全文获取类型
收费全文 | 3162篇 |
免费 | 112篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 16篇 |
妇产科学 | 17篇 |
基础医学 | 671篇 |
口腔科学 | 79篇 |
临床医学 | 132篇 |
内科学 | 182篇 |
皮肤病学 | 541篇 |
神经病学 | 681篇 |
特种医学 | 58篇 |
外国民族医学 | 1篇 |
外科学 | 136篇 |
综合类 | 166篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 210篇 |
眼科学 | 190篇 |
药学 | 130篇 |
中国医学 | 35篇 |
肿瘤学 | 39篇 |
出版年
2024年 | 4篇 |
2023年 | 45篇 |
2022年 | 47篇 |
2021年 | 125篇 |
2020年 | 78篇 |
2019年 | 124篇 |
2018年 | 129篇 |
2017年 | 79篇 |
2016年 | 60篇 |
2015年 | 71篇 |
2014年 | 145篇 |
2013年 | 154篇 |
2012年 | 104篇 |
2011年 | 109篇 |
2010年 | 101篇 |
2009年 | 105篇 |
2008年 | 112篇 |
2007年 | 105篇 |
2006年 | 80篇 |
2005年 | 79篇 |
2004年 | 75篇 |
2003年 | 78篇 |
2002年 | 64篇 |
2001年 | 66篇 |
2000年 | 41篇 |
1999年 | 49篇 |
1998年 | 57篇 |
1997年 | 56篇 |
1996年 | 52篇 |
1995年 | 56篇 |
1994年 | 56篇 |
1993年 | 50篇 |
1992年 | 51篇 |
1991年 | 57篇 |
1990年 | 55篇 |
1989年 | 29篇 |
1988年 | 35篇 |
1987年 | 61篇 |
1986年 | 81篇 |
1985年 | 92篇 |
1984年 | 86篇 |
1983年 | 74篇 |
1982年 | 48篇 |
1981年 | 23篇 |
1980年 | 18篇 |
1979年 | 13篇 |
1978年 | 9篇 |
1977年 | 11篇 |
1976年 | 9篇 |
1975年 | 4篇 |
排序方式: 共有3318条查询结果,搜索用时 265 毫秒
41.
The effects upon the contact allergic reaction in the guinea pig of the 3 cytostatic agents most commonly used for their immunosuppressant properties, cyclophosphamide, methotrexate and azothioprine, have been investigated in an experimental model which allows comparison of the qualitative and quantitative aspects of the dermal inflammatory infiltrate and the macroscopic response. The 3 agents were given in single, relatively high doses and had effects on the dermal inflammatory infiltrate which varied in nature, degree and time course. Changes often showed a cyclical development with time, with "rebound" often following initial changes. Although cyclophosphamide had the most marked effect, all agents affected the mononuclear, basophil and eosinophil dermal infiltrates at some point in the experiment. Cyclophosphamide was the only agent found to affect the total white cell count of peripheral blood, but the leukopenia did not affect recruitment of mononuclear cells to the dermis. In the period immediately after administration of cyclophosphamide and methotrexate, the macroscopic score increased. Whilst the mechanism of this effect is unclear, it may be a manifestation of a basophil, perhaps IgE mediated reaction. Further manipulation of dose and dose interval may result in administration schedules relevant to the treatment of cell-mediated hypersensitivity in clinical practice. 相似文献
42.
L C Massopust D H Hauge J C Ferneding W G Doubek J J Taylor 《The Journal of comparative neurology》1985,237(4):533-544
Projection systems from the gracile nucleus and the cuneate nuclear complex to their terminal sites in the mesencephalon, diencephalon, and cerebellum were examined by means of anterograde autoradiography and retrograde horseradish peroxidase methods. Three projection systems emerge from the dorsal column nuclei, decussate via internal arcuate fibers, and form the contralateral medial lemniscus (ML). At the obex, some fibers split off the ML and course dorsolaterally, forming an ascending lateral system which fits the "lemniscal adjunct channel" (LAC) concept of Graybiel ('72). The ML continues rostrally as the "main lemniscal line channel" (MLLC). At the inferior colliculus, some LAC fibers terminate in the pontine nuclei, parabrachial, dorsal reticular nuclei, and the external and ventral medial part of the central nucleus of the inferior colliculus. More rostrally at the level of the superior colliculus, terminal fields are found in the medial nucleus of the medial geniculate body, the suprageniculate, pretectal, and mesencephalic reticular nuclei, marking the end of the LAC. In the diencephalon, gracile fibers leave the MLLC and form a crescentlike terminal field along the extreme lateral border of the ventral posterior lateral nucleus (VPL) of the thalamus. Cuneate MLLC fibers terminate in a bandlike formation in the VPL medial to the gracile termination. The third fiber system, the cuneocerebellar projection, emerges from the cuneate, the external cuneate nuclei, and the "cellular bridge" and immediately enters the ipsilateral inferior cerebellar peduncle. Upon entering the cerebellum, the major fiber component remains ipsilateral and terminates as vertical bands in vermal and paravermal lobules, and lobules I through IVa. The posterior cerebellar lobe contains terminal bands in lobules VII-IX, the copula pyramidis, and the paramedian lobule. It is concluded that the dorsolateral fiber system conforms to Graybiel's LAC. It is more divergent and probably less modality specific, whereas the medial lemniscal system conforms to the MLLC, which is said to be modality specific, less divergent, and locked to specific sensory-motor response characteristics. The topography of cerebellar terminal bands indicates that there is sensory-motor representation from all parts of the body to all parts of the cerebellum, at least in the rat. 相似文献
43.
44.
Heterogeneity in the Dorsal Subiculum of the Rat. Distinct Neuronal Zones Project to Different Cortical and Subcortical Targets 总被引:2,自引:0,他引:2
The aim of the present study was to relate the distribution of efferents of the dorsal subiculum to their origin along the proximodistal axis of the subiculum. The distribution of subicular projections was studied in detail by means of the sensitive anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L), and the precise origin of these projections analysed with retrogradely transported fluorescent tracers, using double- and triple-labelling protocols. Injections of PHA-L in the proximal part of the dorsal subiculum, i.e. that part which borders field CA1, result in labelling of the infralimbic, entorhinal and perirhinal cortices, the nucleus accumbens and the lateral septal region, the interanteromedial nucleus of the thalamus, the core of the nucleus gelatinosus, and the mammillary nuclei, in particular in the rostral parts of the medial nucleus. In contrast, injections in the distal part of the dorsal subiculum, i.e. that part which borders the presubiculum, give rise to labelling in the retrosplenial and postrhinal cortices, the presubiculum, the anterior thalamic complex, the shell of the nucleus gelatinosus, and the mammillary nuclei, preferentially in the caudal part of the medial nucleus. The results of injections of different retrograde tracers, simultaneously placed in two or three targets of the subicular efferents, confirm the results of the anterograde tracing experiments. Moreover, they clearly demonstrate that the population of subicular neurons which, for example, projects to the nucleus accumbens and the interanteromedial nucleus of the thalamus is almost completely segregated from the population that projects to the retrosplenial cortex and the anterior complex of the thalamus. Thus within the dorsal subiculum, populations of neurons can be differentiated so that each population projects to a unique set of target structures. These cell populations are differentially positioned along the proximo-distal axis. In view of additional evidence indicating that some of the major afferents to the subiculum are organized along the same axis, we suggest that the heterogeneity of the dorsal subiculum along the proximo-distal axis reflects a general organizational characteristic of this hippocampal field. 相似文献
45.
目的 了解混配农药中氰戊菊酯在小鼠体内的代谢和分布。方法 以14 C -氰戊菊酯为示踪剂 ,静脉注射给药。给药后 0 .5~ 12 0min之间采 9次血样 ,8~ 96 0min之间分别对脑、心脏、肝脏和肺脏采 8次样品。样品用 β闪烁计数仪测量 ,并换算成化学浓度。用残数法计算毒代动力学参数。结果 混配农药中的氰戊菊酯的代谢符合二室开放模型。分布相T1/ 2 α为 2 .7min ,消除相T1/ 2 β为 10 6 .6min ,表观分布容积为 2 .9L/kg ,正向扩散系数k12 (0 .17min-1)大于逆向扩散系数k2 1(0 .0 77min-1)。分布浓度肺脏中最高 ,其次为肝脏、心脏、脑。结论 肺脏优势参与了氰戊菊酯的代谢过程 ,应重视此类农药的肺脏毒性。 相似文献
46.
止咳平喘膜剂的经效学研究(1) 总被引:3,自引:2,他引:1
本文对止咳平喘膜剂的药效学进行了初步的研究,结果表明,该膜剂经皮给药能显著延长蛋清所致朋鼠哮和枸橼酸所致豚鼠咳嗽的潜伏期,减少枸橼酸所致豚鼠的咳嗽次数,对小鼠气管酚红排泌量有明显的促进作用,加快小鼠碳粒廓清速率,无论是抗原攻击关给药,还是攻击后给药均可显著抑制2,4-二硝基氯苯所性皮炎。 相似文献
47.
目的 探究Chevron截骨术截骨远端外侧位移距离对外翻足关节接触特征的影响,为临床上选择合适的位移距离提供参考依据。方法 测量踝关节中立位状态下正常足、外翻足及外翻足Chevron截骨术截骨远端分别向外侧位移2.0、4.0、6.0 mm后前足、中足和后足各关节接触力、峰值压强和接触面积,并对结果进行分析。结果 与正常足相比,外翻足第1跖楔关节(t=-3.33, P=0.02)、跟骰关节(t=-2.74, P=0.03)和距下关节(后关节面)(t=-2.89, P=0.03)的接触力显著增高;外翻足距舟关节(t=-2.73, P=0.03)与跟骰关节(t=-2.74, P=0.03)的峰值压强显著增高;行Chevron截骨术后,随着截骨远端向外侧位移距离的增加,外翻足第1跖楔关节和跟骰关节的接触力逐渐减小;外翻足距舟关节和跟骰关节的峰值压强逐渐减小。结论 中度外翻足行Chevron截骨术后,当第1跖骨截骨远端向外侧位移6 mm时能有效恢复部分关节间力的分布,且能缓解部分关节局部应力集中现象。 相似文献
48.
The cell bodies and proximal dendrites of postsynaptic dorsal column neurons were examined for synaptic boutons which displayed immunoreactivity for the principal excitatory and inhibitory neurotransmitters, glutamate and GABA. The neurons were labelled by retrograde transport of horseradish peroxidase and GABA or glutamate-containing boutons were revealed by performing postembedding immunogold reactions on electron microscope sections. Five neurons were examined and all of them were postsynaptic to boutons which contained either GABA or glutamate. Quantitative analysis of two of the cells revealed that more than 90% of the synaptic profiles associated with them displayed immunogold reactions for these transmitters. Analysis of series of alternate sections, which were reacted for either GABA or glutamate, showed that there was no overlap in the populations of immunoreactive boutons. Furthermore, GABA and glutamate immunoreactions were associated with boutons which had different morphological characteristics. In addition, some large glutamate-enriched boutons were postsynaptic to small boutons which displayed immunogold reactions for GABA. This study demonstrates morphological bases for direct excitation, postsynaptic inhibition and presynaptic inhibition of postsynaptic dorsal column cells. 相似文献
49.
The epidemiology of occupational contact dermatitis 总被引:3,自引:0,他引:3
Diepgen TL Coenraads PJ 《International archives of occupational and environmental health》1999,72(8):496-506
Occupational contact dermatitis (OCD) ranks first of all occupational diseases in many countries. The incidence rate is believed
to be around 0.5–1.9 cases per 1000 full-time workers per year. Epidemiological studies play an important role in observing
disease trends, analysing risk factors, and monitoring the effect of preventive measures. In this review article the lack
of truly epidemiologic data on OCD and the difficulties of those studies are illustrated. The following issues are highlighted:
case ascertainment and bias, the distribution of allergic and irritant contact dermatitis in the working population, the interrelationship
between exogenous (allergens, irritants) and endogenous factors, the prognosis, the social and economic impact, and the need
for intervention studies.
Received: 26 January 1999 / Accepted: 24 April 1999 相似文献
50.
Adèle Assadoullina Alexander A. Bialasiewicz Gisbert Richard 《Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft》1999,96(5):319-324
Summary
Autoaggressive syndromes as causes of diseases underlying chronic blepharitis and keratoconjunctivitis that are refractory
to treatment are often difficult to recognize.
Patients: Three female patients (age 21, 25, 41 years) and one male patient (age 42 years) had suffered from a right-(4 × ) or left-(1
× ) handed treatment-refractory blepharokeratoconjunctivitis for 1, 2 ,11 and 30 months prior to admission. In each case more
than 5 ophthalmologists and 2–6 eye hospitals had been consulted, and extraocular surgery had been performed 1–4 times.
Results: Patients presented with a visual acuity of 0.3 p (1 × ), 0.1 (1 × ), FC (1 × ), HM (1 × ). In three patients contact eczema
of the facial skin and lids and a corneal pannus were observed; in two patients we saw purulent pseudomembranous and in two
patients chronic cicatrizing keratoconjunctivitis. Conjunctival smears grew P. aeruginosa, and S. aureus; impression cytology showed infiltration with neutrophils and epithelial keratinization; histopathology indicated chronic
inflammatory, partly purulent subepithelial and stromal conjunctival infiltrate with hyper- and parakeratosis fibrous strands
and epithelial cell loss; the lower lids showed parakeratosis, focal necrosis, intercellular edema and a lymphohistiocytic
round-cell infiltrate. Furthermore, multiple allergies to antibiotics and preservatives (4 × ), lacerations of the arms and
legs (2 × ) and an irritative-toxic dermatitis (1 × ) were substantiated. In the patients who agreed to a psychiatric consultation,
somatized-agitated longing for care combined with a dependent and infantile personality (1 × ) and reactive depression (2
× ) were verified.
Conclusions: In patients suffering from treatment-refractory unilateral chronic blepharokeratoconjunctivitis correlated with the hand,
one must take into consideration the fact that other factors may be involved: possible exacerbation prior to examinations;
multiple inpatient diagnostic and surgical procedures in different locations; histopathological mixed inflammatory patterns;
and psychiatric syndromes.
相似文献