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   20635篇
  免费   1199篇
  国内免费   189篇
耳鼻咽喉   135篇
儿科学   1199篇
妇产科学   295篇
基础医学   2501篇
口腔科学   377篇
临床医学   1255篇
内科学   3554篇
皮肤病学   413篇
神经病学   1302篇
特种医学   790篇
外国民族医学   5篇
外科学   2824篇
综合类   815篇
一般理论   1篇
预防医学   1429篇
眼科学   1067篇
药学   2064篇
  5篇
中国医学   308篇
肿瘤学   1684篇
  2022年   225篇
  2021年   422篇
  2020年   276篇
  2019年   302篇
  2018年   371篇
  2017年   297篇
  2016年   374篇
  2015年   419篇
  2014年   600篇
  2013年   797篇
  2012年   1132篇
  2011年   1138篇
  2010年   690篇
  2009年   564篇
  2008年   942篇
  2007年   953篇
  2006年   898篇
  2005年   851篇
  2004年   762篇
  2003年   770篇
  2002年   716篇
  2001年   626篇
  2000年   642篇
  1999年   587篇
  1998年   277篇
  1997年   246篇
  1996年   216篇
  1995年   196篇
  1994年   165篇
  1993年   176篇
  1992年   368篇
  1991年   393篇
  1990年   352篇
  1989年   401篇
  1988年   308篇
  1987年   314篇
  1986年   258篇
  1985年   275篇
  1984年   239篇
  1983年   212篇
  1982年   137篇
  1981年   127篇
  1980年   117篇
  1979年   187篇
  1978年   127篇
  1975年   136篇
  1974年   144篇
  1973年   136篇
  1972年   123篇
  1971年   142篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
131.
本文报道23例颈椎病手术患者采用1%普鲁卡因与2%利多卡因混合液局麻加静脉哌替啶强化取得满意的效果。文中围绕呼吸管理问题对前、后手术入路的麻醉用药、输血、补液及头部固定等注意事项均作了具体介绍。  相似文献   
132.
BACKGROUND: Acquired Brown syndrome is known to occur after trauma, iatrogenic events, cysts of superior oblique muscle tendon, and inflammation. The purpose of this study is to report a large series of patients with acquired Brown syndrome secondary to superior oblique muscle cysticercosis and to discuss its management. METHODS: Retrospective analysis was performed of clinical and imaging features, management, and outcome in seven patients with cysticercosis of the superior oblique muscle presenting clinically as Brown syndrome. RESULTS: Seven patients were identified (five male and two female) ranging in age from 6 to 45 years. All patients had the ocular motility limitation, ie, limitation of elevation in adduction., characteristic of Brown syndrome. This was associated with pain and swelling in the superior nasal orbit. Diagnosis was established by observing the cysticercus cyst with scolex on imaging (ultrasound B scan, magnetic resonance imaging, and/or computed tomography). Oral albendazole (15 mg/kg) and oral prednisolone (1mg/kg) were given for 4 weeks, and the patients were followed up for 1 year. Clinical recovery with improvement of ocular motility and regression of imaging features was noted in all patients. CONCLUSIONS: Acquired Brown syndrome secondary to superior oblique muscle cysticercosis is a rare entity. Awareness of this condition, which leads to early diagnosis and institution of prompt medical treatment, results in a successful clinical outcome.  相似文献   
133.
134.
Cardiac injuries--a clinical and autopsy profile   总被引:3,自引:0,他引:3  
One hundred two patients sustaining cardiac injuries over a 4-year period were analysed to highlight the natural history of the cardiac injuries. There were 45 blunt, 36 stab, and 21 gunshot injuries. The injury involved the ventricle in 85, atrium in seven, pulmonary artery in five cases, and resulted in crush injury to the heart in the remaining five cases. Thirty-three patients (32.3%) died on the scene and 58 (56.9%) died during the transportation. Only 11 patients (10.8%) reached the hospital alive, and ten of these patients survived following thoracotomy and repair of the cardiac injury. The factors influencing the natural course of cardiac injury were analysed: 2.2% of patients with blunt cardiac trauma reached the hospital alive compared to 19.4% with stab and 14.3% with gunshot injuries; ventricular injuries had a greater prehospital mortality compared to atrial or pulmonary artery injuries; 11.3% of patients sustaining injury to right ventricle reached the hospital alive compared to 3% of those with left ventricular injuries. These data emphasize the need for rapid transport, immediate recognition, and aggressive surgical management, to make a favourable impact on the natural history of cardiac injuries.  相似文献   
135.
136.
The mechanism of the twitch potentiating action of pumiliotoxin-B (PTX-B), an indolizidine alkaloid from the skin of the frog Dendrobates pumilio, was studied on frog skeletal muscles. In the presence of PTX-B, a single stimulus to the muscle produced either a burst of repetitive action potentials superimposed on a depolarizing afterpotential or a single potential with a prolonged afterpotential at junctional as well as extrajunctional regions of the frog skeletal muscle fibers. The alkaloid did not cause repetitive activity in quiescent cells or spontaneous contractions. The duration of the burst of action potentials was related inversely and the amplitude and duration of postburst depolarizing after-potential was related directly to the concentration of PTX-B. The typical pattern of repetitive action potentials and postburst depolarization induced by PTX-B could be mimicked by depolarizing the muscle membrane with current pulses of long duration (150-470 ms). Lowering the external calcium or sodium concentration reduced the ability of PTX-B to initiate repetitive action potentials, whereas a low external chloride concentration had no effect. The frequency of MEPPs evoked by potassium, but not the spontaneous MEPP frequency, was increased by PTX-B, suggesting a selective effect on evoked transmitter release. PTX-B evoked repetitive EPPs in response to a single stimulus applied to the nerve, which was dependent upon the external calcium ion concentration. The amplitudes of EPPs in the train were facilitated, and their amplitude increased linearly at the lowest calcium concentration, but not at concentrations from 0.45 to 1.8 mM.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
137.
Levels of brain creatine kinase (CK), aspartate aminotransferase (ASAT), and lactate dehydrogenase (LD) in CSF after cardiac arrest were studied in dog models. Ventricular fibrillation cardiac arrest lasting 10 min or asphyxiation cardiac arrest lasting 0-10 min was followed by cardiopulmonary resuscitation and 96-h intensive care. Outcome was scored as neurologic deficit (0% = normal, 100% = brain death) and overall performance category (1 = normal, 5 = death). Both measures correlated with EEG return time after asphyxiation cardiac arrest, but not after ventricular fibrillation cardiac arrest. Peak activity of enzymes in CSF at 48-72 h post arrest correlated with outcome, and CK was the best predictor. Brain histopathologic damage score at autopsy 96 h post arrest correlated with CK level in CSF (r = 0.79, n = 39) and neurologic deficit (r = 0.70, n = 50). Ischemic neuronal changes occurred after ventricular fibrillation cardiac arrest of 10 min, and neuronal changes plus microinfarcts occurred after asphyxiation cardiac arrest of 1.5-10 min. Brain enzymes were decreased at 6 h post arrest in regions with worst histologic damage (gray matter of neocortex, hippocampus, caudate nucleus, cerebellum). Brain CK decreased further, ASAT remained low, and LD increased at 72 h after arrest. The temporal changes in CK level paralleled the temporal ischemic neuronal changes in the brain, and time to peak activity was unaffected by the severity of the ischemic insult. Peak activity of individual enzymes in CSF was determined predominantly by the brain concentration, but was also influenced by rate of decomposition. This "chemical brain biopsy method" represents a useful adjunctive tool to predict permanent, severe brain damage during comatose states after cardiac arrest and resuscitation.  相似文献   
138.
A new iridoid glucoside, 5-deoxypulchelloside I, along with the three known iridoid glucosides, phlomiol, lamiid, and lamiidoside, were isolated from the leaves of CITHAREXYLUM FRUTICOSUM. The structure of the new compound was established by spectroscopic methods.  相似文献   
139.
The relationship between various dietary constituents and colon cancer has been demonstrated by previous research. We conducted a study to investigate the combined effects of several dietary constituents on intestinal tumor incidence in azoxymethane (AOM)-induced colon cancer in rats. A nutritionally adequate, "low-risk" (LR) diet was formulated through nonextreme dietary manipulations of dietary fat, fiber, protein, vitamins A and E, and selenium. Seventy-two female F344 weanling rats were given three weekly subcutaneous injections of either AOM or physiological saline solution, and were maintained on either the LR or a "high-risk" (HR) diet. Food consumption and body weights were monitored on a weekly basis throughout the study. Tumor incidence was determined 36 weeks following the first injection of AOM. The incidence of adenocarcinomas in the LR diet group was 4.2% compared with 29.2% in the HR diet group. There were no significant differences in the incidence of small intestinal tumors or in the incidence of benign polyps between the diet groups. The results of the study indicated a significant protective effect of the various chemopreventive dietary factors when combined in an LR diet for colon cancer.  相似文献   
140.
Of the total number of pacemakers implanted each year, 6% must eventually be replaced because of infection, lead failure, or other problems. Often however, removal of the pacing leads is precluded by scarring at the tip of the leads. Because abandoned leads can cause serious problems, we initiated the present study to test the feasibility of using a laser to remove such leads. After performing in vitro experiments to establish the laser settings required for severing leads, we implanted 6 leads, from 4 different manufacturers, in 3 dogs. Five weeks later, we passed a laser fiber through each lead to the tip and delivered a 10-watt impulse for 2 seconds, which resulted in the successful removal of all the leads. When the dogs were killed 3 days later, postmortem examination revealed no thromboembolism in the heart or lungs and no myocardial damage. Subsequent experiments in 3 human cadaver hearts-involving leads implanted for 5 years, 2 years, and 2 months-yielded the same satisfactory results as did the canine experiments.  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