全文获取类型
收费全文 | 4660篇 |
免费 | 193篇 |
国内免费 | 83篇 |
专业分类
耳鼻咽喉 | 123篇 |
儿科学 | 112篇 |
妇产科学 | 35篇 |
基础医学 | 435篇 |
口腔科学 | 124篇 |
临床医学 | 641篇 |
内科学 | 793篇 |
皮肤病学 | 13篇 |
神经病学 | 291篇 |
特种医学 | 558篇 |
外科学 | 983篇 |
综合类 | 411篇 |
预防医学 | 54篇 |
眼科学 | 58篇 |
药学 | 120篇 |
中国医学 | 19篇 |
肿瘤学 | 166篇 |
出版年
2024年 | 7篇 |
2023年 | 73篇 |
2022年 | 139篇 |
2021年 | 165篇 |
2020年 | 160篇 |
2019年 | 130篇 |
2018年 | 167篇 |
2017年 | 131篇 |
2016年 | 101篇 |
2015年 | 118篇 |
2014年 | 275篇 |
2013年 | 238篇 |
2012年 | 209篇 |
2011年 | 252篇 |
2010年 | 185篇 |
2009年 | 241篇 |
2008年 | 237篇 |
2007年 | 229篇 |
2006年 | 223篇 |
2005年 | 179篇 |
2004年 | 139篇 |
2003年 | 146篇 |
2002年 | 131篇 |
2001年 | 100篇 |
2000年 | 97篇 |
1999年 | 84篇 |
1998年 | 64篇 |
1997年 | 91篇 |
1996年 | 63篇 |
1995年 | 64篇 |
1994年 | 45篇 |
1993年 | 41篇 |
1992年 | 38篇 |
1991年 | 39篇 |
1990年 | 45篇 |
1989年 | 27篇 |
1988年 | 32篇 |
1987年 | 34篇 |
1986年 | 32篇 |
1985年 | 25篇 |
1984年 | 21篇 |
1983年 | 7篇 |
1982年 | 25篇 |
1981年 | 12篇 |
1980年 | 15篇 |
1979年 | 11篇 |
1978年 | 15篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1973年 | 4篇 |
排序方式: 共有4936条查询结果,搜索用时 4 毫秒
41.
LeDoux MS Lorden JF 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2002,145(4):457-467
The genetically dystonic rat is an autosomal recessive mutant with a movement disorder that closely resembles the generalized dystonias seen in humans. Abnormal activity of neurons within the cerebellar nuclei is critical to the dystonic rat motor syndrome. Increased glutamic acid decarboxylase activity, increased glucose utilization, and decreased muscimol binding within the cerebellar nuclei of the dystonic rat suggests that Purkinje cell firing rates are increased in these animals. However, under urethane anesthesia, Purkinje cell simple spike firing rates in dystonic rats were less than half the rates seen in normal littermates. In this study, both spontaneous and harmaline-stimulated single-unit Purkinje cell recordings were obtained from awake normal and dystonic rats. In striking contrast to previous results obtained under urethane anesthesia, there was no statistically significant difference in average Purkinje cell spontaneous simple spike frequency between dystonic and normal rats. Similar to previous studies obtained under urethane anesthesia, Purkinje cell spontaneous complex spike frequency was much lower in dystonic than in normal rats. Many Purkinje cells from dystonic rats, particularly those from the vermis or older animals, exhibited rhythmic bursting simple spike firing patterns. Cross-correlations showed that complex spikes produced less suppression of simple spikes in dystonic than in normal rats and harmaline-stimulated complex spike activity was, on average, faster and more rhythmic in normal than in dystonic rats. These findings indicate that olivocerebellar network abnormalities in the dystonic rat are not due to an inability of Purkinje cells to fire at normal rates and suggest that abnormal Purkinje cell bursting firing patterns in the dystonic rat are due to a defect in the pathway from the inferior olive to climbing fiber synapses on Purkinje cells. 相似文献
42.
Keishi Okamoto Kodo Kodama Katsushi Kawai Tetsuaki Wakebe Kazunobu Saiki Seiji Nagashima 《Annals of anatomy》2006,188(1):49-53
Among cases that had multiple renal arteries on one side, an inferior supernumerary renal artery was found in 24/270 cases (ca. 9%) on the right and in 19/270 cases (ca. 7%) on the left, together with the usual renal artery. We have noticed that there are correlations between their levels of origin from the aorta and their positional relation to the ureter and the inferior vena cava (IVC). An inferior supernumerary renal artery (InfRA) of lower origin passes in front of the IVC and behind the ureter. An InfRA of middle origin passes in front of both the IVC and the ureter. An InfRA of upper origin passes behind the IVC and in front of the ureter or renal pelvis. In addition there was a tendency for the lower origin type to have an ureteric branch, while the middle and upper origin types had a gonadal branch. These findings suggest that different derivations lead to the inferior supernumerary renal arteries. 相似文献
43.
J. R. Trott R. Apps 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1991,87(1):126-140
Summary The olivocerebellar projection to the c1,c2 and c3 zones in the paravermal cortex of lobule Vb/c has been investigated in the cat using a combined electrophysiological/neuroanatomical tracing technique. The zonal boundaries in the paravermal cortex were located by recording, on the cerebellar surface, climbing fibre field potentials evoked in response to percutaneous stimulation of one or more paws. A small (10–30 nl) injection of WGA-HRP was then made either into the centre or into the medial or lateral geographical half of a chosen zone and the resultant distribution of retrogradely labelled cells within the contralateral inferior olive was plotted. The c1 and c3 zones were each found to consist of two mediolaterally oriented sub-zones which could be distinguished by their olivocerebellar input. The medial part of the c1 zone received climbing fibre input from the rostromedial part of the dorsal accessory olive (DAO) while the lateral part of the c1 zone received climbing fibre input from middle/rostral regions of the medial accessory olive (MAO). Both medial and lateral sub-zones within the c3 zone were found to receive climbing fibre input from the rostral pole of DAO but, whereas there was heavy overlap between the olivary territories projecting to the medial c1 and medial c3 subzones, olivary cells projecting to the lateral part of c3 were located more rostrally within DAO. The c2 zone was found not to be divisible into mediolaterally oriented subzones and to receive climbing fibre input from a region of MAO located rostral and somewhat lateral to the region projecting to the lateral part of the c1 zone. The sub-zonal organisation of the olivocerebellar projection to the c1, c2 and c3 zones is discussed in relation to the functional properties of the different zones. 相似文献
44.
P. W. F. Poon X. Chen J. C. Hwang 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1991,83(3):598-606
Summary The response of 835 click-sensitive neurons in the inferior colliculus (IC) to ramp frequency modulated (FM) tones was studied in the anaesthetized rat. More than 70% of the cells were sensitive to the FM sound, and over 25% were FM specialized. Systematic variations of the stimulus parameters showed that sweep velocity, sweep range, and intensity of the FM signal were the 3 basic determinants for the unit response. For anFM specialized cell, the response pattern to each of the parameters was either monotonic or bell-shaped. The population statistics of response patterns to the FM parameters, including the tuning factors, were generated. A stimulus domain was proposed to represent thereceptive space of the FM cells. 相似文献
45.
肝尾状叶脉管构筑的应用解剖 总被引:9,自引:1,他引:9
应用55例成人肝剥离标本及45例胎儿、新生儿肝管道铸型,研究了肝尾状叶的鞘系及静脉回流。尾状叶有两个恒定的蒂、接受左、右侧鞘系的双重供应,以左侧为主;而尾状突主要由右后叶鞘系分布。15例肝铸型标本的尾状叶左、右侧动脉形成吻合弓。尾状叶动脉供应形式可分为三种,静脉可分为三型并直接汇入下腔静脉。由于血管吻合的存在,在病理状态下,尾状叶也应是沟通门一腔静脉的桥梁。 相似文献
46.
C. -F. Ekerot Dr. B. Larson 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1979,36(2):201-217
Summary The spino-olivocerebellar paths ascending through the dorsal funiculi (DF-SOCPs) were studied by recording climbing fiber field potentials in the cerebellar cortex. Several DF-SOCPs were identified on the basis of their response latencies, peripheral inputs, and projection areas. The projection areas consist of eight sagittal zones on each side of the anterior lobe denoted a, x, b, C1, c2, c3, d1, and d2. The a and b zones, which are activated exclusively from hindlimb nerves (Oscarsson, 1969a) were not studied.The shortest response latencies in the x, c1, c3 and d2 zones indicate that these zones are activated by direct paths between the dorsal funiculus nuclei and the inferior olive. These zones also have long latency responses evoked through indirect paths. The direct paths are activated from the flexor reflex afferents and the indirect paths from distal cutaneous afferents. The x zone is activated from forelimb nerves only. The c1 and c3 zones and presumably also the d2 zone are activated from hindlimb and forelimb nerves and have a detailed somatotopical organization.The c2 and d1 zones have long latency responses evoked through indirect paths. Both zones are activated from distal cutaneous afferents. The c2 zone has no distinct somatotopical organization, whereas the d1 zone has largely separate forelimb and hindlimb areas. In contrast to all other zones, the c2 zone is activated not only from ipsilateral but also from contralateral nerves. 相似文献
47.
C. Gabrielli E. Olave A. Sarmento C. Mizusaki J. C. Prates 《Surgical and radiologic anatomy : SRA》1997,19(3):139-142
At its extrapelvic course the inferior gluteal a. is found to be strictly related to the sciatic n. This relationship has been described in a general way, emphasizing its medial localization in respect to the nerve. Clinicosurgical reports describe cases of aneurysms of the inferior gluteal a. on its extrapelvic course and subsequent compression at the nerve. In order to get further details on the relationship between these two structures, 80 gluteal regions from 40 cadavers of adult Brazilian individuals, 29 males and 11 females, were dissected. The inferior gluteal a. was found medial to the sciatic n. in 62 cases (77.5%); in the 18 remaining (22.5%) the trunk of the artery or one of its branches perforated the nerve. Of these, 14 (77.8%) were males and 4 (22.2%) females. This disposition was found 8 times (44.4%) on the right and 10 (55.6%) on the left side; was unilateral in 4 individuals (1 on the right and 3 on the left side) and bilateral in 7. The course of the inferior gluteal a. through the sciatic n. and/or the presence of aneurysms of this artery should be considered as a possible cause of nerve compression. 相似文献
48.
P. M. Gochin E. K. Miller C. G. Gross G. L. Gerstein 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1991,84(3):505-516
Summary Functional interactions among inferior temporal cortex (IT) neurons were studied in the awake, fixating macaque monkey during the presentation of visual stimuli. Extracellular recordings were obtained simultaneously from several microelectrodes, and in many cases, spike trains from more than one neuron were extracted from each electrode by the use of spike shape sorting technology. Functional interactions between pairs of neurons were measured using cross-correlation. Discharge patterns of single neurons were evaluated using auto-correlation and PST histograms. Neurons recorded on the same electrode (within about 100 n) had more similar stimulus selectivity and were more likely to show functional interactions than those recorded on different electrodes spaced about 250 to 500 microns apart. Most neurons tended to fire in bursts tens to hundreds of milliseconds in duration, and asynchronously from the stimulus induced rate changes. Correlated neuronal firing indicative of shared inputs and direct interactions was observed. Occurrence of shared input was significantly lower for neuron pairs recorded on different electrodes than for neurons recorded on the same electrode. Direct connections occurred about as often for neurons on different electrodes as for neurons on the same electrode. These results suggest that input projections are usually restricted to less than 500 m patches and are then distributed over greater distances by intrinsic connections. Measurements of synaptic contribution suggest that typically more than 5 near-simultaneous inputs are required to cause an IT neuron to discharge. 相似文献
49.
The intent of the present study was to use chemical or electrical stimulation of cerebellar afferents to determine how different stimulation paradigms affect the pattern of activation of different populations of neurons in the cerebellar cortex. Specifically, we analyzed immediate changes in neuronal activity, identified neurons affected by different stimulation paradigms, and determined the time course over which neuronal activity is altered. In the present study, we used either systemic (harmaline) or electrical stimulation of the inferior cerebellar peduncle (10 and 40 Hz) to alter the firing rate of climbing and mossy fiber afferents to the rat cerebellum and an antibody made against the proto-oncogene, c-fos, as a marker to identify activated neurons and glia. In control animals, only a few scattered granule cells express nuclear Fos-like immunoreactivity. Although no other cells show Fos-like immunoreactivity in their nuclei, Purkinje cells express Fos-like immunoreactivity within their somatic and dendritic cytoplasm in control animals. Within 15 min of chemical or electrical stimulation, numerous granule and glial cells express Fos-like immunoreactivity in their nuclei. Cells in the molecular layer express Fos-like immunoreactivity following harmaline stimulation in a time and lobule specific manner; they do not appear to be activated in the electrical stimulation paradigm. Following harmaline injections, there is an initial loss of Fos-like immunoreactivity in the cytoplasm of Purkinje cells; 90 min later, nuclear staining is observed in a few scattered Purkinje cells. Following electrical stimulation, the cytoplasmic staining in Purkinje cells is enhanced; it is never present in the nucleus. Data derived from this study reveal cell-specific temporal and spatial patterns of c-Fos activation that is unique to each paradigm. Further, it reveals the presence of an activity dependent protein in the cytoplasm of Purkinje cell somata and dendrites. 相似文献
50.
Nicole Chabot Valérie CharbonneauMarie-Eve Laramée Robin TremblayDenis Boire Gilles Bronchti 《Neuroscience letters》2008
Anatomical and imaging studies show ample evidence for auditory activation of the visual cortex following early onset of blindness in both humans and animal models. Anatomical studies in animal models of early blindness clearly show intermodal pathways through which auditory information can reach the primary visual cortex. There is clear evidence for intermodal corticocortical pathways linking auditory and visual cortex and also novel connections between the inferior colliculus and the visual thalamus. A recent publication [L.K. Laemle, N.L. Strominger, D.O. Carpenter, Cross-modal innervation of primary visual cortex by auditory fibers in congenitally anophthalmic mice, Neurosci. Lett. 396 (2006) 108–112] suggested the presence of a direct reciprocal connection between the inferior colliculus and the primary visual cortex (V1) in congenitally anophthalmic ZRDCT/An mice. This implies that this mutant mouse would be the only known vertebrate having a direct tectal connection with a primary sensory cortex. The presence of this peculiar pathway was reinvestigated in the ZRDCT/An mouse with highly sensitive neuronal tracers. We found the connections normally described in the ZRDCT/An mouse between: (i) the inferior colliculus and the dorsal lateral geniculate nucleus, (ii) V1 and the superior colliculus, (iii) the lateral posterior nucleus and V1 and between (iv) the inferior colliculus and the medial geniculate nucleus. We also show unambiguously that the auditory subcortical structures do not connect the primary visual cortex in the anophthalmic mouse. In particular, we find no evidence of a direct projection from the auditory mesencephalon to the cortex in this animal model of blindness. 相似文献