全文获取类型
收费全文 | 110873篇 |
免费 | 7359篇 |
国内免费 | 762篇 |
专业分类
耳鼻咽喉 | 1263篇 |
儿科学 | 3364篇 |
妇产科学 | 2798篇 |
基础医学 | 15166篇 |
口腔科学 | 2449篇 |
临床医学 | 9592篇 |
内科学 | 23866篇 |
皮肤病学 | 2274篇 |
神经病学 | 10577篇 |
特种医学 | 4224篇 |
外国民族医学 | 23篇 |
外科学 | 14767篇 |
综合类 | 1796篇 |
现状与发展 | 1篇 |
一般理论 | 68篇 |
预防医学 | 7335篇 |
眼科学 | 1748篇 |
药学 | 9042篇 |
3篇 | |
中国医学 | 564篇 |
肿瘤学 | 8074篇 |
出版年
2023年 | 620篇 |
2022年 | 1297篇 |
2021年 | 2340篇 |
2020年 | 1548篇 |
2019年 | 2260篇 |
2018年 | 2636篇 |
2017年 | 2035篇 |
2016年 | 2092篇 |
2015年 | 2406篇 |
2014年 | 3162篇 |
2013年 | 4534篇 |
2012年 | 6292篇 |
2011年 | 6378篇 |
2010年 | 3963篇 |
2009年 | 3526篇 |
2008年 | 5498篇 |
2007年 | 5690篇 |
2006年 | 5309篇 |
2005年 | 5185篇 |
2004年 | 5366篇 |
2003年 | 5109篇 |
2002年 | 5111篇 |
2001年 | 3816篇 |
2000年 | 3722篇 |
1999年 | 3053篇 |
1998年 | 1238篇 |
1997年 | 995篇 |
1996年 | 871篇 |
1995年 | 846篇 |
1994年 | 745篇 |
1993年 | 713篇 |
1992年 | 1818篇 |
1991年 | 1785篇 |
1990年 | 1527篇 |
1989年 | 1467篇 |
1988年 | 1354篇 |
1987年 | 1216篇 |
1986年 | 1205篇 |
1985年 | 1056篇 |
1984年 | 787篇 |
1983年 | 706篇 |
1982年 | 477篇 |
1981年 | 408篇 |
1979年 | 581篇 |
1978年 | 429篇 |
1975年 | 442篇 |
1974年 | 493篇 |
1973年 | 467篇 |
1972年 | 428篇 |
1971年 | 402篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
971.
Summary The present report deals with a study of the osmoregulation of young Hymenolepis microstoma using the in vitro cultivation at different osmotic pressures: i.e. in eleven media with freezing point depressions ranging from 0.35 to 1.21° C. It has been shown that H. microstoma is able to develop optimally and equally well in media with freezing point depressions from 0.50 to 0.73° C. The worm seems to have a regulatory system operating successfully between these approximate limits. Media with lower or higher osmotic pressures do not cause death within the present experimental conditions but inhibit development gradually.It is concluded that, although cestodes are regarded as poikilosmotic, the present results with H. microstoma indicate that homoiosmotic properties might exist within a certain limited range of osmotic pressures.Supported by a N.A.T.O. grant.Encouragement by Prof. Dr. C. A. Hopkins is gratefully acknowledged. 相似文献
972.
Individualised, micro CT-based finite element modelling as a tool for biomechanical analysis related to tissue engineering of bone 总被引:10,自引:0,他引:10
Jaecques SV Van Oosterwyck H Muraru L Van Cleynenbreugel T De Smet E Wevers M Naert I Vander Sloten J 《Biomaterials》2004,25(9):1683-1696
Load-bearing tissues, like bone, can be replaced by engineered tissues or tissue constructs. For the success of this treatment, a profound understanding is needed of the mechanical properties of both the native bone tissue and the construct. Also, the interaction between mechanical loading and bone regeneration and adaptation should be well understood. This paper demonstrates that microfocus computer tomography (microCT) based finite element modelling (FEM) can have an important contribution to the field of functional bone engineering as a biomechanical analysis tool to quantify the stress and strain state in native bone tissue and in tissue constructs. Its value is illustrated by two cases: (1) in vivo microCT-based FEM for the analysis of peri-implant bone adaptation and (2) design of biomechanically optimised bone scaffolds. The first case involves a combined animal experimental and numerical study, in which the peri-implant bone adaptive response is monitored by means of in vivo microCT scanning. In the second case microCT-based finite element models were created of native trabecular bone and bone scaffolds and a mechanical analysis of both structures was performed. Procedures to optimise the mechanical properties of bone scaffolds, in relation to those of native trabecular bone are discussed. 相似文献
973.
Recurrent colonization of successively implanted tracheoesophageal vocal prostheses by a member of the Fusarium solani species complex
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Honraet K De Vos MM Summerbell RC van Kempen I De Saeger S Vermeersch H Van Peteghem C Nelis HJ 《Journal of clinical microbiology》2005,43(2):770-777
Tracheoesophageal vocal prostheses (TVP) in laryngectomized patients commonly deteriorate due to overgrowth by yeasts, particularly Candida species. We describe the first case of colonization of such devices by a member of the Fusarium solani species complex in a patient with a history of glottal carcinoma. Three isolates, from three prostheses, were found morphologically consistent with the traditional picture of F. solani. Ribosomal sequence analysis showed that the isolates belonged to a distinct, as yet apparently unnamed phylogenetic species within the F. solani species complex. This species, one of two distinct genetic types (genotype 2) traditionally considered part of the plant-pathogenic subtaxon Fusarium solani f. sp. radicicola, has not previously been identified as an agent of human or animal disease, although it is closely related to a known etiologic agent of mycetoma, an Acremonium-like species recently renamed Fusarium falciforme. Sequence and multisatellite M13 polymorphism analysis revealed no distinctions among the case isolates. Production of cyclosporine was detected for all three case isolates. 相似文献
974.
The significance and use of the cytological diagnosis "atypical squamous cells of undetermined significance" (ASCUS) remain a major problem in cervical cancer screening. The prevalence of ASCUS by patient age has seldom been investigated. The present paper reports the prevalence of ASCUS in a large series of screening Pap smears from the Italian region of Emilia-Romagna. The study was based on the data collected by the Department of Health of the Emilia-Romagna Region for the first 3-year round (1997-1999) of a population-based screening programme (target age, 25-64 years). The age-specific frequency of ASCUS has been calculated as a prevalence rate per 1000 screened patients. A total of 597,386 women participated in the programme. Women diagnosed with ASCUS (n = 8205 or 13.7 per 1000) accounted for 49% of the recalls for colposcopy (n = 16,871, or 28.2 per 1000). The prevalence of diagnoses of low-grade squamous intraepithelial lesions (LG-SIL) decreased progressively with age while that of high-grade SIL was slightly higher between 30 and 39 years. The prevalence of ASCUS peaked at age 45-49 years (17.3 per 1000 subjects). The observed peak reflects the prevalence of (1) cytological changes closely associated with perimenopausal age and at least compatible with the ASCUS diagnosis, and (2) cytological abnormalities induced by hormone replacement therapy. 相似文献
975.
Mutation analysis of the nerve specific promoter of the peripheral myelin protein 22 gene in CMT1 disease and HNPP. 总被引:1,自引:0,他引:1
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)
E Nelis P De Jonghe E De Vriendt P I Patel J J Martin C Van Broeckhoven 《Journal of medical genetics》1998,35(7):590-593
We analysed the nerve specific promoter of the peripheral myelin protein 22 gene (PMP22) in a set of 15 unrelated patients with Charcot-Marie-Tooth type 1 disease (CMT1) and 16 unrelated patients with hereditary neuropathy with liability to pressure palsies (HNPP). In these patients no duplication/deletion nor a mutation in the coding region of the CMT1/ HNPP genes was detected. In one autosomal dominant CMT1 patient, we identified a base change in the non-coding exon 1A of PMP22 which, however, did not cosegregate with the disease in the family. This study indicates that mutations in the nerve specific PMP22 promoter and 5' untranslated exon will not be a common genetic cause of CMT1A and HNPP. 相似文献
976.
PMX2B,a new candidate gene for Hirschsprung's disease 总被引:7,自引:0,他引:7
Benailly HK Lapierre JM Laudier B Amiel J Attié T De Blois MC Vekemans M Romana SP 《Clinical genetics》2003,64(3):204-209
Hirschsprung's (HSCR) disease is a congenital intestinal malformation of the enteric nervous system. It is a multigenic malformation and until now, eight genes have been involved in the etiology of this disease: genes encoding proteins of the RET signaling pathway (RET, GDNF and NTN), genes participating in the endothelin (EDN) type B receptor pathway (EDNRB, EDN3 and ECE-1), the SOX10 gene and the SIP1 gene that is mutated in syndromic forms of HSCR. Mutations of these genes are found in not more than 50-60% of affected individuals. Here, we report on the results of a molecular cytogenetic study performed in a girl who presented with a syndromic short segment HSCR associated with a de novo t(4;8)(p13;p22) translocation. A comparative genomic hybridization (CGH) study found a 4p12p13 deletion. A molecular characterization of this rearrangement showed that the 4p13 deletion was 5 Mb in length and included the paired mesoderm homeobox gene (PMX2B) (MIM 603851), a gene expressed in the human embryonic gut and essential for the development of autonomic neural crest derivatives. The present observation suggests that PMX2B haploinsuffciency might predispose to HSCR. 相似文献
977.
In a patient treated for a non-Hodgkin's lymphoma, a lung abscess caused by Hormographiella aspergillata (stat. anamorph. Coprinus cinereus) was diagnosed using an ultrasound-guided puncture of the lesion. The patient appeared to respond to amphotericin B, but at the same time was also recovering from her neutropenic episode. The extent to which each of these two factors explains the complete resolution of the infection is unclear. Expert classical morphological examination and molecular typing methods were needed to identify this filamentous basidiomycetous fungus. 相似文献
978.
De Fabritiis A Conti E Coccheri S 《Pathophysiology of haemostasis and thrombosis》2002,32(5-6):381-385
Carotid atherosclerosis is one of the main risk factors for ischemic stroke. The annual risk of ipsilateral stroke for asymptomatic, albeit severe stenoses is as low as 1 to 2%, but increases to 13% in patients with recent ischemic symptoms. However the risk decreases after the first 2-3 years from the symptomatic episode, dropping to 3%. Echo-color Doppler ultrasonography is the screening method of choice, being highly accurate, noninvasive and low-cost. Carotid angiography still represents the gold standard, however, less invasive techniques as RM angiography and Angio-CT are becoming increasingly common. Based on NASCET, ECST and ACAS results, carotid endarterectomy (CE) is strongly recommended for severe symptomatic stenoses, while for the moderate symptomatic and the severe asymptomatic ones the benefit in terms of stroke risk reduction is modest and surgery should be restricted to selected cases in surgical centers of high experience. For severe asymptomatic stenoses NNT is too high to recommend indiscriminate surgery; we are waiting for the results of ACSRS trial, designed to identify a subset of patients at risk of ipsilateral stroke greater than 4%/y, that may be considered for CE, while patients at low risk will be spared from unnecessary operation. Apart from surgery, in all patients with carotid atherosclerosis correction of cardiovascular risk factors is mandatory. Antiplatelet therapy (ASA alone or with dypiridamole, ticlopidine) is effective in secondary prophylaxis of athero-thrombotic stroke; its use in asymptomatic carotid stenoses can be recommended, even if more because of a plausible rationale than of clinical trial-based evidences. 相似文献
979.
AIMS: To perform a morphometric analysis of carotid bodies in opiate addicts. METHODS AND RESULTS: Carotid bodies were sampled at autopsy from 35 subjects who died of heroin intoxication (mean age 26 years), and from eight young (22 years) and eight older subjects (66.5 years) who died of trauma. Sections were stained with haematoxylin-eosin, azan-Mallory, and double-labelling immunohistochemistry with antineuronal specific enolase and anti-S100, to count type I and type II cells. Interlobular and intralobular connective tissue was increased both in the opiate cases (43.45 +/- 6.79%, P < 0.001, and 13.34 +/- 5.72%, P < 0.001, respectively) and older cases (46.67 +/- 1.65%, P < 0.001, and 9.62 +/- 2.11%, P < 0.05, respectively) compared with young cases (33.17 +/- 6.41% and 4.33 +/- 1.84%, respectively). The percentage of type II cells in the opiate cases (51.6 +/- 7.3%, P < 0.001) and in the older controls (49.0 +/- 7.2%, P < 0.01) was higher than in the young cases (37.9 +/- 3.0%). Among type I cells, the light cell percentage in the opiate cases (65.85 +/- 11%, P < 0.001) was reduced with respect to the two control groups (82.8 +/- 5.34%, young; 81.62 +/- 8.58%, older). CONCLUSIONS: The increases in connective tissue and type II cells are similar to findings in ageing and chronic pulmonary disease, and may be ascribed to glomic hypoxia. A direct action of opiates should be taken into account for the decrease in light cells in heroin addiction. The histopathological changes in the carotid body, by impairing chemosensivity, may play a role in the fatal cardiorespiratory derangement of heroin addicts. 相似文献
980.
Increased aneuploidy in spermatozoa from testicular tumour patients after chemotherapy with cisplatin, etoposide and bleomycin 总被引:7,自引:0,他引:7
De Mas P Daudin M Vincent MC Bourrouillou G Calvas P Mieusset R Bujan L 《Human reproduction (Oxford, England)》2001,16(6):1204-1208
Testicular cancer is the most common neoplasia occurring in the young male population. The PEB (cisplatin, etoposide and bleomycin) adjuvant chemotherapy usually proposed after orchidectomy in non seminomatous tumours, and in metastatic seminomas, has improved the long-term survival of these patients. Following an azoospermic period, sperm cell recovery is generally observed after treatment delivery, but little is known about the genetic consequences on these new spermatozoa. To estimate the chromosomal consequences of this chemotherapy on sperm cells during the period of recovery of spermatogenesis, sperm cell aneuploidy was studied in testicular cancer patients, at 6-18 months after PEB adjuvant chemotherapy delivery, using fluorescence in-situ hybridization (FISH) of chromosomes 7, 16, 18, X and Y with specific DNA probes. A significant increase in the frequency of diploidy and disomy for chromosomes 16, 18 and XY was observed in treated patients compared with a healthy control group. Spermatozoa aneuploidy occurring during the spermatogenesis recovery period might be a possible side effect of the PEB regimen. Thus, practitioners should be advised to provide counselling about the need for an appropriate duration of contraception. Moreover, genetic counselling should be offered in cases of pregnancy occurring soon after the end of chemotherapy. 相似文献