全文获取类型
收费全文 | 60315篇 |
免费 | 5795篇 |
国内免费 | 3374篇 |
专业分类
耳鼻咽喉 | 511篇 |
儿科学 | 872篇 |
妇产科学 | 1004篇 |
基础医学 | 6985篇 |
口腔科学 | 1077篇 |
临床医学 | 7051篇 |
内科学 | 9647篇 |
皮肤病学 | 733篇 |
神经病学 | 2882篇 |
特种医学 | 2517篇 |
外国民族医学 | 34篇 |
外科学 | 7275篇 |
综合类 | 9031篇 |
现状与发展 | 15篇 |
一般理论 | 16篇 |
预防医学 | 3851篇 |
眼科学 | 1482篇 |
药学 | 6454篇 |
51篇 | |
中国医学 | 3071篇 |
肿瘤学 | 4925篇 |
出版年
2024年 | 132篇 |
2023年 | 765篇 |
2022年 | 1602篇 |
2021年 | 2842篇 |
2020年 | 2045篇 |
2019年 | 1881篇 |
2018年 | 2019篇 |
2017年 | 1802篇 |
2016年 | 1790篇 |
2015年 | 2486篇 |
2014年 | 3148篇 |
2013年 | 3169篇 |
2012年 | 4448篇 |
2011年 | 4722篇 |
2010年 | 3065篇 |
2009年 | 2511篇 |
2008年 | 3360篇 |
2007年 | 3422篇 |
2006年 | 3170篇 |
2005年 | 2957篇 |
2004年 | 2390篇 |
2003年 | 2208篇 |
2002年 | 1999篇 |
2001年 | 1664篇 |
2000年 | 1596篇 |
1999年 | 1440篇 |
1998年 | 771篇 |
1997年 | 777篇 |
1996年 | 630篇 |
1995年 | 530篇 |
1994年 | 463篇 |
1993年 | 313篇 |
1992年 | 506篇 |
1991年 | 412篇 |
1990年 | 388篇 |
1989年 | 345篇 |
1988年 | 274篇 |
1987年 | 252篇 |
1986年 | 202篇 |
1985年 | 160篇 |
1984年 | 117篇 |
1983年 | 84篇 |
1982年 | 60篇 |
1981年 | 73篇 |
1980年 | 39篇 |
1979年 | 72篇 |
1978年 | 37篇 |
1974年 | 36篇 |
1973年 | 33篇 |
1972年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
Purpose: To investigate the relationships between the axonal sprouting and target neurotization by central neurons after nerve heterocon-nection. Methods: Unilateral (right) vagal-hypoglossal nerve anastomosis (VHA) was performed in adult cats. Following 3-315 days postoperation (dpo), quantitative analyses and ultrastructural changes in the proximal portion of the vagal-hypoglossal heteroconnected nerve as well as the time course of neuronal regeneration were studied. Along with this, horseradish peroxidase (HRP) retrograde tracing technique was used to label the neurons of dorsal motor vagal nucleus (DMV) and nucleus ambiguus (NA) to ascertain if target neurotization was established. Results: The contralateral (left) intact vagus nerve proximal to the level of ansa cervicalis showed an average of 33 +/- 1 myelinated and 74 +/- 4 unmyelinated axons in 727 &mgr;m(2) sectional area of the nerve. In the heteroconnected nerve at the corresponding level just proximal to the anastomosis site, there was a marked increase in the number of small axons sprouting from the unmyelinated nerve fibers between 18 and 25 dpo. The number of these axonal sprouts appeared to decline at 32 dpo but its increase of 131 % was sustained until the late regeneration stage at 315 dpo when compared with the contralateral nerve serving as a control. The mean number of myelinated axons per area unit (727 &mgr;m(2)) was reduced to 18 at 3 dpo but was immediately restored to the normal range at 7 dpo. The retrograde labelling of neurons in both the DMV and NA was first detected at 22 dpo and was progressively increased peaking by about 67 dpo. Conclusions: We conclude that compared with the unmyelinated axons, the myelinated axons may acquire a superior interaction with the new target. Furthermore, the postoperative neurotization of tongue muscles may initiate and facilitate the retraction of the redundant axonal sprouts. 相似文献
992.
993.
Intravenous amiodarone for prevention of atrial fibrillation after coronary artery bypass grafting 总被引:6,自引:0,他引:6
Lee SH Chang CM Lu MJ Lee RJ Cheng JJ Hung CR Chen SA 《The Annals of thoracic surgery》2000,70(1):157-161
BACKGROUND: Atrial fibrillation occurs in 10% to 40% of patients who undergo coronary artery bypass grafting. This prospective study assesses the safety and efficacy of low-dose intravenous amiodarone in the prevention of atrial fibrillation after coronary artery bypass grafting. METHODS: One hundred forty patients were randomly divided into two groups: an amiodarone group (n = 74) receiving intravenous amiadarone in a loading dose of 150 mg and maintenance dose of 0.4 mg x kg(-1) x h(-1) for 3 days before and 5 days after operation and a control group (n = 76) receiving matching infusions of 5% glucose solution. RESULTS: Atrial fibrillation occurred in 9 (12%) of the amiodarone group patients and in 26 (34%) of the control group patients during hospitalization (p < 0.01). The maximum ventricular rate during atrial fibrillation was significantly slower in the amiodarone group (107 +/- 21) than in the control group (138 +/- 24 beats per minute, p < 0.01). The duration of atrial fibrillation in the amiodarone group (1.1 +/- 1.2 hours) was significantly shorter than that in the control group (3.2 +/- 1.3 hours, p = 0.01). The two groups had no significant differences in incidence of major morbidity (8 of 74 versus 8 of 76 in amiodarone and control groups, respectively) or mortality (4 of 74 versus 5 of 76). However, the control group had significantly longer intensive care unit stays (132 +/- 24 versus 111 +/- 19 hours, p < 0.01). CONCLUSIONS: Perioperative low-dose intravenous amiodarone significantly reduces the incidence, ventricular rate, and duration of atrial fibrillation after coronary artery bypass grafting. Furthermore, low-dose intravenous amiodarone is well tolerated and does not increase the risk of intraoperative or postoperative complications. 相似文献
994.
995.
Khan SS Siegel RJ DeRobertis MA Blanche CE Kass RM Cheng W Fontana GP Trento A 《The Annals of thoracic surgery》2000,69(2):531-535
BACKGROUND: The purpose of this study was to determine whether significant regression of left ventricular hypertrophy is seen after implantation of small sizes (19 to 23 mm) of the Carpentier-Edwards (CE) pericardial valve, a stented pericardial valve. METHODS: Echocardiograms and electrocardiograms (ECGs) were performed at least 1 year after surgery (mean 18 months) in patients with 19-, 21-, and 23-mm CE pericardial aortic valves and compared with preoperative echocardiograms and ECGs. RESULTS: A total of 41 patients, mean age 79 +/- 9 years (range 46 to 93 years), were studied, including 7 19-mm, 22 21-mm, and 12 23-mm patients. The mean postoperative gradient was 22 +/- 7 mm Hg for 19-mm valves, 18 +/- 5 mm Hg for 21-mm valves, and 16 +/- 4 mm Hg for 23-mm valves. The postoperative valve areas were 1.1 +/- 0.3 cm2 for the 19-mm, 1.3 +/- 0.3 cm2 for the 21-mm, and 1.5 +/- 0.4 cm2 for the 23-mm valves. Left ventricular end diastolic diameter, end systolic diameter, septal thickness, and posterior wall thickness all decreased significantly (p <0.05) postoperatively. The proportion of patients with significant left ventricular hypertrophy on ECG decreased from 63% to 47% (p = 0.001). Left ventricular mass decreased significantly by echocardiography from 265 g preoperatively to 208 g postoperatively (p = 0.004). Left ventricular mass decreased for each valve size, and the greatest absolute reduction in mass occurred in the 19-mm valve recipients. CONCLUSIONS: Implantation of the 19-, 21-, and 23-mm CE pericardial valves results in significant reductions in left ventricular mass. These findings suggest that stented pericardial valves can be used in the small aortic root without the need for aortic root enlargement procedures. 相似文献
996.
997.
ACE基因多态性与2型糖尿病肾病的相关性研究 总被引:2,自引:0,他引:2
目的 探讨血管紧张素Ⅰ转换酶(ACE)基因的插入/缺失多态性与2型糖尿病(type 2 diabetes mellitus,T2DM)患合并肾病的关系。方法采用聚合酶链反应技术检测109例T2DM患(其中合并肾病患37例,未发生肾病患72例)和260例健康对照组ACE基因插入/缺失多态性。结果糖尿病肾病患的DD基因型频率和D等位基因频率有高于无肾病糖尿病患组的趋势,其频率差异接近显性水准(75.7%vs55.6%,P=0.070;87.8%vs77.1%,P=0.057)。DD基因型糖尿病患合并肾病的频率高于其他基因型,差异有统计学意义(41.2%vs22.0%,P=0.040)。对糖尿病病程与ACE基因多态性的交互作用分析发现,DD基因型与5年以上病程存在交互作用(OR=3.75,95%CI;1.019~13.795)。结论ACE基因的DD基因型可增高T2DM患并发肾病的危险性,并且与糖尿病病程有交互作用。 相似文献
998.
武汉市海洛因依赖者流行病学回顾性调查 总被引:3,自引:0,他引:3
目的:了解武汉市海洛因依赖者的流行病学变化。方法:回顾性调查研究2002年-2004年3a在湖北省各戒毒所收治的武汉市户籍海洛因依赖者的社会人口学特征及滥用情况。结果:(1)人口学特征比较:3a来女性吸毒人口所占比例明显上升(P<0.01),无业人员所占比例逐年加大(P<0.01);(2)毒品滥用情况比较:3a来吸毒年限、戒毒次数和静脉注射滥用方式比例逐年增加(P均<0.01)。结论:武汉市常住居民中海洛因滥用形势仍相当严峻,禁毒工作仍需加强。且应加强在吸毒群体中的宣教工作。 相似文献
999.
目的:探索社区康复训练与劳动教养相结合的康复模式对男性海洛因依赖者的治疗效果。方法:以湖南省新开铺劳教大队的50名劳教吸毒人员为对照,对戒毒中心的50名劳教吸毒人员进行为期至少4个月的康复训练。康复训练以海洛因依赖者的需求、所处的康复阶段及接受能力为中心,包括强化戒毒治疗动机、减少吸毒造成的危害、复吸预防等各种技能训练。用成瘾严重度指数和应付方式问卷评估康复训练的疗效,并随访两组在解教后1 a的康复情况。结果:康复训练后海洛因依赖者幻想、退避、自责等不成熟型应付方式分值下降(P<0.01),求助的分值增加(P<0.01)。解教后1 a康复组与劳动教养组的戒断率差异无显著性,但康复训练组在海洛因滥用严重程度、违法犯罪行为和精神健康方面损害显著低于劳动教养组(P<0.05)。结论:劳动教养和社区康复训练都是对吸毒者有效的康复措施,康复训练的作用更大。 相似文献
1000.
国产盐酸舍曲林胶囊和片剂的人体药物动力学及生物等效性 总被引:2,自引:0,他引:2
目的研究国产盐酸舍曲林胶囊及片剂的相对生物利用度、药物动力学特征及生物等效性.方法采用随机、开放、3×3拉丁方设计实验,18名男性健康受试者分别单剂量口服含舍曲林50 mg的试验片剂、胶囊及参比制剂.采用HPLC-MS/MS/MS法测定给药后不同时间的血药浓度,计算3者的药物动力学参数及评价其生物等效性.结果 18例健康志愿者口服参比制剂和试验制剂舍曲林胶囊及片剂后,参比制剂中舍曲林的主要药物动力学参数cmax为(10.14±3.43)μg·L-1;tmax为(4.44±1.10)h;AUC0~96为(262.82±100.66)μg·h·L-1;t1/2为(29.19±4.91)h.试验制剂片剂中舍曲林的主要药物动力学参数cmax为(10.16±3.22)μg·L-1;tmax为(4.33±1.85)h;AUC0~96为(269.71±107.47)μg·h·L-1;t1/2为(30.99±6.49)h.试验制剂胶囊中舍曲林的主要药物动力学参数cmax为(10.39±3.59)μg·L-1;tmax为(4.94±1.30)h;AUC0~96为(264.45±112.57)μg·h·L-1;t1/2为(29.68±5.25)h.试验制剂片剂和胶囊分别对参比制剂的相对生物利用度F为(103.4%±18.2%)、(99.8%±13.6%).结论经统计学分析,国产试验制剂胶囊剂和片剂与参比制剂具有生物等效性. 相似文献