首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   17870篇
  免费   1682篇
  国内免费   348篇
耳鼻咽喉   103篇
儿科学   742篇
妇产科学   69篇
基础医学   2788篇
口腔科学   129篇
临床医学   1311篇
内科学   4158篇
皮肤病学   947篇
神经病学   303篇
特种医学   461篇
外国民族医学   16篇
外科学   641篇
综合类   1396篇
现状与发展   4篇
预防医学   231篇
眼科学   257篇
药学   658篇
  3篇
中国医学   85篇
肿瘤学   5598篇
  2024年   33篇
  2023年   339篇
  2022年   494篇
  2021年   675篇
  2020年   746篇
  2019年   671篇
  2018年   654篇
  2017年   693篇
  2016年   619篇
  2015年   799篇
  2014年   1069篇
  2013年   1156篇
  2012年   861篇
  2011年   867篇
  2010年   701篇
  2009年   725篇
  2008年   853篇
  2007年   818篇
  2006年   798篇
  2005年   738篇
  2004年   565篇
  2003年   559篇
  2002年   500篇
  2001年   456篇
  2000年   379篇
  1999年   328篇
  1998年   295篇
  1997年   282篇
  1996年   280篇
  1995年   245篇
  1994年   224篇
  1993年   160篇
  1992年   184篇
  1991年   184篇
  1990年   137篇
  1989年   124篇
  1988年   98篇
  1987年   70篇
  1986年   69篇
  1985年   107篇
  1984年   62篇
  1983年   33篇
  1982年   54篇
  1981年   49篇
  1980年   39篇
  1979年   44篇
  1978年   29篇
  1977年   11篇
  1976年   12篇
  1966年   5篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Between 1980 and 1993, 680 patients with non-Hodgkin's lymphomas (NHL) and Hodgkin's disese (HD) were studied by ultrasonography. In 210 patients a total of 254 extranodular abdominal lymphoma inflitrates were diagnosed. Infiltrates were confirmed histologically in 118 patients and through the clinical course and follow-up studies in 92 patients. Lymphoma infiltrates were seen most frequently in the spleen (N = 101), the gastrointestinal tract (n=70), the liver (n = 47), the kidneys (n = 17) and other organs (n = 19). The sonographic features of lymphomatous infiltrates in different extranodal sites are described, and possible correlations between lymphoma subtypes and sonographic texture characteristics are investigated. Different infiltration patterns of lymphoma subtypes could be indentical in liver and spleen. High-grade NHLs most frequently showed large-nodular lesions, whereas low-grade NHLs and HD showed a tendency towards small-nodular or diffuse lesions. The role of ultrasonography in the clinical management of lymphoma pateins is discussed.Correspondece to: C. Görg  相似文献   
52.
Classification and diagnostic criteria for oral lesions in HIV infection   总被引:6,自引:0,他引:6  
A consensus has been reached on the classification of the oral manifestations of HIV infection and their diagnostic criteria, based on presumptive and definitive criteria. The former relate to the initial clinical appearance of the lesion and the latter are often the result of special investigations. Candidiasis, hairy leukoplakia, specific forms of periodontal disease [linear gingival erythema, necrotising-(ulcerative) gingivitis and necrotising(ulcerative) periodontitis], Kaposi's sarcoma and non-Hodgkin's lymphoma are strongly associated with HIV infection. Lesions less commonly associated with HIV infection and lesions seen in HIV infection, but not indicative of the disease, are also listed.  相似文献   
53.
54.
Natural killer/T-cell lymphoma (NKTL) and peripheral T-cell lymphomas (PTCL) are prevalent in the Asian population and exhibit a high association with the Epstein-Barr virus (EBV). Moreover, differentiation of these two groups is often difficult and problematic. We investigated 35 cases of NKTL (22 nasal cases and 13 extranasal cases) and 30 cases of PTCL in terms of their clinical features, immunohistology, EBV positivity, EBV strain-type polymorphism and latent membrane protein 1 (LMP1) deletion variant distribution. Eighteen cases (82%) of nasal NKTL and seven (54%) of extranasal NKTL showed EBV positivity by EBV in situ hybridization. Fifteen cases (50%) of PTCL revealed EBV positivity. EBV strain type A was predominant in NKTL (18:5), and EBV strain types A and B were distributed evenly in PTCL (6:6). EBV-positive patients had significantly shorter survival than EBV-negative patients (P < 0.05), and EBV positivity correlated with advanced clinical stage (P < 0.05). Patients harboring type A EBV showed slightly poorer prognoses than those having type B, though it was not obviously statistically different (P = 0.07). The LMP1 deletion variant was prevalent in both NKTL (three wild-type LMP1, 15 deletion variants) and PTCL (three wild-type LMP1, eight deletion variants, two coexistent forms) patients, but did not have prognostic impact. Our results indicate that EBV acts as a negative prognostic factor in NKTL and PTCL, and that the intrinsic properties of a specific viral strain might influence the clinical behavior of these diseases.  相似文献   
55.
Chronic active Epstein-Barr virus infection (CAEBV) is a syndrome that takes diverse clinical courses and is often associated with lymphoproliferative disorders of T/natural killer (NK)-cell lineage. We describe a patient with CAEBV associated with persistent pharyngeal ulcer, and with subsequent nasal T/NK-cell lymphoma in her neck lymph nodes and nasopharynx. Immunophenotyping of lymphoid cells showed that the lineage of Epstein-Barr virus (EBV)-positive cells in the patient was of NK-cell origin. By means of high-dose recombinant interleukin-2, we established an EBV-positive cell line of NK-cell lineage from her peripheral blood. Southern blot analysis for the number of terminal repeat sequences of EBV detected three NK-cell clones in the patient's lymph node. One of these clones was identical to the established cell line but was not observed in the pharyngeal ulcer, while the other two clones were present in the pharyngeal ulcer. These results suggest that the patient had expansion of the three NK-cell clones, one of which had proliferative capacity in vitro and was involved in the formation of the lymphoma. Moreover, the results suggest that the proliferative capacity of EBV-positive cells can be variable even in a single patient, and this variability may explain the clinical diversity in CAEBV.  相似文献   
56.
AIM: To study the clinicopathological and immunohistochemical features of 143 cases of primary small and large intestinal non-Hodgkin's lymphoma (NHL) in Japanese patients who presented between 1981 and 2000. METHODS AND RESULTS: The new World Health Organization (WHO) classification was used to classify NHL. The patients included 109 males and 34 females, with an average age of 54.1 years. Tumour sites were as follows: ileocaecal (n = 51, 35.7%), ileum (n = 29, 20.3%), rectum (n = 13, 9.1%), and duodenum (n = 11, 7.7%). Macroscopically, 124 cases (86.7%) were classified as tumorous type, 12 (8.4%) as diffuse infiltration type (erosion, superficial ulceration), five (3.5%) as polyposis type, and only two cases (1.4%) as ulceration type. Immunohistochemically, 122 lesions (85.3%) were of B-cell phenotype and 21 lesions (14.7%) were of T-cell phenotype. According to the WHO classification, of the B-cell lymphomas, 84 cases (68.9%) were large cell, 16 (13.1%) were Burkitt, 10 (8.2%) were marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT), and seven (5.7%) were mantle cell tumours. Among the T-cell lymphomas, 15 (71.4%) were of unspecified type, two (9.5%) were natural killer type, two were anaplastic large-cell lymphomas, one was lymphoblastic, and one was an adult T-cell leukaemia lymphoma. The survival rate for T-cell lymphomas was poorer than for B-cell lymphomas. Among the B-cell lymphomas, mantle cell lymphoma tended to have a poorer prognosis, whereas MALT lymphomas had a better prognosis than other B-cell tumour types. CONCLUSIONS: Our retrospective study of patients with primary malignant lymphomas in the small and large intestines has illustrated the clinical features and outcomes of patients with this disease.  相似文献   
57.
Summary Using cytochemical, electron microscopic and immunohistochemical techniques in 20 primary malignant lymphomas of the stomach, we found 18 B-cell and 2 T-cell lymphomas. Primary T-cell lymphoma in the stomach has not been previously reported. The T cells in both cases were reminiscent of T immunoblasts with prominent nucleoli and a basophilic cytoplasm. Case 1 showed a cytological relationship to pleomorphic T-cell lymphoma, large cell type. Case 2 contained in addition some cells not previously described in T-cell lymphomas, resembling immature plasma cells with abundant rough endoplasmic reticulum. Focal positivity to acid phosphatase and dipeptidylaminopeptidase IV suggests the T-cell nature of both lymphomas. In both cases the tumour cells were OKT 11 and OKT 4 positive, and negative for OKT 8. Thus, both cases represent high-grade malignant T-cell lymphomas which correspond phenotypically to T-helper cell lymphoma. Case 2 revealed a further immunohistochemical peculiarity: atypical immunoblasts reacted positively with Ki-1 antibody. Thus, it is a Ki-1 lymphoma of T-cell type.  相似文献   
58.
Intrasinusoidal infiltration of bone marrow (BM) may accompany several malignant lymphoproliferative disorders. In small B-cell lymphomas, this pattern is considered specific for splenic marginal zone lymphoma (SMZL) when exclusive or prominent, although it may occur in other subtypes of non-Hodgkin's lymphomas (NHLs) as a minor feature. Here we report 2 cases of mantle cell lymphoma (MCL) with a prominent intrasinusoidal BM infiltration pattern. Both patients presented with massive splenomegaly and peripheral blood involvement characterized by markedly atypical lymphocytes, but no lymphadenopathy. The cytological features and the phenotype of the lymphoma cells were diagnostic of MCL. The malignant B cells showed coexpression of B-cell markers (CD20+ and CD79a+), CD5 antigen, and cyclin D1 by immunohistochemistry. We discuss the specificity of an intrasinusoidal growth pattern in the bone marrow, emphasizing the importance of using a broader immunohistochemical panel in the differential diagnosis of intrasinusoidal BM infiltration by NHL.  相似文献   
59.
A case of primary gastric T-cell lymphoma, which was positive for granzyme B, is reported. The patient was a 47-year-old Japanese female who complained of a dull upper abdominal pain. Radiographic and endoscopic examinations revealed an ulcerative infiltrative lesion in her stomach. Following the confirmation of a high-grade malignant lymphoma, a distal gastrectomy with regional lymph nodal dissection was performed. The histology of the gastric lesion revealed a malignant lymphoma of the diffuse pleomorphic type without lymph nodal involvement. Immunohistochemistry revealed that the tumor cells were positive for LCA, CD3, TIA-1 and granzyme B, but were negative for CD4, CD8, CD56, CD30, L-26, EMA, TCR alpha/beta and TCR gamma/delta. Because the tumor cells showed T cell nature with cytotoxic activity proved by TIA-1 and granzyme B, and without evidence of further maturation of T cell, a malignant lymphoma originating from extrathymic-derived T cells was suggested.  相似文献   
60.
A new mutation in the serine-threonine klnase domain of the transforming growth factor β type II receptor (TGFpRII) was found in a case of diffuse, B cell non-Hodgkin's lymphoma of the stomach. A mfssense mutation (ACA to GCA, Thr to Ala) was detected In exon 5, and a wild type allele was also present. This Is the first naturally occurring mutation in the klnase domain of this gene identified in human primary lymphoma. The replication error at three loci was negative, and the poly A tract of exon 3, which is frequently a target of mismatch repair genes, was intact. Malignant lymphoma of B cell origin in the stomach Is an addition to an expanding catalogue of tumors with TGFβRII alterations, and the biological sequelae of the change in the functional domain and the clinical characteristics of the patient in this study are intriguing.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号