Author Keywords: Event-related potentials; females; menstrual cycle 相似文献
全文获取类型
收费全文 | 18736篇 |
免费 | 1236篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 216篇 |
儿科学 | 419篇 |
妇产科学 | 345篇 |
基础医学 | 2588篇 |
口腔科学 | 320篇 |
临床医学 | 1621篇 |
内科学 | 4826篇 |
皮肤病学 | 411篇 |
神经病学 | 1618篇 |
特种医学 | 613篇 |
外科学 | 2654篇 |
综合类 | 238篇 |
一般理论 | 8篇 |
预防医学 | 1395篇 |
眼科学 | 412篇 |
药学 | 1113篇 |
中国医学 | 77篇 |
肿瘤学 | 1173篇 |
出版年
2023年 | 132篇 |
2022年 | 330篇 |
2021年 | 545篇 |
2020年 | 307篇 |
2019年 | 447篇 |
2018年 | 518篇 |
2017年 | 344篇 |
2016年 | 364篇 |
2015年 | 449篇 |
2014年 | 619篇 |
2013年 | 839篇 |
2012年 | 1332篇 |
2011年 | 1347篇 |
2010年 | 774篇 |
2009年 | 664篇 |
2008年 | 1126篇 |
2007年 | 1194篇 |
2006年 | 1176篇 |
2005年 | 1106篇 |
2004年 | 1007篇 |
2003年 | 960篇 |
2002年 | 952篇 |
2001年 | 132篇 |
2000年 | 117篇 |
1999年 | 160篇 |
1998年 | 198篇 |
1997年 | 164篇 |
1996年 | 164篇 |
1995年 | 120篇 |
1994年 | 115篇 |
1993年 | 98篇 |
1992年 | 100篇 |
1991年 | 99篇 |
1990年 | 88篇 |
1989年 | 69篇 |
1988年 | 79篇 |
1987年 | 83篇 |
1986年 | 66篇 |
1985年 | 87篇 |
1984年 | 97篇 |
1983年 | 92篇 |
1982年 | 110篇 |
1981年 | 123篇 |
1980年 | 107篇 |
1979年 | 64篇 |
1978年 | 74篇 |
1977年 | 87篇 |
1976年 | 61篇 |
1974年 | 52篇 |
1973年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Amir-Reza Hosseinpour Shay Cullen Victor T Tsang 《European journal of cardio-thoracic surgery》2006,30(3):508-514
Heart transplantation is a recognised treatment for end-stage heart failure of any cause including congenital heart disease. Congenital heart disease has contributed relatively little to the adult heart transplant activities in the past two decades. However, this is likely to change as an increasing number of children with congenital heart disease reach adulthood because of the advances in paediatric cardiology and surgery. Some of these grown-ups with congenital heart disease (GUCH patients) will need transplantation for late myocardial dysfunction either secondary to uncorrected lesions, or despite previous repair or palliative surgery. These patients are managed along the same clinical principles as those with cardiac failure of other aetiologies, despite the lack of any evidence to support this approach. Nevertheless, they introduce new challenges. First, some may have pulmonary vascular disease and require heart-lung transplantation, or lung transplantation combined with repair of their cardiac defects. Second, those with failing Fontan circulation are usually much sicker than other transplant candidates, with protein-losing enteropathy along with renal and hepatic dysfunction. Third, a suitable donor organ may not be found due to elevated levels of antibodies in response to previous blood transfusions and possibly the previous implantation of homografts. Fourth, the operation may be technically difficult because of the presence of adhesions secondary to previous operations, collaterals, and unusual anatomy. Fifth, postoperative care may be complicated because of predisposition to bleeding, infection and pulmonary hypertension, and the presence of residual aortopulmonary collaterals resulting in a significant left-to-right shunt. Despite a higher early mortality, the overall results of heart transplantation so far have been encouraging with survivals similar to that of adults with acquired heart disease and that of the paediatric population. However, this may change as the proportion of high-risk patients (failing Fontans) increases. GUCH patients with Eisenmenger's syndrome may be offered lung transplantation with repair of the cardiac defect or heart-lung transplantation. However, because of the limited success of these approaches, and improved management of pulmonary hypertension, patient selection remains difficult. 相似文献
32.
PURPOSE: We report an unusual case of vocal cord edema associated with the use of a ProSeal laryngeal mask airway (PLMA) in an adult patient with an undiagnosed upper respiratory tract infection (URTI). CLINICAL FEATURES: A 55-yr-old woman had fixation of a radial fracture under general anesthesia with muscle relaxation. She developed audible wheezing 30 min after PLMA insertion. Bronchoscopic examination revealed significant vocal cord edema. Adequate ventilation was possible at increased airway pressures, and the administration of dexamethasone 4 mg iv produced clinical resolution of the stridor and airway obstruction. The patient admitted to having mild symptoms of an URTI on postoperative questioning. CONCLUSION: Airway hyperreactivity secondary to the URTI is the most likely etiological factor; other possibilities include trauma from insertion and chemical irritation. Although pediatric studies suggest that the LMA-Classic carries less risk than endotracheal intubation in the presence of URTI, this case report demonstrates that caution is still warranted when using supraglottic airways. The PLMA permitted effective ventilation despite increased airway resistance; nevertheless its role in patients with URTI is unclear. It is possible that the bulkier cuff design of the PLMA, compared to that of the LMA-Classic, may have partly contributed to the development of edema in this setting. 相似文献
33.
34.
Deborah G Murdoch Eaton David Wertheim Rowena Oozeer Lilly MS Dubowitz Victor Dubowitz 《Acta paediatrica (Oslo, Norway : 1992)》1994,83(5):486-492
Murdoch Eaton DG, Wertheim D, Oozeer R, Dubowitz LMS, Dubowitz V. Reversible changes in cerebral activity associated with acidosis in preterm neonates. Acta Paediatr 1994;83:486–92. Stockholm. ISSN 0803–5253
Computerized online EEG monitoring in ventilated preterm infants less than 32 weeks' gestation enabled evaluation of the effect of acidosis on cerebral function. All episodes of acidosis were found to be associated with changes in the levels of cerebral activity. In 21 of the 32 episodes, EEG activity returned to pre-acidosis levels after therapeutic intervention. The duration of EEG abnormality was related to the severity of acidosis. However, the time to recovery of the EEG after therapeutic procedures was not related to duration of the EEG change. 相似文献
Computerized online EEG monitoring in ventilated preterm infants less than 32 weeks' gestation enabled evaluation of the effect of acidosis on cerebral function. All episodes of acidosis were found to be associated with changes in the levels of cerebral activity. In 21 of the 32 episodes, EEG activity returned to pre-acidosis levels after therapeutic intervention. The duration of EEG abnormality was related to the severity of acidosis. However, the time to recovery of the EEG after therapeutic procedures was not related to duration of the EEG change. 相似文献
35.
BACKGROUND. Previous studies in humans advanced the concept that cardiac filling pressure and contractility, the primary determinants of ventricular mechanoreceptor discharge, are important determinants of sympathetic outflow during orthostatic stress. Thus, intravenous propranolol greatly attenuated forearm vasoconstrictor response to venous pooling with lower body negative pressure (LBNP). The aim of this study was to reevaluate the experimental support for this concept by using direct measurements of sympathetic nerve activity. METHODS AND RESULTS. In 11 healthy humans, we recorded muscle sympathetic nerve activity (MSNA) with microelectrodes (peroneal nerve), as well as blood flow in the forearm and calf (venous occlusion plethysmography) at baseline and during graded LBNP. The same experiments were repeated after administration of propranolol (0.15 mg/kg i.v.), which is thought to decrease ventricular mechanoreceptor discharge. The major new findings are that propranolol neither increased baseline MSNA nor attenuated the increases in MSNA during graded orthostatic stress even though in the same subjects, propranolol simultaneously increased the baseline level of vascular resistance in both the forearm and calf and substantially attenuated the increases in regional vascular resistance during orthostatic stress. CONCLUSIONS. Systemic beta-blockade causes a marked dissociation between sympathetic outflow and vascular resistance that invalidates the use of intravenous propranolol as an experimental model to examine the reflex effects of ventricular mechanoreceptors on peripheral vascular resistance in humans. 相似文献
36.
Surgical Management of Marfan Syndrome in Children 总被引:1,自引:0,他引:1
Victor T. Tsang FRCS Ash Pawade M.S. FRCS Tom R. Karl M.S. M.D. Roger B.B. Mee FRACS 《Journal of cardiac surgery》1994,9(1):50-54
Between August 1983 and January 1991, seven patients with Marfan syndrome underwent surgery for severe cardiovascular complications. The mean age at presentation was 5.7 months (range 4 to 9 months) in the infant group (n = 3), and 13.3 years (range 10 to 16 years) in a group of older children (n = 4). The primary indications for surgery in the infant group (performed at a mean of 3 years after diagnosis) were ascending aortic aneurysm with valvar regurgitation in one patient, and severe mitral valve prolapse with regurgitation in two. In the older group, surgical indications (performed at a mean of 2.8 years after diagnosis) were ascending aortic aneurysm with valvar regurgitation in three patients and acute aortic dissection in one. For aortic surgery, a composite valved conduit was used in four patients, and an aortic homograft in one. For mitral valve surgery, mechanical prostheses were used. Ail patients survived the primary operation. Over a mean follow-up of 17.5 patient-years (range 1 to 9 years), two patients in the infant Marfan group went on to further successful surgery (prosthetic mitral valve replacement and aortic root repair with aortic homograft) at a mean interval of 4.3 years after the Initial surgery. Our results suggest that the major cardiovascular risk factors of Marfan syndrome in the young, even in those diagnosed during infancy, have been favorably changed by surgery with an encouraging medium-term outlook. The correct timing of surgery is aided by echocardiography. (J Card Surg 1994;9:50–54) 相似文献
37.
Beverly M. Genez M.D. Victor L. Zirilli M.D. Alan E. Schlesinger M.D. Elizabeth A. Harden M.D. Kim D. Murphy M.D. Randall F. Dryer M.D. 《Skeletal radiology》1988,17(4):306-309
The opinions or assertions contained herein are the private views of the authors and are not to be construed as official nor as reflecting the views of the United States Air Force 相似文献
38.
39.
Nancy Kluck Sean O'Connor Victor Hesselbrock Allan Tasman Donald Maier Lance Bauer 《Progress in neuro-psychopharmacology & biological psychiatry》1992,16(6):901-911
Nancy Kluck, Scan J. O'Connor, Victor M. Hesselbrock, Allan Tasman and Donald Maier, Lance Bauer: Variation in Evoked Potential Measures Over the Menstrual Cycle: A Pilot Study. Prog. Neuro. Psychopharmacol. Biol. Psychiat. 1992. 16(6): 901–911.
1. 1. The P3 component of a visual event related potential (ERP) was studied for five consecutive weeks in six women with normal menstrual cycles. Serum concentrations of luteinizing hormone (LH), estradiol (E2) and progesterone were studied during the same period.
2. 2. Increases in P3 amplitude, although nonsignificant, were noted in the week preceding onset of menses.
3. 3. No significant changes in reaction times to target/nontarget stimuli were noted over the same time period.
40.
Esther Kahana Nelly Zilber Joseph H. Abramson Victor Biton Yaffa Leibowitz Oded Abramsky 《Journal of neurology》1994,241(5):341-346
The incidence and prevalence of multiple sclerosis (MS) were compared, controlling for age, in native-born Israelis of different origins and in immigrants to Israel. This comparison was carried out in two populations, countrywide and in Jerusalem. In the countrywide population, ascertainment was based mainly on hospitalizations; it included 252 patients who were native-born and 150 who had immigrated from Africa-Asia (AA immigrants). The 89 MS patients of Jerusalem also included patients diagnosed in outpatient clinics. In native-born Israelis whose father was born in Europe-America (I-EA), the incidence and prevalence of MS were found to be as high as or even higher than that found previously in immigrants from Europe-America. Among native-born Israelis whose father was born in Africa or Asia (I-AA), the yearly age-adjusted incidence and prevalence rates were found to be 1.4- to 1.8-fold higher than among AA immigrants, pointing to environmental factors. The incidence and prevalence rates in the I-EA were 1.2- to 1.6-fold higher than in the I-AA, pointing to genetic factors. These results seem to point to both environmental and genetic factors in the aetiology of MS. Further research is needed, however, to disentangle the genetic factors from possible environmental differences in the two ethnic groups. 相似文献