全文获取类型
收费全文 | 2454篇 |
免费 | 136篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 95篇 |
妇产科学 | 47篇 |
基础医学 | 277篇 |
口腔科学 | 78篇 |
临床医学 | 159篇 |
内科学 | 667篇 |
皮肤病学 | 70篇 |
神经病学 | 203篇 |
特种医学 | 192篇 |
外国民族医学 | 2篇 |
外科学 | 246篇 |
综合类 | 45篇 |
预防医学 | 160篇 |
眼科学 | 28篇 |
药学 | 165篇 |
中国医学 | 9篇 |
肿瘤学 | 149篇 |
出版年
2023年 | 12篇 |
2022年 | 17篇 |
2021年 | 43篇 |
2020年 | 31篇 |
2019年 | 43篇 |
2018年 | 65篇 |
2017年 | 36篇 |
2016年 | 38篇 |
2015年 | 56篇 |
2014年 | 68篇 |
2013年 | 88篇 |
2012年 | 117篇 |
2011年 | 130篇 |
2010年 | 88篇 |
2009年 | 120篇 |
2008年 | 128篇 |
2007年 | 111篇 |
2006年 | 107篇 |
2005年 | 103篇 |
2004年 | 116篇 |
2003年 | 65篇 |
2002年 | 79篇 |
2001年 | 55篇 |
2000年 | 44篇 |
1999年 | 61篇 |
1998年 | 65篇 |
1997年 | 74篇 |
1996年 | 72篇 |
1995年 | 52篇 |
1994年 | 50篇 |
1993年 | 49篇 |
1992年 | 26篇 |
1991年 | 24篇 |
1990年 | 36篇 |
1989年 | 31篇 |
1988年 | 37篇 |
1987年 | 39篇 |
1986年 | 32篇 |
1985年 | 25篇 |
1984年 | 17篇 |
1983年 | 16篇 |
1982年 | 19篇 |
1981年 | 8篇 |
1980年 | 14篇 |
1979年 | 12篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 10篇 |
1974年 | 9篇 |
1966年 | 6篇 |
排序方式: 共有2607条查询结果,搜索用时 500 毫秒
31.
Scapagnini G Ravagna A Bella R Colombrita C Pennisi G Calvani M Alkon D Calabrese V 《International journal of tissue reactions》2002,24(3):89-96
Evidence is accumulating that intermediates of oxygen reduction may be associated with the development of alcoholic disease. Free radical-induced perturbation of the oxidant/antioxidant balance in the cell is widely recognized as the main causative factor of age-related disorders. In the present study we investigated the effects of 20 months of ethanol consumption on the antioxidant defense system in different rat organs compared with normal aging in the absence and presence of treatment with L-acetyl carnitine. We demonstrate that aged rats underwent significant perturbation of the antioxidant defense system, as indicated by depletion of reduced glutathione (GSH) content, increased oxidized GSH, free radical-induced luminescence associated with increased hydroxynonenal content and decreased GSH reductase activity. These modifications, observed particularly in brain and liver compared with other organs, were enhanced by long-term alcohol exposure and, interestingly, were significantly reduced with acetyl carnitine supplements. Our results indicate that decreased GSH reductase activity and thiol depletion are important factors in effecting a pathogenic role for oxidative stress in aging and in all situations in which age-correlated and oxidant-induced changes occur, such as in alcoholism. Administration of acetyl carnitine greatly reduces these metabolic abnormalities. Our findings support its pharmacological potential in the management of alcoholic disturbances. 相似文献
32.
Anne Silvy Peter Altevogt Paul Mondire Chantal Bella Thierry Defrance 《European journal of immunology》1997,27(11):2757-2764
It is generally recognized that activation through membrane effector molecules such as CD40 or the B cell receptor (BCR) is mandatory to allow B cells to proliferate and differentiate into antibody (Ab)-secreting cells in response to cytokines. We show here that purified tonsillar B cells can be stimulated directly by a cytokine combination to proliferate and secrete immunoglobulins when cultures are performed at high cell density. The contact-mediated activation of B cells in this experimental system is strongly inhibited both by anti-very late antigen (VLA)-4 monoclonal Ab and by a peptide containing the LDV sequence specifically recognized by the α4 integrin binding site. These reagents also significantly suppressed the B cell responses elicited by engagement of the BCR or CD40. Our data reveal that memory B cells but not virgin or germinal center B cells are sensitive to the direct stimulatory effect of cytokines in high-density cultures. Finally, we found that the dual expression of the α and β chains of VLA-4 is a distinctive feature of the memory B cell population. Collectively, our findings support the notion that VLA-4-dependent homotypic B cell interactions can mediate a co-stimulatory signal to human memory B cells and might participate in the B cell activation triggered through the BCR and CD40. 相似文献
33.
Kennedy J Jackson GC Barker FS Nundlall S Bella J Wright MJ Mortier GR Neas K Thompson E Elles R Briggs MD 《Human mutation》2005,25(6):593-594
Pseudoachondroplasia (PSACH) and some forms of multiple epiphyseal dysplasia (MED) result from mutations in the gene encoding cartilage oligomeric matrix protein (COMP). COMP is a large pentameric glycoprotein found predominantly in the extracellular matrix of cartilage, tendon, and ligament. As a modular protein, it is composed of a coiled-coil domain, four type II (T2) repeats, eight type III (T3) repeats, and a large globular C-terminal domain (CTD). The majority (>85%) of COMP mutations causing PSACH or MED are found in the exons encoding the T3 repeats, and the disease mechanism has been characterised in detail. Much less is known about disease-causing mutations in the CTD; in 10 years only seven mutations have been identified. In this study, we describe eight novel and two recurrent mutations that we have recently identified in patients with PSACH or MED. Interestingly, these mutations result in a spectrum of disease, ranging from mild MED to severe PSACH. Mapping of all known COMP CTD mutations on a three-dimensional model of the C-terminal domain shows that the CTD mutations cluster in two distinct regions. These regions are probably important in stabilising the T3-CTD structure and mediating intra- or intermolecular interactions. 相似文献
34.
Mina Ben-bassat Diana Braslavsky Danny Lotan Bella Eisenstein Miriam Davidovitz Harry Stark 《Ultrastructural pathology》1988,12(1):1-16
In an attempt to recognize early stages of focal segmental glomerulosclerosis (FSGS) in patients with a clinical course suggesting a diagnosis other than minimal change disease (MCD) and normal histology, or minor, nondiagnostic changes on light microscopy (LM), we used a protocol for systematic and extensive electron microscopy (EM) examination of kidney biopsies obtained from such patients. By this method ultrastructural pathology was found in 8 patients. These changes were localized, involving only portions of single glomerular segments. The findings included mild to moderate increase of the mesangial matrix, focal wrinkling of the capillary basement membrane, and early obliteration of the normal architecture of individual capillary loops, as well as electron-dense deposits in a mesangial and subendothelial distribution. Of these 8 patients, 2 are at present in remission without therapy (in 1, following therapy with cyclophosphamide); 3 are in remission on steroid therapy; 1 developed massive proteinuria during pregnancy, after a spontaneous remission lasting almost 2 years; 1 patient advanced to terminal renal failure 3 1/2 years after biopsy; and 1 died of sepsis 1 month after biopsy. We believe that the ultrastructural changes found may represent early or mild FSGS and that the protocol described can add valuable information in clinically worrisome patients in whom renal histology appears normal. 相似文献
35.
Debelenko LV; Brambilla E; Agarwal SK; Swalwell JI; Kester MB; Lubensky IA; Zhuang Z; Guru SC; Manickam P; Olufemi SE; Chandrasekharappa SC; Crabtree JS; Kim YS; Heppner C; Burns AL; Spiegel AM; Marx SJ; Liotta LA; Collins FS; Travis WD; Emmert-Buck MR 《Human molecular genetics》1997,6(13):2285-2290
Lung carcinoids occur sporadically and rarely in association with multiple
endocrine neoplasia type 1 (MEN1). There are no well defined genetic
abnormalities known to occur in these tumors. We studied 11 sporadic lung
carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene
on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy
fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was
studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene
were inactivated. All four tumors showed the presence of a MEN1 gene
mutation and loss of the other allele. Observed mutations included a 1 bp
insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide
substitution affecting a donor splice site. Each mutation predicts
truncation or potentially complete loss of menin. The remaining seven
tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH.
The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a
complex germline MEN1 gene mutation. The data implicate the MEN1 gene in
the pathogenesis of sporadic lung carcinoids, representing the first
defined genetic alteration in these tumors.
相似文献
36.
Paolo Cabas Michele Rizzo Mauro Giuffrè Roberta Maria Antonello Carlo Trombetta Roberto Luzzati Giovanni Liguori Stefano Di Bella 《Urologic oncology》2021,39(2):85-92
Objective: Intravesical Bacillus Calmette-Guèrin (BCG) is an effective treatment in non––muscle-invasive bladder cancer, however, extravesical BCG infection may occur in remote organs as a potentially serious complication. Researchers aimed to assess whether a different timing of BCG infection after intravesical administration of BCG could be identified and estimated for each single involved organ. Methods: We performed a systematic literature review over systemic and genitourinary BCG infection case reports, including 271 published case reports for a total of 307 patients. Demographic data, clinical features, and timing of BCG infection development were collected and analyzed for each patient. Results: BCG infection developed with a different timing from last instillation, depending on the involved organ. Among the genitourinary complications, penile lesions occurred as early as 1 (1;3) weeks, while orchiepididymitis occurred as late as 56 (6.25;156) weeks. At the same time, granulomatous hepatitis and lungs involvement such as miliary pulmonary BCG infection occurred earlier, with a median time of 1 (1;4) and 1 (1;6) weeks respectively, whereas vascular, osteoarticular, and muscular complications developed with a median timing from last instillation of 52 (20;104), 68 (14;156), and 93 (29;156) weeks, respectively. The analysis detected a cluster between lungs, liver, and bone marrow complications on one side and muscular and osteoarticular or vascular complications on the other side was also observed. Conclusions: BCG infection after intravesical BCG for bladder cancer may develop even several months or years after the last instillation, depending on the involved organs. When BCG infection interests one or more organ, 2 main associative patterns are common: one involving lungs, liver, and bone marrow, with earlier occurrence but lower rates of microbiological diagnosis achievement, and one involving muscular and osteoarticular or vascular districts, with later occurrence but higher rates of microbiological evidence. 相似文献
37.
38.
Deckert J Catalano M Syagailo YV Bosi M Okladnova O Di Bella D Nöthen MM Maffei P Franke P Fritze J Maier W Propping P Beckmann H Bellodi L Lesch KP 《Human molecular genetics》1999,8(4):621-624
A genetic contribution to the pathogenesis of panic disorder has been demonstrated by clinical genetic studies. Molecular genetic studies have focused on candidate genes suggested by the molecular mechanisms implied in the action of drugs utilized for therapy or in challenge tests. One class of drugs effective in the treatment of panic disorder is represented by monoamine oxidase A inhibitors. Therefore, the monoamine oxidase A gene on chromosome X is a prime candidate gene. In the present study we investigated a novel repeat polymorphism in the promoter of the monoamine oxidase A gene for association with panic disorder in two independent samples (German sample, n = 80; Italian sample, n = 129). Two alleles (3 and 4 repeats) were most common and constituted >97% of the observed alleles. Functional characterization in a luciferase assay demonstrated that the longer alleles (3a, 4 and 5) were more active than allele 3. Among females of both the German and the Italian samples of panic disorder patients (combined, n = 209) the longer alleles (3a, 4 and 5) were significantly more frequent than among females of the corresponding control samples (combined, n = 190, chi2 = 10.27, df = 1, P = 0.001). Together with the observation that inhibition of monoamine oxidase A is clinically effective in the treatment of panic disorder these findings suggest that increased monoamine oxidase A activity is a risk factor for panic disorder in female patients. 相似文献
39.
Bella H 《IPPF medical bulletin》1980,14(1):2-4
The Sudanese village midwife can be defined as "an illiterate (or sometimes literate) woman, usually a mother, community chose, trained in a district midwifery school for about 9 months, after which she receives a certificate, is registered and becomes responsible for antenatal; intrapartum; and postnatal care of the mother and child in her village. She is a part-time worker, not salaried and she is supervised by the community." The difference between the village midwife and the TBA (traditional birth attendant) as defined by WHO is that the village midwife receives formal training from the beginning, and ends by being registered and being legally recognized. The activities and standard of performance of the village midwife are of high standard, even approximating English standards. The community employs the midwife and fees are paid on an optional basis, as midwives who demand fees are generally looked upon with disapproval. The midwives are not only trained to conduct deliveries at home, but also to be "missionaries in the homes of people in the cause of cleanliness and hygiene" and to spread a "health sense" among mothers and thus promote the health of the next generation. Over all, the midwifery training program shows that utilization of part-time health workers can be a valid and feasible concept. 相似文献
40.
Zusammenassung In der vorliegenden Studie sollte untersucht werden, ob die vonPetrovic, Lavergne undStutzmann vorgeschlagene Kategorisierung des mandibulären Wachstumspotentials für die Behandlung mit dem Funktionsregler Geltung hat. Dazu wurden die Fernröntgenaufnahmen von 140 Patienten der Angle-Klasse II nach zirka zweijähriger Behandlung mit Funktionsreglern analysiert. Im Vergleich zu 133 unbehandelten Kindern mit Angle-Klasse II trat in fast allen Rotationsgruppen eine signifikant größere Zunahme der Unterkiefergesamtlänge ein. Zwischen der Kategorie 2 mit niedrigem Wachstumpotential und Kategorie 5 mit hohem Wachstumspotential wurden keine signifikant unterschiedlichen Zunahmen der Unterkieferlänge festgestellt.
Summary The results of the study show whether the classification of mandibular growth potential, as proposed by Petrovic, Lavergne and Stutzmann has any influence on the treatment with a function regulator. X-rays of 140 class II patients were analysed after a treatment time of approximately 2 years. In comparison with 133 class II children without any treatment, a significant increase of the overall mandibular length was observed in almost all children treated. There was no significant difference in the increase of mandibular length between category 2 (low growth potential) and category 5 (high growth potential).相似文献