全文获取类型
收费全文 | 42849篇 |
免费 | 3904篇 |
国内免费 | 1603篇 |
专业分类
耳鼻咽喉 | 556篇 |
儿科学 | 812篇 |
妇产科学 | 384篇 |
基础医学 | 3583篇 |
口腔科学 | 965篇 |
临床医学 | 4582篇 |
内科学 | 5524篇 |
皮肤病学 | 688篇 |
神经病学 | 1917篇 |
特种医学 | 1966篇 |
外国民族医学 | 10篇 |
外科学 | 4542篇 |
综合类 | 8108篇 |
现状与发展 | 4篇 |
一般理论 | 2篇 |
预防医学 | 4543篇 |
眼科学 | 508篇 |
药学 | 4261篇 |
32篇 | |
中国医学 | 2912篇 |
肿瘤学 | 2457篇 |
出版年
2024年 | 138篇 |
2023年 | 375篇 |
2022年 | 1014篇 |
2021年 | 1308篇 |
2020年 | 1053篇 |
2019年 | 691篇 |
2018年 | 753篇 |
2017年 | 995篇 |
2016年 | 876篇 |
2015年 | 1404篇 |
2014年 | 1769篇 |
2013年 | 2225篇 |
2012年 | 3278篇 |
2011年 | 3489篇 |
2010年 | 2875篇 |
2009年 | 2547篇 |
2008年 | 2853篇 |
2007年 | 2780篇 |
2006年 | 2558篇 |
2005年 | 2194篇 |
2004年 | 1697篇 |
2003年 | 1433篇 |
2002年 | 1274篇 |
2001年 | 1210篇 |
2000年 | 1058篇 |
1999年 | 696篇 |
1998年 | 246篇 |
1997年 | 200篇 |
1996年 | 180篇 |
1995年 | 151篇 |
1994年 | 154篇 |
1993年 | 154篇 |
1992年 | 351篇 |
1991年 | 312篇 |
1990年 | 335篇 |
1989年 | 302篇 |
1988年 | 269篇 |
1987年 | 259篇 |
1986年 | 237篇 |
1985年 | 228篇 |
1984年 | 193篇 |
1983年 | 162篇 |
1982年 | 110篇 |
1979年 | 156篇 |
1978年 | 115篇 |
1975年 | 108篇 |
1974年 | 105篇 |
1973年 | 100篇 |
1970年 | 96篇 |
1969年 | 94篇 |
排序方式: 共有10000条查询结果,搜索用时 515 毫秒
61.
伴ADHD的对立违抗性障碍儿童行为特征分析 总被引:6,自引:0,他引:6
目的:了解伴注意缺陷/多动障碍(ADHD)的对立违抗性障碍(0DD)患儿的行为特征。方法:以ICD-10作为诊断标准对门诊就诊儿童进行诊断,得到ODD伴ADHD者40例(64.52%).ODD不伴ADHD者22例(35.48%)。自编家庭情况调查表调查患儿的基本情况。用家长填Achenbach儿章行为量表评定儿童行为。结果:与ODD组相比。合并ADHD组的家长更多对患儿经常打骂和严厉管教:对儿童的不良行为更多地采取打骂的方式。合并组父亲急燥易怒者比ODD组多;合并组起病年龄及就诊年龄比ODD组早:合并组在CBCI。思维、注意问题,违纪、攻击行为,外化性问题,行为总分均高于ODD组。结论:ODD合并ADHD的患儿在思维、注意问题,违纪、攻击行为,外化性问题方面表现更突出,家长对儿童管教方式及不良行为处理方式影响ODD的发生。提示要注重ODD、ADHD的早期干预。 相似文献
62.
自体表皮细胞培养与异体真皮组合应用研究 总被引:13,自引:0,他引:13
严重烧伤病人皮肤修复中主要未解决的问题是真皮的替代。动物实验结果表明,异体皮移植后5天,用自体培养表皮细胞膜片覆盖真皮床,14天后复合皮成活率是84.6%±2.4%。组织学检查证实表皮已形成了复层结构,可见基底层、颗粒层和角质层。临床应用中,异体皮移植后10天,去除异体表皮覆盖病人的自体培养表皮,35天后未见排斥征象,异体真皮促进了培养表皮的分层、成熟和完整,组织学检查证实表皮细胞的边缘清楚,已分化形成颗粒层和角质层,真皮多细胞,已血管化,但表皮嵴缺乏。 相似文献
63.
Sufentanil and vecuronium are commonly used simultaneously in anaesthesia. Bradycardia and asystole have been described immediately after the administration of these two compounds. Therefore, the purpose of the present study was to evaluate the direct cardiac effects of sufentanil and vecuronium in all parts of the cardiac pacemaker and conduction system.
The electrophysiological effects of sufentanil and vecuronium were studied in isolated spontaneously beating guinea-pig hearts perfused by the method of Langendorff. At a concentration of 0.1 μmol/1 sufentanil a significant reduction of the spontaneous sinus rate, prolongation of atrioventricular, intraventricular and His' bundle conduction could be observed. The highest concentration of 10 μmol/1 of sufentanil led to an overall slowing of conduction velocity and to an profound slowing of spontaneous sinus rate. AV nodal as well as atrial and ventricular refractoriness were markedly prolonged at this high concentration of sufentanil. In contrast, during perfusion with vecuronium at a concentration of 0.1 μmol/1 up to 10 μmol/1 no significant effects on cardiac conduction and pacemaker activity could be observed.
In conclusion, the electrophysiological effects of sufentanil are comparable to that of unspecific calcium antagonists. Therefore, especially in patients with a preexisting damage of the cardiac conduction system, the indirect effect of the combination of sufentanil and vecuronium which is predominantly responsible for bradycardia and asystole may be worsened by the direct effects of sufentanil. 相似文献
The electrophysiological effects of sufentanil and vecuronium were studied in isolated spontaneously beating guinea-pig hearts perfused by the method of Langendorff. At a concentration of 0.1 μmol/1 sufentanil a significant reduction of the spontaneous sinus rate, prolongation of atrioventricular, intraventricular and His' bundle conduction could be observed. The highest concentration of 10 μmol/1 of sufentanil led to an overall slowing of conduction velocity and to an profound slowing of spontaneous sinus rate. AV nodal as well as atrial and ventricular refractoriness were markedly prolonged at this high concentration of sufentanil. In contrast, during perfusion with vecuronium at a concentration of 0.1 μmol/1 up to 10 μmol/1 no significant effects on cardiac conduction and pacemaker activity could be observed.
In conclusion, the electrophysiological effects of sufentanil are comparable to that of unspecific calcium antagonists. Therefore, especially in patients with a preexisting damage of the cardiac conduction system, the indirect effect of the combination of sufentanil and vecuronium which is predominantly responsible for bradycardia and asystole may be worsened by the direct effects of sufentanil. 相似文献
64.
Background - A case of primary thyroid T cell lymphoma leading to lethal tracheal perforation during chemotherapy is described. 相似文献
65.
目的:研究重组人内皮细胞衍生的白细胞介素-8(IL8)对失血性休克的作用.方法:大鼠股动脉放血至MABP532kPa,维持90min,复制晚期失血性休克模型.输血后,静脉注射IL8250μg·kg-1.放免法测定血浆ET1和6KPGF1α含量.结果:给予IL8后,MABP显著提高,休克状态改善,2h存活率相应提高;休克晚期血浆ET1水平比正常明显升高(21±4vs82±18ng·L-1,P<001),血浆6KPGF1α含量明显降低(107±12vs157±11ng·L-1,P<001).IL8显著降低血浆ET1水平(10±4ng·L-1,P<001),提高血浆6KPGF1α含量(368±16ng·L-1,P<001).结论:IL8具有较好的抗休克作用. 相似文献
66.
Hypochlorite has been used as a disinfectant for more than 100 years. It has many of the properties of an ideal disinfectant, including a broad antimicrobial activity, rapid bactericidal action, reasonable persistence in treated potable water, ease of use, solubility in water, relative stability, relative nontoxicity at use concentrations, no poisonous residuals, no color, no staining, and low cost. The active species is undissociated hypochlorous acid (HOCl). Hypochlorites are lethal to most microbes, although viruses and vegetative bacteria are more susceptible than endospore-forming bacteria, fungi, and protozoa. Activity is reduced by the presence of heavy metal ions, a biofilm, organic material, low temperature, low pH, or UV radiation. Clinical uses in health-care facilities include hyperchlorination of potable water to prevent Legionella colonization, chlorination of water distribution systems used in hemodialysis centers, cleaning of environmental surfaces, disinfection of laundry, local use to decontaminate blood spills, disinfection of equipment, decontamination of medical waste prior to disposal, and dental therapy. Despite the increasing availability of other disinfectants, hypochlorites continue to find wide use in hospitals. 相似文献
67.
Long-term survival in an infant with urethral atresia 总被引:2,自引:0,他引:2
Complete urethral atresia is an anomaly that previously was incompatible with life. We report on a surviving infant with this anomaly. As a fetus urinary decompression was accomplished with a vesicoamniotic shunt. Peritoneal dialysis was initiated shortly after birth and at 9 months supramembranous scrotal inlay urethroplasty was performed to provide for egress of urine from the bladder. A maternal renal allograft was performed when he was 12 months old. When the patient was 3 1/2 years old he had normal renal function and emptied the bladder to completion through the reconstructed urethra. Although mildly delayed, he continues to progress with all developmental milestones. 相似文献
68.
The role of CD4+ helper T cells in the destruction of microencapsulated islet xenografts in nod mice 总被引:4,自引:0,他引:4
C J Weber S Zabinski T Koschitzky L Wicker R Rajotte V D'Agati L Peterson J Norton K Reemtsma 《Transplantation》1990,49(2):396-404
Islet transplants for large numbers of patients with diabetes will require xenografts. Microencapsulation is an appealing method for islet xenografting. However, graft function has been limited by a cellular reaction, particularly intense in spontaneously diabetic, NOD mice. The purpose of this study was to elucidate the mechanism of this reaction. Poly-1-lysine-alginate microcapsules containing 4000-12,000 dog or 1800-2000 rat islets were xenografted intraperitoneally into streptozotocin (SZN)-diabetic C57BL/6J and NOD mice, with or without recipient treatment with GK 1.5 (anti-CD4 monoclonal antibody) (20-30 microliters i.p. every 5 days, begun on day -7. Grafts were considered technically successful if random blood glucose (BG) was normalized (less than 150 mg/dl) within 36 hr. Graft failure was defined as BG greater than 250 mg/dl. Dog and rat islets in microcapsules normalized BG in both SZN and NOD mice within 24 hr routinely. Empty microcapsules and GK 1.5 treatments alone did not affect BG. NODs destroyed both microencapsulated dog and rat islets more rapidly than did SZN-diabetic mice (P less than .01). Graft biopsies showed an intense cellular reaction, composed of lymphocytes, macrophages and giant cells, and no viable islets. GK 1.5 treatment significantly prolonged both dog-to-NOD and rat-to-NOD grafts (P less than 0.01). Biopsies of long-term functioning grafts (on days 65-85) demonstrated viable islets and no cellular reaction around microcapsules; 1/4 rat and 1/8 dog islet xenografts continued to function indefinitely in NOD recipients, even after cessation of GK 1.5 therapy. Prediabetic NODs receiving encapsulated dog or rat islets mounted a moderate cellular reaction to grafts. Empty microcapsules excited no cellular reaction in diabetic or prediabetic NODs. We conclude that the NOD reaction to microencapsulated xenogeneic islets is helper T cell-dependent, and that the target of this reaction is not the microcapsule itself, but the donor cells within. 相似文献
69.
70.
花生四烯酸和二十二碳六烯酸对海马神经细胞生长发育的影响 总被引:2,自引:0,他引:2
【目的】观察不同浓度花生四烯酸 (AA)和 (或 )二十二碳六烯酸 (DHA)对体外培养海马神经细胞生长发育的影响。【方法】无血清培养液中分别加入不同剂量的AA和 (或 )DHA ,采用噻唑蓝比色试验 (MTT法 )反映各组海马神经细胞存活状况 ,神经元特异性烯醇化酶 (NSE)染色鉴定神经细胞 ,图像分析技术测量神经细胞的胞体大小和突起长度。【结果】培养液中分别添加AA为 4~ 8μmol/L、DHA为 2~ 8μmol/L时 ,神经细胞活力高于对照组 ;当培养液中AA和DHA总浓度为 4μmol/L、比例为 2∶1或 4∶1时 ,神经细胞的活力、胞体面积、最大长径、最大短径和平均突起长度均显著高于单一添加 4μmol/LAA、4μmol/LDHA和对照组。【结论】AA、DHA均具有促进体外培养海马神经细胞生长发育的作用 ;与单独添加AA、DHA相比 ,AA和DHA共同作用的促海马神经细胞生长发育作用更好。 相似文献