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   18579篇
  免费   1227篇
  国内免费   988篇
耳鼻咽喉   157篇
儿科学   124篇
妇产科学   229篇
基础医学   5529篇
口腔科学   860篇
临床医学   547篇
内科学   1060篇
皮肤病学   480篇
神经病学   1810篇
特种医学   213篇
外国民族医学   30篇
外科学   999篇
综合类   4215篇
预防医学   144篇
眼科学   318篇
药学   604篇
  3篇
中国医学   147篇
肿瘤学   3325篇
  2023年   86篇
  2022年   107篇
  2021年   226篇
  2020年   298篇
  2019年   294篇
  2018年   316篇
  2017年   397篇
  2016年   500篇
  2015年   599篇
  2014年   885篇
  2013年   866篇
  2012年   1013篇
  2011年   1043篇
  2010年   804篇
  2009年   809篇
  2008年   961篇
  2007年   1089篇
  2006年   1101篇
  2005年   1067篇
  2004年   1057篇
  2003年   983篇
  2002年   870篇
  2001年   827篇
  2000年   672篇
  1999年   537篇
  1998年   433篇
  1997年   365篇
  1996年   349篇
  1995年   277篇
  1994年   284篇
  1993年   264篇
  1992年   233篇
  1991年   226篇
  1990年   168篇
  1989年   156篇
  1988年   127篇
  1987年   90篇
  1986年   93篇
  1985年   106篇
  1984年   100篇
  1983年   55篇
  1982年   32篇
  1981年   15篇
  1980年   7篇
  1979年   3篇
  1978年   3篇
  1976年   1篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
李雯霞  文璋  蒋菲  薛玲 《现代肿瘤医学》2022,(22):4068-4071
目的:研究结直肠癌及其配对的癌旁组织的自然杀伤(nature killer,NK)细胞数量及分布情况。方法:结直肠癌及其配对的癌旁组织各40例,以SP免疫组化法检测NK细胞。结果:结直肠癌及其配对的癌旁组织中均未检测到NK细胞的浸润。结论:结直肠癌及其配对的癌旁组织中缺乏NK细胞浸润可能与肿瘤微环境、生理微环境、未知的NK细胞亚型相关,结直肠癌患者可能不适用NK细胞进行免疫治疗。  相似文献   
2.
牙源性始基瘤是颌面部罕见的良性牙源性肿瘤。本文报道1例牙源性始基瘤,并结合文献探讨其临床病理特征及治疗原则。  相似文献   
3.
Breast implant associated anaplastic large cell lymphoma (BIA-ALCL) is an emergent rare T cell non-Hodgkin lymphoma arising in association with a breast implant, particularly textured ones. Recent guidelines list cytopathological examination as the first essential step for diagnosis, routinely followed by CD30 immunohistochemistry (IHC) and flow cytometry (FC) for a T cell clone. The majority of BIA-ALCL literature regarding cytopathological evaluation describes morphology based on various preparation methods limited to cytospins and smears with the exception of at least one case report detailing cytomorphological and IHC findings on ThinPrep. This case report details initial diagnosis of BIA-ALCL rendered with CytoLyt prepared ThinPrep and cell block, including the specific antibodies used for IHC. The ThinPrep slide showed numerous singly dispersed large, atypical cells with abundant cytoplasm containing irregular nuclei with dispersed chromatin and prominent nucleoli in a background of macrophages, inflammatory cells and granular debris. TIA-1 and CD30 along with other T-cell markers, including specific antibodies, remains immunoreactive in tissue collected in CytoLyt solution. Cell size reduction, artifactual lymphoid cell aggregation and prominent nucleoli in benign and reactive conditions are among other ThinPrep cellular alterations pathologists should bear in mind.  相似文献   
4.
Employing orexin-A immunohistochemical staining we describe the nuclear parcellation of orexinergic neurons in the hypothalami of a lar gibbon and a chimpanzee. The clustering of orexinergic neurons within the hypothalamus and the terminal networks follow the patterns generally observed in other mammals, including laboratory rodents, strepsirrhine primates and humans. The orexinergic neurons were found within three distinct clusters in the ape hypothalamus, which include the main cluster, zona incerta cluster and optic tract cluster. In addition, the orexinergic neurons of the optic tract cluster appear to extend to a more rostral and medial location than observed in other species, being observed in the tuberal region in the anterior ventromedial aspect of the hypothalamus. While orexinergic terminal networks were observed throughout the brain, high density terminal networks were observed within the hypothalamus, medial and intralaminar nuclei of the dorsal thalamus, and within the serotonergic and noradrenergic regions of the midbrain and pons, which is typical for mammals. The expanded distribution of orexinergic neurons into the tuberal region of the ape hypothalamus, is a feature that needs to be investigated in other primate species, but appears to correlate with orexin gene expression in the same region of the human hypothalamus, but these neurons are not revealed with immunohistochemical staining in humans. Thus, it appears that apes have a broader distribution of orexinergic neurons compared to other primate species, but that the neurons within this extension of the optic tract cluster in humans, while expressing the orexin gene, do not produce the neuropeptide.  相似文献   
5.
6.
The adrenal cortex gives rise to a biologically heterogenous group of neoplasms, each with a distinct morphology, antigen expression and molecular profile. Adrenal cortical adenomas have excellent prognosis and are usually cured by surgical resection alone, while adrenal cortical carcinomas are very aggressive tumors with a poor prognosis regardless of therapy. These tumors are rare and often challenging for a pathologist to diagnose, as significant overlap exists between benign and malignant lesions in some cases. In this review, we attempt to summarize most important histologic and clinical features of adrenal cortical adenomas and carcinomas, clarify the use of different grading systems, the use of special stains and the differential diagnosis for practicing pathologists. Most relevant hereditary syndromes associated with adrenal cortical tumors are listed. Updates in molecular alterations in adrenal cortical neoplasms and hyperplastic diseases as well as their clinical significance and potential therapeutic implications are also discussed.  相似文献   
7.
Here, we review the development, morphology, genes, and proteins of claws in reptiles. Claws likely form owing to the inductive influence of phalangeal mesenchyme on the apical epidermis of developing digits, resulting in hyperproliferation and intense protein synthesis in the dorsal epidermis, which forms the unguis. The tip of claws results from prevalent cell proliferation and distal movement along most of the ungueal epidermis in comparison to the ventral surface forming the subunguis. Asymmetrical growth between the unguis and subunguis forces beta-cells from the unguis to rotate into the apical part of the subunguis, sharpening the claw tip. Further sharpening occurs by scratching and mechanical wearing. Ungueal keratinocytes elongate, form an intricate perimeter and cementing junctions, and remain united impeding desquamation. In contrast, thin keratinocytes in the subunguis form a smooth perimeter, accumulate less corneous beta proteins (CBPs) and cysteine-poor intermediate filament (IF)-keratins, and desquamate. In addition to prevalent glycine–cysteine–tyrosine rich CBPs, special cysteine-rich IF-keratins are also synthesized in the claw, generating numerous  S S bonds that harden the thick and compact corneous material. Desquamation and mechanical wear at the tip ensure that the unguis curvature remains approximately stable over time. Reptilian claws are likely very ancient in evolution, although the unguis differentiated like the outer scale surface of scales, while the subunguis might have derived from the inner scale surface. The few hair-like IF-keratins synthesized in reptilian claws indicate that ancestors of sauropsids and mammals shared cysteine-rich IF-keratins. However, the number of these keratins remained low in reptiles, while new types of CBPs function to strengthen claws.  相似文献   
8.
ObjectiveTo study the clinical features and identify unique renal neoplasia subtypes and their prognostic implications in individuals with tuberous sclerosis complex (TSC).Patients and MethodsThe Mayo Clinic nephrectomy registry included 37 patients with TSC diagnosed between 1970 and 2018. Four additional patients were identified from the pathology consultation and autopsy files. All available renal tumors were further characterized using immunohistochemistry and fluorescence in situ hybridization. Clinicopathologic features and follow-up were obtained from the medical record. The American Association for Cancer Research Project GENIE registry was accessed using cBioPortal for molecular profiling of angiomyolipoma (AML).ResultsA total of 276 renal tumors from 41 patients were analyzed. Renal tumors were classified into 9 distinct morphological subtypes, with AML predominating (238 [86%]). Interestingly, all these tumors acted in a benign fashion except one renal cell carcinoma with clear cells and fibromyomatous stroma and one epithelioid AML that metastasized. Molecular profiling studies revealed that epithelioid AMLs were enriched for alterations of TP53, RB1, and ATRX. Eight patients died of direct complications of TSC, including 3 of end-stage renal disease. To date, none have died of a renal epithelial neoplasm.ConclusionThe identification of unique renal neoplasia subtypes may provide important clues to establish a diagnosis of TSC, and in the somatic setting, this finding has important implications for accurate prognostication. These tumors tend to be indolent, and only 2 of 276 tumors in our study exhibited metastatic behavior. Our results support multidisciplinary management with a focus on preservation of renal function.  相似文献   
9.
CKLF-like MARVEL transmembrane domain–containing protein 6 (CMTM6) maintains membrane PD-L1 expression by controlling its endosomal recycling. However, in patients with hepatocellular carcinoma (HCC), the correlation among CMTM6, B7 family ligands, and CD8-positive cytotoxic T lymphocytes (CTLs), and the molecular function of CMTM6 in HCC have not been established. We performed immunohistochemistry to evaluate the relationships among CMTM6 expression, clinicopathological factors, B7 family ligands expression, and CTL infiltration in HCC samples. Moreover, we established CMTM6-knockout human HCC cell lines to evaluate the function of human CMTM6 in immune regulation and tumor viability. CMTM6 expression was positively associated with membrane B7 family ligands expression and CTL infiltration in HCC samples. High CMTM6 expression in HCC tissues was associated with the expression of the proliferation marker Ki-67 and shorter recurrence-free survival. In vitro analysis showed the downregulation of membrane B7 family ligands and proliferation potency in the CMTM6-knockout human HCC cell line. High membrane CMTM6 expression was associated with tumor recurrence and proliferation via the regulation of membranous B7 family ligands expression. Thus, CMTM6 might be a biomarker to predict the risk of HCC recurrence and a therapeutic target to suppress tumor growth and increase CTL activity.  相似文献   
10.
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