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   790篇
  免费   94篇
  国内免费   9篇
  2023年   14篇
  2022年   13篇
  2021年   26篇
  2020年   32篇
  2019年   44篇
  2018年   29篇
  2017年   42篇
  2016年   26篇
  2015年   31篇
  2014年   46篇
  2013年   81篇
  2012年   24篇
  2011年   31篇
  2010年   31篇
  2009年   32篇
  2008年   25篇
  2007年   35篇
  2006年   38篇
  2005年   29篇
  2004年   24篇
  2003年   24篇
  2002年   29篇
  2001年   15篇
  2000年   12篇
  1999年   14篇
  1998年   18篇
  1997年   9篇
  1996年   12篇
  1995年   11篇
  1994年   10篇
  1993年   11篇
  1992年   3篇
  1991年   2篇
  1990年   2篇
  1989年   5篇
  1988年   7篇
  1987年   7篇
  1986年   5篇
  1985年   6篇
  1984年   9篇
  1983年   5篇
  1982年   6篇
  1981年   3篇
  1980年   3篇
  1979年   4篇
  1978年   3篇
  1977年   1篇
  1976年   3篇
  1975年   1篇
排序方式: 共有893条查询结果,搜索用时 46 毫秒
41.
目的:探讨鼻中隔成形术中鼻腔填塞法及鼻中隔"8"字缝合法的疗效。方法:选取2017年7月~2018年7月期间我院收治的拟行鼻中隔成形术的鼻中隔偏曲患者60例。采用乱数表法将患者分为对照组、实验组两组,各30例患者,两组患者均行鼻内镜下鼻中隔成形术,术后对照组给予鼻腔填塞法处理,实验组给予鼻中隔"8"字缝合法处理。比较两组术后临床疗效、鼻粘膜水肿情况,观察两组不同时间点视觉疼痛模拟评分(VAS)情况,记录两组患者术后鼻中隔并发症发生情况。结果:实验组术后7d临床总有效率为96.67%(29/30),显著高于对照组患者的80.00%(24/30),差异有统计学意义(P0.05)。与术前相比,两组患者术后12hVAS评分升高,术后24h、术后48hVAS评分下降(P0.05);与术后12h相比,两组患者术后24h、术后48hVAS评分均下降,且术后48hVAS评分低于术后24h(P0.05);实验组术后12h、术后24h、术后48hVAS评分均低于对照组(P0.05)。实验组鼻粘膜水肿0级患者数量显著高于对照组,鼻粘膜水肿1级患者数量显著低于对照组(P0.05);两组鼻粘膜水肿2级患者数量比较差异无统计学意义(P0.05);两组患者鼻中隔并发症总发生率比较差异无统计学意义(P0.05)。结论:相较于鼻腔填塞法,鼻中隔成形术中采用鼻中隔"8"字缝合法疗效显著,可减轻患者疼痛,改善患者鼻粘膜水肿情况,且不会增加并发症发生率,具有一定的临床应用价值。  相似文献   
42.
目的:探讨血清胆红素、人类软骨糖蛋白-39(YKL-40)、高迁移率族蛋白1(HMGB-1)对糖尿病合并冠心病患者的临床意义方法:选择2017年1月至2018年12月我院接诊的190例2型糖尿病患者,根据是否合并冠心病分为单纯糖尿病组121例和糖尿病合并冠心病组69例,并选择同期在我院接受体检的100例健康者作为对照组。比较三组临床生化指标、血清胆红素、YKL-40、HMGB-1及不同病变支数、不同病变程度糖尿病合并冠心病组血清胆红素、YKL-40、HMGB-1的表达。结果:三组空腹血糖(FBG)、糖化血红蛋白(HbA1c)、三酰甘油(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、血清胆红素、YKL-40、HMGB-1比较差异均有统计学意义(P0.05);不同病变支数、病变程度糖尿病合并冠心病患者血清胆红素、YKL-40、HMGB-1比较差异均有统计学意义(P0.05);经两两Pearson线性相关性分析结果显示,血清胆红素和Gensini评分呈负相关(r=-0.812,P0.01),YKL-40、HMGB-和Gensini评分正相关(r=0.873、0.801,P0.01)。结论:在糖尿病合并冠心病患者中,血清胆红素的表达明显降低,YKL-40、HMGB-1明显升高,且随着冠脉病变程度的加重变化更明显,本研究也为后期血清胆红素、YKL-40、HMGB-1在该病的早期诊断、预防、治疗效果评价等方面提供了依据  相似文献   
43.
According to previous studies, the nonlinear susceptibility tensor ratio χ33/χ31 obtained from polarization‐resolved second harmonic generation (P‐SHG) under the assumption of cylindrical symmetry can be used to distinguish between fibrillar collagen types. Discriminating between collagen fibrils of types I and II is important in tissue engineering of cartilage. However, cartilage has a random organization of collagen fibrils, and the assumption of cylindrical symmetry may be incorrect. In this study, we simulated the P‐SHG response from different collagen organizations and demonstrated a possible method to exclude areas where cylindrical symmetry is not fulfilled and where fibrils are located in the imaging plane. The χ33/χ31‐ratio for collagen type I in tendon and collagen type II in cartilage was estimated to be 1.33 and 1.36, respectively, using this method. These ratios are now much closer than what has been reported previously in the literature, and the larger reported differences between collagen types can be explained by variation in the structural organization.   相似文献   
44.
Osteoarthritis (OA) is considered to be a highly heterogeneous disease with progressive cartilage loss, subchondral bone remodeling, and low-grade inflammation. It is one of the world's leading causes of disability. Most conventional clinical treatments for OA are palliative drugs, which cannot fundamentally cure this disease. The stromal vascular fraction (SVF) from adipose tissues is a heterogeneous cell population. According to previous studies, it contains a large number of mesenchymal stem cells, which have been used to treat OA with good therapeutic results. This safe, simple, and effective therapy is expected to be applied and promoted in the future. In this paper, the detailed pathogenesis, diagnosis, and current clinical treatments for OA are introduced. Then, clinical studies and the therapeutic mechanism of SVF for the treatment of OA are summarized.  相似文献   
45.
《Palaeoworld》2022,31(4):658-678
Conglomerates, exposed on either side of the Yarlung Tsangpo suture zone (YTSZ) in southern Tibet, have attracted wide attention in elucidating uplift and erosion histories of the Himalayan-Tibetan orogen. However, the provenance of these conglomerates remains controversial. Although radiolarian-bearing chert clasts within these conglomerates have received little focus, identification of the radiolarian assemblages they contain could shed light on the provenance of these sedimentary units. We present the first report of Upper Jurassic to Lower Cretaceous (upper Kimmeridgian–lower Barremian) radiolarian assemblages recovered from chert clasts within the Liuqu and Gangrinboche conglomerates in the Xigaze area. To extract radiolarian fossils from independent clasts in the conglomerates, a detailed and efficient experimental process is illustrated. The assemblages are well correlated to those in the YTSZ and Tethyan Himalaya, showing typical Tethyan characteristics. The lithology of chert clasts and ages of constituent radiolarian faunas suggest that the chert clasts in Liuqu and Gangrinboche conglomerates were derived from the Bainang terrane. This interpretation implies that Early Cretaceous accretionary complexes in the YTSZ had been exposed and eroded before deposited as clasts in the Cenozoic Liuqu and Gangrinboche conglomerates.  相似文献   
46.
During craniofacial development, Meckel's cartilage and the mandible bone derive from the first branchial arch, and their development depends upon the contribution of cranial neural crest (CNC) cells. We previously demonstrated that conditional inactivation of Tgfbr2 in the neural crest of mice (Tgfbr2fl/fl;Wnt1-Cre) results in severe defects in mandibular development, although the specific cellular and molecular mechanisms by which TGF-β signaling regulates the fate of CNC cells during mandibular development remain unknown. We show here that loss of Tgfbr2 does not affect the migration of CNC cells during mandibular development. TGF-β signaling is specifically required for cell proliferation in Meckel's cartilage and the mandibular anlagen and for the formation of the coronoid, condyle and angular processes. TGF-β-mediated connective tissue growth factor (CTGF) signaling is critical for CNC cell proliferation. Exogenous CTGF rescues the cell proliferation defect in Meckel's cartilage of Tgfbr2fl/fl;Wnt1-Cre mutants, demonstrating the biological significance of this signaling cascade in chondrogenesis during mandibular development. Furthermore, TGF-β signaling controls Msx1 expression to regulate mandibular osteogenesis as Msx1 expression is significantly reduced in Tgfbr2fl/fl;Wnt1-Cre mutants. Collectively, our data suggest that there are differential signal cascades in response to TGF-β to control chondrogenesis and osteogenesis during mandibular development.  相似文献   
47.
BACKGROUND: The most comprehensive evaluation of vertebrate skeletal development involves the use of Alizarin Red S dye to stain ossified bone and various other dyes to stain cartilage. The dye used most widely to stain fetal cartilage in rodents and rabbits is Alcian Blue 8GX. However, the global supply of this specific dye has been exhausted. Several forms of the dye marketed as Alcian Blue 8GX are now available, although they are not synthesized via the original 8GX manufacturing process. METHODS: One new Alcian Blue 8GX form and two Alcian Blue dye variants were evaluated in rats and rabbits using standard staining procedures. The staining quality of these dyes were evaluated relative to the original form of Alcian Blue 8GX based on cartilage uptake of the dye, clarity of the cartilaginous components, staining intensity of the dye, and overall readability of the specimens under stereomicroscopic evaluation. RESULTS: Staining with the newer form of Alcian Blue 8GX resulted in poor staining quality. The Alcian Blue-Pyridine variant performed well, although staining intensity was less than optimal. The Alcian Blue-Tetrakis variant provided staining characteristics that were most similar to the original form of Alcian Blue 8GX. CONCLUSIONS: Alcian Blue-Tetrakis was markedly better in its ability to stain fetal cartilage than the newer form of Alcian Blue 8GX.  相似文献   
48.
骨关节炎(osteoarthritis,OA)是运动系统常见的退行性疾病,具有高发病率和高致残率。骨关节炎的发病机制目前尚不明确,既往研究认为骨关节炎发病主要与创伤因素相关,而近期研究表明,以胆固醇代谢异常为主的代谢性因素同样与骨关节炎密切相关,骨关节炎的治疗以早期对症治疗和晚期手术治疗为主,尚无针对病因的特效药物。既往研究中发现,有一种具有软骨保护作用的小分子药物BNTA,其在创伤引起的骨关节炎中具有较好的疗效,但其对高胆固醇引起的骨关节炎的作用尚不明确。本研究为探究BNTA对高胆固醇引起的骨关节炎的治疗作用及其机制,采用高胆固醇饮食构建了大鼠骨关节炎模型,取膝关节石蜡切片进行组织学评估,使用油红O染色评估大鼠软骨细胞内的脂质积聚情况,使用RT-qPCR、免疫荧光和免疫组化评估软骨细胞合成代谢、分解代谢及胆固醇代谢相关基因和蛋白质的表达。结果显示,BNTA可缓解高胆固醇大鼠骨关节炎模型中的病理表现,改善OARSI评分。在大鼠软骨细胞中,BNTA可促进合成代谢相关基因col2、sox9、acan的表达,抑制分解代谢相关基因mmp13、adamts5的表达,可改善高胆固醇引起的大鼠软骨细胞脂质积聚。在大鼠软骨细胞和高胆固醇大鼠骨关节炎模型中BNTA均可上调Insig1表达。本研究证实,高胆固醇可在体内和体外实验中加重骨关节炎,可引起大鼠软骨细胞脂质积聚增加。在体内和体外实验中BNTA均能缓解高胆固醇引起的骨关节炎表型,改善软骨细胞内的异常脂质积聚,其作用可能为通过上调Insig1抑制细胞内的胆固醇生物合成,从而缓解脂质异常积聚。  相似文献   
49.
50.
Proinflammatory cytokine such as interleukin (IL)-1β causes inflammation of articular cartilage. In this current study, we explored the chondroprotective effects of long noncoding RNA (lncRNA) MALAT-1 on cell proliferation, apoptosis, and matrix metabolism in IL-1β-induced inflammation in articular chondrocytes. Articular chondrocytes from knee joints of normal rats were isolated and cultured, followed by identification through observation of toluidine blue and COL II immunocytochemical stainings. The proliferation of chondrocytes at passage 2 was detected by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The inflammatory chondrocytes induced by 10 ng/mL IL-1β were observed and identified by toluidine blue and COL II immunocytochemical stainings. pcDNA 3.1 and pcDNA-MALAT-1 were transfected in the chondrocytes. Ultrastructure of chondrocytes was observed by using a transmission electron microscope. The MTT assay was carried out to evaluate chondrocyte viability. Hoechst 33258 staining and flow cytometry were adopted to assess chondrocyte apoptosis. The chondrocytes at passage 2 with the biological characteristics of chondrocytes were used for subsequent experiments. In IL-1β-treated chondrocytes, the growth rate of chondrocytes slowed down, the cells became narrow and long, the vacuoles were seen in the cells, and the morphology of the chondrocytes was irregular. The toluidine blue staining and the immunohistochemical staining of COL II became weaker. In response to IL-1β induction, articular chondrocytes showed reduced MALAT-1 expression; moreover, obvious cartilage injury was observed with decreased chondrocyte viability and Col II expression and elevated chondrocyte apoptosis, MMP-13 expression, and p-JNK expression. With the treatment of pcDNA-MALAT-1, the cartilage injury was alleviated with increased chondrocyte viability and type II collagen (Col II) expression and reduced chondrocyte apoptosis, MMP-13 expression and p-JNK expression. Taken together these results, lncRNA MALAT-1 blocked the activation of the JNK signaling pathway; thereby, IL-1β-induced inflammation in articular chondrocytes was reduced with enhanced chondrocyte proliferation and suppressed chondrocyte apoptosis and extracellular matrix degradation.  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