全文获取类型
收费全文 | 48838篇 |
免费 | 3271篇 |
国内免费 | 188篇 |
专业分类
耳鼻咽喉 | 524篇 |
儿科学 | 1231篇 |
妇产科学 | 858篇 |
基础医学 | 6394篇 |
口腔科学 | 1249篇 |
临床医学 | 4749篇 |
内科学 | 9948篇 |
皮肤病学 | 725篇 |
神经病学 | 4778篇 |
特种医学 | 2551篇 |
外国民族医学 | 6篇 |
外科学 | 7211篇 |
综合类 | 592篇 |
一般理论 | 40篇 |
预防医学 | 4023篇 |
眼科学 | 1199篇 |
药学 | 2925篇 |
中国医学 | 69篇 |
肿瘤学 | 3225篇 |
出版年
2023年 | 204篇 |
2022年 | 346篇 |
2021年 | 807篇 |
2020年 | 612篇 |
2019年 | 810篇 |
2018年 | 951篇 |
2017年 | 773篇 |
2016年 | 914篇 |
2015年 | 1051篇 |
2014年 | 1469篇 |
2013年 | 2043篇 |
2012年 | 3102篇 |
2011年 | 3287篇 |
2010年 | 1866篇 |
2009年 | 1707篇 |
2008年 | 3054篇 |
2007年 | 3144篇 |
2006年 | 3104篇 |
2005年 | 3036篇 |
2004年 | 2843篇 |
2003年 | 2758篇 |
2002年 | 2655篇 |
2001年 | 613篇 |
2000年 | 567篇 |
1999年 | 634篇 |
1998年 | 601篇 |
1997年 | 468篇 |
1996年 | 421篇 |
1995年 | 402篇 |
1994年 | 322篇 |
1993年 | 292篇 |
1992年 | 370篇 |
1991年 | 338篇 |
1990年 | 308篇 |
1989年 | 325篇 |
1988年 | 292篇 |
1987年 | 308篇 |
1986年 | 279篇 |
1985年 | 300篇 |
1984年 | 305篇 |
1983年 | 292篇 |
1982年 | 318篇 |
1981年 | 297篇 |
1980年 | 263篇 |
1979年 | 225篇 |
1978年 | 233篇 |
1977年 | 195篇 |
1976年 | 168篇 |
1975年 | 177篇 |
1974年 | 183篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Correlation between 5-HT7 receptor affinity and protection against sound-induced seizures in DBA/2J mice 总被引:2,自引:0,他引:2
Anne Bourson Véronique Kapps Catherine Zwingelstein Alain Rudler Frank G. Boess A. J. Sleight 《Naunyn-Schmiedeberg's archives of pharmacology》1997,356(6):820-826
Audiogenic seizures can be induced in DBA/2J mice following intense auditory stimulation. A number of neurotransmitters, including
5-hydroxytryptamine (5-HT), are believed to be involved in mediating this effect since it has been shown previously that depletion
of 5-HT or blockade of 5-HT receptors protects DBA/2J mice from these audiogenic seizures. The present study was undertaken
to determine whether antagonism of the newly identified 5-HT7 receptor may protect DBA/2J mice from audiogenic seizures by attempting to correlate in vivo potency of compounds with their
affinity at the 5-HT7 receptor. All compounds used in the correlation were shown to be antagonists at the 5-HT7 receptor and a statistically significant correlation was observed between 5-HT7 affinity and doses for half-maximal response (ED50) for protection of DBA/2J mice from sound-induced seizures (r = 0.80; P < 0.05). No significant correlation was observed between in vivo activity and affinity at either 5-HT1A, 5-HT2A or 5-HT2C receptors. It is also unlikely that interactions between the 5-ht5 receptor will protect DBA/2J mice from audiogenic seizures since metergoline and mesulergine which are both active in this
in vivo model have no affinity for the 5-ht5 receptor. There are similarities between the pharmacology of the 5-HT7 receptor and that of the 5-HT1A receptor, however the correlation between the in vivo potency in DBA/2J mice and 5-HT1A affinity was not significant. Furthermore, the 5-HT1A receptor antagonist WAY 100135 did not protect DBA/2J mice from audiogenic seizures at doses that antagonise 5-HT1A receptor-mediated effects in mice. These data suggest that antagonism of 5-HT7 receptors may protect against audiogenic seizures in DBA/2J mice although a definitive conclusion must await studies with
selective 5-HT7 antagonists.
Received: 20 March 1997 / Accepted: 10 August 1997 相似文献
52.
Frank G. Holz Caren Bellmann Heimo Steffen Bernhard Nölle Jens Huober Hermann Krastel Evangelos Alexandridis 《Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft》1997,94(5):337-342
Fragestellung: Die Karzinomassoziierte Retinopathie (CAR) stellt ein seltenes paraneoplastisches Syndrom dar, das bislang
am h?ufigsten bei kleinzelligen Bronchialkarzinomen beschrieben wurde. Wir berichten über 3 Patientinnen mit CAR in Gegenwart
eines Mammakarzinoms bzw. eines Karzinoids der Cervix uteri.
Patienten und Methode: Es wurden biomikroskopische, perimetrische, angiographische und elektrophysiologische Befunde erhoben.
Au?erdem erfolgte eine Testung der Immunreaktivit?t der Seren an humaner Retina.
Ergebnisse: Die Befunde umfa?ten ringf?rmige Gesichtsfelddefekte mit statokinetischer Dissoziation und eine pathologische
St?bchen- und Zapfenantwort im ERG. Bei 1 Patientin wurde immunhistochemisch eine Reaktion im Bereich der Photorezeptorinnensegmente,
der ?u?eren K?rnerschicht sowie der ?u?eren plexiformen Schicht bei fehlendem Nachweis von Antik?rpern gegen Recoverin gefunden.
Diskussion: Neben dem kleinzelligen Bronchialkarzinom k?nnen auch andere Prim?rtumoren mit einer CAR vergesellschaftet sein.
Der Nachweis von retinalen Autoantik?rpern unterstützt die Annahme einer tumorinduzierten Immunantwort aufgrund der Expression
identischer Epitope durch die Tumorzellen. Dabei kommen offensichtlich verschiedene retinale Proteine als Autoantigene in
Betracht.
相似文献
53.
Peter L. Forster Frank B. Schoenfeld Charles R. Marmar Ariel Janna Lang 《Journal of traumatic stress》1995,8(1):143-149
Irritability is often a problem for patients with Post-Traumatic Stress Disorder (PTSD). We describe two cases that illustrate the use of lithium in the treatment of veterans with PTSD who complained of serious problems with irritability or angry outbursts. These cases are discussed in the context of evidence that lithium may be useful in other patients with disorders of impulse control. The evidence linking disorders of anger and impulse control to a dysregulation in neurotransmitter regulation, particularly in serotonergic pathways, supports a psychopharmacologic approach to treatment. These findings should lead to further study of the role of lithium in the treatment of this symptom complex in patients with PTSD. 相似文献
54.
A novel retractor has been designed to achieve atraumatic retraction of the liver and displacement of hollow viscera during endoscopic surgery. The functional section of the instrument, when locked, forms a silicon-covered uniplanar hook which can be deployed for horizontal lift of solid organs such as the liver or be used to engage bowel for displacement from the operative field. Following laboratory testing, the instrument has been evaluated clinically and its ease of deployment and atraumatic nature have been confirmed. It has been found to be particularly effective for elevation of the thick fatty left lobe of the liver during antireflux surgery. 相似文献
55.
David R. Dunt Frank Oberklaid Meredith J. Temple-Smith 《Australian and New Zealand journal of public health》1988,12(2):167-175
An interview study investigating attitudinal and other factors influencing the selection of primary medical care (PMC) agency is described. It focuses on adult patients excluding those with trauma of medical/surgical emergencies and was conducted in part of the Western Region of Melbourne in late 1983, the period immediately prior to the introduction of Medicare. It is based on a cross-sectional survey of in-hours attenders of eight general practices (GP), the Western Region (Community) Health Centre (WRCHC) and the general clinic of the casualty department at the Western General Hospital (WGH). Attenders of these different services differed significantly in their socio-demographic characteristics. WGH attenders were significantly younger and had migrated from non-English speaking countries significantly more often. Male attenders at the WGH had significantly lower socioeconomic status. 71 per cent being not in the workforce. The most commonly stated reasons for attendance at particular services generally were “closeness to home, work”, “recommendation” and “good service”. Reasons given by attenders at the different clinics generally were similar. However GP attenders offered “good service” significantly more often as a reason for choice; WGH attenders offered “cheap/economic reasons” significantly more often and “recommendation” significantly less so. WRCHC attenders offered “workers' compensation” significantly more often. Thirty per cent of attenders overall had attended other than their current clinic during their past three to four illness episodes. While a large majority of patients still attend GP for PMC it is concluded that a pluralist model recognising the legitimacy of different PMC arrangements and multiple use of them by individuals best meets community need. This is likely to be even more true under Medicare. It is concluded that instrumental factors and social networks are important in the selection of PMC, particularly given the limited knowledge of respondents about health services. It is also concluded that cost and economic factors have been given undue weight in selection of primary medical care agency. The use of the WGH casualty department by groups not in the work force, given no real financial advantage in doing so, requires further study. 相似文献
56.
Molecular basis of variegate porphyria: a missense mutation in the protoporphyrinogen oxidase gene.
下载免费PDF全文
![点击此处可从《Journal of medical genetics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J Frank H Lam E Zaider M Poh-Fitzpatrick A M Christiano 《Journal of medical genetics》1998,35(3):244-247
Variegate porphyria (VP) is an autosomal dominant disorder characterised by a partial defect in the activity of protoporphyrinogen oxidase (PPO), and has recently been genetically linked to the PPO gene on chromosome 1q22-23 (Z=6.62). In this study, we identified a mutation in the PPO gene in a patient with VP and two unaffected family members. The mutation consisted of a previously unreported T to C transition in exon 13 of the PPO gene, resulting in the substitution of a polar serine by a non-polar proline (S450P). This serine residue is evolutionarily highly conserved in man, mouse, and Bacillus subtilis, attesting to the importance of this residue. Interestingly, the gene for Gardner's syndrome (FAP) also segregates in this family, independently of the VP mutation. Gardner's syndrome or familial adenomatous polyposis (FAP) is also an autosomal dominantly inherited genodermatosis, and typically presents with colorectal cancer in early adult life secondary to extensive adenomatous polyps of the colon. The specific gene on chromosome 5 that is the site of the mutation in this disorder is known as APC (adenomatous polyposis coli), and the gene has been genetically linked to the region of 5q22. 相似文献
57.
Treatment of dyskeratosis congenita with Granulocyte Colony-Stimulating Factor and Erythropoietin 总被引:1,自引:0,他引:1
Blanche P. Alter Frank H. Gardner & Robert E. Hall 《British journal of haematology》1997,97(2):309-311
Aplastic anaemia is both frequent and difficult to manage in patients with dyskeratosis congenita (DC). We recently treated a 23-year-old male for a year with granulocyte colony-stimulating factor (G-CSF) and erythropoietin (Ep), with an excellent neutrophil response, and a transient effect on haemoglobin levels. G-CSF alone or combined with other cytokines may provide at least a partial effect in pancytopenic patients with DC. 相似文献
58.
59.
60.
Klaus Edvardsen Nils Brünner Mogens Spang-Thomsen Frank S. Walsh Elisabeth Bock 《International journal of developmental neuroscience》1993,11(5)
A cDNA encoding a transmembrane 140 kDa isoform of the neural cell adhesion molecule, NCAM, was transfected into the rat glioma cell line BT4Cn. Transfectants with a homogeneously high expression of NCAM-B showed a decreased capacity for penetration of an artificial basement membrane when compared to cells transfected with expression-vector alone or untransfected cells. However, when injected subcutaneously into nude mice, both NCAM expressing cells and control cells produced invasive tumors. Nude mice injected with NCAM positive cells developed tumors with slower growth rates as compared to those induced by NCAM negative cells. This implies that NCAM may not only be involved in adhesive and motile behaviour of glioma cells, but also in their growth regulation. 相似文献