全文获取类型
收费全文 | 26386篇 |
免费 | 2081篇 |
国内免费 | 510篇 |
专业分类
耳鼻咽喉 | 440篇 |
儿科学 | 786篇 |
妇产科学 | 468篇 |
基础医学 | 2934篇 |
口腔科学 | 526篇 |
临床医学 | 2644篇 |
内科学 | 3955篇 |
皮肤病学 | 360篇 |
神经病学 | 2259篇 |
特种医学 | 1266篇 |
外国民族医学 | 1篇 |
外科学 | 2869篇 |
综合类 | 2547篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 3307篇 |
眼科学 | 900篇 |
药学 | 1201篇 |
9篇 | |
中国医学 | 777篇 |
肿瘤学 | 1723篇 |
出版年
2024年 | 65篇 |
2023年 | 570篇 |
2022年 | 1067篇 |
2021年 | 1485篇 |
2020年 | 1270篇 |
2019年 | 1284篇 |
2018年 | 1149篇 |
2017年 | 1033篇 |
2016年 | 935篇 |
2015年 | 840篇 |
2014年 | 1694篇 |
2013年 | 1920篇 |
2012年 | 1318篇 |
2011年 | 1448篇 |
2010年 | 1147篇 |
2009年 | 1134篇 |
2008年 | 1175篇 |
2007年 | 1181篇 |
2006年 | 949篇 |
2005年 | 864篇 |
2004年 | 717篇 |
2003年 | 676篇 |
2002年 | 555篇 |
2001年 | 462篇 |
2000年 | 369篇 |
1999年 | 359篇 |
1998年 | 332篇 |
1997年 | 308篇 |
1996年 | 242篇 |
1995年 | 239篇 |
1994年 | 215篇 |
1993年 | 195篇 |
1992年 | 172篇 |
1991年 | 136篇 |
1990年 | 130篇 |
1989年 | 128篇 |
1988年 | 106篇 |
1987年 | 128篇 |
1986年 | 112篇 |
1985年 | 142篇 |
1984年 | 121篇 |
1983年 | 101篇 |
1982年 | 99篇 |
1981年 | 83篇 |
1980年 | 68篇 |
1979年 | 68篇 |
1978年 | 44篇 |
1977年 | 40篇 |
1976年 | 18篇 |
1973年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Efficient high-frequency body coil for high-field MRI. 总被引:1,自引:0,他引:1
J T Vaughan G Adriany C J Snyder J Tian T Thiel L Bolinger H Liu L DelaBarre K Ugurbil 《Magnetic resonance in medicine》2004,52(4):851-859
The use of body coils is favored for homogeneous excitation, and such coils are often paired with surface coils or arrays for sensitive reception in many MRI applications. While the body coil's physical size and resultant electrical length make this circuit difficult to design for any field strength, recent efforts to build efficient body coils for applications at 3T and above have been especially challenging. To meet this challenge, we developed an efficient new transverse electromagnetic (TEM) body coil and demonstrated its use in human studies at field strengths up to 4 T. Head, body, and breast images were acquired within peak power constraints of <8 kW. Bench studies indicate that these body coils are feasible to 8 T. RF shimming was used to remove a high-field-related cardiac imaging artifact in these preliminary studies. P41RR13230 相似文献
62.
经皮椎体成形术治疗胸腰椎椎体转移癌的疗效观察 总被引:4,自引:0,他引:4
目的:观察经皮椎体成形术治疗胸腰椎椎体转移癌的效果。方法:对25例胸腰椎椎体转移癌患者的37个椎体在C型臂X线透视下经皮椎体穿刺并注入骨水泥成形,术后按疼痛缓解程度6级评定法及简明健康状况调查表(SF-36)对治疗后患者生活质量进行评估。结果:所有患者术后均未发生感染、脊髓压迫和肺栓塞等并发症。24例患者术后2~72h内疼痛得到不同程度缓解,1例多发脊柱严重破坏者术后疼痛无缓解,术后1周疼痛缓解优良率为72.0%。术后随访3~27个月,平均7个月,根据SF-36评分,患者总体生活质量评分由术前的平均232分提高到末次随访时的平均349分。结论:经皮椎体成形术治疗胸腰椎椎体转移癌安全可行,具有良好的止痛效果.能够有效改善患者的生活质量。 相似文献
63.
Abdulbari BENER Omer F. EL‐RUFAIE Saadat KAMRAN Ana B. GEORGIEVSKI Abdulaziz FAROOQ Martin RYSAVY 《International journal of rheumatic diseases》2006,9(3):257-263
Objective: The aim of this study was to determine the prevalence of low back pain (LBP) in a primary care setting population and examine its association with the symptoms of depression and somatization. Methods: This is a cross‐sectional study, utilising a survey carried out in primary health care clinics (PHCs) in Al‐Ain, United Arab Emirates (UAE). A multistage stratified sampling design was used and a representative sample of 1304 UAE nationals aged 18–65 years who attended PHC clinics for any reason were included and 1103 (84.5%) subjects agreed to participate and responded to the questionnaire during a period from June 2001 to January 2002. A specially designed questionnaire with three parts was used for the data collection: socio‐demographic information of the studied subjects, modified version of the Roland‐Morris scale for evaluating back‐related functional disability and SCL‐90 R for depression and somatization subscales was used to assess depressive and somatic symptoms. Results: Of the total number of subjects surveyed (1103), 586 (53.1%) were men and 517 (46.9%) women. The mean age was 34.9 ± 13.4 years for men and 33.5 ± 11.8 years for women. The prevalence of LBP in the studied subjects was 64.7% (95% CI, 60.7–68.5] with 46.7% among men and 53.3% among women. There were a significant differences between the subjects with LBP and without LBP with respect to gender (P < 0.001), body mass index (BMI) (P < 0.001), occupational status (P < 0.001) and living environment (P = 0.016). Functional disability was higher in patients with LBP. Young patients in aged 15–34 years, patients with preparatory/secondary educational level and students showed higher depressive symptoms. A similar pattern was found in patients with somatic symptoms. Factor analysis revealed a strong association between depression and somatization in LBP patients. Conclusions: Functional disability was higher in with LBP. Furthermore, symptoms of depression and somatization are prevalent among LBP patients. 相似文献
64.
出血性玻璃体混浊行玻璃体切除术后假性前房积脓分析 总被引:3,自引:0,他引:3
目的介绍一种发生于玻璃体切除术后的非感染性前房积脓现象,即假性前房积脓。方法收集我中心收治的需行玻璃体切除术的连续病例1250例,其中各种原因引起的玻璃体积血418例。术后发生假性前房积脓者7例,均为玻璃体积血者。主要治疗方法是前房冲洗及其自然吸收。结果假性前房积脓发生于术后3~5天,呈泥沙样沉积,局部抗生素及激素加强治疗无效。眼内穿刺行涂片、细菌和真菌培养未发现病原体。患者无疼痛等自觉症状及刺激征。随访时3例视力在0.05以上。结论玻璃体积血行玻璃体切除术后可能出现假性前房积脓,须与眼内感染相鉴别。 相似文献
65.
Maximal and submaximal oxygen uptake during running: how should body mass be accounted for? 总被引:1,自引:0,他引:1
J. Svedenhag 《Scandinavian journal of medicine & science in sports》1995,5(4):175-180
Oxygen uptake during running, i.e., the running economy, is an important factor in determining running performance in endurance events. The relation to performance is particularly strong when the aerobic running capacity is calculated, i.e., when running economy is related to the maximal oxygen uptake. There is considerable interindividual variation in running economy, and the reason for this is only partly understood. To some extent, this may be due to the way in which the oxygen uptake during running is usually expressed. This may expecially be true when subjects with different or changing body masses are compared. Several lines of evidence, including earlier animal studies as well as more recent human studies, favor the expression of submaximal and maximal oxygen uptake during running in terms of ml · kg−0.75 · min−1 rather than as ml · kg−1 · min−1. 相似文献
66.
目的:研究松果体和褪黑激素(Mel)是否通过下丘脑影响腹腔巨噬细胞功能.方法:松果体切除术;腹腔巨噬细胞化学发光测定;下丘脑地诺前列酮放射免疫测定;下丘脑注射Mel.结果:松果体切除后腹腔巨噬细胞化学发光值降低,下丘脑地诺前列酮含量升高,16:00 ip Mel(10 μg kg~(-1)d~(-1)×7d)可使其恢复,并升高正常大鼠腹腔巨噬细胞化学发光值,降低其下丘脑地诺前列酮含量.腹腔巨噬细胞化学发光值与下丘脑地诺前列酮含量的变化存在负相关(相关系数,r=-0.78,P<0.01).于下丘脑注射Mel 2μg,能提高正常大鼠和松果体切除大鼠腹腔巨噬细胞化学发光值.结论:下丘脑是松果体Mel影响腹腔巨噬细胞功能的主要作用部位之一. 相似文献
67.
妊娠期妇女的人体测量及脂肪贮存 总被引:1,自引:0,他引:1
本文对30名居住北京城近郊区的健康初产孕妇,于妊娠早期、中期及末期连续进行人体测量,包括身长,体重,皮下脂肪厚度和肢体围,以观察孕期体重增长,身体脂肪含量及肌肉情况。测量结果,受试者从妊娠6周至37周平均体重增长13.0kg。三头肌、二头肌部位皮脂厚度在孕期无明显变化。肩胛下皮脂厚度至孕末期时明显较早期增加。髂骨上皮脂厚度在孕中期及末期均有明显增长,与早期相比差別显著。据皮脂厚度计算身体密度及脂肪含量络果,至孕末期身体脂肪含量占体重的百分比共增加3.7%。肢体围测量结果,仅臀围在妊娠中期后至末期明显较早期增大。大腿上部围略有增加,但与早期差别无显著意义。大腿中部、小腿腓肠肌部及上臂围孕期均无明显变化。 相似文献
68.
Patrick M. Rao M.D. A. John Kuta M.D. Michele H. Johnson M.D. 《Emergency radiology》1995,2(5):303-304
We present a case in which an open fracture of the ulna penetrated the skull and caused a comminuted, depressed skull fracture
with a large intraparenchymal hematoma containing bone fragments. 相似文献
69.
Y. Spyckerelle B. Herbeth J.-P. Deschamps ‡ 《Journal of human nutrition and dietetics》1992,5(3):161-168
The dietary history method was used to determine the total energy and macronutrient intake, the distribution of daily energy from the different meals and the energy contribution of various food groups, in a population of 299 boys, aged between 10 and 15 years. The effects of age, the social status of the father (SPS), the ponderal index, the importance of breakfast or lunch, and the level of energy intake on dietary indicators, were studied. In our population, energy intake increased with increasing age but the energy contribution of macronutrients did not vary. The diet of boys whose fathers were in the upper SPS classes differed from the diet of those boys whose fathers were manual workers: for example they consumed less energy and pastries, but more animal protein (in percentage of energy intake), more dairy products, and more fruit. The ponderal index was negatively related to energy intake but positively related to protein intake, especially from meat and meat products. The energy intake from protein, animal protein and the energy contribution of dairy products, meat and meat products, fish and vegetables was lower among large eaters than among small eaters. The energy contribution of pastries, sugar and sweets was higher among large eaters.
Similarily, the energy intake from morning and evening snacks was also higher among large eaters. It should be noted that boys who had a substantial breakfast took in less energy from all other meals (including snacks and main meals). Such informaton is necessary in order to develop an effective health programme. 相似文献
Similarily, the energy intake from morning and evening snacks was also higher among large eaters. It should be noted that boys who had a substantial breakfast took in less energy from all other meals (including snacks and main meals). Such informaton is necessary in order to develop an effective health programme. 相似文献
70.
赖玉熔 《福建医科大学学报》1992,(1)
对20~25岁的健康学生进行肺功能测定,肺活量(VC)、第一秒时间肺活量(FEV_1)、最大通气量(MBC)存在性别差异;而中期流速(MMEF_(25~75%))和第一秒时间肺活量占用力肺活量的百分比(FEV_1/FVC)无显著性差异。以身高(X_1),体重(X_2)为自变量,VC,FEV_1,MBC分别为应变量进行多元回归分析,显示肺功能指标和身高、体重有密切的相关性(P<0.05)。按体育锻炼指标将机体的素质分为较好、中等、较差3组,计算其肺功能实测值占预计值124.3±11.2%,105.8±13.3%,84.9±11.8%。 相似文献