全文获取类型
收费全文 | 1787篇 |
免费 | 155篇 |
国内免费 | 94篇 |
专业分类
耳鼻咽喉 | 30篇 |
儿科学 | 20篇 |
妇产科学 | 18篇 |
基础医学 | 278篇 |
口腔科学 | 25篇 |
临床医学 | 144篇 |
内科学 | 254篇 |
皮肤病学 | 8篇 |
神经病学 | 112篇 |
特种医学 | 48篇 |
外国民族医学 | 2篇 |
外科学 | 154篇 |
综合类 | 248篇 |
预防医学 | 49篇 |
眼科学 | 88篇 |
药学 | 185篇 |
中国医学 | 58篇 |
肿瘤学 | 315篇 |
出版年
2024年 | 3篇 |
2023年 | 22篇 |
2022年 | 58篇 |
2021年 | 71篇 |
2020年 | 54篇 |
2019年 | 53篇 |
2018年 | 56篇 |
2017年 | 71篇 |
2016年 | 66篇 |
2015年 | 94篇 |
2014年 | 133篇 |
2013年 | 140篇 |
2012年 | 136篇 |
2011年 | 182篇 |
2010年 | 141篇 |
2009年 | 111篇 |
2008年 | 106篇 |
2007年 | 80篇 |
2006年 | 55篇 |
2005年 | 42篇 |
2004年 | 37篇 |
2003年 | 33篇 |
2002年 | 24篇 |
2001年 | 23篇 |
2000年 | 12篇 |
1999年 | 16篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 10篇 |
1995年 | 13篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1989年 | 4篇 |
1988年 | 9篇 |
1987年 | 10篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 12篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1967年 | 2篇 |
排序方式: 共有2036条查询结果,搜索用时 15 毫秒
51.
52.
Hiroaki Motegi Yuuta Kamoshima Shunsuke Terasaka Hiroyuki Kobayashi Kiyohiro Houkin 《Neuropathology》2014,34(4):378-385
Cancer stem cells are thought to be closely related to tumor progression and recurrence, making them attractive therapeutic targets. Stem cells of various tissues exist within niches maintaining their stemness. Glioblastoma stem cells (GSCs) are located at tumor capillaries and the perivascular niche, which are considered to have an important role in maintaining GSCs. There were some extracellular matrices (ECM) on the perivascular connective tissue, including type 1 collagen. We here evaluated whether type 1 collagen has a potential niche for GSCs. Imunohistochemical staining of type 1 collagen and CD133, one of the GSCs markers, on glioblastoma (GBM) tissues showed CD133‐positive cells were located in immediate proximity to type 1 collagen around tumor vessels. We cultured human GBM cell lines, U87MG and GBM cells obtained from fresh surgical tissues, T472 and T555, with serum‐containing medium (SCM) or serum‐free medium with some growth factors (SFM) and in non‐coated (Non‐coat) or type 1 collagen‐coated plates (Col). The RNA expression levels of CD133 and Nestin as stem cell markers in each condition were examined. The Col condition not only with SFM but SCM made GBM cells more enhanced in RNA expression of CD133, compared to Non‐coat/SCM. Semi‐quantitative measurement of CD133‐positive cells by immunocytochemistry showed a statistically significant increase of CD133‐positive cells in Col/SFM. In addition, T472 cell line cultured in the Col/SFM had capabilities of sphere formation and tumorigenesis. Type 1 collagen was found in the perivascular area and showed a possibility to maintain GSCs. These findings suggest that type 1 collagen could be one important niche component for CD133‐positive GSCs and maintain GSCs in adherent culture. 相似文献
53.
《Parkinsonism & related disorders》2014,20(11):1177-1180
IntroductionThe cause of low serum ceruloplasmin levels in Parkinson's disease (PD) remains to be clarified. In this study, we explored serum miR-133b expression to determine whether it correlates with serum ceruloplasmin level in PD patients.MethodsForty-six patients with PD and forty-six control subjects were evaluated for miR-133b expression using qRT-PCR. The serum ceruloplasmin levels in all of the subjects were also determined.ResultsSerum miR-133b expression levels were significantly decreased in PD patients compared with those in the control subjects. Furthermore, PD patients with low serum ceruloplasmin levels also exhibited significantly lower expression of miR-133b compared with that of patients with normal ceruloplasmin levels. MiR-133b expression was correlated with the ceruloplasmin level in patients with PD, whereas no correlation was found between miR-133b and disease severity or motor phenotype.ConclusionOur observations suggest that miR-133b might be involved in ceruloplasmin dysmetabolism in PD patients and a further investigation is warranted to confirm this hypothesis. 相似文献
54.
H. Zhang W.J. Chang X.Y. Li N. Zhang J.J. Kong Y.F. Wang 《Brazilian journal of medical and biological research》2014,47(6):478-482
Accumulating evidence has indicated the importance of cancer stem cells in
carcinogenesis. The goal of the present study was to determine the effect of low-dose
cisplatin on enriched liver cancer stem cells (LCSCs). Human hepatoblastoma HepG2
cells were treated with concentrations of cisplatin ranging from 1 to 5 μg/mL. Cell
survival and proliferation were evaluated using a tetrazolium dye (MTT) assay. LCSCs
were identified using specific markers, namely aldehyde dehydrogenase-1 (ALDH1) and
CD133. The percentage of ALDH1+ or CD133+ cells was examined by flow cytometric
analysis. The expression of ALDH1 and/or CD133 in HepG2 cells was determined by
immunocytochemical analysis. Low-dose cisplatin treatment significantly decreased
cell survival in HepG2 cells after 24 or 72 h. However, the percentage of LCSCs in
the surviving cells was greatly increased. The percentage of ALDH1+ or CD133+ cells
was increased in a time- and dose-dependent manner after treatment with 1-4 μg/mL
cisplatin, whereas 5 μg/mL cisplatin exposure slightly reduced the number of positive
cells. These findings indicate that low-dose cisplatin treatment may efficiently
enrich the LCSC population in HepG2 cells. 相似文献
55.
目的 探讨肿瘤干细胞(cancer stem cells,CSC)标志物CD133及CD44在甲状腺髓样癌(medullary thyroid cancer,MTC)组织中的表达及临床病理意义.方法 采用免疫组化SP法检测51例MTC组织中CD133和CD44的表达.结果 (1)CD133蛋白在MTC伴有包膜浸润组的阳性率(76.2%,16/21)明显高于无包膜浸润组(43.3%,13/30);CD133蛋白在MTC病灶直径≥1 cm组的阳性率(64.4%,29/45)显著高于病灶直径<1 cm组(0,0/6),差异均有统计学意义(P均<0.05).(2)CD44蛋白在MTC伴有包膜浸润组的阳性率(66.7%,14/21)明显高于无包膜浸润组(20%,6/30),差异有统计学意义(P<0.01).(3) MTC中CD133和CD44蛋白的表达与患者年龄、性别、是否散发、甲状腺受累范围、淋巴结转移、远处脏器转移、TNM分期均无关(P>0.05).(4)CD133与CD44共表达与MTC包膜浸润密切相关(P<0.01).结论 MTC中存在CSC,其与肿瘤的浸润生长及恶性增殖相关,可考虑将CD133及CD44作为MTC临床评价肿瘤生物学行为的指标.二者可能存在互相调节的机制,共表达在MTC的恶性进展中发挥作用. 相似文献
56.
57.
The dynamic voltage is a unique phenomenon of superconducting materials. It arises when the superconductor is carrying a DC transport current and spontaneously in subject to an AC magnetic field. This study excavates the aspects that previous studies have not comprehensively investigated: the dynamic voltage in a DC-carrying superconducting tape exposed to different oscillating AC magnetic fields. First, the fundamental physics of dynamic voltage/flux of superconductors is reviewed and further analysed in detail. We used the superconducting modelling method using the H-formulation merged into the finite-element method (FEM) software, to re-produce the typical dynamic voltage behaviour of a superconducting tape. The modelling was verified by both the analytical and experimental results, in order to precisely prove the reliability of the modelling. Afterwards, the modelling was performed for a DC-carrying superconducting tape under four different oscillating magnetic fields (sine, triangle, sawtooth and square), and their corresponding dynamic voltages and energy losses were analysed and compared. Results show the sinusoidal magnetic field can lead to the optimal combination of reasonable dynamic voltage but relatively lower loss, which is suitable for those superconducting applications requiring dynamic voltage as the energy source, e.g., flux pumps. This article presents novel investigation and analysis of the dynamic voltage in superconducting materials, and both the methodology and results can provide useful information for the future design/analysis of superconducting applications with DC transport currents and AC magnetic fields. 相似文献
58.
《Clinical Lymphoma, Myeloma & Leukemia》2020,20(6):383-393
BackgroundAcute myeloid leukemia (AML) evolves from neoplastic transformation of stem cell disease termed “leukemia stem cells” (LSCs). An unsatisfactory response to AML therapy is determined by the presence of minimal residual disease (MRD). The predominance of LSCs might anticipate sustained MRD results. The present study aimed to demonstrate the effect of LSCs on MRD at induction days 14 and 28 on overall survival (OS) and disease-free survival (DFS) and to compare LSC expression with MRD status.Patients and MethodsA total of 84 patients with de novo adult AML underwent testing using LSC panels for CD38/CD123/CD34/CD45 and CD90/CD133/CD45/CD33 and different regular MRD panels.ResultsAt day 14 after induction, the high expression of CD123 and CD133 had adverse effects on both OS and DFS (P = .004 and P ≤ .001 and P ≤ .001 and P ≤ .001, respectively). Greater expression of CD34+/CD38−/CD123+ resulted in unfavorable OS and DFS (P ≤ .001 for both). Both CD34+/CD38−/CD123+ and CD34−/CD38+/CD123+ expression at day 14 after induction had an adverse effect on DFS only (P < .001 and P = .029, respectively). On multivariate analysis, CD133 expression and MRD status were independent prognostic parameters (hazard ratio [HR], 2.3; 95% confidence interval [CI], 1.2-4.4; P = .015; and HR, 2.9; 95% CI, 1.0-7.9; P = .041). At day 28 after induction, MRD and increased CD123+/CD34−, CD34+/CD38−/CD123+, CD133+/CD33− expression were associated with inferior OS (P = .016, P = .0035, P = .0.002, and P = .002, respectively). MRD and high expression of CD34+CD123+, CD133+/CD33−, CD34+/CD38−/CD123+ were associated with inferior DFS (P < .001, P = .002, P < .001, P < .001, respectively). On multivariate analysis, only CD133+/CD33− expression was the independent prognostic factor (HR, 3.1; 95% CI, 1.5-6.7; P = .003).ConclusionsEstimation of LSC expression is a sensitive indicator of the response to therapy in adult patients with AML and might be a better prognosticator than the findings from regular MRD panels. 相似文献
59.
目的 检测脑肿瘤干细胞(BTSC)标记物CD133、巢蛋白(Nestin)和增殖细胞核抗原(PCNA)在74例脑胶质瘤标本中的表达,探讨肿瘤干细胞生存的微环境一壁龛的组成、形态及其在脑肿瘤组织中的分布. 方法 选取安徽医科大学附属省立医院神经外科自2007年1月至2008年10月间手术切除的74例胶质瘤标本,按照WH02000年的神经系统肿瘤分类分级标准分为Ⅱ级22例(低级别组)、Ⅲ级27例和Ⅳ级25例(高级别组),采用免疫组织化学染色和免疫荧光双标法分别检测标本中CD133的表达及其与Nestin、PCNA的共表达情况.计算并比较不同级别胶质瘤组织CD133+细胞、CD133+血管和CD133+壁龛所占的百分比.并对CD133+血管和CD133+壁龛的表达进行相关性分析. 结果 CD133+细胞聚集于壁龛内生长,低级别组胶质瘤中CD133+壁龛阳性率较低.壁龛内增殖细胞较少,与相邻肇龛之间界限清晰,周围CD133+血管分布较少.高级别组胶质瘤中CD133+壁龛阳性率高,壁龛之间无明显界限,壁龛内细胞增殖活跃,周围可见丰富的CD133+血管分布:壁龛中除CD133+/Nestin+BTSC外,可见CD133+/Nestin-细胞、CD133/PCNA+细胞等亚群细胞;不同级别胶质瘤CD133+细胞、CD133+血管、CD133+壁龛百分比不同,且肿瘤级别越高,三者表达越高,差异有统计学意义(P<0.05).CD133+壁龛与CD133+血管的表达呈正相关(r=0.425,P=0.000). 结论 在脑胶质瘤组织中存在着由CD133+/Nestin+BTSC和一些亚群细胞组成的壁龛结构,CD133+血管对于壁龛结构的维持起着非常重要的作用. 相似文献
60.
目的:初步探讨As2O3/CD133抗体双面涂层药物洗脱支架在动物体内的治疗作用。方法:60只中华小型猪非高脂饮食喂养4周,随机分为球囊损伤组、假手术组和双面涂层支架组,造模后继续喂养4周,行冠状动脉光学相干断层成像(OCT)后处死动物,取心肌组织行免疫组化检测。结果:OCT图像显示,球囊损伤组冠状动脉斑块明显扩大,内膜增厚,纤维帽厚度明显增加;与球囊损伤组相比,双面涂层支架组斑块明显缩小,内膜增厚不明显,纤维帽厚度无明显增加;假手术组冠状动脉基本正常。双面涂层支架组冠状动脉的内膜/中膜面积比和厚度比低于球囊损伤组,但仍高于假手术组(P〈0.05)。免疫组化结果表明,球囊损伤组心肌Bax和Bcl-22的表达明显高于假手术组,双面涂层支架组Bax和Bcl-22的表达明显低于球囊损伤组(P均〈0.01),而与假手术组无明显差异。结论:As2O3/CD133抗体双面药物涂层支架能显著抑制冠状动脉内膜增殖,抑制心肌凋亡。 相似文献