in Deiters neurones arising from a wide area of the cerebellar cortex thus were attributed to activation through mossy fiber-granule cell pathway of Purkinje cells of the corticovestibular projection. 相似文献
9.
J. C. Eccles D. S. Faber J. T. Murphy N. H. Sabah Helena Táboříková 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1971,13(1):15-35
Summary This paper is the first of a series in which the processing of information in the cerebellum has been studied by investigating the effects that known inputs from limb nerves produce on the unitary spike potentials in the cerebellar cortex. These spikes have been recorded extracellularly at all depths along microelectrode tracks in the 5th, 4th and 3rd lobules of the anterior lobe in the lateral vermis or in the pars intermedia. These units have a background frequency of discharge, often very irregular, and computer averaging techniques have been employed in order to derive reliable information on the time course and intensity of the excitatory and/or inhibitory actions produced by the input against this background.Most of the spike responses recorded from the granular layer fall into two classes, one characteristic of impulses in mossy fibers, and the other of impulse discharges from granule cells. Both in the spontaneous background and in the response to afferent volleys in limb nerves the mossy fibers exhibit a performance in close accord with that described for the discharges up the spino-cerebellar tracts. The short latency of 6–9 msec for hindlimb stimuli and the high frequency burst response of 2–4 impulses are characteristic. The mossy fibers displayed a wide variety of responses to the wide range of testing inputs, there being various combinations of excitatory and inhibitory responses and also delayed excitatory actions, all of which must be assumed to be reflections of synaptic influences on the cells of origin of the mossy fibers in the spinal cord.Granule cells have a longer latency by several milliseconds, 9–20 msec for the hindlimb, and a slower frequency in their burst response which tended to be longer and more irregular. The small unitary spike potentials are more difficult to isolate. Also with repetitive stimulation granule cells are more readily depressed than are mossy fibers.Usually a granule cell exhibits a wider range of response to the various cutaneous and muscular afferents of a limb. Both mossy fibers and granule cells may display reciprocal responses to volleys from muscle nerves to antagonistic muscles. This attempt to define properties of the mossy fiber and granule cell spike potentials should help in their identification in future investigations.Post-Doctoral Fellow NINDS (1F2NB40,544101 NSRB).Post-Doctoral Fellow UHF Grant No. FTF-3-UB-70. 相似文献
10.
Elee Hofferer Christian Kelche Bruno Will Jean-Christophe Cassel 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1996,111(2):187-207
This study compared the morphological characteristics and the behavioural effects of intrahippocampal septal cell suspension grafts injected either just above the pyramidal cell layer of the hippocampal region CA1 or within the dorsal leaf of the dentate gyrus (DG) in rats subjected to electrolytic fimbria-fornix lesions. The behavioural tests determined home-cage and open-field activity, as well as radial-maze performance. Cresyl-violet staining, acetylcholinesterase (AChE) histochemistry, and parvalbumin, glial fibrillary acidic protein and glutamic acid decarboxylase immunocytochemistry were used for morphological assessments. The cross-sectional area of the grafts was measured between 0.8 mm and 5.3 mm posterior to Bregma and used as an index of their development. Whether injected into CA1 or DG, the grafts provided the partially denervated hippocampus with a dense AChE-positive reinnervation. Both types of grafts were devoid of reactive astrocytes (although reactive astrocytes were found close to the graft-host interface), contained almost no parvalbumin-positive neurons and showed a high density of GAD-positive terminals. One of the main differences between the two groups of grafted rats was that the suspension injected into the DG yielded grafts that, in the vicinity of the injection sites (between 2.3 mm and 4.3 mm posterior to Bregma), had a cross ectional area exceeding that of the grafts placed into CA1 by about 63–110% (average 79%), the latter being more dispersed than the former in the coronal plane. In addition, rats with grafts in the DG exhibited granule cell degeneration in the vicinity of the injection sites, whereas rats with grafts in region CA1 showed no damage near the injection sites. Concerning the behavioural data, we found that fimbria-fornix lesions induced hyperactivity in both the home cage and the open field and impaired radial-maze performance. Compared with the lesion-only rats, the grafted rats in both groups had further increased open-field and home-cage activity. While the grafts placed into region CA1 slightly, but significantly, accentuated the lesion-induced deficit in radial-maze performance, those placed into the DG had no effect. These results suggest that intrahippocampal grafts may, in some (still unspecified) conditions, produce adverse behavioural effects or no behavioural effects, despite an acceptable graft-induced cholinergic reinnervation of the hippocampus. They do not allow a clear answer to the question of whether intra-DG and intra-CA1 septal suspension grafts exhibiting almost comparable morphological features (except in their size and their dispersion in the vicinity of the injection sites) induce behavioural effects that would depend on intrahippocampal location of the grafts. They suggest, however, that the granule cell degeneration caused by the implantation procedure, in conjunction with the intragyral development of the graft, probably does not account for some of the reported adverse behavioural effects of intrahippocampal basal forebrain grafts. Finally, the finding that septal cell suspensions placed into the DG yielded larger grafts than when an equivalent number of cells was injected into CA1 might be explained by a larger lesion-induced neurotrophic activity in DG than in region CA1, although both regions had undergone a similar degree of cholinergic denervation. 相似文献