全文获取类型
收费全文 | 170061篇 |
免费 | 9683篇 |
国内免费 | 425篇 |
专业分类
耳鼻咽喉 | 2223篇 |
儿科学 | 5500篇 |
妇产科学 | 3565篇 |
基础医学 | 23024篇 |
口腔科学 | 7501篇 |
临床医学 | 12403篇 |
内科学 | 38132篇 |
皮肤病学 | 4327篇 |
神经病学 | 14162篇 |
特种医学 | 5261篇 |
外国民族医学 | 26篇 |
外科学 | 20966篇 |
综合类 | 1386篇 |
现状与发展 | 1篇 |
一般理论 | 60篇 |
预防医学 | 17775篇 |
眼科学 | 3146篇 |
药学 | 10282篇 |
中国医学 | 688篇 |
肿瘤学 | 9741篇 |
出版年
2023年 | 884篇 |
2022年 | 1934篇 |
2021年 | 3607篇 |
2020年 | 2419篇 |
2019年 | 3414篇 |
2018年 | 4811篇 |
2017年 | 3609篇 |
2016年 | 3351篇 |
2015年 | 3924篇 |
2014年 | 5389篇 |
2013年 | 6807篇 |
2012年 | 10614篇 |
2011年 | 11097篇 |
2010年 | 5595篇 |
2009年 | 5037篇 |
2008年 | 8574篇 |
2007年 | 9183篇 |
2006年 | 8514篇 |
2005年 | 8800篇 |
2004年 | 8287篇 |
2003年 | 7567篇 |
2002年 | 5627篇 |
2001年 | 4937篇 |
2000年 | 4933篇 |
1999年 | 4336篇 |
1998年 | 1535篇 |
1997年 | 1278篇 |
1996年 | 1267篇 |
1995年 | 1074篇 |
1994年 | 1068篇 |
1993年 | 973篇 |
1992年 | 2646篇 |
1991年 | 2559篇 |
1990年 | 2332篇 |
1989年 | 2330篇 |
1988年 | 2101篇 |
1987年 | 1950篇 |
1986年 | 1823篇 |
1985年 | 1748篇 |
1984年 | 1253篇 |
1983年 | 1007篇 |
1982年 | 565篇 |
1981年 | 512篇 |
1980年 | 492篇 |
1979年 | 919篇 |
1978年 | 604篇 |
1977年 | 474篇 |
1975年 | 542篇 |
1974年 | 539篇 |
1973年 | 540篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The anatomical basis of the osteo-musculo-cutaneous trapezius flap in mandibular reconstruction 总被引:1,自引:0,他引:1
The osteo-musculo-cutaneous trapezius flap has seen its indications in mandibular reconstruction reduced since the appearance of micro-anastomotic flaps. However, it may still be useful when the patient has marked atheroma contraindicating a free flap. While the arterial supply of this flap is well known, the same is not true for its venous drainage. The preservation of the accessory nerve and its limits in mandibular reconstruction has been little studied. We carried out a study on 30 subjects (60 cadaveric dissections of trapezius flaps) in order to address these questions. The study has been completed by a surgical series of five patients. The cadaveric study allowed demonstration of the variability of venous drainage of this flap, which depended on the external jugular vein in 80% of cases, the subclavian vein in 12% of cases and on both veins in about 8% of cases. The accessory nerve in one third of cases passed through the middle of the arteriovenous pedicle making its preservation impossible. The segment of the scapular spine allowed reconstruction of about 9 cm of mandible including the mental protuberance in 95% of cases. The surgical study confirmed the data of the cadaveric study and showed the value of this flap when free flaps are contraindicated. 相似文献
992.
Schwerer MJ Hemmer J Kraft K Maier H Möller P Barth TF 《Virchows Archiv : an international journal of pathology》2003,443(1):98-103
We report the case of a 58-year-old man who presented with a squamous cell carcinoma pT1a G2 of the left vocal cord. Six months after histologically verified complete resection, the patient experienced an endolaryngeal and extralaryngeal local recurrence pT4 pN2b G2. We applied DNA flow cytometry (FCM) and comparative genomic hybridization (CGH) on both primary and recurrent tumor. The primary tumor and the endolaryngeal compartment of the relapse was an aneuploid cell clone with a FCM DNA index of 1.42 and 1.44, respectively. The extralaryngeal compartment showed a shift featuring a DNA index of 2.78. In the primary tumor and in both compartments of the recurrence there was an identical pattern of complex chromosomal imbalances as detected in CGH (CGH karyotype: rev ish enh [8q24.2-q24.3, 10q26.1-q26.3, 11q24-q25, 12q24.2-q23.33,X], dim [4q, 13q14.3-q31], amp[1p36.1-p36.2]). Hence, the recurrence was not associated with further gains and losses of chromosomal material. However, in the anterior part of the recurrence, the aneuploid tumor cell genome had completely doubled, obviously due to endoreduplication. Immunohistochemical analysis of several cell-cycle regulators revealed altered expression of checkpoint proteins, pointing to a complex disturbance in cell-cycle regulation. 相似文献
993.
Cationic immune complex arthritis in mice--a new model. Synergistic effect of complement and interleukin-1. 下载免费PDF全文
P. L. van Lent L. A. van den Bersselaar A. E. van den Hoek A. A. van de Loo W. B. van den Berg 《The American journal of pathology》1992,140(6):1451-1461
A novel cationic immune-complex-mediated arthritis (ICA) model was developed in mice. The highly cationic protein lysozyme was coupled to poly-L-lysine (PLL) and injected intra-articularly into the knee joint of the mouse, shortly after systemic administration of specific antibodies. A vehement joint inflammation developed, characterized by severe joint swelling and the influx of predominantly polymorphonuclear (PMN) leukocyte. Unique properties were combined in this protein. First, an excellent retention of the antigen in joint structures was found, facilitating sufficient IC formation in the synovial tissue and at the cartilage surface. Secondly, PLL.lysozyme appeared to be a potent inducer of interleukin-1 (IL-1). Similar IL-1 production was measured at 6 hours, in both immune or nonimmune mice. Neutralization with antibodies against either IL-1 alpha or IL-1 beta revealed that IL-1 alpha was the dominant cytokine. Resident cells were responsible for this IL-1 production since a comparable IL-1 signal was measured after intra-articular injection of PLL.lys in neutropenic mice. We further investigated whether IL-1 and complement factors were involved in the onset of this ICA. Neutralizing the IL-1 production with antibodies directed against IL-1 alpha and beta showed a significant decrease in joint swelling. Complement depletion by cobra venom factor also prevented the onset of arthritis for the greater part. Only a minor swelling remained at 6 hours after eliciting arthritis, which was similar to the swelling after injecting the antigen alone and probably reflects IL-1 mediated inflammation. In this study, the authors show a synergistic action of IL-1 and complement in the onset of cationic ICA. Unique properties of the antigen such as excellent retention and its ability to induce IL-1 are combined within one molecule and make this antigen arthritogenic in the presence of antibodies and complement activation. 相似文献
994.
Tetanus toxin fragment C expressed in live Salmonella vaccines enhances antibody responses to its fusion partner Schistosoma haematobium glutathione S-transferase 总被引:3,自引:0,他引:3 下载免费PDF全文
Lee JJ Sinha KA Harrison JA de Hormaeche RD Riveau G Pierce RJ Capron A Wilson RA Khan CM 《Infection and immunity》2000,68(5):2503-2512
Tetanus toxoid has been used widely as an adjuvant. The atoxic fragment C from tetanus toxin (TetC) is potently immunogenic when expressed in Salmonella vaccine strains and has been used as a fusion partner for antigens (Ag). However, there has been no formal comparison of the immunomodulatory impact of TetC on its fusion partners. In this study, we have addressed this important issue. The protective 28-kDa glutathione S-transferase (GST) from Schistosoma haematobium (Sh28GST) was expressed either as a fusion to TetC or as the full-length Sh28GST alone in a nonvirulent aroA-attenuated strain of Salmonella enterica serovar Typhimurium. The Sh28GST proteins were soluble and stably expressed in Salmonella, as evaluated by Western blotting with TetC and/or Sh28GST antisera. Mice were immunized orally with a single dose of the live recombinant Salmonella. The constructs were stable in mice but, dramatically, only the strain expressing the TetC-Sh28GST fusion elicited significant antibody (Ab) responses directed against Sh28GST as determined by enzyme-linked immunosorbent assay. An analysis of the isotype profiles showed that these mice also produced anti-Sh28GST immunoglobulin A and GST-neutralizing assays revealed high levels of neutralizing Abs in sera. These are important correlates of protection in schistosomiasis. In addition, stimulation of spleen cells from immunized mice with Sh28GST Ag showed that both strains, expressing Sh28GST alone or the TetC-Sh28GST fusion, were able to stimulate the secretion of Th1-related cytokines (gamma interferon and interleukin 2) to comparable levels. Thus, TetC has modulated the immune responses generated against its fusion partner, Sh28GST, by markedly enhancing the Ab responses elicited. These results have important implications in the rational development of live vaccines. 相似文献
995.
The role of the eaeA gene in diarrhea and neurological complications in a gnotobiotic piglet model of enterohemorrhagic Escherichia coli infection. 总被引:9,自引:3,他引:9 下载免费PDF全文
S Tzipori F Gunzer M S Donnenberg L de Montigny J B Kaper A Donohue-Rolfe 《Infection and immunity》1995,63(9):3621-3627
We reported previously that mutation of the chromosomal gene eaeA from enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 prevented bacterial attachment in vivo. Attachment was restored when the EHEC or enteropathogenic E. coli (EPEC) eaeA gene was introduced into the mutant on a plasmid. In this communication we have compared in gnotobiotic piglets the pathogenicities of wild-type O157:H7 strain 86-24 and its eaeA mutant UMD619 with those of the two plasmid-complemented strains expressing IntiminO157 (EHEC) and IntiminO127 (EPEC). 86-24 colonized the surface and glandular epithelium of the large intestine and induced diarrhea, while UMD619 did not colonize any intestinal site and induced little or no diarrhea. Surprisingly, strain UMD619 expressing IntiminO127 behaved in pigs more like EPEC than EHEC strains; it colonized the distal half of the small intestine and the surface of the large intestine, inducing serious diarrhea. In contrast, strain UMD619 expressing IntiminO157 colonized the colon extremely poorly, inducing little or no diarrhea. While only the two strains causing extensive attachment--86-24 and UMD619 expressing IntiminO127--induced diarrhea, neurological symptoms attributed to Shiga-like toxin II occurred equally in all four groups of animals. The intimate bacterial attachment and mucosal damage were not a prerequisite for Shiga-like toxin II translocation from the gut lumen into the circulation. IntiminO127 appears not only to facilitate intimate attachment to cells but also to influence the site of intestinal colonization and other characteristics of EPEC infection. 相似文献
996.
Parietal cell surface reactive autoantibody in pernicious anaemia demonstrated by indirect membrane immunofluorescence. 总被引:1,自引:4,他引:1 下载免费PDF全文
We examined, in a 'double blind' study, 60 sera from patients with pernicious anaemia for immunofluorescence reactivity with the surface membranes of viable parietal cells isolated from dog stomachs. Fifty-three sera (88%) gave an IgG autoantibody reaction with the surface membranes of parietal cells. Surface staining was also seen with parietal cells from monkey, pig, rat and mouse. The parietal cell surface reactive autoantibody was not found in any of 14 sera from patients with chronic active hepatitis, 10 from patients with systemic lupus erythematosus and 50 from healthy persons. The surface reactivity autoantibody was present in 13 of 14 sera without parietal cell microsomal antibody, 28 of 31 sera without intrinsic factor antibody and in four of four sera without microsomal and intrinsic factor antibodies. Absorption with parietal cell enriched gastric mucosal cells neutralized the activity of the surface reactive but not the microsomal antibody and cross absorption with gastric microsomes neutralized the activity of the microsomal but not the surface reactive antibody. Surface staining of parietal cells was not abolished by absorption with dog or rat hepatocytes, dog or rat kidney cells, human fibroblasts or human AB red blood cells. The results suggest that the parietal cell surface reactive antibody is probably different from the microsomal antibody. Immune reactions of the cell surface reactive antibody with parietal cell surface antigens may play a role in the pathogenesis of the gastric lesion in pernicious anaemia. 相似文献
997.
Functional activity of antibodies against the recombinant OpaJ protein from Neisseria meningitidis 下载免费PDF全文
de Jonge MI Vidarsson G van Dijken HH Hoogerhout P van Alphen L Dankert J van der Ley P 《Infection and immunity》2003,71(5):2331-2340
The opacity proteins belong to the major outer membrane proteins of the pathogenic Neisseria and are involved in adhesion and invasion. We studied the functional activity of antibodies raised against the OpaJ protein from strain H44/76. Recombinant OpaJ protein was obtained from Escherichia coli in two different ways: cytoplasmic expression in the form of inclusion bodies followed by purification and refolding and cell surface expression followed by isolation of outer membrane complexes (OMCs). Immunization with purified protein and Quillaja saponin A (QuilA) induced high levels of Opa-specific antibodies, whereas the E. coli OMC preparations generally induced lower levels of antibodies. Two chimeric Opa proteins, hybrids between OpaB and OpaJ, were generated to demonstrate that the hypervariable region 2 is immunodominant. Denatured OpaJ with QuilA induced high levels of immunoglobulin G2a (IgG2a) in addition to IgG1, whereas refolded OpaJ with QuilA induced IgG1 exclusively. These sera did not induce significant complement-mediated killing. However, all sera blocked the interaction of OpaJ-expressing bacteria to CEACAM1-transfected cells. In addition, cross-reactive blocking of OpaB-expressing bacteria to both CEACAM1- and CEA-transfected cells was found for all sera. Sera raised against purified OpaJ and against OpaJ-containing meningococcal OMCs also blocked the nonopsonic interaction of Opa-expressing meningococci with human polymorphonuclear leukocytes. 相似文献
998.
Carrière C Godreuil S Gouby A Vincent V Marchandin H Terru D Delaporte E Sorokaty JM Jumas-Bilak E Van de Perre P 《Pathologie-biologie》2005,53(6):324-327
We report two cases of Mycobacterium simiae infections differing by the site of infection, the immunological status of the patients and the diagnostic methods used. The first case is a disseminated infection in an advanced immunosuppressed patient who died quickly confirming the severity of this infection in the context of HIV infection. The second case presented is a respiratory disease in a women with a past history of tuberculosis and an uneventful evolution of the M. simiae infection under treatment. These two cases demontrate the importance of molecular methods to correctly identify M. simiae. 相似文献
999.
Determination of Blomia tropicalis-specific IgE and IgG subclasses in atopic dermatitis patients 总被引:2,自引:0,他引:2
BACKGROUND: To verify the importance of Blomia tropicalis in atopic dermatitis (AD), we determined the cutaneous reactivity and the serum level of B. tropicalis-specific IgE and IgG subclasses in AD patients. METHODS: B. tropicalis-specific IgE and IgG subclasses were determined in AD patients and compared with bronchial asthma (BA) patients and a control group (CG) of nonatopic subjects. Specific IgE was obtained by skin prick test and RAST. B. tropicalis-specific IgG subclasses were determined by ELISA. The data were statistically analyzed by chi-square test (Mantel-Haenszel) and odds ratio (OR). RESULTS: We detected positive skin prick tests in 61.76% of AD and 83.33% of BA patients, and in 12.5% of the CG. RAST was positive in 44.12% of AD and in 61.90% of BA patients, but not in the CG. B. tropicalis-specific IgG1 and IgG2 subclasses showed no significant differences between the three groups. IgG3 subclass positivity was statistically significant in AD patients (41.17%) when compared to BA patients (14.29%) and the CG (16.67%). The determination of B. tropicalis-specific IgG4 was positive in 32.35% of AD patients, 21.43% of BA patients, and 8.33% of the CG. CONCLUSIONS: These results confirm that the storage mite B. tropicalis is an important allergen in AD. It is possible that IgG3 activates the complement in AD patients, releasing vasoactive amines that further amplify the allergic reaction. The positive results of the B. tropicalis-specific IgG4 found in AD and BA were probably due to chronic exposure to this storage mite in the home environment. 相似文献
1000.
Detection of human papillomavirus in matched cervical smears and biopsy specimens by non-isotopic in situ hybridisation. 下载免费PDF全文
G. Troncone C. S. Herrington K. Cooper M. L. de Angelis J. O. McGee 《Journal of clinical pathology》1992,45(4):308-313
AIMS: To determine the relative diagnostic sensitivity of non-isotopic in situ hybridisation (NISH) for the diagnosis of human papillomavirus (HPV) on matched smears and biopsy specimens; to compare the NISH signal type in the two samples; and to correlate the NISH data with the morphological diagnosis. METHODS: HPV samples were assayed individually by NISH with digoxigenin labelled probes (HPV6, 11, 16, 18, and 33) on routinely collected paraffin wax embedded cervical biopsy specimens and for high risk HPVs with a cocktail of similarly labelled probes (HPV16, 18, 33) on matched smears. These were taken at the same colposcopic examination from 32 patients investigated for an abnormal cervical Papanicolaou (PAP) stained smear. RESULTS: An HPV signal was present in 18 (56%) biopsy specimens and in 14 (44%) smears. There was higher concordance of sets of data in the presence of cytopathic wart virus changes. The superiority of biopsy over smear in detecting HPV was mainly the result of examining the entire cervical biopsy specimen rather than cells scraped from the cervical surface. The NISH signal type in both biopsy specimen and smear was similar; it has been shown that NISH type 1 signal correlates with episomal viral replication and type 2 and 3 signals with viral integration. CONCLUSIONS: These data show that NISH on cervical smears is a worthwhile primary screen for HPV infection. The NISH signal types in cervical smears are similar to those previously described in cervical biopsy specimens. 相似文献