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   1094篇
  免费   58篇
  国内免费   19篇
耳鼻咽喉   9篇
儿科学   45篇
妇产科学   56篇
基础医学   115篇
口腔科学   4篇
临床医学   90篇
内科学   200篇
皮肤病学   5篇
神经病学   54篇
特种医学   82篇
外科学   278篇
综合类   46篇
一般理论   2篇
预防医学   53篇
眼科学   16篇
药学   67篇
  1篇
中国医学   15篇
肿瘤学   33篇
  2023年   4篇
  2022年   12篇
  2021年   19篇
  2020年   7篇
  2019年   19篇
  2018年   17篇
  2017年   15篇
  2016年   14篇
  2015年   15篇
  2014年   20篇
  2013年   31篇
  2012年   53篇
  2011年   45篇
  2010年   42篇
  2009年   38篇
  2008年   59篇
  2007年   56篇
  2006年   58篇
  2005年   41篇
  2004年   37篇
  2003年   38篇
  2002年   36篇
  2001年   42篇
  2000年   35篇
  1999年   26篇
  1998年   28篇
  1997年   19篇
  1996年   29篇
  1995年   16篇
  1994年   18篇
  1993年   19篇
  1992年   23篇
  1991年   25篇
  1990年   22篇
  1989年   33篇
  1988年   35篇
  1987年   30篇
  1986年   22篇
  1985年   17篇
  1984年   8篇
  1983年   11篇
  1982年   8篇
  1981年   3篇
  1980年   3篇
  1979年   3篇
  1978年   7篇
  1977年   2篇
  1975年   3篇
  1973年   2篇
  1958年   1篇
排序方式: 共有1171条查询结果,搜索用时 109 毫秒
1.
Priapism: a refined approach to diagnosis and treatment   总被引:4,自引:0,他引:4  
The recent introduction of intracorporeal injections of papaverine and phentolamine for the diagnosis and treatment of impotence has resulted in an increased incidence of iatrogenic priapism. Based on our research into penile hemodynamics we propose a refined approach to all types of priapism. Intracorporeal blood gas and pressure monitoring should be used to differentiate ischemic (low flow) from nonischemic (high flow) types. Most cases of papaverine-induced or phentolamine-induced priapism will respond to aspiration alone or in combination with intracorporeal instillation of a diluted alpha-adrenergic agent. In spontaneous priapism alpha-adrenergic agents can be tried first if patients have only mild or no ischemia. In patients with severe ischemia stagnant blood should be evacuated and a shunt procedure should be performed to allow metabolic replenishment of tissue. Intracorporeal pressure monitoring will help to determine the size and number of shunts needed to re-establish corporeal circulation.  相似文献   
2.
Extracellular phospholipase A2 (PLA2) is a proinflammatory enzyme found especially in the inflammatory exudate to modulate blood flow to areas of antigen stimulation. In this study we found that PLA2 exerted a biphasic effect on the proliferation of phytohemagglutinin (PHA)-stimulated human mononuclear cells (PHA MNC). At low concentrations range from 0.001 to 1 U/ml, PLA2 enhanced the proliferation of PHA MNC (maximal increase was 37.0 +/- 5.67%). Conversely, at concentrations over 10 U/ml, PLA2 markedly suppressed the PHA-induced MNC proliferation (maximal decrease was 88.86 +/- 2.89%). PLA2 was non-toxic to lymphocytes after three days culture, unless the concentration was higher than 100 U/ml. The membrane polarization of PHA-stimulated lymphocytes was also increased by PLA2 at a low concentration. In addition, PLA2 displayed a similar effect on the proliferation of streptokinase-streptodornase (SK/SD) or allogeneic cell stimulated lymphocytes. The change of lymphocyte proliferation by PLA2, was parallel to the change of percentage of helper T cells. Furthermore--a CD4-rich population was proved more susceptible to PLA2 effect than a CD8-rich population. Para-bromophenacyl bromide (pBPB), an irreversible inhibitor of PLA2, abrogated the biphasic effect of PLA2 on PHA MNC proliferation. These results suggest that PLA2 plays a regulatory role on immune reactions by modulating the percentage of helper T cells.  相似文献   
3.
Blood gas analysis in drug-induced penile erection   总被引:1,自引:0,他引:1  
To elucidate the hemodynamic changes during erection, we measured corporeal blood gases in 6 monkeys before, during, and after erection induced by either papaverine or phentolamine or a combination of the two. Papaverine alone caused a strong erection (maximal tumescence and rigidity) by means of a rapid, large increase in pO2 and pCO2 with a pH drop to the acidic range. Phentolamine alone caused 'delayed' tumescence with less rigidity; the intracorporeal pO2 level increased, but pCO2 and pH values did not change significantly. The combination of both drugs offered no advantage over papaverine alone. We conclude that papaverine is a potent erection-inducing drug that acts in a bimodal manner, namely, it increases the arterial inflow and, at the same time, decreases the venous outflow. Phentolamine affects the arterial component of erectile function only.  相似文献   
4.
Leukotriene receptor antagonists (LTRAs) were recently added to the method of treating allergic rhinitis (AR). However, in children under 6 yr old, there has been no study about its efficacy in treating AR. We aim to compare the clinical efficacy of montelukast, cetirizine and placebo in the treatment of children from 2 to 6 yr old with perennial allergic rhinitis (PAR), to see if there are any significant differences. Sixty children were selected and treated with montelukast, or cetirizine, or placebo once daily. The efficacy of the three agents was compared with the Pediatric Rhinoconjunctivitis Quality of Life Questionnaire (PRQLQ) and Total Symptom Score (TSS) by diary. In addition, we also examined serum IgE, serum eosinophil cationic protein (ECP), blood eosinophil counts, nasal airway resistance (NAR) and eosinophil percentage in nasal smears. The results revealed that both montelukast and cetirizine were significantly efficacious compared with placebo in NAR, eosinophil percentage in nasal smears, PRQLQ, TSS and all symptom items except nasal itching, throat itching and tearing. For nasal itching, only cetirizine was significantly efficacious. On the other hand, for night sleep quality, montelukast was significantly superior to cetirizine.  相似文献   
5.
Hemodynamics of penile erection   总被引:2,自引:0,他引:2  
In the flaccid state, the smooth muscles of the cavernous arterioles and trabeculae are contracted, and minimal blood flow enters the sinusoids. Relaxation of these smooth muscles incites arterial dilation, venous compression, and sinusoidal relaxation and results in penile erection.  相似文献   
6.
W M Lue  P A Boyden 《Circulation》1992,85(3):1175-1188
BACKGROUND. Reentrant ventricular arrhythmias can occur in the surviving muscle fibers of the epicardial border zone of the canine heart 5 days after coronary artery occlusion. To understand the cellular basis of these arrhythmias, we developed a method of dispersing myocytes (IZs) from the epicardial border zone. METHODS AND RESULTS. We compared the electrophysiological properties of IZs with those of cells dispersed from the epicardium of control noninfarcted (NZs) and of sham-operated animals (NZsham). Transmembrane action potentials of IZs are reduced in total action potential amplitude and maximum upstroke velocity compared with NZs. However, resting potential of IZs is no different from that of NZs. Action potential duration at -10 mV is significantly reduced in IZs compared with control, and IZ potentials do not show the typical "spike and dome" morphology that is evident in all NZs. Using Vmax as an indirect measure of the peak inward current available for the upstroke of the action potential, we found that the availability curve for IZs is significantly different from the NZ curve. Furthermore, the time course of recovery of Vmax after a depolarizing voltage clamp step was significantly altered in IZs. Using whole-cell voltage clamp techniques, we determined that the voltage-dependent, Ca(2+)-independent, 4-aminopyridine-sensitive transient outward current (ito1) occurred in all NZs (n = 16) but existed in only 37% of IZs (n = 16). There was a significant reduction in the density of ito1 elicited by depolarizing steps in those IZs showing ito1 compared with ito1 density in NZs. CONCLUSIONS. We have developed a single-cell model of cells that survive in the infarcted heart. Our studies indicate that there are changes in Vmax in IZs. In addition, there is no prominent phase 1 of repolarization in IZ action potentials. This is consistent with the dramatic loss in the function of the ionic channel responsible for the voltage-dependent transient outward current, ito1.  相似文献   
7.
The clinical features and sleep physiology of 11 female patients with "fibrositis syndrome" or rheumatic pain modulation disorder (RPMD) were compared with 11 female postaccident pain (PAP) patients who complained of widespread musculoskeletal pain, fatigue, and nonrestorative sleep following a nonphysically injurious motor vehicle or work-related accident. Both groups had similar musculoskeletal pain, fatigue, sleepiness and an alpha (7.5-11 Hz) EEG non-rapid eye movement (NREM) sleep anomaly. A psychophysiologic arousal mechanism during NREM sleep induced by the emotional stress of the accident may mediate the subsequent nonrestorative sleep, musculoskeletal pain, and fatigue symptoms in the posttraumatic pain disorder.  相似文献   
8.
This study investigates the synaptic relation between -aminobutyric acid-immunoreactive (GABA-IR) and cuneothalamic relay neurons (CTNs) in the rat cuneate nucleus. Retrograde transport of wheat germ agglutinin conjugated with horseradish peroxidase complex (WGA-HRP) was used to label CTNs while anti-GABA immunogold serum was used for the detection of GABA-IR boutons associated with CTNs. With these procedures, immunogold-labelled GABA-IR boutons were found to form axosomatic, axodendritic and axospinous synapses with the WGA-HRP-labelled but immunonegative CTNs. Quantitative estimation showed that the mean ratios of GABA-IR to GABA-immunonegative boutons making synaptic contacts with somata, proximal dendrites, and distal dendrites were 47.9%, 49.1% and 34.7%, respectively. Statistical analysis showed that the incidence of GABA-IR boutons on the somata and proximal dendrites of CTNs was significantly higher than on the distal dendrites. Our results indicate that GABA is the primary inhibitory neurotransmitter in the cuneate nucleus, thereby emphasizing the importance of postsynaptic inhibition on cuneothalamic relay neurons.  相似文献   
9.
SUMMARY  Animal and human studies have related the sleeping/waking brain to the immune system. Because women are more susceptible to certain immunological illnesses, and sex steroids regulate immune functions, it was investigated whether the diurnal sleep/wake pattern of aspects of cellular immune functions and interleukin-1 (IL-1) and IL-2-like activities differed during low and high progesterone phases of the menstrual cycle.
Eleven healthy women, mean age 24y, were assessed over 24h with serial venous blood samples. Peripheral blood monocytes were assayed for mitogen responses, i.e. phytohemagglutin (PHA) and pokeweed (PWM) and natural killer (NK) cell activities. Plasma was assayed for IL-1 and IL-2-like activities, cortisol and progesterone. Data were standardized by Z transformation and analysed by repeated-measures analysis of variance by comparing high ( N = 5) vs. low ( N = 6) progesterone phases.
During the high progesterone phase, delayed slow-wave sleep (SWS) onset time and reduced amount of SWS was accompanied by a delay in the decline of NK cell activity, but rise in PHA activity following sleep onset. With the low progesterone phase, the pattern was similar to men with an early sleep decline in NK cell and late sleep rise in PHA activities. PWM rose during the night and plasma IL-1-like activity peaked during midday and during nocturnal sleep irrespective of the amount of progesterone.
Slow-wave sleep and sleep-related NK cell and PHA activities differed over the menstrual cycle, but not PWM response. Increases in plasma IL-1 functions during midday and night are consistent with predisposition to sleepiness during these times.  相似文献   
10.
PURPOSE: We evaluated the results of chronic intermittent stretching with a vacuum erection device after circumferential tunical incision and circular venous grafting in 4 patients with penile shortening from severe Peyronie's disease. MATERIALS AND METHODS: We performed complete circumferential tunical incision and covered the defect with a circular venous graft in 4 patients with shortened penis as a result of Peyronie's disease. Preoperative evaluation included determination of patient and partner expectations, potency status, measurement of penile length after intracavernous injection and color duplex ultrasonography to determine possible vascular communication. Lower saphenous, upper saphenous and deep dorsal veins served as graft materials. We advised patients to use a vacuum device on a daily basis for 6 months starting 1 month after surgery. Postoperative evaluations were done at 6 and 18 months postoperatively. RESULTS: At 6-month followup 1 patient who did not use the vacuum device gained 1 inch in penile length and was not available for further followup. The other 3 patients each gained 2 inches but had decreased erectile rigidity due to narrowing in the grafted area (hourglass deformity). One patient who wanted a more natural erection elected penile prosthesis implantation about 1 year after grafting. The remaining 2 patients gained 3 inches at 18-month followup and regained partial penile rigidity similar to preoperative erections when the hourglass deformity improved. All patients were satisfied and indicated that surgery improved psychological well-being as well as relationships with partners. CONCLUSIONS: The results in this small group are satisfactory. Our technique offers a reasonable solution for correction of penile shortening in patients with Peyronie's disease.  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