全文获取类型
收费全文 | 72686篇 |
免费 | 5611篇 |
国内免费 | 3904篇 |
专业分类
耳鼻咽喉 | 1997篇 |
儿科学 | 232篇 |
妇产科学 | 2353篇 |
基础医学 | 3865篇 |
口腔科学 | 525篇 |
临床医学 | 8116篇 |
内科学 | 5152篇 |
皮肤病学 | 339篇 |
神经病学 | 553篇 |
特种医学 | 4703篇 |
外国民族医学 | 52篇 |
外科学 | 14870篇 |
综合类 | 12884篇 |
现状与发展 | 3篇 |
预防医学 | 1861篇 |
眼科学 | 227篇 |
药学 | 3069篇 |
8篇 | |
中国医学 | 139篇 |
肿瘤学 | 21253篇 |
出版年
2024年 | 162篇 |
2023年 | 710篇 |
2022年 | 1537篇 |
2021年 | 1913篇 |
2020年 | 1839篇 |
2019年 | 1601篇 |
2018年 | 1457篇 |
2017年 | 1803篇 |
2016年 | 2388篇 |
2015年 | 2085篇 |
2014年 | 4116篇 |
2013年 | 3556篇 |
2012年 | 4729篇 |
2011年 | 5255篇 |
2010年 | 4609篇 |
2009年 | 4453篇 |
2008年 | 4371篇 |
2007年 | 4890篇 |
2006年 | 4612篇 |
2005年 | 4509篇 |
2004年 | 3511篇 |
2003年 | 3094篇 |
2002年 | 2642篇 |
2001年 | 2546篇 |
2000年 | 2067篇 |
1999年 | 1549篇 |
1998年 | 1330篇 |
1997年 | 1171篇 |
1996年 | 690篇 |
1995年 | 596篇 |
1994年 | 507篇 |
1993年 | 286篇 |
1992年 | 254篇 |
1991年 | 208篇 |
1990年 | 190篇 |
1989年 | 172篇 |
1988年 | 173篇 |
1987年 | 141篇 |
1986年 | 127篇 |
1985年 | 95篇 |
1984年 | 49篇 |
1983年 | 31篇 |
1982年 | 47篇 |
1981年 | 39篇 |
1980年 | 32篇 |
1979年 | 17篇 |
1978年 | 16篇 |
1977年 | 10篇 |
1976年 | 7篇 |
1975年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
目的研究肺腺癌细胞生长环境及转移性与黏附分子CD44v6和CD29的表达关系。方法将起源相同、转移性不同的两个肺腺癌细胞系AGZY和Anip分别用简便肿瘤多细胞球体(MTS)培养法培养,并设常规单层贴壁细胞培养对照。通过倒置显微镜、扫描及透射电镜观察MTS形成情况,并用免疫组化法分别对MTS及贴壁细胞上CD44v6和CD29表达进行检测。结果MTS培养成功,贴壁细胞与MTS在细胞结构及细胞连接结构上相似,两种MTS在形态及结构上差异无显著性。免疫组化结果显示,CD29在高转移性的Anip细胞及其MTS上呈阳性表达;在低转移性的AGZY细胞及其MTS上阴性表达。CD44v6在Anip和AGZY细胞及MTS上均呈阳性表达,差异无显著性。贴壁细胞与MTS上两种黏附分子表达均无差异。结论成功建立了一种简易制备MTS的方法。细胞生长方式(单层贴壁与MTS)可能不影响CD44v6和CD29的表达。CD29表达可能与肺腺痛转移性相关;CD44v6表达可能与肺腺癌转移无关。 相似文献
92.
肝素酶和碱性成纤维细胞生长因子与非小细胞肺癌转移和预后的关系 总被引:6,自引:0,他引:6
目的 探讨肝素酶(heparanase)和碱性成纤维细胞生长因子(bFGF)在人非小细胞肺癌(NSCLC)组织中表达的临床意义及其与肺癌转移和预后的关系。方法 采用免疫组织化学、原位杂交和Western blot方法,检测115例人NSCLC石蜡切片和45例新鲜肺癌及对应癌旁正常组织中肝素酶和bFGF的表达情况。采用χ^2检验、t检验、生存曲线和Cox比例风险回归等方法分析肝素酶和bFGF分别表达及共表达的意义。结果 免疫组织化学染色证实肝素酶(91/115)和bFGF(89/115)主要表达在癌细胞质和(或)细胞膜中,在正常肺泡上皮和支气管上皮中则呈阴性表达。Western blot也证实肝素酶在肺癌中的表达明显增高(P=0.041)。统计分析结果显示:肝素酶和bFGF的表达具有明显的一致性(P:0.0001),二者单独表达和共表达均与肺癌的分期、血管侵袭、淋巴结转移、微血管密度和预后有关,其中,二者共表达时与分期和微血管密度的相关性更显著;另外,bFGF还与肺癌的分化程度有关。多因素分析结果显示,肺癌的分化程度、血管浸润、淋巴结转移和bFGF的表达可以作为判断肺癌预后的危险因素,但肝素酶不是影响预后的独立因素。结论 肝素酶和bFGF均与肺癌的转移、血管生成和预后密切相关。 相似文献
93.
涎腺癌肉瘤临床及病理分析 总被引:6,自引:0,他引:6
目的:探讨涎腺癌肉瘤的临床病理学特点及其鉴别诊断。方法:对3例涎腺癌肉瘤患者的临床资料进行回顾性研究并复习相关文献,对全部病例的组织学标本重新进行镜下观察。结果:涎腺癌肉瘤临床表现常为迅速增大的颜面部肿物并伴疼豢。光匀下组织学观察常可见肉瘤和癌两种成分并存,癌多为鳞状细胞癌和腺癌,肉瘤以骨或软骨肉瘤为主。结论:涎腺癌肉瘤的临床特点与涎腺其他恶性肿瘤较难区别,但涎腺癌肉瘤的恶性程度极高。 相似文献
94.
Pileri SA Grogan TM Harris NL Banks P Campo E Chan JK Favera RD Delsol G De Wolf-Peeters C Falini B Gascoyne RD Gaulard P Gatter KC Isaacson PG Jaffe ES Kluin P Knowles DM Mason DY Mori S Müller-Hermelink HK Piris MA Ralfkiaer E Stein H Su IJ Warnke RA Weiss LM 《Histopathology》2002,41(1):1-29
Neoplasms of histiocytes and dendritic cells are rare, and their phenotypic and biological definition is incomplete. Seeking to identify antigens detectable in paraffin-embedded sections that might allow a more complete, rational immunophenotypic classification of histiocytic/dendritic cell neoplasms, the International Lymphoma Study Group (ILSG) stained 61 tumours of suspected histiocytic/dendritic cell type with a panel of 15 antibodies including those reactive with histiocytes (CD68, lysozyme (LYS)), Langerhans cells (CD1a), follicular dendritic cells (FDC: CD21, CD35) and S100 protein. This analysis revealed that 57 cases (93%) fit into four major immunophenotypic groups (one histiocytic and three dendritic cell types) utilizing six markers: CD68, LYS, CD1a, S100, CD21, and CD35. The four (7%) unclassified cases were further classifiable into the above four groups using additional morphological and ultrastructural features. The four groups then included: (i) histiocytic sarcoma (n=18) with the following phenotype: CD68 (100%), LYS (94%), CD1a (0%), S100 (33%), CD21/35 (0%). The median age was 46 years. Presentation was predominantly extranodal (72%) with high mortality (58% dead of disease (DOD)). Three had systemic involvement consistent with 'malignant histiocytosis'; (ii) Langerhans cell tumour (LCT) (n=26) which expressed: CD68 (96%), LYS (42%), CD1a (100%), S100 (100%), CD21/35 (0%). There were two morphological variants: cytologically typical (n=17) designated LCT; and cytologically malignant (n=9) designated Langerhans cell sarcoma (LCS). The LCS were often not easily recognized morphologically as LC-derived, but were diagnosed based on CD1a staining. LCT and LCS differed in median age (33 versus 41 years), male:female ratio (3.7:1 versus 1:2), and death rate (31% versus 50% DOD). Four LCT patients had systemic involvement typical of Letterer-Siwe disease; (iii) follicular dendritic cell tumour/sarcoma (FDCT) (n=13) which expressed: CD68 (54%), LYS (8%), CD1a (0%), S100 (16%), FDC markers CD21/35 (100%), EMA (40%). These patients were adults (median age 65 years) with predominantly localized nodal disease (75%) and low mortality (9% DOD); (iv) interdigitating dendritic cell tumour/sarcoma (IDCT) (n=4) which expressed: CD68 (50%), LYS (25%), CD1a (0%), S100 (100%), CD21/35 (0%). The patients were adults (median 71 years) with localized nodal disease (75%) without mortality (0% DOD). In conclusion, definitive immunophenotypic classification of histiocytic and accessory cell neoplasms into four categories was possible in 93% of the cases using six antigens detected in paraffin-embedded sections. Exceptional cases (7%) were resolvable when added morphological and ultrastructural features were considered. We propose a classification combining immunophenotype and morphology with five categories, including Langerhans cell sarcoma. This simplified scheme is practical for everyday diagnostic use and should provide a framework for additional investigation of these unusual neoplasms. 相似文献
95.
Kenichi Ohashi Yo Kato Jun Kanno Tsutomu Kasuga 《Virchows Archiv : an international journal of pathology》1990,417(2):137-143
Summary Normal oesophagus specimens taken from 65 autopsy cases and surgical specimens from 127 oesophageal carcinoma cases were examined
histopathologically to determine melanocyte incidence and distribution. Melanocytes were found in the epithelio-stromal junction
in 7.7% of normal oesophagus specimens examined at autopsy, and in 29.9% of surgical cases with oesophageal carcinoma. Positive
specimens in the latter groups, especially from pre-operatively irradiated individuals, showed a more remarkable increase
of melanocytes than was evident in any of the normal oesophageal samples. There were no significant differences in incidence
between males and females, or between age groups. In cases where the cancer invaded into deeper stroma, the melanocytes were
mainly observed in the normal epithelium around the carcinomas. Epithelial and stromal elements of the melanotic mucosa commonly
showed hyperplastic changes such as acanthosis or basal cell hyperplasia, and chronic oesophagitis. Melanocytes were observed
most commonly in the lower part of the oesophagus, the site where malignant melanoma of the oesophagus, most often originates.
These results strongly suggest that the melanocyte increase observed in areas of hyperplastic epithelium and chronic oesophagitis
may play an important role as a precursor lesion for malignant melanoma in the oesophagus. 相似文献
96.
人大肠癌中Ⅳ型胶原酶与基底膜免疫组织化学双重染色研究 总被引:1,自引:0,他引:1
目的观察Ⅳ型胶原酶和基底膜在大肠癌生长中的相互关系及Ⅳ型胶原酶的表达与p21的表达之间的关系。方法应用免疫组化双标记方法,对86例人大肠癌组织的Ⅳ型胶原酶表达及基底膜的改变作对照研究。结果大肠癌组织中Ⅳ型胶原酶的阳性率为83.72%(73/86),与对照组癌周正常肠粘膜的阳性率10%差异有非常显著意义(P<0.01)。同时,双染色显示Ⅳ型胶原酶阳性的癌组织基底膜表现为不连续,出现缺口、片段缺失或完全消失等形态。此外,肠癌中Ⅳ型胶原酶的分布与p21的表达呈正相关(r=0.974,p<0.01)。结论Ⅳ型胶原酶的分泌对肠癌基底膜破坏起重要作用,可以作为判断大肠癌生长特性的辅助指标。 相似文献
97.
我们应用三维结构(3-D)再构成计算机系统,以0.2mm间隔连续切片,HE染色,对50例经纤维结肠镜切除的大肠腺瘤各种异型上皮的体积及分布规律进行研究。其中癌变17例(34%),其平均体积是单纯腺瘤的3.4倍。腺瘤体积越大,其癌变率越高,但体积较小的亚有蒂型腺瘤也有很高癌变率(25%)。研究结果表明腺瘤体积大小与平均异型度无相关关系。用常规方法切片,仅检出14例有癌变,漏诊率18%。为提高腺瘤癌变检出率,至少应以0.6mm间隔连续切片。此种方法对准确判定断端有无癌浸润也有重要意义。 相似文献
98.
肢端黏液样炎性纤维母细胞肉瘤2例及文献复习 总被引:1,自引:2,他引:1
目的探讨肢端黏液样炎性纤维母细胞肉瘤的临床病理学特征及鉴别诊断。方法对2例发生在下肢末端的黏液样炎性纤维母细胞肉瘤进行光镜观察和免疫组化标记,并复习文献。结果2例发生在下肢末端的病程较长的渐进性肿块,术后局部复发。镜检:病变呈多结节状,边界不清;黏液样基质中见数量不等的各类炎细胞浸润,散在或灶性分布梭形、奇异形和多空泡状脂肪母细胞样3种形态的瘤细胞。免疫表型:肿瘤细胞Vim弥漫阳性,CD68和CD34灶性阳性,CK、SMA、HHF-35、S-100蛋白、CD45、CD45R0、CD15、CD30均阴性。结论此病病程较长,术后易局部复发,是一种低度恶性的肿瘤。鉴于病变黏液样基质及各类炎细胞浸润的背景较为突出,而特征性的瘤细胞稀疏,应注意与炎症性病变或具有相似组织形态的良性或恶性肿瘤鉴别。 相似文献
99.
P. Delvenne B. Kaschten J. M. Deneufbourg L. Demanez A. Stevenaert M. Reznik J. Boniver 《Virchows Archiv : an international journal of pathology》1993,423(2):145-150
A case of nasopharyngeal carcinoma is presented. Epstein-Barr viral genome was identified in the neoplastic cells by in situ hybridization with digoxigeninlabelled polymerase chain reaction-generated probes. We report the development of this technique in paraffinembedded sections and propose that such identification may prove valuable for the diagnosis of this tumour in routine material.P. Delvenne is a research associate of the National Fund for Scientific Research (Belgium) 相似文献
100.
Helin H Lundin M Lundin J Martikainen P Tammela T Helin H van der Kwast T Isola J 《Human pathology》2005,36(4):381-386
Gleason grading forms the basis of prognostic and therapeutic assessment in prostatic carcinoma despite its subjective nature and substantial interobserver variation. The accuracy of Gleason grading can be improved by the use of educational tools such as reference images. However, conventional microscopy images are of limited educational value because it is neither possible to view the sample at different magnifications nor to navigate into different areas of the specimen. This limitation can be overcome by the use of virtual microscopy, which allows viewing entire digitized microscope slides. We created an interactive Web site ( www.webmicroscope.net/gleason ) featuring a comprehensive set of prostatic needle biopsies as virtual slides, which can be viewed with a standard Web browser (Internet Explorer or Netscape). To evaluate the validity of Web-based virtual microscopy for Gleason grading, an experienced uropathologist (TK) scored a series of 62 biopsies from the original glass slides and 6 weeks later from virtual slides on the Web site using an ordinary desktop computer. The intraobserver agreement was excellent, with identical Gleason scores found in 48 of the 62 cases ( kappa = 0.73). The 14 remaining scores differed only by 1 point on the Gleason scale (2-10). The virtual slides were viewed by 2 other uropathologists (PM and HH), with interobserver kappa coefficients ranging from 0.55 to 0.62, which is within the range of previously reported studies using glass slides. The 3 uropathologists' Gleason scores were included as reference scores on the Web site, which now serves as a publicly open platform for self-testing and learning of Gleason grading. We conclude that Web-based virtual microscopy is a promising new tool for teaching and standardizing Gleason grading. 相似文献