全文获取类型
收费全文 | 7719篇 |
免费 | 417篇 |
国内免费 | 56篇 |
专业分类
耳鼻咽喉 | 62篇 |
儿科学 | 158篇 |
妇产科学 | 60篇 |
基础医学 | 848篇 |
口腔科学 | 150篇 |
临床医学 | 537篇 |
内科学 | 1943篇 |
皮肤病学 | 256篇 |
神经病学 | 454篇 |
特种医学 | 271篇 |
外科学 | 1657篇 |
综合类 | 40篇 |
预防医学 | 199篇 |
眼科学 | 102篇 |
药学 | 483篇 |
中国医学 | 14篇 |
肿瘤学 | 958篇 |
出版年
2023年 | 73篇 |
2022年 | 112篇 |
2021年 | 274篇 |
2020年 | 145篇 |
2019年 | 171篇 |
2018年 | 257篇 |
2017年 | 205篇 |
2016年 | 232篇 |
2015年 | 231篇 |
2014年 | 244篇 |
2013年 | 310篇 |
2012年 | 482篇 |
2011年 | 564篇 |
2010年 | 314篇 |
2009年 | 241篇 |
2008年 | 362篇 |
2007年 | 428篇 |
2006年 | 399篇 |
2005年 | 369篇 |
2004年 | 393篇 |
2003年 | 396篇 |
2002年 | 355篇 |
2001年 | 123篇 |
2000年 | 105篇 |
1999年 | 98篇 |
1998年 | 75篇 |
1997年 | 57篇 |
1996年 | 57篇 |
1995年 | 59篇 |
1994年 | 48篇 |
1993年 | 44篇 |
1992年 | 59篇 |
1991年 | 66篇 |
1990年 | 47篇 |
1989年 | 66篇 |
1988年 | 62篇 |
1987年 | 59篇 |
1986年 | 37篇 |
1985年 | 47篇 |
1984年 | 50篇 |
1983年 | 52篇 |
1982年 | 22篇 |
1979年 | 34篇 |
1977年 | 24篇 |
1975年 | 26篇 |
1972年 | 40篇 |
1971年 | 31篇 |
1970年 | 31篇 |
1969年 | 33篇 |
1968年 | 27篇 |
排序方式: 共有8192条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
Seung Yong Park Hisashi Arase Keisuke Wakizaka Nakami Hirayama Shigehiro Masaki So-Ichiro Sato Jeffrey V. Ravetch Takashi Saito 《European journal of immunology》1995,25(7):2107-2110
The function of the Fc receptors γ chain (FcRγ) for the expression of the T cell receptor (TCR) complex and for T cell development, especially for T cells localized in epithelia, was investigated by analyzing FcRγ-deficient mice. In wildtype mice, CD8αα+β?TCRαβ+ T cells of intestinal intraepithelial lymphocytes (i-IEL) utilized CD3ζ homodimers and ζ-FcRγ heterodimers, whereas CD8α α+β?TCRγδ+ i-IEL used ζ-FcRγ and FcRγ homodimers in the TCR complex. On the other hand, these T cells in FcRγ-deficient mice contained only ζ homodimers. The surface expression of the TCR complex was reduced in CD8αα+β?i-IEL and dendritic epidermal T cells (DETC) in these mice, whereas the development of these T cells was normal. The degree of reduction appeared to depend on the expression level of FcRγ. In contrast to these populations, TCRγδ+ intraepithelial T cells in reproductive organs (r-IEL) were dramatically decreased, suggesting that the development of r-IEL is FcRγ-dependent, probably due to the predominant usage of FcRγ homodimers in the TCR complex. These results indicate that the FcRγ chain contributes differently to the TCR expression and to the development of T cells localized in epithelia. 相似文献
65.
S Nakamura N Takagi K Kitoh T Koshikawa K Hayashi K Yamamoto H Suzuki A Oyama R Ueda T Suchi 《Acta pathologica japonica》1992,42(2):141-149
A case of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) which showed widespread involvement of the gastrointestinal tract is reported. A lymph node biopsy specimen showed the characteristic histological features of AILD. During the progression of the illness, lymphomatous lesions developed in the gastrointestinal tract, complicated by cytomegalovirus infection. A double immunoenzymatic study using a combination of Ki-67 antibody and antibodies against surface antigens demonstrated that CD3+, CD4+, and/or T-cell receptor (TCR) beta+ cells were predominant (67-68%) among the population of proliferating Ki-67% cells, rather than CD8+ or CD22+ cells. Clonal rearrangement of the TCR beta chain gene was also detected. These findings provide further evidence for the neoplastic nature of lesions of this type, and the diagnosis of peripheral T-cell lymphoma. 相似文献
66.
In order to confirm the role of 14-3-3 sigma (sigma) as a tumor suppressor in breast carcinogenesis, we have studied the expression of 14-3-3sigma immunohistochemically in usual ductal hyperplasia (UDH), ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) breast lesions. Immunostaining for estrogen receptor alpha (ERalpha), p53 and estrogen-responsive RING finger protein (Efp) was also carried out. Immunohistochemically, expression of 14-3-3sigma was seen in 92% UDH lesions and gradually decreased from 65% in DCIS to 23% in IDC. The expression of ERalpha decreased gradually from UDH to DCIS to IDC, while p53 showed an inverse staining pattern to that of ERalpha. The expression of Efp showed no significant difference among the three breast lesions. Hence, the present immunohistochemical study confirmed 14-3-3sigma as a tumor suppressor in breast carcinogenesis. A similar immunohistochemical analysis was then carried out on columnar cell hyperplasia with atypia (CCHA), in which the expression pattern of tumor suppressor 14-3-3sigma, ERalpha and p53 suggested that it might be possible that CCHA is a precancerous lesion. 相似文献
67.
Face recognition in preschool children: effects of familiarity, facial expression and angle of view]
M Oyama 《Shinrigaku kenkyu : The Japanese journal of psychology》1992,63(4):248-255
The purpose of this study was to investigate the face recognition processes in preschool children. Two experiments were carried out to examine the effects, on face recognition, of familiarity, facial expression and angle of view of faces as well as changes or no changes in facial expression and/or angle of view occurring between the first presentation and the subsequent recognition test. The subjects were 188 five- and six-year old children. In Experiments 1 and 2, half of the faces were highly familiar to the subjects, and the remaining half unfamiliar to them. In Experiment 1, the facial expressions (e.g., smiling or serious) were either changed or unchanged. In Experiment 2, the facial expressions or angles of view (e.g., full-face views or three-quarter views of faces) were either changed or unchanged. The major findings were that the familiar faces and the smiling faces were recognized more correctly than the unfamiliar faces and the serious faces respectively. The results were discussed in terms of 'identity-specific semantic codes' and 'visually-derived semantic codes'. 相似文献
68.
Toshiyuki Tanaka Yasuhiko Nagasaka Fujiko Kitamura Keisuke Kuida Hiroshi Suwa Masayuki Miyasaka 《European journal of immunology》1993,23(6):1378-1380
Autoimmune MRL/MP-lpr/lpr (MRL/lpr) mice spontaneously develop a systemic lupus erythematosus-like disease accompanied by a profound lymphadenopathy that consists of CD4?8?B220+ a P T cells. By the use of cross-linking experiments with radiolabeled interleukin-2 (IL-2), these abnormal T cells have been reported to constitutively express the IL-2 receptor β chain (IL-2Rα), a signal transducing component of IL-2R, in the absence of the a chain (IL-2Rα).To critically reevaluate the role of the IL-2/IL-2R pathway in the pathogenesis of lymphadenophathy we examined expression of the IL-2Rα and IL-2Rβ in MRL/lpr mice by 125I-IL-2 binding analysis and also by flow cytometric analysis using monoclonal antibodies against each component of the receptor. We found that, contrary to the previous report, the CD4?8?B220+ α β T cells in lymph node (LN) of MRL/lpr mice were negative for both IL-2Rα and IL-2Rβ expression. The lpr liver CD4?8?B220+ a P T cells that had been implicated in the genesis of these abnormal LN T cells were also negative for IL-2Rβ expression. Therefore, our results indicate that the IL-2/IL-2R system plays little role, if any, in the expansion of abnormal CD4?8? B220+ α β T cells in MRL/lpr mice. 相似文献
69.
Inhibition of human immunodeficiency virus replication in a human T cell line by antisense RNA expressed in the cell 总被引:2,自引:0,他引:2
70.
Diagnostic utility of galectin-3 and CD26/DPPIV as preoperative diagnostic markers for thyroid nodules 总被引:3,自引:0,他引:3
Aratake Y Umeki K Kiyoyama K Hinoura Y Sato S Ohno A Kuribayashi T Hirai K Nabeshima K Kotani T 《Diagnostic cytopathology》2002,26(6):366-372
The aim of this study was to search for diagnostic markers that could correctly identify thyroid nodular lesions requiring urgent surgical treatment. We investigated whether galectin-3 and dipeptidyl peptidase IV (CD26/DPPIV) could be potential markers for improving the diagnostic accuracy of conventional cytology. Seventy-nine patients with histologically proven thyroid diseases were analyzed. The immunocytochemical staining results showed galectin-3 expression in neoplastic cells of all 37 papillary carcinomas, five of six follicular carcinomas, all three anaplastic carcinomas, one of three medullary carcinomas, and two of 14 follicular adenomas. All 16 adenomatous goiters were negative for galectin-3 immunostaining. On the other hand, all 37 papillary carcinomas, all six follicular carcinomas, and one of three anaplastic carcinomas revealed CD26/DPPIV expression, whereas all three medullary carcinomas were negative. Among benign thyroid lesions, four of 14 follicular adenomas and two of 16 adenomatous goiters exhibited varying degrees of immunoreactivity for CD26/DPPIV. RT-PCR analysis demonstrated overexpression of galectin-3 and CD26/DPPIV mRNAs in all six papillary and all three follicular carcinomas analyzed, whereas the mRNA expressions of these molecules were barely or not detectable in benign thyroid lesions and normal thyroid tissues, except for one case of follicular adenoma. In conclusion, we demonstrate that galectin-3 and CD26/DPPIV were consistently coexpressed at protein and mRNA levels in differentiated thyroid carcinomas. We propose that combined immunostaining for galectin-3 and CD26/DPPIV in the preoperative evaluation of thyroid nodules may play a role in accurate cytodiagnosis. 相似文献