全文获取类型
收费全文 | 23055篇 |
免费 | 1420篇 |
国内免费 | 132篇 |
专业分类
耳鼻咽喉 | 210篇 |
儿科学 | 599篇 |
妇产科学 | 590篇 |
基础医学 | 3599篇 |
口腔科学 | 365篇 |
临床医学 | 1896篇 |
内科学 | 5830篇 |
皮肤病学 | 566篇 |
神经病学 | 2505篇 |
特种医学 | 485篇 |
外科学 | 2102篇 |
综合类 | 101篇 |
一般理论 | 11篇 |
预防医学 | 1761篇 |
眼科学 | 437篇 |
药学 | 1587篇 |
中国医学 | 54篇 |
肿瘤学 | 1909篇 |
出版年
2024年 | 35篇 |
2023年 | 284篇 |
2022年 | 634篇 |
2021年 | 999篇 |
2020年 | 515篇 |
2019年 | 792篇 |
2018年 | 832篇 |
2017年 | 628篇 |
2016年 | 714篇 |
2015年 | 770篇 |
2014年 | 1053篇 |
2013年 | 1210篇 |
2012年 | 1854篇 |
2011年 | 1920篇 |
2010年 | 1059篇 |
2009年 | 958篇 |
2008年 | 1492篇 |
2007年 | 1539篇 |
2006年 | 1413篇 |
2005年 | 1302篇 |
2004年 | 1129篇 |
2003年 | 1022篇 |
2002年 | 870篇 |
2001年 | 126篇 |
2000年 | 87篇 |
1999年 | 147篇 |
1998年 | 159篇 |
1997年 | 121篇 |
1996年 | 103篇 |
1995年 | 86篇 |
1994年 | 57篇 |
1993年 | 51篇 |
1992年 | 60篇 |
1991年 | 57篇 |
1990年 | 59篇 |
1989年 | 50篇 |
1988年 | 40篇 |
1987年 | 36篇 |
1986年 | 38篇 |
1985年 | 29篇 |
1984年 | 20篇 |
1983年 | 24篇 |
1982年 | 21篇 |
1981年 | 21篇 |
1980年 | 20篇 |
1979年 | 20篇 |
1978年 | 13篇 |
1975年 | 16篇 |
1974年 | 15篇 |
1971年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Elena Christoforou Ioannis Papassotiriou Christophille Skarmoutsou Stavros Doudounakis Alexandra Stamoulakatou Emmanuel Kanavakis 《Journal of cystic fibrosis》2005,4(3):151-156
BACKGROUND: Chronic pulmonary disease and progressive tissue hypoxia are major causes of morbidity and mortality in cystic fibrosis (CF). Normally the body adapts to tissue hypoxia by increasing the red cell mass and decreasing the Hb-O(2) affinity. These adaptations are commonly observed in patients with cyanotic heart disease and individuals living at high altitude. However, patients with CF not only have an impaired erythroid response to hypoxia, but also are frequently anaemic. METHODS: In order to evaluate erythroid marrow activity and tissue oxygenation in 37 patients with CF we measured: the haematological and blood chemistry parameters; including red cell indices, ferritin, erythropoietin (Epo) and soluble transferrin receptors (sTfR) levels; arterial blood gases, P(50) and oxygen release to the tissues (O(2)(R)) and the 2,3-BPG levels. RESULTS: The main results showed that a) patients with CF have a mild degree of tissue hypoxia which is expressed by the moderately decreased of P(50) and O(2)(R) values and the relative increase of Epo level, b) 2,3-BPG synthesis in patients with CF is normal and c) sTfR levels are significantly increased (3-fold normal) in patients with CF compared to normal controls. CONCLUSIONS: The above observations indicate that erythroid marrow activity in patients with CF is increased. 相似文献
12.
13.
Anke Sambeth Minna Huotilainen Elena Kushnerenko Vineta Fellman Elina Pihko 《Clinical neurophysiology》2006,117(3):496-503
OBJECTIVE: We investigated whether newborns respond differently to novel and deviant sounds during quiet sleep. METHODS: Twelve healthy neonates were presented with a three-stimulus oddball paradigm, consisting of frequent standard (76%), infrequent deviant (12%), and infrequent novel stimuli (12%). The standards and deviants were counterbalanced between the newborns and consisted of 500 and 750 Hz tones with two upper harmonics. The novel stimuli contained animal, human, and mechanical sounds. All stimuli had a duration of 300 ms and the stimulus onset asynchrony was 1s. Evoked magnetic responses during quiet sleep were recorded and averaged offline. RESULTS: Two deflections peaking at 345 and 615 ms after stimulus onset were observed in the evoked responses of most of the newborns. The first deflection was larger to novel and deviant stimuli than to the standard and, furthermore, larger to novel than to deviant stimuli. The second deflection was larger to novel and deviant stimuli than to standards, but did not differ between the novels and deviants. CONCLUSIONS: The two deflections found in the present study reflect different mechanisms of auditory change detection and discriminative processes. SIGNIFICANCE: The early brain indicators of novelty detection may be crucial in assessing the normal and abnormal cortical function in newborns. Further, studying evoked magnetic fields to complex auditory stimulation in healthy newborns is needed for studying the newborns at-risk for cognitive or language problems. 相似文献
14.
Reduction of scar formation in full-thickness wounds with topical celecoxib treatment 总被引:4,自引:0,他引:4
Traci A. Wilgus PhD ; Yael Vodovotz PhD ; Elena Vittadini PhD ; Elizabeth A. Clubbs BS ; Tatiana M. Oberyszyn PhD 《Wound repair and regeneration》2003,11(1):25-34
Adult wound repair occurs with an initial inflammatory response, reepithelialization, and the formation of a permanent scar. Although the inflammatory phase is often considered a necessity for successful adult wound healing, fetal healing studies have shown the ability to regenerate skin and to heal wounds in a scarless manner in the absence of inflammation. The cyclooxygenase-2 (COX-2) enzyme, a known mediator of inflammation, has been shown to contribute to a variety of inflammatory conditions and to the development of cancer in many organs. To examine the role of COX-2 in the wound healing process, incisional wounds were treated topically with the anti-inflammatory COX-2 inhibitor celecoxib. Acutely, celecoxib inhibited several parameters of inflammation in the wound site. This decrease in the early inflammatory phase of wound healing had a significant effect on later events in the wound healing process, namely a reduction in scar tissue formation, without disrupting reepithelialization or decreasing tensile strength. Our data suggest that in the absence of infection, adult wound healing is able to commence with decreased inflammation and that anti-inflammatory drugs may be used to improve the outcome of the repair process in the skin by limiting scar formation. 相似文献
15.
Functional or unexplained medical symptoms (physical symptoms that are not adequately explained by organic factors and where a major role for psychological factors is assumed) are common amongst children in the general population but can also be an expression of somatisation and somatoform disorders. Co-morbid psychopathology is common. We describe measures mostly used in research into problems related to somatisation in children and adolescents that may be helpful to clinical researchers. Some address the nature and severity of physical symptoms, others document illness attitudes, beliefs and functional impairment, and a third group assesses emotional symptoms. Questionnaires can be helpful for clinicians in quantifying (i) the nature and severity of somatic symptoms and associated functional impairment, (ii) contributory health attitudes and illness beliefs and (iii) co-morbid or primary anxiety and depressive disorders. Together with pain and activity diaries and careful documentation of school attendance, these measures may also be helpful in monitoring treatment response. 相似文献
16.
Effect of olanzapine treatment on platelet glutamine synthetase-like protein and glutamate dehydrogenase immunoreactivity in schizophrenia. 总被引:1,自引:0,他引:1
Gulnur Sh Burbaeva Irina S Boksha Elena B Tereshkina Olga K Savushkina Marina S Turishcheva Lubov I Starodubtseva Oleg S Brusov Margarita A Morozova 《The world journal of biological psychiatry》2006,7(2):75-81
According to contemporary views, the glutamatergic system is implicated in the pathogenesis of schizophrenia, and atypical neuroleptics exert their effects (at least partially) through the glutamatergic system. Immunoreactive glutamate-metabolising enzymes, such as glutamine synthetase-like protein (GSLP) and two glutamate dehydrogenase isoenzymes (GDH), have been discovered in human platelets. The amount of GSLP in the platelets of 40 chronic patients with schizophrenia was found to be significantly higher than in 33 controls (consistent with our previous finding of increased amounts of GSLP in the prefrontal cortex of chronic schizophrenia patients). Moreover, survival analysis of the group of patients treated with olanzapine for 28 weeks showed that the larger amount of GSLP measured in platelets before treatment, the shorter the treatment time needed to achieve a positive clinical response (defined a priori as > or = 20% reduction in PANSS total score from the initial level before the treatment). Hence, GSLP level may serve as a predictor of the treatment duration to achieve a positive outcome with olanzapine. Both GSLP and GDH were found significantly changed in the course of treatment; hence, treatment with olanzapine influences the amounts of glutamate-metabolising enzymes in the platelets of chronic schizophrenia patients. 相似文献
17.
Francisco J. Romero Juan Segura-Aguilar Elena Monsalve Carlos Hermenegildo Eberhard Nies Francisco J. Puertas Joaquí n Rom 《Neurotoxicology and teratology》1990,12(6):603-605
The present work tries to establish the antioxidant capacity of the peripheral nervous tissue of the rat, in terms of the enzymatic activities present in this tissue that either prevent the formation of activated species as the semiquinone radical (DT-diaphorase), protect against activated oxygen species (superoxide dismutase, glutathione peroxidase), conjugate natural toxic products or xenobiotics (glutathione S-transferases, especially the activity conjugating 4-hydroxy-nonenal), or complete the glutathione system metabolism (glutathione disulfide reductase, γ-glutamyl transpeptidase). All the activities studied are lower in this tissue than they are in liver, except for γ-glutamyl transpeptidase. The relevance of the results obtained and its possible relationship with different neuropathies is discussed. It is concluded that the peripheral nervous tissue is by far less protected than the liver against oxidative damage. 相似文献
18.
Iwar Klime Antonian Vraana Jaroslav Kune Elena eboUkovaA Zdena Dobe ovaa Pavel tolba Josef Zicha 《Blood pressure》1995,4(3):137-142
Hereditary hypertriglyceridemic rats (hHTg) were developed as a new genetic model for the study of relationships between blood pressure (BP) and metabolic abnormalities. This strain has been produced by selective inbreeding from Wistar rats according to the rise of plasma triglycerides induced by a high-sucrose diet. Though hHTg rats display hypertriglyceridemia, impaired glucose tolerrance, hyperinsulinemia, insulin resistance and increased BP even without nutritional stimuli, high sucrose feeding further aggravates these symptoms. High plasma triglycerides levels in hHTg rats seem to be a consequence of their hyperproduction. Impaired insulin action is responsible for the defective glucoregulation in this strain. The loss of insulin responsiveness might be due to a reduction in the number of glucose transporters. Highly significant relationships among plasma triglycerides, ouabain-resistant Na+ transport and BP were demonstrated in the hHTg rats. Segregating populations (F2 hybrids) should be used for genetic analysis of the primary role of lipid and/or ion transport abnormalities in the pathogenesis of this form of genetic hypertension. 相似文献
19.
Central sensory and motor conduction in vitamin B12 deficiency. 总被引:7,自引:0,他引:7
V Di Lazzaro D Restuccia D Fogli R Nardone S Mazza P Tonali 《Electroencephalography and clinical neurophysiology》1992,84(5):433-439
Four patients with subacute combined degeneration were studied through upper and lower limb SEPs recorded with a non-cephalic reference montage and through cortical and spinal magnetic stimulation. Clinical signs were confined to the lower limbs in 3 patients; the remaining patient presented only paraesthesiae in 4 limbs. Median nerve SEPs showed a normal cervical N13 response with a significant increase of central conduction time concerning exclusively the P9-P14 interpeak interval. Central motor conduction to upper and lower limb muscles was abnormal. Nerve conduction studies provided no evidence of peripheral nerve involvement. These electrophysiological findings suggest that in vitamin B12 deficiency the higher segments of the cervical cord are usually affected first and that central sensory and motor conduction studies are sensitive methods for detecting such damage. 相似文献
20.
Gennadi Naumov Elena Naumova Hilkka Turakainen Pirkko Suominen Matti Korhola 《Current genetics》1991,20(4):269-276
Summary We used a combination of genetic hybridization analysis and electrokaryotyping with radioactively labelled MEL1 gene probe hybridization to isolate and identify seven polymeric genes for the fermentation of melibiose in strain CBS 5378 of Saccharomyces cerevisiae (syn. norbensis). Four of the MEL genes, i.e. MEL3, MEL4, MEL6 and MEL7, were allelic to those found in S. cerevisiae strain CBS 4411 (syn. S. oleaginosus) whereas three genes, i.e. MEL8, MEL9 and MEL10 occupied new loci. Electrokaryotyping showed that all seven MEL genes in CBS 5378 were located on different chromosomes. The new MEL8, MEL9 and MEL10 genes were found on chromosomes XV, X/XIV and XII, respectively. 相似文献