全文获取类型
收费全文 | 176094篇 |
免费 | 10788篇 |
国内免费 | 448篇 |
专业分类
耳鼻咽喉 | 2313篇 |
儿科学 | 5730篇 |
妇产科学 | 3666篇 |
基础医学 | 23962篇 |
口腔科学 | 7660篇 |
临床医学 | 13111篇 |
内科学 | 39588篇 |
皮肤病学 | 4410篇 |
神经病学 | 14779篇 |
特种医学 | 5645篇 |
外国民族医学 | 26篇 |
外科学 | 22010篇 |
综合类 | 1478篇 |
现状与发展 | 1篇 |
一般理论 | 65篇 |
预防医学 | 18063篇 |
眼科学 | 3271篇 |
药学 | 10599篇 |
中国医学 | 699篇 |
肿瘤学 | 10254篇 |
出版年
2023年 | 864篇 |
2022年 | 1657篇 |
2021年 | 3783篇 |
2020年 | 2542篇 |
2019年 | 3559篇 |
2018年 | 5030篇 |
2017年 | 3775篇 |
2016年 | 3530篇 |
2015年 | 4128篇 |
2014年 | 5662篇 |
2013年 | 7170篇 |
2012年 | 11121篇 |
2011年 | 11576篇 |
2010年 | 5940篇 |
2009年 | 5329篇 |
2008年 | 9046篇 |
2007年 | 9632篇 |
2006年 | 8906篇 |
2005年 | 9181篇 |
2004年 | 8594篇 |
2003年 | 7877篇 |
2002年 | 5893篇 |
2001年 | 5005篇 |
2000年 | 4975篇 |
1999年 | 4396篇 |
1998年 | 1639篇 |
1997年 | 1365篇 |
1996年 | 1355篇 |
1995年 | 1166篇 |
1994年 | 1125篇 |
1993年 | 1052篇 |
1992年 | 2694篇 |
1991年 | 2609篇 |
1990年 | 2379篇 |
1989年 | 2374篇 |
1988年 | 2163篇 |
1987年 | 2004篇 |
1986年 | 1863篇 |
1985年 | 1780篇 |
1984年 | 1292篇 |
1983年 | 1049篇 |
1982年 | 596篇 |
1981年 | 554篇 |
1980年 | 512篇 |
1979年 | 940篇 |
1978年 | 621篇 |
1977年 | 495篇 |
1975年 | 557篇 |
1974年 | 556篇 |
1973年 | 553篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
M Nilles P A de Viragh H Mossmann C Heinrichs F Eckert 《Der Hautarzt; Zeitschrift für Dermatologie, Venerologie, und verwandte Gebiete》1992,43(4):205-209
The clinical, histological and histogenetic aspects of naevus follicularis keratosus (NFK) ("naevus comedonicus") are reported. Clinically, NFK appears mostly as linear and unilateral groups of dark comedo-like plugs. Clinical forms include variants with minimal and distinctive deviations from the basic form. Recurrent inflammation is not mandatory. Histological examination reveals keratin-filled infundibula, with granular layers that are always present but though not always equally obvious. This finding corresponds to the mode of keratinization in the follicular infundibulum. Overall, the findings are indicative of a harmartoma of the follicular infundibulum with additional rudimentary sebaceous glands. 相似文献
992.
It was reviewed a series of 2860 cerebral computed tomography (CCT) in order to compare the main reasons at referral to investigation with the CCT results and the costs with normal and abnormal CCT. It was also studied the age and sex of the patients. Data were collected from one out of three diagnostic centers in Salvador, Brasil, for a three years period. The 2860 CCT exclude all investigation carried out for the follow-up of a previously diagnosed abnormality. CCT abnormalities were detected in 1152 (40.3%). The following reasons showed the highest proportion of abnormal CCT, for males and females respectively: demential syndrome (91.7 and 83.3%); cerebrovascular accidents (85.1 and 73.6%); infectious and parasitary diseases (76.5 and 78.6%); tumors (65.8 and 55.4%); and head injuries, 63.6% for males. In the female group, 65.0% of the CCT were normal, in a range of 65.0 to 80.0% for the age groups under 54 years old. In the male group, the highest proportion of normal CCT was found in the age groups: 25-34 (68.4%), < 15 (62.9%) and 35-44 (62.7%). The most common reasons for normal CCT for males and females were: headache (81.3 and 87.5%); dizziness/vertigo (79.3 and 78.6%); seizures (67.3 and 70.0%); psychomotor deficiency (72.0 and 67.7%) and "endocrine disorders", 75.0% for each sex. The highest proportion of normal CCT (65.3%) was requested by medical "convenios". The cost with normal CCT reached US$565,225 and with the abnormal ones, US$381,247. Costs with normal CCT were 2.2 higher for medical "convenios" as compared to those of the National Institute of Security requests and 2.8 more than those of private medicine. 相似文献
993.
M A de Almeida 《Arquivos de neuro-psiquiatria》1992,50(1):60-64
The author presents 83 cases of "a frigore" peripheral facial palsy, occurred in the mountain city of Petropolis which has characteristics such as a tropical climate without any traces of a dry season and an average temperature of 50 degrees F to 73.5 degrees F. The author relates them with virus infections which appear within a year period. Fifty six patients belong to his clinic and have a follow up, while other 25 patients proceed from another clinics and from them he only has reports on sex, age, side of palsy and the beginning of illness. He shows that the largest number of cases occurred along the months of May, August, September and October. Season distribution for southern hemisphere is analysed. He also considers etiology, incidence, prevalence, treatment and results on patients studied. 相似文献
994.
F Martínez Soriano T Hernandez Gil de Tejada C Cimas Garcia E Arma?anzas 《Journal für Hirnforschung》1992,33(3):271-275
A comparative statistical analysis of "synaptic ribbons" evolution over a 24 hour period during two different photoluminous seasons (September, and winter) is carried out. Seventy male rats were used. Statistical analysis involved the Kolmogorov-Smirnov test, variance analysis, the Student t-test and Pearson's correlation test. The results show that "synaptic ribbons" evolve during the circadian phase and through two different seasons, with a clear and marked influence of point-time (p < 0.0001) and season (p < 0.0001). 相似文献
995.
Italy's mental health law of 1978 provided for the gradual phasing out of psychiatric hospitals (PH) and the creation of comprehensive community-based systems. However, these changes have taken place at different times and in different forms. There are now three different organizational and care models operating in Italy: in the first, common in Southern Italy, the former PH and the new general hospital general wards (GHPW) coexist; in the second, outpatient departments complement the above facilities, but the hospital activity remains central; in the third model, a community model has been given priority-the so-called community priority. While many reports have been published describing the activity of some of the services adhering to the third model, no report has been published specifically describing the activity of services which work according to the second model, such as Cremona. In this paper, the activity of the Cremona psychiatric services is described, and the consequences of the reform law and the problems related to an hospital-based activity are emphasized. 相似文献
996.
S G de Azevedo 《Revista portuguesa de cardiologia》1989,8(3):225-227
Upon the development, divulgation and improvement of the Ambulatory Electrocardiographic Monitoring (AEM) techniques, the problem of the arrhythmias after an acute myocardial infarction (AMI) has acquired a new acuteness. Its importance becomes clearly evident from the fact today recognized that about 10% of the patients die within the first year after AMI and that the great majority of them dies suddenly. The prognostic value of certain types of ventricular arrhythmias is now well proved to be an independent risk factor respecting to the late complications of AMI, namely the sudden death issue. In this paper, after referring the prognostic criteria for the ventricular arrhythmias, the Author proposes an AEM execution calendar for the AMI patients, since the late hospital phase (hospital discharge). Afterwards, the controversial therapeutic problem of the ventricular arrhythmias is approached, quoting the pharmacological set-backs and pointing out the AEM limitations in regard to the selection and efficacy confirmation of the anti-arrhythmic drugs. At last, a few conclusions of the "Cardiac Arrhythmia Pilot Study" (CAPS, 1986) are mentioned and an other ongoing multicenter study is referred, whose conclusions will be of capital importance to define the anti-arrhythmic therapy utility in the setting of the post-AMI patients. 相似文献
997.
S Yazulla K M Studholme J Vitorica A L de Blas 《The Journal of comparative neurology》1989,280(1):15-26
A monoclonal antibody (mAb 62-3G1) to the GABAA receptor/benzodiazepine receptor/Cl- channel complex from bovine brain was used with light and electron microscopy in goldfish retina and light microscopy in chicken retina to localize GABAA receptor immunoreactivity (GABAr-IR). GABAr-IR was found in the outer plexiform layer (OPL) in both species, in three broad bands in the inner plexiform layer (IPL) of goldfish, and in seven major bands of the chicken IPL. A small percentage of amacrine cell bodies (composing at least three types) were stained in chicken. In goldfish OPL, GABAr-IR was localized intracellularly and along the plasma membrane of cone pedicles, whereas rod spherules were lightly stained, but always only intracellularly. In chicken, all three sublayers of the OPL were GABAr-IR. The presence of GABAr-IR on photoreceptor terminals is consistent with data indicating feedback from GABAergic horizontal cells to cones. In the goldfish IPL, GABAr-IR was localized to postsynaptic sites of amacrine cell synapses; intracellular staining of processes in the IPL also was observed in presumed "GABAergic" targets. A comparison of GABAr-IR with the distributions of 3H-muscimol uptake/binding, glutamate decarboxylase-IR, GABA-IR, and 3H-GABA uptake in the IPL showed either a reasonable correspondence or mismatch, depending on the marker, species, and lamina within the IPL. The distribution of GABAr-IR in the retina corresponded better with the 3H-muscimol than with 3H-benzodiazepine binding patterns yet overall was in excellent agreement with many other physiological and anatomical indicators of GABAergic function. We suggest that intracellular GABAr-IR represents the biosynthetic and/or degradative pathway of the receptor and we conclude that mAb 62-3G1 is a valid marker of GABAA receptors in these retinas and will serve as a useful probe with which to address the issue of mismatches between the localization of GABAA receptors and indicators of presynaptic GABAergic terminals. 相似文献
998.
Louis D. Van de Kar 《Neuroscience and biobehavioral reviews》1989,13(4):237-246
This review examines the role of serotonin (5-HT) in depression. Dysfunction of serotonergic neurons has been implicated as one of the causes of endogenous depression. Since serotonergic neurons innervate the hypothalamus and these neurons send collaterals to several other brain areas, it is possible that hypothalamic sites which control hormone secretion receive the same serotonergic afferents that innervate other limbic areas in the brain. Several investigators have devised neuroendocrine challenge tests measuring the effect of 5-HT agonists on plasma cortisol and prolactin in depressed patients. These tests help to identify dysfunctional 5-HT neurons, and are a "window into the brain." The secretion of cortisol and prolactin is increased predominantly by 5-HT1 receptors. However, changes in 5-HT2 receptors have also been implicated in depression. Results from our laboratory and by others suggest that brain serotonergic neurons stimulate renin and vasopressin secretion by activation of 5-HT2 receptors. Therefore, the renin and vasopressin response to 5-HT agonists should be included in neuroendocrine tests of serotonergic function in affective disorders. Since antidepressants produce a decrease in the density of 5-HT2 receptors, renin and vasopressin could be used to evaluate the antidepressant potential of new drugs. 相似文献
999.
Bisby MA Redshaw JD Tetzlaff W de Leon M Carlsen RC 《Restorative neurology and neuroscience》1989,1(1):25-29
Labelled proteins conveyed by fast axonal transport into the sensory axons of frog sciatic nerve following axotomy have been studied by 2D gel electrophoresis. Previous work showed that in frogs acclimatized to 25 °C a cell body reaction occurs, along with regeneration of axons to their targets. In contrast, frogs acclimatized to 15 °C showed no cell body reaction and though regeneration began, it stalled after approximately 35 days. We found that axotomy at 25 °C was followed by an increase in transport of specific labelled proteins corresponding to growth-associated proteins (GAPs) identified in other regenerating systems. Surprisingly, axotomy at 15 °C also induced a similar increase, though with a slower onset, so that the highest levels of expression of GAPs occurred during the time when the axons had stalled. We conclude that sensory neurons in 15 °C frogs do detect that their axons have been injured, as shown by their ability to increase GAP synthesis. Slow and limited axonal growth is possible during a period when GAP synthesis is low compared to levels in rapidly regenerating nerves, but even when the ability to produce GAPs increases, this alone is not sufficient to sustain regeneration in the absence of other components of the cell body reaction to injury. 相似文献
1000.
David de Wied Jan M. van Ree 《European archives of psychiatry and clinical neuroscience》1989,238(5-6):323-331
Summary Animal studies have demonstrated that neuropeptides modulate nervous system functions. It has been postulated that disturbances in neuropeptide systems may be aetiological factors in psychiatric and neurological disorders. Neuropeptides related to ACTH/MSH, including ORG 2766, increase motivation and attention and facilitate recovery processes after nerve damage. These peptides may be effective during the early stage of dementia. Vasopressin and related peptides improve memory processes in animals and humans. In addition, these peptides influence social behaviour, mood and addictive behaviour. The non-opioid -type endorphins have neurolepticlike activities in animals and antipsychotic effects in a category of schizophrenic patients. Peptides related to CCK have also been found to be effective in these patients. Some neuropeptides, e.g. TRH and PLG, have been reported to exert antidepressant effects. Further research may eventually produce neuropeptides with therapeutic action in psychiatric and neurological diseases.Parts of this article were presented on the occasion of the inauguration ceremony of the Department of Psychiatry of the University of Mainz on April 2 and 3, 1987 相似文献