全文获取类型
收费全文 | 3137篇 |
免费 | 211篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 55篇 |
妇产科学 | 41篇 |
基础医学 | 462篇 |
口腔科学 | 281篇 |
临床医学 | 249篇 |
内科学 | 554篇 |
皮肤病学 | 59篇 |
神经病学 | 214篇 |
特种医学 | 217篇 |
外科学 | 286篇 |
综合类 | 45篇 |
预防医学 | 423篇 |
眼科学 | 56篇 |
药学 | 263篇 |
1篇 | |
中国医学 | 32篇 |
肿瘤学 | 98篇 |
出版年
2024年 | 5篇 |
2023年 | 42篇 |
2022年 | 56篇 |
2021年 | 120篇 |
2020年 | 99篇 |
2019年 | 99篇 |
2018年 | 139篇 |
2017年 | 73篇 |
2016年 | 95篇 |
2015年 | 120篇 |
2014年 | 143篇 |
2013年 | 142篇 |
2012年 | 218篇 |
2011年 | 273篇 |
2010年 | 136篇 |
2009年 | 106篇 |
2008年 | 172篇 |
2007年 | 159篇 |
2006年 | 152篇 |
2005年 | 121篇 |
2004年 | 98篇 |
2003年 | 89篇 |
2002年 | 82篇 |
2001年 | 73篇 |
2000年 | 34篇 |
1999年 | 36篇 |
1998年 | 35篇 |
1997年 | 30篇 |
1996年 | 20篇 |
1995年 | 28篇 |
1994年 | 28篇 |
1993年 | 35篇 |
1992年 | 12篇 |
1991年 | 16篇 |
1990年 | 20篇 |
1989年 | 26篇 |
1988年 | 26篇 |
1987年 | 38篇 |
1986年 | 27篇 |
1985年 | 32篇 |
1984年 | 12篇 |
1983年 | 16篇 |
1982年 | 7篇 |
1981年 | 13篇 |
1980年 | 13篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 9篇 |
1976年 | 6篇 |
1975年 | 8篇 |
排序方式: 共有3368条查询结果,搜索用时 93 毫秒
21.
Xavier AC Siqueira SA Costa LJ Mauad T Nascimento Saldiva PH 《Virchows Archiv : an international journal of pathology》2005,446(3):225-231
Autopsy findings of missed diagnoses that would probably have changed management or prognosis occur in up to 29% of cases in general hospitals. Such proportions may be higher in subsets of patients with complex diseases. We reviewed 2908 consecutive autopsies performed over a period of 29 months in a large-volume hospital, analyzing 118 autopsies of patients with hematological malignancies or severe aplastic anemia. A review of macroscopic reports as well as microscopic examination of tissue samples was performed. Medical records were reviewed for clinical diagnoses. Discordances between clinical and autopsy diagnoses were classified using Goldmans criteria. Additionally, we searched for clinical parameters correlated with occurrence of class-I discrepancy using a multivariate method. Median age was 46.5 years, and 25.4% had received a hematopoietic stem-cell transplant. Overall, 11.9% (6.6–19.1%) of patients died before conclusion of the hematological diagnosis and 33% (24.6–42.3%) died with no active hematological disease. We found class-I discrepancy in 31.3% (23.1–40.5 %) of cases. The most common among these diagnoses were hematological disease, pneumonia and gastrointestinal bleeding. In a univariate analysis, being elderly (P=0.04) was positively correlated with the finding of class-I discrepancies; while, having received previous specific hematological treatment (P=0.0005) or hematopoietic stem-cell transplants (P=0.013), or being admitted to a specialized hematology unit (P=0.0006) were negatively correlated to the occurrence of such discrepancies. Multivariate analysis showed that care in a specialized hematology unit (OR 0.34, 0.12–0.93) was independently associated with lower occurrence of discrepancies. We concluded that critical diagnoses are often missed in highly complex hematological patients especially in the absence of admission to specialized hematology units. 相似文献
22.
23.
24.
Crude antigenic extract (CAE) and a scolex protein antigen (SPA) of Taenia solium cysticerci were used in indirect haemagglutination (IH) and enzyme-linked immunosorbent assay (ELISA) to detect serum antibodies in cysticercosis patients. Complement fixation (CF) was used for comparison with antigens obtained as an alcoholic extract of CAE (ACAE) and SPA (ASPA). For each test, a dilution was chosen which showed no cross-reactivity with sera from patients with other parasitic diseases such as taeniasis, schistosomiasis, ancylostomiasis, ascaridiasis, strongyloidiasis, Chagas' disease and syphilis. For the CF, 14 was the discriminative dilution determined; for IH, 116 and for ELISA, 1256. The CF could detect serum antibodies to cysticerci in 45% of patients when ACAE antigen was used and 73% using ASPA. In the IH, serum antibody was detected in 73% of patients when CAE was used and 86% using SPA. In ELISA 63% of patients were positive when CAE was used and 91% using SPA. The use of SPA improved the serological distinction between infected and uninfected patients in all tests and the ELISA showed a significantly higher capacity to detect infected patients. 相似文献
25.
Primary and revision total knee arthroplasty have become common orthopaedic procedures. The operating surgeon, at times, may be faced with a difficult surgical case due to soft tissue contractures or bone deformities. A review of multiple surgical techniques using soft tissue releases and osteotomies are presented including their potential complications. Although these techniques are aimed at the atypical operative case, the operating surgeon may utilize them for ‘routine’ exposures as well. Importance is focused on the functional integrity of the knee extensor mechanism. 相似文献
26.
The recognition and classification of preinvasive vulvar neoplasia are complicated by the facts that (a) their respective carcinomas have a diverse (human papillomavirus [HPV]- and non-HPV-related) pathogenesis; (b) not all vulvar squamous carcinomas are associated with precursors with strictly defined morphologic features; (c) many carcinomas have epithelial changes that are abnormal but lack sufficient nuclear atypia to warrant classification as an intraepithelial neoplasm; and (d) even lesions associated with a common etiologic agent (HPV) present a diverse morphologic spectrum. In this review, five categories of early vulvar neoplasia are defined, based on the available literature, into (a) low-grade lesions with minimal cancer risk, (b) high-grade lesions associated with HPV, (c) high-grade lesions associated with other etiologies, (d) squamous atypias defined by abnormalities in differentiation rather than abnormalities in nuclear morphology, and (d) early carcinomas that do not exhibit conspicuous stromal invasion. The first three groups are arranged into low- and high-grade intraepithelial lesions, the fourth into intraepithelial atypias that bear careful follow-up and attention to the co-existing squamous mucosa, and the fifth into a category that, depending on the degree of cell differentiation, may warrant local excision or lymph node dissection. Recognition of these five categories is germane to proper management of women with squamous lesions of the vulva. 相似文献
27.
We evaluated the immunohistochemical staining profile of clusterin in paraffin sections of 143 neoplasms (non-Hodgkin lymphoma, 83, including 41 anaplastic large cell lymphomas [ALCLs]; Hodgkin lymphoma, 17; primary and metastatic carcinoma, 30; and other neoplasms, 13). In 40 of 41 ALCLs (34 systemic, 7 cutaneous), neoplastic cells revealed clusterin reactivity characterized by a Golgi staining pattern. The proportion of reactive cells varied with more than 25% positive cells in the majority of cases. In 7 non-Hodgkin lymphomas of other types, fine cytoplasmic (3 cases) or strong membranous reactivity (4 cases) was observed for clusterin. In Hodgkin lymphoma, rare Reed-Sternberg cells exhibited focal cytoplasmic or membranous clusterin positivity. In the nonhematopoietic neoplasms, a Golgi staining pattern was apparent in only 2 cases, 1 lobular carcinoma of the breast and 1 poorly differentiated colonic carcinoma; however, cytoplasmic reactivity was noted in 12 of 30 carcinomas and 1 of 5 neuroendocrine neoplasms. A Golgi pattern of reactivity for clusterin seems highly characteristic of ALCL among hematopoietic neoplasms, but also might be observed in rare nonhematopoietic tumors, necessitating the use of a broad immunohistochemical panel for evaluation of poorly differentiated neoplasms of indeterminate derivation. 相似文献
28.
Gender-related cytokine patterns in sera of schistosomiasis patients with Symmers' fibrosis 总被引:1,自引:0,他引:1
Silva-Teixeira DN Contigli C Lambertucci JR Serufo JC Rodrigues V 《Clinical and diagnostic laboratory immunology》2004,11(3):627-630
Cytokine levels were compared between schistosomiasis patients affected by intense fibrosis defined by ultrasound examination and graded from F-0 to F-3. The concentrations of interleukin-1beta (IL-1beta), IL-4, IL-5, IL-10, IL-13, gamma interferon, and tumor necrosis factor alpha (TNF-alpha) were determined by enzyme-linked immunosorbent assay of serum samples. Levels of IL-4, IL-5, and TNF-alpha in the sera of F-3 patients were significantly higher than those found in F-0 individuals, while levels of IL-13 were lower. Levels of IL-4, IL-5, and TNF-alpha in serum were significantly higher in F-3 males than in F-0 males or F-3 females. Conversely, levels of IL-13 were significantly lower in F-3 females than in F-0 females and males. 相似文献
29.
Nascimento Jdos S Giambiagi-deMarval M de Oliveira SS Ceotto H dos Santos KR Bastos Mdo C 《Research in microbiology》2005,156(8):837-842
Among 363 strains of Staphylococcus aureus, 21 were shown to produce bacteriocins (Bac), antimicrobial peptides with potential biotechnological applications. This collection includes strains which are either isolated from food, patients and healthy cattle, or are involved in subclinical bovine mastitis. From these 21 strains, 17 were shown to carry closely-related 8.0-kb Bac plasmids encoding bacteriocins either identical to or similar to aureocin A70, a bacteriocin able to inhibit strains of Listeria monocytogenes, a food-borne pathogen. Such findings prompted us to investigate the genetic relationships among these Bac+ strains. To obtain more discriminatory results, a combined analysis of AP-PCR, rep-PCR, and a modified PCR technique that we designated SD-PCR was employed. The 17 Bac+ strains harboring 8.0-kb Bac plasmids exhibited seven fingerprint patterns. One such genotype was composed of 8 out of the 11 strains associated with bovine mastitis, which suggests the prevalence of a clone of Bac+ strains involved in this animal infection carrying 8.0-kb Bac plasmids. Our data support the assumption that Bac+ strains of S. aureus carrying genetically related 8.0-kb Bac plasmids do not belong to a single clone. It seems, therefore, that 8.0-kb Bac plasmids have spread horizontally among different S. aureus strains. There also seems to be genetic diversity among the remaining Bac+ strains analyzed. 相似文献
30.
Maria C Nascimento Natalie Wilder Claudio S Pannuti Helen A Weiss Philippe Mayaud 《Journal of clinical virology》2005,33(1):52-59
BACKGROUND: Kaposi's sarcoma (KS) is caused by Kaposi's sarcoma associated herpesvirus (KSHV/HHV-8), the eighth Herpesvirus found to infect humans. The molecular epidemiology of KSHV is related closely to ethnicity and geographical location of studied populations. There is little epidemiological and molecular information about KSHV strains circulating in Brazil. OBJECTIVES: To characterize KSHV strains isolated from AIDS patients with Kaposi's sarcoma (AIDS-KS) in Sao Paulo, Brazil, and to examine associations between KSHV subtypes, ethnicity and HIV risk categories. METHODS: AIDS-KS patients were recruited consecutively at the largest AIDS reference hospital in Sao Paulo. Fragments (420 bp) of the VR1 and VR2 regions of KSHV open reading frame (ORF) K1 were amplified by nested PCR and sequenced directly. RESULTS: We analysed 37 samples from 33 patients, and found subtypes A-C in 48%, 21% and 30% of patients respectively, including two patients infected with subtype A5, a first report from Brazil. Sexual orientation was associated with subtype: 12/14 (86%) patients with subtype A were male homo/bisexual, compared with 3/8 (38%) among patients infected with subtype C (P = 0.05). A higher proportion of male patients with subtype C were of Caucasian origin (7/8 (87%)), compared with 7/16 (44%) among male patients with subtype A (P = 0.08). CONCLUSIONS: This first detailed report of KSHV subtypes among AIDS-KS patients in Brazil reports the first isolation of KSHV subtype A5 in this country, and suggests KSHV strain transmission between different ethnic groups, and association of specific strains with sexual orientation. 相似文献