首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5726篇
  免费   507篇
  国内免费   98篇
耳鼻咽喉   112篇
儿科学   20篇
妇产科学   30篇
基础医学   630篇
口腔科学   351篇
临床医学   499篇
内科学   250篇
皮肤病学   24篇
神经病学   237篇
特种医学   498篇
外科学   989篇
综合类   747篇
预防医学   161篇
眼科学   1323篇
药学   252篇
  3篇
中国医学   122篇
肿瘤学   83篇
  2024年   18篇
  2023年   120篇
  2022年   213篇
  2021年   326篇
  2020年   274篇
  2019年   253篇
  2018年   293篇
  2017年   229篇
  2016年   245篇
  2015年   218篇
  2014年   392篇
  2013年   404篇
  2012年   330篇
  2011年   341篇
  2010年   309篇
  2009年   272篇
  2008年   247篇
  2007年   280篇
  2006年   220篇
  2005年   192篇
  2004年   144篇
  2003年   128篇
  2002年   119篇
  2001年   107篇
  2000年   76篇
  1999年   74篇
  1998年   66篇
  1997年   46篇
  1996年   44篇
  1995年   35篇
  1994年   26篇
  1993年   29篇
  1992年   25篇
  1991年   29篇
  1990年   26篇
  1989年   21篇
  1988年   19篇
  1987年   17篇
  1986年   10篇
  1985年   18篇
  1984年   18篇
  1983年   10篇
  1982年   13篇
  1981年   19篇
  1980年   11篇
  1979年   6篇
  1978年   6篇
  1977年   3篇
  1976年   5篇
  1975年   3篇
排序方式: 共有6331条查询结果,搜索用时 15 毫秒
41.
目的:下颌角肥大有多种式术可选,对于低角型下颌角肥大,往往一种式术很难达到满意的矫治效果,本文选择了一组低角型下颌角肥大患者,来研究下颌角截骨术与下颌角外板矢状劈开术联合应用治疗低角型下颌角肥大的治疗效果。方法:选择本科室2005年8月~2005年11月间治疗的24例低角型下颌角肥大患者,完善术前检查与分析。在全麻下应用下颌角截骨术与下颌角外板矢状劈开术进行联合矫治。术后观察治疗效果,并在8周后对所有患者进行随访,调查患者满意度。结果:所有24例患者矫治后Ⅰ期愈合,所有患者下颌角角度增大,两下颌角间宽度明显减小,达到了下颌角的正常美学标准。8周后随访,所有患者均对治疗效果表示满意。结论:下颌角截骨术与下颌角外板矢状劈开术联合应用,可有效地矫治低角型下颌角肥大,使患者下颌角达到一个理想的美学标准。  相似文献   
42.
Drug-induced secondary angle closure is quite common and in the majority of cases simply stopping the medication leads to rapid reversal of the condition and resolution of glaucoma. We describe here a patient who presented with secondary angle closure glaucoma and myopia following mefenamic acid ingestion which was managed successfully by stopping the medication, symptomatic treatment and reassurance.  相似文献   
43.
目的:下颌角截骨是面型轮廓重塑中最常见的一种手术,为了提高手术的精确性,避免不必要的损伤,我们对各种下颌角截骨术操作技巧进行探讨.方法:术前进行面部测量、下颌骨曲面断层X线和头颅正侧位定位X线片投影测量,设计截骨线和去骨量,术式选择口内切口下颌角截骨术、口内切口下颌角外板矢状劈开截骨术、耳后切口下颌角截骨术、耳后和口内联合切口下颌角截骨术;结果:面下部过宽同时下颌角肥大者单纯下颌角截骨效果往往不会很理想,需要同时进行下颌角外侧骨板部分去除,减少面下部的宽度,206例术后两侧对称,效果良好;1例面瘫;2例下颌骨骨折,术中做内固定;3例下颌骨体部成角,3个月后第二手术将突出部分磨平.结论:术前测量设计下颌角截骨的术式和截骨线是十分必要的,根据下颌角肥大的不同类型选择相适应的截骨术式.  相似文献   
44.
Summary In 50 rats, different types of end-to-side carotid artery anastomoses were compared. In one technique, a longitudinal split in the long axis of the vessel was performed to enhance the diameter of the anastomosis. This theoretical advantage was not confirmed in this series. The clamping time, anastomoses time, and tamponade time were increased significantly when compared with a simple, slightly oblique end-to-side anastomosis. This study highlighted that the most simple type of end-to-side anastomosis gave less bleeding, achieved a quicker water-tight anastomosis and decreased the risk of late problems.  相似文献   
45.
本文报道在B超监护下经母腹作脐静脉穿刺取胎血33例,其中30例咨询孕妇作产前诊断,3例中孕引产。成功率为93.9%。孕龄与穿刺命中率,胎盘位置与穿刺命中率均不相关(P>0.05及P>0.05)。手术最佳时间是孕24周前后。手术并发症有胎心率变慢(或快),胎盘渗血,脐带渗血,脐血管空气栓塞等。但未发生死胎、流产、胎膜早破及感染。胎血的脆性X(fra(x))表达率较高,但脆性X并不复制。本法有可能成为fra(x)综合征的一种快速,可靠,安全,经济的产前诊断新方法。  相似文献   
46.
目的:探讨骨盆多发性骨折各部位的摄影角度及影像显示的原理及方法,优势与不足以及临床应用价值。方法:首先选择骨髂标本做研究对象进行不同角度的摄影,并选择了最佳摄影角度及方法,进行了30例患者的摄片,均符合临床诊断要求。结果:骨盆多发性骨折的各部位最适宜的摄影角度。骨盆入口位,摄影角度向头侧倾斜25°位;骨盆出口位,摄影角度向足侧倾斜25°位;髂骨及闭孔斜位,一侧抬高25°位,影像显示效果较佳,优于有关报导的摄影角度及方法。结论:对外伤性骨盆多发骨折的患者,各部位摄影角度上述所示,此方法可行,完全符合临床诊断要求。  相似文献   
47.
目的探讨下颌骨侧位摄影分别采用一倾斜角度为α的垫板及未采用时,X线中心线倾斜角度各为β、γ之间的关系,为更简捷地拍好下颌骨提供理论参数和实践依据。方法立足于教科书,运用X线摄影原则与数学几何原理进行推理演绎。结果二者之间存在着可替换的关系,即γ=α+β,可以大胆地去除垫板进行直接拍摄。结论不用垫板,只需通过增大X线中心线倾斜角度的方法,同样也能拍摄出一张好照片,且可操作性强,简便易行,实际使用价值更大。  相似文献   
48.
The solid-state nuclear magnetic resonance (NMR) technique of carbon-13 cross-polarization/magic angle spinning (CP/MAS) has been successfully used to obtain high-resolution spectra of whole-thickness, hairy rat skin and to characterize the influence of hydration on the efficiency of cross-polarization and the proton spin-lattice relaxation time in the rotating frame (T1H). Spectra obtained with hydrated samples, which were obtained with 50% more accumulations, had comparable signal-to-noise ratio relative to spectra obtained with dried skin, indicating a disordering effect with the presence of water. The integrated area of spectra of low-shifted peaks rose more rapidly with increasing contact time relative to the high-shifted peaks for both hydrated and dried skin. In addition, the carbonyl intensity of the hydrated skin relative to dried skin reached a maximum at shorter times, reflecting an efficient relaxation mechanism of the protons. The shift of the peak maximum to shorter mixing times quantitatively reflects the interaction of the protons of water with the carbonyl moiety.  相似文献   
49.
The study objectives were to compare in vitro transportability and physical properties of respiratory mucus, obtained invasively by direct collection (DC) right after endotracheal intubation and non-invasively by sputum induction with 3% hypertonic saline solution inhalation (SI) 24 h before the anesthesia. Twenty-two patients with no pulmonary disease scheduled for elective abdominal surgical procedures were studied. The parameters analyzed and the main results are as follows. (1) Transportability by cilia (MCT), SI was higher than DC (0.94+/-0.25 and 0.62+/-0.25; P<0.001). There was a significant correlation between the two methods and DC could be estimated by: DC=0.21+(0.44 SI) (r=0.44; P<0.001). (2) Transportability by cough (CC), SI was higher than DC (68.23+/-32.1 and 33.58+/-19.04 mm; P=0.002). (3) Contact angle (CA), SI was lower than DC (10+/-3 degrees and 22+/-14 degrees ; P=0.025). (4) Rheological properties (no significant difference obtained between SI and DC). These results indicated that SI changes mucus physical properties and transportability in non-expectorators.  相似文献   
50.
The effects of the local blood circulation and absolute torque on muscle endurance at different knee-joint angles were determined. The rate of muscle deoxygenation (using near-infrared spectroscopy), and the rate of muscle fatigue (using the slope of integrated electromyography, iEMG) were evaluated concurrently. Nine healthy subjects performed submaximal (50% maximal voluntary contraction, MVC) static knee extension at 50° (extended position, EXT) and 90° (flexed position, FLEX) joint angles until the target torque could no longer be maintained: that time was measured as the endurance time. They exercised with the circulation occluded (OCCL), and without (FREE) to study the possible effects of the local circulation. Although MVC torque was independent of joint angle [mean (SD) FLEX 250.6 (51.7) N·m and EXT 246.5 (46.6) N·m], significantly shorter (P<0.01) endurance time in FLEX [FREE 71.1 (10) s and OCCL 63.1 (8.8) s] than at EXT [FREE 115.3 (30) s and OCCL 106.7 (29.1) s] were obtained in both circulatory conditions. The iEMG-time slope was significantly greater in FLEX at the proximal and distal portion (P<0.05) in both circulatory conditions. Muscle deoxygenation rate in OCCL was significantly greater (P<0.05) at FLEX [20.8 (8.0)%] than EXT [10.9 (4.0)%]. The results would suggest that different knee-joint angle affects muscle endurance even if the local circulation is controlled. Circulatory disturbance would further reduce muscle endurance in EXT, but not in FLEX. Because of the greater muscle internal force in FLEX, local blood flow might be already limited even with a free circulation. The greater muscle deoxygenation and muscle fatigability would be related to the shorter muscle endurance in FLEX. Electronic Publication  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号