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   1216篇
  免费   68篇
  国内免费   38篇
耳鼻咽喉   11篇
儿科学   62篇
妇产科学   60篇
基础医学   135篇
口腔科学   11篇
临床医学   128篇
内科学   216篇
皮肤病学   23篇
神经病学   55篇
特种医学   87篇
外科学   282篇
综合类   53篇
一般理论   2篇
预防医学   50篇
眼科学   22篇
药学   62篇
  1篇
中国医学   17篇
肿瘤学   45篇
  2023年   4篇
  2022年   15篇
  2021年   19篇
  2020年   8篇
  2019年   18篇
  2018年   18篇
  2017年   15篇
  2016年   21篇
  2015年   20篇
  2014年   26篇
  2013年   38篇
  2012年   59篇
  2011年   53篇
  2010年   49篇
  2009年   56篇
  2008年   64篇
  2007年   86篇
  2006年   65篇
  2005年   39篇
  2004年   45篇
  2003年   38篇
  2002年   43篇
  2001年   50篇
  2000年   34篇
  1999年   28篇
  1998年   28篇
  1997年   27篇
  1996年   31篇
  1995年   19篇
  1994年   31篇
  1993年   11篇
  1992年   20篇
  1991年   27篇
  1990年   22篇
  1989年   30篇
  1988年   26篇
  1987年   26篇
  1986年   28篇
  1985年   17篇
  1984年   9篇
  1983年   8篇
  1982年   4篇
  1981年   3篇
  1980年   4篇
  1979年   5篇
  1978年   11篇
  1977年   12篇
  1976年   3篇
  1973年   2篇
  1958年   1篇
排序方式: 共有1322条查询结果,搜索用时 15 毫秒
71.
Castration and erection. An animal study   总被引:1,自引:0,他引:1  
Castrated dogs (n = 3) need a much higher threshold level of energy to induce erection by electrical stimulation of the cavernous nerve than noncastrated animals (n = 24). In addition the resulting quality of erection, measured as maximal intracavernous pressure (pCC) versus peak systolic blood pressure (BP), was weaker in castrated dogs (pCC = 57% of BP on average) than in noncastrated dogs (pCC = 80% of BP on average). A high venous outflow from the corpora cavernosa in castrated dogs can also explain the shorter duration of erection. This experimental model excludes the interference of subjective factors, such as erotic stimuli and libido on erection, and it seems that androgen deficiency has a direct effect on the neurophysiology of the erectile tissues resulting in a higher tonus of the detumescence factors, which can be explained by an incomplete relaxation of the sinusoidal smooth muscle.  相似文献   
72.
During a 13-month period, 13 patients with asplenia syndrome were evaluated with MRI for cardiovascular and visceral anomalies. The MR images were reviewed for the presence of hiatus hernia which was found in three patients. One of the remaining ten patients with no MRI evidence of hiatus hernia was diagnosed as having gastro-oesophageal reflux and hiatus hernia by an oesophagogram and 24-h pH monitoring. This patient had undergone fundoplication prior to MRI. Out of the 13 patients (31%) with asplenia syndrome, 4 had hiatus hernia. It appears that among patients with the asplenia syndrome, hiatus hernia is a frequent finding. Recurrent pneumonia or bronchiolitis in patients with asplenia syndrome requires evaluation for the presence of hiatus hernia and gastro-oesophageal reflux.  相似文献   
73.
BACKGROUND: Intraoperative transesophageal echocardiography (TEE) is useful in evaluating the repair of lesions in patients with congenital heart disease. But the use of TEE in infants with total anomalous pulmonary venous connection (TAPVC) remains unclear. We reviewed the safety and efficacy of intraoperative TEE during TAPVC repair. METHODS: Twenty-eight consecutive 1 day to 7 month-old infants with TAPVC (14 supracardiac, six intracardiac and eight infracardiac type) had surgical repair with intraoperative TEE monitoring. RESULTS: Four patients received immediate surgical revision after primary surgery for residual anastomotic stenosis diagnosed by TEE. In addition, two unsuspected ventricular septal defects and three persistent ductus arteriosus were detected before surgery. Eight infants (29%) had hypotension and hypoxemia associated with TEE probe insertion before surgery, but this hemodynamic disturbance returned to baseline value after withdrawing the TEE probe from the esophagus. However, these eight patients had uneventful TEE probe insertion following sternotomy. The mechanism was probably because of the reduction of intrathoracic pressure when the chest was opened. CONCLUSIONS: TEE probe insertion in TAPVC patients may pose a potential risk of compression of pulmonary venous confluence resulting in hemodynamic instability. Therefore, we suggest that the use of TEE in such TAPVC patients appears to be safer after sternotomy.  相似文献   
74.
OBJECTIVE: To describe a technique of externally bulking the urethra with a soft-tissue graft before placing another artificial urinary sphincter (AUS), as when placing another AUS for recurrent male stress urinary incontinence (SUI) other manoeuvres, e.g. placing a tandem cuff or transcorporal cuff, must be used to obtain urinary continence in an atrophic urethra, and each is associated with morbidity. PATIENTS AND METHODS: From January 2003 to July 2004, five patients (mean age 74 years, range 62-84) treated by radical prostatectomy were referred for recurrent SUI after placing an AUS (four, including one with urethral erosion) or a male sling (one, with a resulting atrophic urethra). Each patient was treated with an external urethral bulking agent (Surgisis) ES, Cook Urological, Spencer, Indiana) and had an AUS placed. RESULTS: In each patient the greatest urethral circumference was <4 cm. To place a functional 4 cm cuff, the diameter of the urethra was enhanced by wrapping it with Surgisis ES. Continence was significantly improved in all patients except one 84-year-old man who had the replanted artificial sphincter removed because of erosion 14 months after surgery. CONCLUSION: In cases of severe recurrent SUI from urethral atrophy after placing an AUS, externally bulking the urethra with Surgisis ES before placing another AUS is well tolerated, and gives satisfactory results.  相似文献   
75.
OBJECTIVE: To test the hypothesis that combined intracavernosal injection with vascular endothelial growth factor (VEGF) with adeno-associated virus-mediated brain-derived neurotrophic factor (AAV-BDNF) synergistically facilitates the neural regeneration and erectile function after cavernosal nerve injury. MATERIALS AND METHODS: Forty Sprague-Dawley male rats were randomly divided into five equal groups: eight had a sham operation while 32 had bilateral cavernosal nerve freezing followed by an immediate intracavernosal injection with either phosphate-buffered saline (PBS), VEGF, AAV-BDNF, or AAV-BDNF + VEGF. Erectile function was assessed by cavernosal nerve electrostimulation at 3 months, and samples of the major pelvic ganglia and penile tissue were evaluated histologically. RESULTS: In this animal model of impotence from nerve injury, the recovery of erectile function was greatest in those receiving AAV-BDNF + VEGF; the mean (sd) maximal intracavernosal pressure in this group was 87.2 (20.78) cmH2O, compared with 37.3 (11.39) for VEGF alone and 49.8 (29.58) for AAV-BDNF alone. No erectile dysfunction was identified in the sham group, with a pressure of 100.7 (22.70) cmH2O, while all treatment groups significantly outperformed the PBS (control) group, at 29.3 (13.52) cmH2O. Furthermore, all animals receiving monotherapy or combined treatment had more NADPH-diaphorase-positive nerve fibres than controls but less than in the sham group. CONCLUSION: Bilateral cavernosal nerve freezing causes erectile dysfunction with accompanying neurological changes. Intracavernosal injection with either VEGF or AAV-BDNF alone enhances nerve regeneration, with combined therapy (VEGF and AAV-BDNF) promoting neural and erectile recovery additively.  相似文献   
76.
Background Heterotaxy syndrome, including right isomerism and left isomerism, is characterized by an abnormal symmetry of the viscera and veins and is frequently associated with complex cardiac anomalies. We sought to define the feasibility of in utero diagnosis and the postnatal outcome. Methods Patients with heterotaxy syndrome were identified from 579 fetal echocardiograms performed from January 1994 to December 1998. The diagnosis was made on the basis of the fetal echocardiographic findings and was confirmed with autopsy or postnatal evaluation. Results A total of 25 fetuses with right isomerism and 4 with left isomerism constitute the study population. The pregnancies of 7 fetuses (6 right and 1 left isomerism) were terminated before the 24th gestational week and subjected to autopsy. Twelve fetuses (10 right and 2 left isomerism) were lost to follow-up. Nine with right isomerism and 1 with left isomerism were delivered and underwent palliation. Among them, 5 patients (56%) with right isomerism died and more than half of the deaths occurred during infancy. The major cardiac anomalies detected and confirmed with postnatal evaluation or autopsy in fetuses with right isomerism were total anomalous pulmonary venous connection (6/15; 40%), common atrium (15/15; 100%), complete atrioventricular canal (15/15; 100%), double outlet right ventricle (15/15; 100%), and pulmonary stenosis (11/15; 73%). The major cardiac anomalies in fetuses with left isomerism were interruption of inferior vena cava (2/2; 100%), common atrium (1/2; 50%), and complete atrioventricular canal (1/2; 50%). Undetected lesions with fetal echocardiogram were abnormal pulmonary venous return to systemic veins in 1 case (sensitivity, 83%; 5/6; and specificity, 90%; 9/10) and outflow obstruction in 1 case (sensitivity, 91%; 11/12; and specificity, 67%; 2/3). Different patterns of rhythm disturbances were identified: supraventricular tachycardia in 1 case with right isomerism and sinus bradycardia with junctional rhythm in 3 cases with left isomerism (2 of them lost to follow-up). After birth, another 2 patients with right isomerism had supraventricular tachycardia, and 1 with left isomerism had sinus bradycardia develop at age 2 years. Conclusion Heterotaxy syndrome is usually detected in fetuses with the sonographic cardiac abnormalities. Visualization of the pulmonary venous return and outflow obstruction and characterization of the rhythm disturbances are feasible. However, in spite of prenatal diagnosis, the prognosis remains poor. (Am Heart J 2002;143:1002-8.)  相似文献   
77.
78.
Peyronie's disease: a review   总被引:3,自引:0,他引:3  
PURPOSE: We provide a current review of Peyronie's disease. MATERIALS AND METHODS: We reviewed the world peer reviewed literature on the pathology, pathogenesis, diagnosis and treatment of Peyronie's disease. RESULTS: The incidence of Peyronie's disease has continuously increased during the last 30 years. However, fewer patients need prosthesis surgery as the sole treatment option because of earlier diagnosis, improved medical therapy, refinement in surgical technique and better understanding of the basic sciences of the disease. CONCLUSIONS: Currently patients with Peyronie's disease have had improvements in prognosis and experienced an expansion of the available therapeutic options.  相似文献   
79.
Short-term exposure (43 C for 15 min) of the rat testis to mild heat results within 6 h in stage- and cell-specific activation of germ cell apoptosis. Initiation of apoptosis was preceded by a redistribution of Bax from a cytoplasmic to paranuclear localization in heat-susceptible germ cells. Here we show that the relocation of Bax is accompanied by cytosolic translocation of cytochrome c and is associated with activation of the initiator caspase 9 and the executioner caspases 3, 6, and 7 and cleavage of poly(ADP) ribose polymerase. Furthermore, early in apoptosis, a significant amount of Bax also accumulates in endoplasmic reticulum, as assessed by Western blot analyses of fractionated testicular lysates. In additional studies using the FasL-defective gld mice, we have shown that heat-induced germ cell apoptosis is not blocked, thus providing evidence that the Fas signaling system may be dispensable for heat-induced germ cell apoptosis in the testis. Taken together, these results demonstrate that the mitochondria- and possibly also endoplasmic reticulum-dependent pathways are the key apoptotic pathways for heat-induced germ cell death in the testis.  相似文献   
80.
OBJECTIVE: Little is known regarding how diabetic men with erectile dysfunction (ED) differ from the general population of impotent men. The primary objective of this study was to compare disease-specific health-related quality of life (HRQOL) and severity of ED in impotent men with and without diabetes. RESEARCH DESIGN AND METHODS: Validated functional and HRQOL questionnaires (including the International Index of Erectile Function, the Sexual Self-Efficacy Scale, and the Psychological Impact of Erectile Dysfunction scales) were administered to patients in an ED disease registry. Men with ED and a history of diabetes (n = 20) were compared with men with ED and no history of diabetes (n = 90) at baseline and at the 12-month follow-up. RESULTS: Diabetic impotent men reported worse erectile function and intercourse satisfaction at baseline, and ED had a greater impact on their emotional life. Diabetic men with ED had significantly different trends over time in the Erectile Function (P < 0.001), Intercourse Satisfaction (P < 0.013), Sexual Desire (P < 0.016), Overall Satisfaction (P < 0.023), and the Sexual Experience-Psychological Impact domains (P < 0.002). In addition, there was a trend toward a difference over time in the Emotional Life-Psychological Impact domain (P < 0.067). CONCLUSIONS: Impotent men with diabetes present with worse ED than nondiabetic men with ED, resulting in worse disease-specific HRQOL in the diabetic men. Although diabetic patients initially respond well to ED treatment, responses do not appear to be durable over time. Therefore, clinicians must provide longer-term follow-up when treating ED in diabetic patients.  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