全文获取类型
收费全文 | 86040篇 |
免费 | 7266篇 |
国内免费 | 5410篇 |
专业分类
耳鼻咽喉 | 1015篇 |
儿科学 | 855篇 |
妇产科学 | 688篇 |
基础医学 | 8999篇 |
口腔科学 | 1243篇 |
临床医学 | 9275篇 |
内科学 | 11682篇 |
皮肤病学 | 951篇 |
神经病学 | 3719篇 |
特种医学 | 3935篇 |
外国民族医学 | 19篇 |
外科学 | 10907篇 |
综合类 | 16686篇 |
现状与发展 | 14篇 |
一般理论 | 5篇 |
预防医学 | 6274篇 |
眼科学 | 1815篇 |
药学 | 8915篇 |
72篇 | |
中国医学 | 5073篇 |
肿瘤学 | 6574篇 |
出版年
2024年 | 221篇 |
2023年 | 981篇 |
2022年 | 2481篇 |
2021年 | 3438篇 |
2020年 | 2638篇 |
2019年 | 2277篇 |
2018年 | 2478篇 |
2017年 | 2418篇 |
2016年 | 2463篇 |
2015年 | 3749篇 |
2014年 | 4756篇 |
2013年 | 4994篇 |
2012年 | 7354篇 |
2011年 | 7648篇 |
2010年 | 5762篇 |
2009年 | 4942篇 |
2008年 | 5721篇 |
2007年 | 5530篇 |
2006年 | 5166篇 |
2005年 | 4470篇 |
2004年 | 3376篇 |
2003年 | 3289篇 |
2002年 | 2888篇 |
2001年 | 2170篇 |
2000年 | 1621篇 |
1999年 | 1142篇 |
1998年 | 727篇 |
1997年 | 698篇 |
1996年 | 555篇 |
1995年 | 473篇 |
1994年 | 347篇 |
1993年 | 229篇 |
1992年 | 265篇 |
1991年 | 264篇 |
1990年 | 195篇 |
1989年 | 184篇 |
1988年 | 164篇 |
1987年 | 148篇 |
1986年 | 133篇 |
1985年 | 96篇 |
1984年 | 42篇 |
1983年 | 40篇 |
1982年 | 27篇 |
1981年 | 25篇 |
1980年 | 18篇 |
1979年 | 20篇 |
1978年 | 18篇 |
1977年 | 10篇 |
1975年 | 10篇 |
1974年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Kevin O'Brien Jean Wright Frances Conboy YeWeng Sanjie Nicky Mandall Stephen Chadwick Ivan Connolly Paul Cook David Birnie Mark Hammond Nigel Harradine David Lewis Cathy McDade Laura Mitchell Alison Murray Julian O'Neill Mike Read Stephen Robinson Dai Roberts-Harry Jonathan Sandler Ian Shaw 《American journal of orthodontics and dentofacial orthopedics》2003,124(3):234-43; quiz 339
This study evaluated the effectiveness of early orthodontic treatment with the Twin-block appliance for the developing Class II Division 1 malocclusion. This multicenter trial was carried out in the United Kingdom. A total of 174 children, aged 8 to 10 years old, with Class II Division 1 malocclusion were randomly allocated to receive treatment with a Twin-block appliance or to an untreated, control group. Data were collected at the start of the study and 15 months later. Results showed that early treatment with Twin-block appliances resulted in reduction of overjet, correction of molar relationships, and reduction in severity of malocclusion. Most of this correction was due to dentoalveolar change, but some was due to favorable skeletal change. Early treatment with the Twin-block appliance is effective in reducing overjet and severity of malocclusion. The small change in the skeletal relationship might not be considered clinically significant. 相似文献
82.
目的比较强化胰岛素治疗的2型糖尿病患者在脱离胰岛素治疗和继续胰岛素治疗时的临床特点,分析脱离胰岛素的相关因素。方法统计66例入院的2型糖尿病患者的患病时间,检测开始胰岛素强化治疗、治疗过程、治疗结束时的糖化血红蛋白(HbA1 c)、体重指数(BM I)、胰岛素用量,观察脱离胰岛素所需时间。结果34例患者脱离胰岛素治疗,32例继续治疗,两组患者在年龄、治疗开始时间、BM I、HbA1 c差异均无统计学意义,而患病时间比较差异有统计学意义(P<0.05),脱离时的胰岛素用量和HbA1 c比继续治疗患者显著减低(P<0.01)。结论患病时间长短是胰岛素脱离与否的重要因素,胰岛素投入量及HbA1 c数值对脱离胰岛素与否有积极作用。 相似文献
83.
胫骨平台解剖型钢板的结构特点及临床运用 总被引:6,自引:0,他引:6
目的探讨解剖型钢板治疗胫骨平台骨折的结构特点。方法2001年1月-2003年12月,应用解剖型钢板治疗胫骨平台骨折34例,其中男20例,女14例;年龄23~54岁,平均38.7岁。结果34例均获得随访,随访时间8~28个月,平均19个月。术后1个月膝关节屈曲70°~120°,平均90.2°;术后3个月膝关节屈曲90°~135°,平均110.3°;术后半年膝关节屈曲100°~135°,平均125.0°。按Merchant评分,终末随访时优18例,良12例,可4例。术后无切口皮肤坏死、感染和钢板松动及断裂。结论解剖钢板治疗胫骨平台骨折效果满意,其三维结构符合胫骨平台解剖特点,可以提供持续坚强的固定,有利术后膝关节早期活动,骨折愈合率高,并发症少。 相似文献
84.
Ji Young Kim Helen Shinn Young Jun Oh Yong Woo Hong Hyun Jeong Kwak Young Lan Kwak 《European journal of cardio-thoracic surgery》2006,29(3):343-347
OBJECTIVE: Redistribution hypothermia adversely affects hemodynamics and postoperative recovery in patients undergoing cardiac surgery. In off-pump coronary bypass surgery (OPCAB), maintaining the temperature is important because warming by cardiopulmonary bypass is omitted. Pre-warming studies reported earlier showing pre-warming as an effective means of preventing redistribution hypothermia was time consuming since it required at least 1-2h to pre-warm the patients before the surgery. Because pre-warming for such a long time is impractical in clinical practice, this study evaluated the efficacy of active warming during the preanesthetic period for the prevention of redistribution hypothermia in the early operative period of OPCAB. METHODS: After gaining the approval of Institutional Review Board and informed consent from the patients, 40 patients undergoing OPCAB were divided into control and pre-warming groups. The patients in control group (n=20) were managed with warm mattresses and cotton blankets, whereas patients in pre-warming group (n=20) were actively warmed with a forced-air warming device before the induction of anesthesia. Hemodynamic variables and temperature were recorded before anesthesia (Tpre) and at 30 min intervals after anesthesia for 90 min (T30, T60, and T90). RESULTS: Active warming duration was 49.7+/-9.9 min. There were no statistically significant differences in skin temperature, core temperature and hemodynamic variables between the two groups at preinduction period except for mean arterial pressure and central venous pressure. The core temperature at T30, T60, and T90 was statistically higher in pre-warming group than that in control group. Core temperature of six (30%) and seven patients (35%) in control group was reduced below 35 degrees C at T60 and T90, respectively, whereas core temperature of only one patient (5%) in pre-warming group was reduced below 35 degrees C at T90 (P=0.02). CONCLUSIONS: Active warming using forced air blanket before the induction of anesthesia reduced the incidence and degree of redistribution hypothermia in patients undergoing OPCAB. It is a simple method with reasonable cost, which does not delay the induction of anesthesia nor the surgery. 相似文献
85.
The role of MHC class Ⅱ transactivator (CⅡTA) in constitutive or IFN-γ inducib|e expression of HLA molecules in human malignant hematological cell lines was investigated. The expression of HLA molecules and CⅡTA protein was detected by Western blot, immunohistochemistry and flow cytometry. The expression of CⅡTA gene was determined by RT-PCR. The capability of peripheral blood T cell reaction stimulated by tumor cells was monitored by mixed lymphocyte reaction. It was found that the HLA Ⅱ-positive tumor cells expressed the CⅡTA quite well, andthe expression of HLA Ⅰ+Ⅱ was increased in the tumor cells with constitutive or inducible expression of CⅡTA after induced by IFN-γ. The tumor cells which did not express CⅡTA after in-duced by IFN-γ were not response to the expression of HLA Ⅱ promoted by IFN-γ. It suggests a correlation between the inability of some malignant hematological cell lines in response to IFN-γ for HLA expression and the deficiency in the inducible expression of CⅡTA, indicating CⅡTA might take part in the regu|ation of HLA Ⅰ+Ⅱ expression in the tumor cells, which might p|ay an important role in tumor immunologic escape. 相似文献
86.
重组耻垢分枝杆菌-Sj26GST疫苗的免疫保护作用研究 总被引:1,自引:1,他引:0
目的初步研究重组耻垢分枝杆菌疫苗rMc-Sj26GST(recombinant M.smegmatis mc2155-Sj26GST)对小鼠的免疫保护作用.方法用耻垢分枝杆菌重组疫苗rMc-Sj26GST免疫雄性BALB/c小鼠,检测小鼠淋巴细胞刺激指数(SI),腹腔巨噬细胞培养上清释放NO量,小鼠血清IFN-γ、IL-2的含量,并计数小鼠肝、肺活细菌数.结果小鼠脾淋巴细胞刺激指数(SI)为2.64±1.37,与Mc组(载体组)1.28±0.41相比,差异具有显著性;小鼠血清IFN-γ为196.43 pg*ml-1,与Mc组112.57 pg*ml-1相比,差异有显著性,较对照组高41%;小鼠血清中IL-2的浓度较对照组高.经rMc-Sj26GST疫苗免疫的小鼠受结核杆菌攻击后其肺、肝脏结核杆菌数较对照组少.结论耻垢分枝杆菌重组疫苗rMc-Sj26GST增强了小鼠细胞免疫功能,并使小鼠能抵抗结核杆菌的攻击. 相似文献
87.
目的克隆和鉴定日本血吸虫磷酸丙糖异构酶(SjTPI)编码基因,为寻找血吸虫病的候选疫苗联合应用打基础.方法设计合成引物,抽提日本血吸虫成虫总RNA,用RT-PCR法从中扩增出SjTPI基因编码序列,将其克隆入pGEM-T载体,用双酶切、以重组质粒为模板进行PCR扩增和测序进行鉴定.结果 RT-PCR法从成虫总RNA中扩增出大小为759 bp SjTPI基因编码序列,重组质粒pGEM-SjTPI经双酶切、PCR扩增,均可获得一条与RT-PCR产物一致的DNA片段,序列测定结果表明具有一个长度为759 bp的完整开放阅读框,与日本血吸虫(菲律宾株)和曼氏血吸虫磷酸丙糖异构酶核苷酸序列有高度同源性(分别为99%和88%).结论该实验成功地克隆了SjTPI编码基因,为进一步研究提供了条件. 相似文献
88.
目的 探讨富氧对高原人体运动心力储备方面的影响。方法 对海拔 3 70 0m高原的 1 2名健康青年富氧 (氧浓度为 2 4%~ 2 5 %)前后分别进行踏阶运动 ,采用心力监护仪采集和记录心动周期和心力信息 ,把完成规定运动量运动后第一心音 (S1 )幅值对安静时S1 幅值增加的相应倍数评估心肌收缩能力储备指数 (CCRI) ;利用舒张期和收缩期时限数据计算舒张期 /收缩期比值 (D/S比 )。结果 运动后较安静时HR ,D/S ,S1 幅值均增高 ,有非常显著性差异 (P <0 .0 1 ) ;富氧运动较未富氧运动CCRI,D/S ,S1 幅值增高 ,有显著性差异 (P <0 .0 5 ) ,HR无统计学意义 (P >0 .0 5 )。结论 高原低氧环境下心脏储备主要是心肌收缩能力储备而不是心率储备。富氧对增强机体心力储备具有重要作用 相似文献
89.
Jai Hoon Yoon Yoon Kyung Park Byong Kwan Sohn Yong Chul Jeon Joo Hyun Sohn Dong Soo Han 《Taehan Sohwagi Hakhoe chi》2007,49(1):41-44
Torsion of greater omentum is a rare cause of acute abdomen. However, it should be included in the differential diagnoses in addition to acute cholecystitis, acute appendicitis, cecal diverticulitis, and other variable causes of acute abdomen. Diagnosis is usually made at laparotomy for suspected appendicitis. In some cases, computed tomography demonstrates a successful preoperative detection of omental torsion. We report a case of surgically and pathologically proven torsion with subsequent infarction of greater omentum presented as an acute abdominal pain. 相似文献
90.
蟾毒灵抗小鼠原位移植性肝癌整体药效学研究 总被引:5,自引:0,他引:5
目的 探讨蟾毒灵对小鼠原位移植性肝癌的抗肿瘤作用。方法 建立肝原位移植瘤模型。随机分为 5组 ,每组 15只 ,蟾毒灵 3组分别给予 1.5、1.0、0 .5mg/kg体重 ,腹腔注射 ;生理盐水 (NS)组给予等体积的生理盐水 ,用法同蟾毒灵组 ;阿霉素 (ADM )组按 8mg/kg体重给药。用药后第 11天每组分别处死 10只荷瘤鼠 ,测量肿瘤大小 ,取瘤组织行病理学检查和瘤细胞超微结构观察。剩余各组观察带瘤生存期。结果 蟾毒灵组肿瘤大小均较NS组明显缩小 (P <0 .0 1) ;中、大剂量的蟾毒灵组带瘤生存期较NS组明显延长 (P <0 .0 5 ,P <0 .0 1)。大、中剂量的蟾毒灵瘤组织以中重度坏死为主 ,小剂量以轻中度坏死为主。电镜下大、中剂量蟾毒灵组可见肿瘤细胞凋亡征象。结论 蟾毒灵对小鼠原位移植性肝癌有显著的抗肿瘤作用 ,诱导肿瘤细胞凋亡可能是蟾毒灵的抗肿瘤机理之一。 相似文献