全文获取类型
收费全文 | 319027篇 |
免费 | 66368篇 |
国内免费 | 16348篇 |
学科分类
医药卫生 | 401743篇 |
出版年
2024年 | 680篇 |
2023年 | 3641篇 |
2022年 | 6829篇 |
2021年 | 14328篇 |
2020年 | 14867篇 |
2019年 | 18545篇 |
2018年 | 18546篇 |
2017年 | 19303篇 |
2016年 | 19315篇 |
2015年 | 23428篇 |
2014年 | 25959篇 |
2013年 | 25664篇 |
2012年 | 24182篇 |
2011年 | 25609篇 |
2010年 | 22863篇 |
2009年 | 16317篇 |
2008年 | 16286篇 |
2007年 | 14405篇 |
2006年 | 13916篇 |
2005年 | 13004篇 |
2004年 | 8778篇 |
2003年 | 8177篇 |
2002年 | 6874篇 |
2001年 | 5854篇 |
2000年 | 5769篇 |
1999年 | 5258篇 |
1998年 | 3029篇 |
1997年 | 2988篇 |
1996年 | 2328篇 |
1995年 | 2231篇 |
1994年 | 1911篇 |
1993年 | 1188篇 |
1992年 | 1636篇 |
1991年 | 1446篇 |
1990年 | 1125篇 |
1989年 | 1024篇 |
1988年 | 958篇 |
1987年 | 780篇 |
1986年 | 586篇 |
1985年 | 503篇 |
1984年 | 268篇 |
1983年 | 213篇 |
1982年 | 141篇 |
1981年 | 169篇 |
1980年 | 119篇 |
1979年 | 165篇 |
1978年 | 76篇 |
1977年 | 65篇 |
1976年 | 58篇 |
1974年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
961.
全面康复:勃起功能障碍治疗的新目标 总被引:1,自引:1,他引:0
5型磷酸二酯酶(PDE5)抑制剂有效改善勃起功能障碍(ED)患者的勃起功能。枸橼酸西地那非的应用范围不断扩展,肺动脉高压已成为新的适应证。临床研究发现,西地那非能改善多种血管性疾病患者的内皮功能。在ED领域的研究进展包括:动物实验发现,西地那非可以改善海绵体内皮功能,增强磷酸化内皮型一氧化氮合酶(eNOS)蛋白表达,逆转缺血或缺氧导致的海绵体内压(ICP)降低。临床研究证实,西地那非可以使50%以上ED患者阴茎勃起恢复到最充分的硬度(4级勃起);使50%以上保留神经的根治性前列腺切除术后患者勃起功能康复,自发产生足以性交的勃起;使ED患者的自尊心、自信心和性关系满意度等社会心理功能恢复正常。从勃起功能到社会心理功能的全面恢复可能成为今后ED治疗的新目标。 相似文献
962.
Edgar Krtzsch Arturo Surez‐Colín Rosa M. Salgado Ana M.Z. Apis 《Wound repair and regeneration》2004,12(2):A35-A35
Venous leg ulcers derived from tissue destruction is the consequence of a chronic inflammatory process that produces pain and physical disability, diminishing quality of life in patients. In this work, Lassar ointment and lyophilized collagen‐polyvinylpyrrolidone were administered separated each on one half in the same ulcer to 9 patients at the beginning and every 4 days. On day 16, all patients were auto‐grafted with partial thickness skin. Granulation tissue and graft integration were assessed clinically during 3 months. Inflammatory infiltrate, type I and III collagens, elastic fibers, alkaline phosphatase as well as blood vessels were evaluated histologically or histochemically in biopsies taken at the beginning and 16 days after the local treatment. Clinically and morphologically, both treatments demonstrated appropriate granulation tissue promotion and optimal graft integration since the beginning. Nevertheless, in Lassar ointment treated group regionalization of alkaline phosphatase activity was observed, as well as the presence of granuloma in 2 of the 9 patients. In conclusion, Lassar ointment or lyophilized collagen‐polyvinylpyrrolidone are two different promoters of granulation tissue in venous leg ulcers, however Lassar ointment has the capability to produce granuloma and an exacerbated immune response; in consequence, ulcer recidivism could be present, may be due to mineral deposits in the wound. 相似文献
963.
Chun-Hsiung Huang Fang-Yuan Ho Hon-Ming Ma Chan-Tsung Yang Jiann-Jong Liau Hung-Chan Kao Tai-Horng Young Cheng-Kung Cheng 《Journal of orthopaedic research》2002,20(5):1038-1041
Osteolysis induced by ultrahigh molecular weight polyethylene wear debris has been recognized as the major cause of long-term failure in total joint arthroplasties. In a previous study, the prevalence of intraoperatively identified osteolysis during primary revision surgery was much higher in mobile bearing knee replacements (47%) than in fixed bearing knee replacements (13%). We postulated that mobile bearing knee implants tend to produce smaller sized particles. In our current study, we compared the particle size and morphology of polyethylene wear debris between failed mobile bearing and fixed bearing knees. Tissue specimens from interfacial and lytic regions were extracted during revision surgery of 10 mobile bearing knees (all of the low contact stress (LCS) design) and 17 fixed bearing knees (10 of the porous-coated anatomic (PCA) and 7 of the Miller/Galante design). Polyethylene particles were isolated from the tissue specimens and examined using both scanning electron microscopy and light-scattering analyses. The LCS mobile bearing knees produced smaller particulate debris (mean equivalent spherical diameter: 0.58 microm in LCS, 1.17 microm in PCA and 5.23 microm in M/G) and more granular debris (mean value: 93% in LCS, 77% in PCA and 15% in M/G). 相似文献
964.
It has been suggested that reward dependence, as measured by the Tridimensional Personality Questionnaire (TPQ), is related to central noradrenergic activity, a proposition supported by two studies of urinary norepinephrine metabolite. In the current investigation, 190 normal young Han Chinese were examined, with genetic polymorphisms determined for the norepinephrine transporter (1287G/A) and the α2c‐adrenoceptor (Del322–325) to test the association with TPQ personality traits. No significant association was demonstrated for these two polymorphisms and any of the TPQ personality‐factor scores, including reward dependence and its subscales. Our negative findings suggest that the investigated polymorphisms of the norepinephrine transporter and the α2c adrenoceptor do not play a major role in the reward‐dependence personality trait as assessed by TPQ. © 2002 Wiley‐Liss, Inc. 相似文献
965.
Jing‐Long Huang Liang‐Shiou Ou Ching‐Hsiung Tsao Li‐Chen Chen Ming‐Ling Kuo 《Pediatric allergy and immunology》2002,13(6):426-433
T lymphocytes play a fundamental role in the initiation and regulation of chronic inflammatory responses in patients with asthma. CD69 is an early marker of T‐cell activation. The levels of intercellular adhesion molecule‐1 (ICAM‐1, CD54) and L ‐selectin have been reported to increase in patients with allergic diseases and asthma. The present study was therefore undertaken to investigate the expression of CD69, CD54, and L ‐selectin by T lymphocytes of children with asthma, before and after immunotherapy. Eighteen children newly diagnosed with asthma, 11 good and nine poor responders to immunotherapy, and 16 normal subjects, were enrolled in this study. The percentages of CD69+, CD54+, and CD62L+ cells in T lymphocytes were measured by using flow cytometry. The levels of CD69, CD54, and CD62L in serum and culture supernatants were determined by using enzyme‐linked immunosorbent assay (ELISA). The expression of CD69 and CD54 on CD3+ T lymphocytes was significantly higher in children with asthma than in control patients. All the patient groups expressed (spontaneously and following stimulation with phorbol myristate acetate and ionomycin together with mite‐extract proteins) greater amounts of CD69 and CD54 than did control subjects. With long‐term immunotherapy, the percentages of CD69+ and CD54+ T lymphocytes were significantly lower in patients with a good response to immunotherapy. Our results also showed significantly lower serum L ‐selectin levels following immunotherapy. In conclusion, successful immunotherapy resulted in decreased expression and production of CD69 and CD54. These results may explain, in part, the clinical efficacy of immunotherapy. 相似文献
966.
967.
目的 :探讨SARS患者外周血T淋巴细胞亚群变化。方法 :采用流式细胞仪检测10 0例SARS住院患者外周血T淋巴细胞亚群。结果 :与正常组比较 ,SARS组白细胞总数显著下降 ,淋巴细胞百分数和绝对数显著下降 ,粒细胞绝对数显著下降 ,CD3 、CD4 、CD8 细胞绝对数显著下降 ,CD4 细胞百分数 ,CD8 细胞百分数及CD4 /CD8 比值差异无统计学意义。比较SARS患者各病程CD3 、CD4 、CD8 ,于病程第一至第三周较第四周下降明显 (P <0 .0 5 ) ,病程第一至第三周之间差别无显著性 (P >0 .0 5 ) ;结论 :SARS患者外周血T淋巴细胞亚群的变化对阐明SARS的发病机制有一定意义。 相似文献
968.
一氧化氮和纤维结合蛋白在引导性骨缺损修复中的动态变化 总被引:2,自引:1,他引:1
目的:观察一氧化氮(NO)和纤维结合蛋白(FN)在引导性骨再生中的动态变化,探讨隔膜技术引导性骨再生促进骨缺损修复的作用机制.方法:新西兰兔20只,桡骨中段截骨10 mm制备标准骨缺损模型;实验组(10只)在缺损处填充自体血凝块,并用胶原膜包绕固定,对照组(10只)不作任何处理;于术前和术后1、2、4、6、8、10周时耳静脉取血,以改良Gress法检测NO含量,以火箭免疫电泳法检测FN含量.结果:实验组NO峰时较对照组后移,FN水平在峰值上明显高于对照组.结论:胶原膜引导性骨再生促进骨缺损修复机制与NO和FN的动态调控作用有关. 相似文献
969.
970.
激光穴位点射疗法对痛风急性期的疗效观察 总被引:9,自引:0,他引:9
杨惠琴 《中国中医骨伤科杂志》2006,14(1):18-20
目的:观察500MW激光风湿治疗机穴位点射治疗痛风急性期的疗效,探讨其作用原理。方法:痛风急性期患者48例,随机分为激光组和对照组,每组24例。激光组用输出波长为810 NM,功率为500 MW激光风湿治疗机,通过穴位点射方法治疗。对照组口服非甾体类消炎药。疗程均为3~7 d,观察患者关节疼痛肿胀情况及不良反应表现。结果:激光组疗效优于对照组,且毒副作用明显小于对照组。结论:激光穴位点射治疗对痛风急性期有良好的治疗作用,且无明显不良反应,患者依从性好。 相似文献