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   80883篇
  免费   5589篇
  国内免费   1692篇
耳鼻咽喉   895篇
儿科学   1545篇
妇产科学   1128篇
基础医学   5798篇
口腔科学   1874篇
临床医学   17401篇
内科学   11370篇
皮肤病学   383篇
神经病学   6472篇
特种医学   2284篇
外国民族医学   7篇
外科学   11386篇
综合类   9042篇
现状与发展   4篇
一般理论   4篇
预防医学   4132篇
眼科学   2757篇
药学   7392篇
  83篇
中国医学   3123篇
肿瘤学   1084篇
  2024年   204篇
  2023年   1646篇
  2022年   2593篇
  2021年   3704篇
  2020年   3529篇
  2019年   3323篇
  2018年   3216篇
  2017年   3023篇
  2016年   2813篇
  2015年   2681篇
  2014年   5412篇
  2013年   6531篇
  2012年   4089篇
  2011年   4622篇
  2010年   3542篇
  2009年   3467篇
  2008年   3779篇
  2007年   3528篇
  2006年   3190篇
  2005年   2600篇
  2004年   2277篇
  2003年   1875篇
  2002年   1633篇
  2001年   1507篇
  2000年   1194篇
  1999年   1114篇
  1998年   971篇
  1997年   977篇
  1996年   797篇
  1995年   817篇
  1994年   746篇
  1993年   646篇
  1992年   655篇
  1991年   566篇
  1990年   492篇
  1989年   454篇
  1988年   444篇
  1987年   414篇
  1986年   393篇
  1985年   442篇
  1984年   430篇
  1983年   272篇
  1982年   335篇
  1981年   265篇
  1980年   225篇
  1979年   190篇
  1978年   166篇
  1977年   95篇
  1976年   93篇
  1975年   59篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
高渗盐水与甘露醇对颅脑手术患者脑氧代谢的影响   总被引:2,自引:0,他引:2  
目的 比较3%高渗盐水(HTS)与20%甘露醇对颅脑手术患者脑氧代谢的影响。方法 择期大脑半球胶质瘤切除术患者40例,ASAⅠ级或Ⅱ级,随机分为2组(n=20):3%HTS组(HTS组)和20%甘露醇组(M组)。采用静吸复合麻醉,呼气末异氟醚浓度为1 MAC、血液动力学稳定15.min后,分别于15 min内静脉输注3%HTS 5.35 ml/kg或20%,甘露醇1 g/kg。L3,4珠网膜下腔置管测脑脊液压力(CSFP),行右颈静脉球穿刺置管、采血,测定颈静脉球氧饱和度。分别于输注前(T0)、输注完即刻(T1)、输注完15min(T2)、30min(T3)、60min(T4)、120min(T5)监测CSFP;于T0、T3-T5时监测平均动脉压,采集颈静脉球部和桡动脉血,进行血气分析,计算动脉-静脉氧含量差(Da-jvO2)、脑氧摄取率(CERO2)。结果 与T0比较,2组CSFP在T2-T5时降低,Da-jvO2和CERO2在T4,5时降低(P〈0.05);与M组比较,HTS组CSFP在T2时降低(P〈0.05)。结论 3%HTS与20%甘露醇均可有效地降低颅内压,改善颅脑手术患者的脑氧代谢。  相似文献   
102.
冰点下降法测定血、尿渗透压的临床应用及注意事项   总被引:1,自引:0,他引:1  
本文应用溶液冰点下降法测定了178例正常血清渗透压。结果为287±13毫渗量/kg水。并对20例尿崩症病人在限水加压素试验过程中测定血清,尿渗透压。尿崩症病人尿渗透压明显低于正常人。注射加压素后,尿渗透压升到正常。在多尿症的鉴别诊断中,此法是一种简便,灵敏的手段。有重要的诊断价值。  相似文献   
103.
A 70-year-old female presented with the clinical triad of normal pressure hydrocephalus (NPH) and senile tremor. Neuroimaging disclosed findings of both NPH and empty sella (ES). A ventriculoperitoneal shunt did not modify the clinical course except for a mild and transient improvement, and shunt malfunction occured later on. The association of NPH and ES may result from a common underlying mechanism such as transient increases in intracranial pressure.  相似文献   
104.
The aim of this article is to make the reader familiar with the history and current status of vulvodynia. The account is presented as a historical survey, from the seventies to the nineties. It explains how and why the term came to be defined, and how some sub-groups – in particular dysaesthetic vulvodynia and vulval vestibulitis – have been identified and described. Their management is discussed. The importance of distinguishing these conditions from those which are variants of normal is stressed.
It is noted that these sub-groups have much in common, so that a degree of convergence or overlap has come to be recognised. In parallel with this, ideas concerning aetiology and optimal management have been clarified and are explored.
Appreciation of the present state of affairs, and of how it has been arrived at, will help to improve management. It will also facilitate the collection of data, which in turn may lead to further research and understanding of vulvodynia.  相似文献   
105.
Abstract: In an experimental dog model of acute biventricular failure, the effects of left ventricular (LV) assist on renal hemodynamics and function were evaluated. After the induction of severe cardiac failure by multiple ligation of the coronary arteries, LV assist with a 40 ml pneumatic pulsatile pump was initiated, and the aortic flow was maintained at control values. The right atrial pressure (RAP) rose to 21.3 mm Hg with the appearance of profound right ventricular (RV) failure. Renal arterial blood flow (RAF) decreased to about 60% of the control value after 2 h of LV assist. The urine volume decreased and renal function deteriorated progressively. RV assist decreased the RAP to 4.8 mm Hg, and the reduced RAF recovered. After 3 h of RV assist, the RAF returned to initial values and the urine volume increased, but renal function did not recover. Advanced biventricular failure with elevated RAP during LV assist reduced renal perfusion and impaired renal function and may be an indication for early RV assist  相似文献   
106.
A clinical study was carried out on nonvital maxillary central incisors to evaluate the incidence of postoperative pain following single-visit root canal treatment using three different instrumentation techniques. Ninety teeth from 78 patients whose ages ranged from 14 to 63 years were selected and divided into three groups. Each group (30 teeth) was prepared by a different coronal-to-apical technique using different instrument movement depending upon the technique employed: modified double-flared, crown-downpressureless and balanced force techniques. No difference was observed in the incidence of postoperative pain among the groups.  相似文献   
107.
This study deals primarily with the stability of the base of the spine. The sacroiliac joints are vulnerable to shear loading on account of their predominantly flat surfaces. This raises the question of what mechanisms are brought into action to prevent dislocation of the sacroiliac joints when they are loaded by the weight of the upper part of the body and by trunk muscle forces. First a model is introduced to compare load transfer in joints with spherical and with flat joint surfaces. Next we consider a biomechanical model for the equilibrium of the sacrum under load, describing a self-bracing effect that protects the sacroiliac joints against shear according to ‘the sacroiliac joint compression theory’, which has been demonstrated in vitro. The model shows joint stability by the application of bending moments and the configuration of the pelvic arch. The model includes a large number of muscles (e.g. the gluteus maximus and piriformis muscles), ligaments (e.g. the sacrotuberous, sacrospinal, and dorsal and interosseous sacroiliac ligaments) as well as the coarse texture and the ridges and grooves of the joint surfaces.  相似文献   
108.
Lamotrigine in the treatment of painful diabetic neuropathy   总被引:1,自引:0,他引:1  
An open trial was conducted to study the potential efficacy of lamotrigine, a novel antiepileptic agent that blocks voltage-sensitive sodium channels and inhibits the release of glutamate, in relieving the pain associated with diabetic neuropathy. Subsequent to a 1 week washout period from previous analgesics, lamotrigine was administered at a dose of 25 mg/day for 1 week. The dose was doubled on a weekly basis up to 400 mg/day over 6 weeks. The McGill pain questionnaire (MPQ), spontaneous pain and a series of mechanical and thermal stimuli-induced pain were measured with the use of 0–100 visual analogue scale (VAS), on seven office visits. Pain level was also recorded by each patient twice daily, 1 week before, during, and 2 weeks after the treatment period with the use of a 0–10 numerical pain scale (NPS). Quantitative mechanical (Von Frey filaments) and thermal testing (QTT), and routine blood tests were performed at the beginning and at the end of the study. Thirteen patients completed the study. Spontaneous pain measured by VAS and NPS gradually dropped from a baseline of 49 ± 8 and 6.8 ± 0.6, to 20 ± 8.6 ( p < 0.001) and 4.3 ± 0.9 ( p < 0.001), respectively, at the end of the treatment period. Similarly, cold allodynia dropped from 38 ± 9.2 to 16 ± 15.3 ( p = 0.01), and the MPQ score from 13.6 ± 0.8 to 11.0 ± 1.5 ( p < 0.01). In contrast, no significant changes were found in the QTT, mechanical pain thresholds and laboratory results. Two patients were withdrawn from the study because of adverse effects. A long-term follow up showed that most patients were still using lamotrigine 6 months after the end of the study. The results of the study suggest that lamotrigine is potentially effective and safe in treating painful diabetic neuropathy.  相似文献   
109.
The effects of left- and right-sided hemispheric brain infarction on variability in circadian blood pressure and cardiovascular measures were investigated in 35 patients to test for asymmetry of the sympathetic consequences of stroke. No significant differences regarding age, size of infarction or extent and frequency of damage to the insular cortex could be detected between the two groups. Patients with right-sided infarction showed a significantly reduced circadian blood pressure variability [diastolic: -1% (95% CI -4 to 1) vs -6% (-9 to -2);P < 0.05] and a higher frequency of nocturnal blood pressure increase (47% vs 35%;P < 0.05) as compared with patients with left-sided infarction. Right-sided infarction was also associated with higher serum noradrenaline concentrations [546 pg/ml (95% CI 415–677) vs 405 pg/ml (266–544);P < 0.05], and ECG more frequently showed QT prolongation (53% vs 35%;P < 0.05) and cardiac arrhythmias (67% vs 20%;P < 0.005). However, irrespective of the hemisphere damaged, patients with insular infarction showed the most pronounced changes of these parameters. In addition, two patients with right-sided strokes (13%) involving the insula, but none with a left-sided infarction, developed myocardial infarction. These findings suggest lateralization of sympathetic activation with right-sided dominance for sympathetic effects following hemispheric stroke.Supported by the Friedrich-Schiedel-Stiftung  相似文献   
110.
The purpose of this study was to assess, in subjects with low back pain, the changes and their permanence in muscular performance after a 3 month progressive physical exercise program. Ninety subjects with chronic low back pain participated in the study. The study design was controlled and it was carried out in three groups: intensive training, home exercise, and control group. Isometric and dynamic muscle strength of the trunk and lower limb were measured, at the beginning of the study and after the 3 months exercise program, and then during each of the follow-up sessions. The Oswestry Index and back pain intensity were also determined. Both exercise groups received benefit from the progressive exercise program. Their muscular performance improved and their back pain intensity decreased significantly. Among the home exercise group, the Oswestry Index also changed positively. The results demonstrate that the home exercise program could be as effective as the intensive training program in increasing muscle strength, as well as decreasing back pain and functional disability among low back pain patients with mild functional limitations.  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