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   36450篇
  免费   3637篇
  国内免费   811篇
耳鼻咽喉   1261篇
儿科学   884篇
妇产科学   325篇
基础医学   5179篇
口腔科学   916篇
临床医学   4285篇
内科学   5356篇
皮肤病学   183篇
神经病学   5021篇
特种医学   1677篇
外国民族医学   4篇
外科学   2367篇
综合类   4105篇
现状与发展   2篇
一般理论   2篇
预防医学   3087篇
眼科学   536篇
药学   3224篇
  39篇
中国医学   1359篇
肿瘤学   1086篇
  2024年   135篇
  2023年   755篇
  2022年   1193篇
  2021年   1910篇
  2020年   1902篇
  2019年   1615篇
  2018年   1578篇
  2017年   1643篇
  2016年   1447篇
  2015年   1414篇
  2014年   2434篇
  2013年   2473篇
  2012年   2011篇
  2011年   2100篇
  2010年   1872篇
  2009年   1753篇
  2008年   1696篇
  2007年   1598篇
  2006年   1437篇
  2005年   1157篇
  2004年   1014篇
  2003年   879篇
  2002年   795篇
  2001年   574篇
  2000年   534篇
  1999年   516篇
  1998年   417篇
  1997年   337篇
  1996年   285篇
  1995年   296篇
  1994年   265篇
  1993年   235篇
  1992年   237篇
  1991年   183篇
  1990年   187篇
  1989年   179篇
  1988年   161篇
  1987年   138篇
  1986年   137篇
  1985年   186篇
  1984年   184篇
  1983年   157篇
  1982年   155篇
  1981年   152篇
  1980年   139篇
  1979年   92篇
  1978年   75篇
  1977年   56篇
  1976年   51篇
  1975年   35篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
.学者论坛·在动物实验中解决临床难题···························,·······································································……顾玉东(3)基因〕:程  相似文献   
52.
黄海 《右江医学》2002,30(6):469-470
目的 :探讨胃癌穿孔的临床特点 ,指导临床诊治和提高疗效。方法 :对本院 2 4例胃癌穿孔病人采用不同手术方式治疗。其中 8例行单纯修补术 ,2例在穿孔修补术后 3周早期施行二期根治性手术 ,3例行穿孔修补加胃空肠吻合术 ,7例行姑息性胃大部切除术 ,4例行胃癌根治术。结果 :本组死亡 4例 ,其余病例中位生存期分别为 7,13 .2 ,2 5 .1个月。结论 :采取积极的治疗措施 ,可望延长患者的生存时间和提高生存质量  相似文献   
53.
A discrete time optimal control for linear time-delay systems is developed to ensure that all closed-loop eigenvalues will lie inside a circular region centred at (β;, 0) with radius α. It is shown that by suitable manipulations the problem can be reduced to a standard discrete time quadratic regulator problem. An illustrative example is included to demonstrate the applicability of the proposed method.  相似文献   
54.
Ocular autonomic function was assessed in 4 patients with progressive autonomic failure (PAF) and age-matched control subjects, by measurement of the pupil cycle time, and determination of autonomic denervation hypersensitivity of the iris. Pupil cycle time was abnormal in all patients with PAF; sustained pupil cycling was absent in 5 of the 8 eyes tested of the PAF patients, compared with only 16 eyes from 70 control subjects. Pupil constriction in response to 2.5% methacholine, indicative of parasympathetic denervation hypersensitivity, was significantly increased in patients with PAF (p < 0.001), whilst pupil dilation in response to 0.5% phenylephrine, indicative of sympathetic denervation hypersensitivity, was also significantly higher in the PAF patients (p < 0.001). The results suggest that ocular autonomic function may provide a sensitive early indicator of generalised autonomic dysfunction.  相似文献   
55.
While the benefits of training manuals can hardly be questioned, they are exceedingly limited in reducing variability attributed to the "therapist factor." We propose that manuals provide a useful outline of the general principles of a therapeutic approach, but can only reduce therapist variability at the expense of other essential therapeutic phenomena. Manuals cannot adequately convey, for example, how the effective therapist functions as a model of adult living and as a person who provides guidance. We suggest that such an experience cannot readily be packaged in manualized form, though manuals may serve as a useful beginning. Recommendations for therapist manualized training include greater attention to the subtleties of human relationships and adequately conveying that any technique is effective only when catalysed by a living, relational process.  相似文献   
56.
Summary Schizophrenics are known to have various disturbances of the visuomotor system. Whereas smooth pursuit eye movement disorders have been repeatedly confirmed, there are relatively few reports regarding possible disturbances of the saccadic system. In this study, the saccadic reaction times of 47 schizophrenic inpatients were investigated upon admission and later in the remitted state; 28 age- and sex-matched normal volunteers were tested as controls. Psychopathology and outcome were evaluated according to the Brief Psychiatric Rating Scale and the Prognostic Scale. Light stimuli were presented at random direction, location (ranging from 0° to 20°) and duration (800, 1000, and 1200 ms). The eye movements were recorded by electro-oculography. Compared with the control group, schizophrenics revealed prolonged saccadic reaction times, which correlated with pronounced negative symptoms and an unfavourable course of the illness. The saccadic reaction times remained prolonged in schizophrenic patients. These findings suggest attentional deficits in schizophrenics.This article was presented in part at the Symposium on Eye Movements and Psychopathology, Berlin, 23–24 June 1988  相似文献   
57.
阻塞性睡眠呼吸暂停综合征相关高血压病的临床特点   总被引:4,自引:0,他引:4  
探讨阻塞性睡眠呼吸暂停综合征相关性高血压病 (obstructive sleep apnea associated hypertension,OSAAHT)的临床特点。对照分析 2 4例 OSAAHT和年龄及病期相匹配的 2 2例原发性高血压病患者 ,比较症状、体重指数、治疗前睡眠前后血压变化及 2 4h血压动态监测等指标。结果发现 OSAAHT患者白天明显过度困倦 ,睡眠监测呼吸紊乱指数 (AHI)为 (4 5 .1± 15 .3)次 / h,体重指数高于对照组 [(2 7.9± 2 .5 ) kg/ m2比 (2 3.9± 1.7) kg/ m2 ,P<0 .0 1]。OSAAHT睡前血压 (137.1± 10 .5 ) / (88.4± 6 .6 ) mm Hg,清晨血压 (15 5 .9± 14.4) / (10 1.8± 4.9) m m Hg;原发性高血压病组睡前血压 (149.2± 12 .5 ) / (91.7± 6 .2 ) mm Hg,清晨血压 (140 .7± 9.4) / (83.4± 5 .9) mm Hg;两组睡前收缩压及清晨收缩压和舒张压均有差异 ,P<0 .0 1。OSAAHT夜间血压下降率明显小于原发性高血压病对照组[(13.3± 4.9) %比 (4 .5± 1.6 ) % ,P<0 .0 1]。提示 OSAAHT除了睡眠呼吸障碍外 ,还具有以下临床特点 :清晨睡醒时血压较高 ,夜间血压下降幅度变小 ,白天过度困倦以及肥胖等  相似文献   
58.
In a large study on 1,220 patients with ovarian carcinoma in FIGO stages I-IV, the prognostic importance of the time factor for start of postoperative chemotherapy was studied together with other important factors for long-term survival. The patient series was a total geographic material of ovarian carcinoma patients treated during the years 1975-1993. All patients were followed up for 10 years or until death. The 5-year cancer-specific survival rate of the complete series was 50%. Significant and independent prognostic factors with regard to long-term cancer-specific survival were FIGO stage, histology, tumor grade, and completeness of the primary surgery. Special attention was paid to the prognostic importance of the time interval between primary surgery and the first course of chemotherapy. Patient groups with intervals shorter or longer than the median value were compared. In early-stage disease, no significant difference was noted. In advanced and bulky disease, an interval longer than the median value seemed to be beneficial compared with a shorter interval. However, after correction for other prognostic factors, the interval was not a significant factor (P = 0.647) with regard to the cancer-specific survival rate. Therefore, the time factor should not be an important argument for how to best organize the gynecologic oncology service.  相似文献   
59.
目的:探讨运用DSA设备作吞咽功能检查的价值。材料和方法:用DSA设备对正常组24例,咽异感症患者32例,做上至颅底、下达第七颈椎平面的正侧位动态采集,了解吞咽状况,并行咽传输时间测定,进行对照研究。结果:正常对照组咽传输时间为1.441±0.302s,咽异感症患者咽传输时间为1.367±0.409s,两组结果相比统计学上无显著差异,但后者较易发生咽部钡剂滞留等改变。结论:DSA机由于采集速度快,不但在心血管检查及介入治疗方面有重要意义,而且在非血管性脏器的动力学检查中也起着一定的作用。由于能完整记录钡剂通过咽部的全过程,故此方法是吞咽功能检查的良好方法之一。  相似文献   
60.
Blood velocity is a functional parameter that is not easily assessed noninvasively, especially in small animals. A new noninvasive method that uses magnetic resonance angiography (MRA) to measure blood flows is proposed. This method is based on the time-of-flight (TOF) phenomenon. By initially suppressing the signal from the stationary spins in the area of interest, it is possible to sequentially visualize only the signal from the moving spins entering a given volume. With this method, 3D cine images of the blood flow can be generated by positive contrast, with unparalleled spatial (<200 microm) and temporal resolutions (<10 ms/image). As a result, it is possible to measure flow in sinuous paths. The present method was applied in vivo to measure the blood velocity in mouse carotid arteries. Because of its robustness and simplicity of implementation, this method has numerous potential applications for fundamental studies in small animal models.  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