全文获取类型
收费全文 | 7285篇 |
免费 | 420篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 200篇 |
儿科学 | 462篇 |
妇产科学 | 75篇 |
基础医学 | 747篇 |
口腔科学 | 240篇 |
临床医学 | 596篇 |
内科学 | 1740篇 |
皮肤病学 | 89篇 |
神经病学 | 546篇 |
特种医学 | 193篇 |
外科学 | 1057篇 |
综合类 | 219篇 |
一般理论 | 1篇 |
预防医学 | 328篇 |
眼科学 | 303篇 |
药学 | 488篇 |
中国医学 | 36篇 |
肿瘤学 | 429篇 |
出版年
2023年 | 51篇 |
2022年 | 68篇 |
2021年 | 270篇 |
2020年 | 139篇 |
2019年 | 168篇 |
2018年 | 217篇 |
2017年 | 150篇 |
2016年 | 188篇 |
2015年 | 216篇 |
2014年 | 303篇 |
2013年 | 368篇 |
2012年 | 569篇 |
2011年 | 558篇 |
2010年 | 331篇 |
2009年 | 257篇 |
2008年 | 470篇 |
2007年 | 507篇 |
2006年 | 397篇 |
2005年 | 330篇 |
2004年 | 326篇 |
2003年 | 287篇 |
2002年 | 248篇 |
2001年 | 125篇 |
2000年 | 104篇 |
1999年 | 96篇 |
1998年 | 61篇 |
1997年 | 43篇 |
1996年 | 28篇 |
1995年 | 25篇 |
1994年 | 32篇 |
1993年 | 26篇 |
1992年 | 70篇 |
1991年 | 74篇 |
1990年 | 66篇 |
1989年 | 59篇 |
1988年 | 54篇 |
1987年 | 51篇 |
1986年 | 42篇 |
1985年 | 45篇 |
1984年 | 19篇 |
1983年 | 28篇 |
1982年 | 14篇 |
1980年 | 14篇 |
1979年 | 39篇 |
1978年 | 23篇 |
1975年 | 21篇 |
1972年 | 21篇 |
1970年 | 14篇 |
1966年 | 14篇 |
1965年 | 13篇 |
排序方式: 共有7749条查询结果,搜索用时 31 毫秒
61.
Ricardo Pietrobon Anand Shah Paul Kuo Matthew Harker Mariana McCready Christeen Butler Henrique Martins CT Moorman Danny O Jacobs 《BMC medical informatics and decision making》2006,6(1):32-11
Background
Although regulatory compliance in academic research is enforced by law to ensure high quality and safety to participants, its implementation is frequently hindered by cost and logistical barriers. In order to decrease these barriers, we have developed a Web-based application, Duke Surgery Research Central (DSRC), to monitor and streamline the regulatory research process. 相似文献62.
An experimental model of carditis has been produced in the rhesus monkey by giving 12 weekly injections of a streptococcal membrane antigen. There was histological evidence of focal myocarditis, subendocardial infiltration with lymphomononuclear cells and in one animal myocardial granuloma formation. No valvular lesions were seen. Humoral immune responses monitored throughout the experiment showed that anti-heart antibodies appeared in circulation after the 2nd injection, attained maximal titres by the 6th injection, and thereafter the titres declined. The anti-membrane antibodies appeared slightly later and these titres kept rising till sacrifice. By the 6th injection there was evidence of complement consumption and appearance of circulating immune complexes. It is concluded that these immunological responses might have a role to play in the pathogenesis of carditis. 相似文献
63.
Pulmonary endocrine cells in various species in the Himalaya 总被引:1,自引:0,他引:1
J Gosney D Heath D Williams M Deen P Harris I Anand R Ferrari 《Journal of comparative pathology》1988,99(1):93-100
The numbers, morphology and distribution of pulmonary endocrine cells in goats, sheep and the yak and its interbreeds with cattle, dzos and stols, were studied after their demonstration by means of the peroxidase-antiperoxidase technique with a polyclonal antiserum raised in the rabbit to human neuron-specific enolase, a marker for neuroendocrine cells. The numbers, morphology and distribution were related to species and not to residence at high altitude. Pulmonary endocrine cells were common and mainly distributed as solitary cells in the epithelium of the bronchial tree in sheep. They were much less common and found mainly as clusters in the alveolar capillary walls in goats and in the yak and its interbreeds with cattle. 相似文献
64.
Spondyloarthropathy represents a group of joint diseases with a tendency to reactive new bone formation. Spondyloarthropathy includes Reiter's syndrome, ankylosing spondylitis, and the arthropathy of inflammatory diseases (ulcerative colitis and Crohn's disease). Usually, an extensive investigation is required to distinguish spondyloarthropathy of the knee joint from rheumatoid arthritis. Recently, Reddy et al. (Ann. Biomed. Eng. 23:78–84, 1995) have developed the accelerometry technique to characterize various types of arthritis. The question remains if noninvasive acceleration measurements can be used to distinguish between spondyloarthropathy and rheumatoid arthritis. An ultraminiature accelerometer was placed on the patella, and the subject was asked to rhythmically rotate the knee from 90 flexion to full extension. Results have shown that the mean power of acceleration signal in the range of 100–500 Hz is significantly different (p < 0.05) for spondyloarthropathy patients when compared to rheumatoid arthritis patients. The noninvasive accelerometry technique represents a potential tool for characterization of spondyloarthropathy patients. © 2001 Biomedical Engineering Society.
PAC01: 8719St, 8719Xx, 0630Gv 相似文献
65.
66.
Depletion of neuropeptides during wound healing in rat skin 总被引:1,自引:0,他引:1
A Senapati P Anand G P McGregor M A Ghatei R P Thompson S R Bloom 《Neuroscience letters》1986,71(1):101-105
The peptides substance P, calcitonin gene-related peptide and somatostatin are present in nerve fibres in mammalian, including human, skin. There is evidence that in addition to having a putative neurotransmitter role, they may be trophic agents: a study was therefore undertaken of peptide changes during wound healing in rat skin. A significant depletion of the neuropeptides was found in the region of the wound within two days, and this persisted for two weeks. A smaller and delayed depletion also occurred in intact skin of the same dermatome, but not in an adjacent dermatome. 相似文献
67.
A study was conducted in Santa Cruz County to estimate the prevalence and distribution of the agents of Lyme disease, human granulocytic (HGE), and human monocytic (HME) ehrlichiosis in 1,187 adult ixodid ticks collected from eight public-use recreation areas over a 2-yr period. Borrelia burgdorferi, the causative agent of Lyme disease, was detected by a polymerase chain reaction (PCR) in 44 of 776 (5.67%) Ixodes pacificus ticks and in 3 of 58 (5.17%) Dermacentor variabilis ticks. Anaplasma phagocytophilum, the causative agent of HGE, was detected by PCR in 48 (6.19%) I. pacificus ticks and 5 (8.62%) D. variabilis ticks. Ehrlichia chaffeensis, the causative agent of HME, was detected by nested PCR in just five (0.64%) I. pacificus ticks and four (6.9%) D. variabilis ticks. Interestingly, eight (1.03%) I. pacificus ticks were co-infected with B. burgdorferi and A. phagocytophilum, and just one (0.12%) tick was co-infected with B. burgdorferi and E. chaffeensis. Less than 1% of 353 Dermacentor occidentalis ticks showed evidence of infection with any of the agents tested. To our knowledge, this is the first reported identification of A. phagocytophilum and E. chaffeensis in D. occidentalis ticks from California This study represents the first extensive survey of Lyme and the ehrlichial diseases across multiple areas of Santa Cruz County, and suggests that prevalence of B. burgdorferi in Santa Cruz County may be higher than other areas of the state. 相似文献
68.
As a means for assessing cardiac function, electrical field plethysmography (EFP) has been shown to have some features quite
different from electrical impedance plethysmography (EIP). Here the two techniques are compared by using the two systems simultaneously
on a subject and also with independent use in different electrode configurations. The results conform with the view that EIP
is related primarily to volumetric changes of the aorta, whereas EFP is affected predominantly by changes in cardiac dimensions
and orientation. Because of this difference, the standard time differential formula used for EIP is not applicable for the
computation of cardiac output from the EFP waveforms. An alternative method of computation based on the amplitude of the EFP
waveform is suggested. 相似文献
69.
PCR-Enzyme Immunoassay for Detection of Streptococcus pneumoniae DNA in Cerebrospinal Fluid Samples from Patients With Culture-Negative Meningitis 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 clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Thomas Cherian M. K. Lalitha Anand Manoharan Kurien Thomas Robert H. Yolken Mark C. Steinhoff 《Journal of clinical microbiology》1998,36(12):3605-3608
A PCR-based assay was developed to amplify a conserved region of the pneumococcal autolysin gene. The amplified product was labelled with digoxigenin-labelled dUTP and was detected with a biotin-labelled probe in an enzyme immunoassay (EIA). The assay was initially tested with suspensions of various serotypes of Streptococcus pneumoniae and other gram-positive and gram-negative bacteria and was then applied to cerebrospinal fluid (CSF) specimens from patients with meningitis and those with other neurological disorders. The assay detected all the serotypes of S. pneumoniae tested, whereas all the other bacterial strains tested were negative. Seven of the 8 CSF specimens positive for pneumococcus by culture or latex agglutination (LA) were positive by PCR-EIA, whereas all 10 specimens positive for other organisms were negative. Among 11 patients with clinically diagnosed meningitis but with negative culture and LA results, 5 were positive by PCR-EIA. The assay was negative for all but one patient without meningitis; it was positive with the CSF from a child with immunodeficiency and pneumococcal abscesses on the scalp. PCR-EIA is a useful tool for the diagnosis of meningitis, especially when culture and LA are negative because of prior antibiotic treatment. 相似文献
70.
Chetan Anand Akmal Pasha M. D. Swetha Putte Gowda B. E. Amitha Rani N. G. K. Karanth 《Food and Agricultural Immunology》2007,18(1):39-51
A polyclonal antibody-based enzyme-linked immunosorbent assay (ELISA) method was developed for the N-methylcarbamate insecticide bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-yl methylcarbamate). Two novel haptens having dimethylbenzodioxyl and dimethylbenzofuranyl groups connected to oxyacetyl-γ-aminobutanoic acid and oxyacetyl-β-alanine spacer arm respectively were synthesised. The first hapten was conjugated to carrier proteins to make antigens that were used to raise polyclonal antibodies in rabbits. The antibodies specifically recognised bendiocarb and its metabolite 2,2-dimethyl-1,3-benzodiox-4-ol with an IC50 value of 9 ppb (ng ml-1). The assay was standardised using the competitive ELISA format at 0.0625 µg antibody concentration and at 1/10k pesticide-HRP dilution. Matrix effect studies were carried out in four vegetable and cereal food samples. Matrix effect elimination in cabbage, cauliflower and rice was achieved by simple dilution of the extract. Five different approaches were attempted to achieve matrix clean up in paddy rice. C-18 column and gel permeation column chromatography (GPC) helped in the matrix removal. The spike and recovery studies for all the four food samples gave a recovery in the range of 75-95%, thus indicating the efficiency of the matrix elimination procedures developed. 相似文献