全文获取类型
收费全文 | 11396篇 |
免费 | 714篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 113篇 |
儿科学 | 208篇 |
妇产科学 | 242篇 |
基础医学 | 1869篇 |
口腔科学 | 1176篇 |
临床医学 | 741篇 |
内科学 | 2288篇 |
皮肤病学 | 272篇 |
神经病学 | 946篇 |
特种医学 | 222篇 |
外科学 | 1039篇 |
综合类 | 53篇 |
一般理论 | 2篇 |
预防医学 | 1175篇 |
眼科学 | 192篇 |
药学 | 1028篇 |
中国医学 | 110篇 |
肿瘤学 | 480篇 |
出版年
2023年 | 101篇 |
2022年 | 248篇 |
2021年 | 376篇 |
2020年 | 243篇 |
2019年 | 337篇 |
2018年 | 433篇 |
2017年 | 290篇 |
2016年 | 311篇 |
2015年 | 352篇 |
2014年 | 523篇 |
2013年 | 590篇 |
2012年 | 898篇 |
2011年 | 1015篇 |
2010年 | 525篇 |
2009年 | 400篇 |
2008年 | 708篇 |
2007年 | 737篇 |
2006年 | 555篇 |
2005年 | 567篇 |
2004年 | 487篇 |
2003年 | 397篇 |
2002年 | 321篇 |
2001年 | 233篇 |
2000年 | 231篇 |
1999年 | 206篇 |
1998年 | 71篇 |
1997年 | 58篇 |
1996年 | 36篇 |
1995年 | 35篇 |
1994年 | 29篇 |
1993年 | 24篇 |
1992年 | 102篇 |
1991年 | 76篇 |
1990年 | 78篇 |
1989年 | 60篇 |
1988年 | 50篇 |
1987年 | 28篇 |
1986年 | 34篇 |
1985年 | 39篇 |
1984年 | 18篇 |
1983年 | 17篇 |
1979年 | 28篇 |
1977年 | 15篇 |
1974年 | 23篇 |
1973年 | 28篇 |
1971年 | 19篇 |
1970年 | 17篇 |
1969年 | 21篇 |
1967年 | 16篇 |
1965年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
A species-specific nucleotide sequence of Mycobacterium tuberculosis encodes a protein that exhibits hemolytic activity when expressed in Escherichia coli. 总被引:3,自引:2,他引:1
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Species-specific proteins may be implicated in the unique pathogenic mechanisms characteristic of Mycobacterium tuberculosis. In previous studies, a 3.0-kb species-specific DNA fragment of M. tuberculosis was identified (C. A. Parra, L. P. Londoño, P. del Portillo, and M. E. Patarroyo, Immun. 59:3411-3417, 1991). The nucleotide sequence of this 3.0-kb fragment has been obtained. This sequence was shown to contain two open reading frames (ORFs) whose putative gene products share 68.9% identity between each other. The major ORF shows 57.8% similarity with PLC-N and 53.2% similarity with PLC-H, two phospholipase C enzymes from Pseudomonas aeruginosa. The major ORF was amplified by PCR and cloned into the pGEX-5T expression vector. Cell extracts of Escherichia coli overexpressing this glutathione S-transferase fusion protein were shown to produce beta-hemolysis suggestive of phospholipase activity. Since phospholipase C enzymes have been reported as virulence factors of P. aeruginosa and also of the intracellular pathogen Listeria monocytogenes, it is possible that the proteins identified in this study could also play a role in sustaining tuberculosis infection in humans. 相似文献
12.
Milena Soares Santos Guilherme de Sousa Ribeiro Tainara Queiroz Oliveira Renan Cardoso Nery Santos Edilane Gouveia Kátia Salgado Daniele Takahashi Cleuber Fontes Leila Carvalho Campos Mitermayer Galvão Reis Albert Icksang Ko Joice Neves Reis 《International journal of infectious diseases》2009,13(4):456-461
13.
A C Meneses M A Lopes A Rocha M C Fatureto G P Lopes E R Lopes E Chapadeiro 《Arquivos de gastroenterologia》1989,26(1-2):13-16
This is a review of 4.690 necropsies and 24.209 surgical pathology specimens describing the association between megacolon chagasic and malignant tumors of the large bowel. The prevalence of malignant tumors of the large bowel was not higher in megacolon. 相似文献
14.
Luisa Rocha Manola Cuellar-Herrera Marcos Velasco Francisco Velasco Ana-Luisa Velasco Fiacro Jiménez Sandra Orozco-Suarez Anna Borsodi 《Seizure》2007,16(7):645-652
Opioid receptor binding was evaluated in parahippocampal cortex (PHC) obtained from patients with intractable mesial temporal lobe epilepsy (MTLE) with and without subacute high frequency electrical stimulation (HFS) in this brain area. Mu, delta and nociceptin receptor binding was determined by autoradiography in PHC of five patients (ESAE group) with MTLE history of 14.8 +/- 2.5 years and seizure frequency of 11 +/- 2.9 per month, two of them (40%) with mesial sclerosis. This group demonstrated antiepileptic effects following subacute HFS (130 Hz, 450 micros, 200-400 microA), applied continuously during 16-20 days in PHC. Values were compared with those obtained from patients with severe MTLE (history of 21.7 +/- 2.8 years and seizure frequency of 28.2 +/- 14 per month) in whom electrical stimulation did not induce antiepileptic effects (ESWAE group, n = 4), patients with MTLE in whom no electrical stimulation was applied (MTLE group, n = 4) and autopsy material acquired from subjects without epilepsy (n = 4 obtained from three subjects). Enhanced 3H-DAMGO (MTLE, 755%; ESAE, 375%; ESWAE, 693%), 3H-DPDPE (MTLE, 242%; ESAE, 80%; ESWAE, 346%) and 3H-nociceptin (MTLE, 424%; ESAE, 217%; ESWAE, 451%) binding was detected in the PHC of all epileptic groups. However, tissue obtained from ESAE group demonstrated lower opioid receptor binding (3H-DAMGO, 44.5%, p < 0.05; 3H-DPDPE, 47%, p < 0.05; 3H-nociceptin, 39.3%, p < 0.5) when compared with MTLE group. The present results indicate that a high effectiveness to the antiepileptic effects induced by HFS is associated with reduced opioid peptide binding. 相似文献
15.
Sérgio Carreir?o Leandro Pereira Marcelo Wilson Rocha Almeida 《Aesthetic plastic surgery》2009,33(3):445-451
Surgical procedures for the mammary region currently are assuming an important role in body-contouring surgery. Enhancement
of results is a constant challenge to the plastic surgeon. A simple and efficient maneuver for resection of the breast’s lateral
pole based on the mammoplasty technique of Professor Ivo Pitanguy is described.
This study realized at the Private Clinic Sérgio Carreir?o, Rio de Janeiro, RJ, Brazil. 相似文献
16.
17.
18.
A. B. Soares P. R. Faria L. A. Magna M. E. P. Correa C. A. de Sousa O. P. Almeida M. L. Cintra 《Journal of oral pathology & medicine》2005,34(6):368-373
BACKGROUND: Graft-vs.-host disease (GVHD) is the major cause of morbidity and mortality in patients undergoing allogeneic Bone Marrow Transplantation (BMT). The aim of our study was to identify the most relevant histological features for diagnosis of chronic Graft-vs.-Host Disease (cGVHD) in oral mucosa and minor salivary glands of 25 patients, as well as to evaluate the immunophenotype of the inflammatory cells. METHODS: Sixteen patients that were submitted to allogeneic BMT but did not present cGVHD were selected as a control group. The sections were studied on H & E and CD68, CD45, CD4, CD8, CD20 staining. RESULTS: The most frequent histologic findings in oral mucosa at the day of diagnosis of cGVHD were: hydropic degeneration of the basal layer of the epithelium, apoptotic bodies, lymphocytic infiltration, and focal or total cleavage between the epithelial and connective tissue. In the labial salivary glands (LSG), lymphocytic infiltration, acinar loss and fibrosis were the main alterations. Cytotoxic CD8-T cells and macrophages were predominant both in the epithelium and connective tissue, as well as in minor salivary glands. CONCLUSIONS: Histological features were useful in the diagnosis of oral cGVHD. It is suggested that CD8-T cells and macrophages play important role in the pathogenesis of the disease. 相似文献
19.
Jocivania O da Silva Renata S Fernandes Fábio K Ticli Clayton Z Oliveira Maurício V Mazzi Jo?o J Franco Silvana Giuliatti Paulo S Pereira Andreimar M Soares Suely V Sampaio 《Toxicon》2007,50(2):283-291
We report here the antiproteolytic and antihemorrhagic properties of triterpenoid saponin inhibitors, named macrolobin-A and B, from Pentaclethra macroloba, against Bothrops snake venoms. The inhibitors were able to neutralize the hemorrhagic, fibrin(ogen)olytic, and proteolytic activities of class P-I and P-III metalloproteases isolated from B. neuwiedi and B. jararacussu venoms. Clotting and fibrinogenolytic activities induced by snake venoms and isolated thrombin-like enzymes were partially inhibited. Furthermore, the potential use of these inhibitors to complement antivenom therapy as an alternative treatment and/or used as molecular models for development of new therapeutical agents in the treatment of snake bite envenomations needs to be evaluated in future studies. 相似文献
20.