全文获取类型
收费全文 | 18694篇 |
免费 | 1267篇 |
国内免费 | 74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 | 2583篇 |
口腔科学 | 318篇 |
临床医学 | 1618篇 |
内科学 | 4829篇 |
皮肤病学 | 410篇 |
神经病学 | 1618篇 |
特种医学 | 613篇 |
外科学 | 2653篇 |
综合类 | 238篇 |
一般理论 | 8篇 |
预防医学 | 1394篇 |
眼科学 | 411篇 |
药学 | 1113篇 |
中国医学 | 77篇 |
肿瘤学 | 1172篇 |
出版年
2023年 | 131篇 |
2022年 | 329篇 |
2021年 | 545篇 |
2020年 | 307篇 |
2019年 | 447篇 |
2018年 | 515篇 |
2017年 | 343篇 |
2016年 | 364篇 |
2015年 | 450篇 |
2014年 | 619篇 |
2013年 | 838篇 |
2012年 | 1331篇 |
2011年 | 1347篇 |
2010年 | 773篇 |
2009年 | 664篇 |
2008年 | 1125篇 |
2007年 | 1194篇 |
2006年 | 1175篇 |
2005年 | 1105篇 |
2004年 | 1007篇 |
2003年 | 959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
41.
John A. Procaccino M.D. Ian C. Lavery M.D. Victor W. Fazio M.D. John R. Oakley M.D. 《Diseases of the colon and rectum》1991,34(9):784-789
From 1961 to 1989, 67 patients underwent various surgical procedures for psoas abscess. Retrospective analysis was undertaken in an effort to determine optimal surgical therapy. Forty patients were cured with one operation. Twenty-one patients required two operations, four patients required three operations, and two patients required more than three operations. The reason for failure of treatment was failure to resect the diseased bowel or to drain the psoas abscess adequately. A technique to recognize and treat the abscess definitively will be illustrated. The most common etiologies were Crohn's disease in 49 patients, postoperative sepsis in eight patients, and complications of renal disease in four patients. The length of hospital stay ranged from 5 to 392 days (mean, 26 days). There were two deaths. Failure to recognize and treat psoas abscess results in considerable morbidity.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, St. Louis, Missouri, April 29 to May 4, 1990. 相似文献
42.
Francisca M Vera Juan M Manzaneque Enrique F Maldonado Gabriel A Carranque Victor M Cubero Maria J Blanca Miguel Morell 《Medical science monitor》2007,13(12):CR560-CR566
BACKGROUND: The aim of the present study was to analyze the effects of a qigong training program on blood biochemical parameters. MATERIAL/METHODS: Twenty-nine healthy subjects participated in the study of whom 16 were randomly assigned to the experimental group and 13 to the control. The experimental subjects underwent daily qigong training for one month. Blood samples for the quantification of biochemical parameters (total cholesterol, HDL, LDL, triglycerides, phospholipids, GOT, GPT, GGT, urea, creatinine) were taken before and after the training program. As statistical analysis, ANCOVA was performed. RESULTS: Statistically significant differences were found showing that the experimental group had lower serum levels of GOT (glutamic-oxaloacetic transaminase), GPT (glutamic-pyruvic transaminase), and urea and that there was a trend towards significance in GGT (gamma-glutamyltransferase). CONCLUSIONS: This study demonstrates that after practicing qigong for the short period of one month, noteworthy changes in several blood biochemical parameters were induced. While it is tempting to speculate on the relevance and implications of these biochemical variations, further investigation is needed to elucidate the scope of these findings. 相似文献
43.
44.
John J Doyle Alfred I Neugut Judith S Jacobson Victor R Grann Dawn L Hershman 《Journal of clinical oncology》2005,23(34):8597-8605
PURPOSE: Adjuvant chemotherapy, especially with anthracyclines, is known to cause acute and chronic cardiotoxicity in breast cancer patients. We studied the cardiac effects of chemotherapy in a population-based sample of breast cancer patients aged > or = 65 years with long-term follow-up. PATIENTS AND METHODS: In the Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we analyzed treatments and outcomes among women > or = 65 years of age who were diagnosed with stage I to III breast cancer from January 1, 1992 to December 31, 1999. Propensity scores were used to control for baseline heart disease (HD) and other known predictors of chemotherapy, and Cox proportional hazards models were used to estimate the risk of cardiomyopathy (CM), congestive heart failure (CHF), and HD after chemotherapy. RESULTS: Of 31,748 women with stage I to III breast cancer, 5,575 (18%) received chemotherapy. Chemotherapy was associated with younger age, fewer comorbidities, hormone receptor negativity, multiple primary tumors, and advanced disease. Patients who received chemotherapy were less likely than other patients to have pre-existing HD (45% v 55%, respectively; P < .001). The hazard ratios for CM, CHF, and HD for patients treated with doxorubicin (DOX) compared with patients who received no chemotherapy were 2.48 (95% CI, 2.10 to 2.93), 1.38 (95% CI, 1.25 to 1.52), and 1.35 (95% CI, 1.26 to 1.44), respectively. The relative risk of cardiotoxicity among patients who received DOX compared with untreated patients remained elevated 5 years after diagnosis. CONCLUSION: When baseline HD was taken into account, chemotherapy, especially with anthracyclines, was associated with a substantially increased risk of CM. As the number of long-term survivors grows, identifying and minimizing the late effects of treatment will become increasingly important. 相似文献
45.
This article reviews the current status and controversies of the 3 commonly used antifibrinolytics-epsilon-aminocaproic acid, tranexamic acid and aprotinin-during liver transplantation. There is no general consensus on how, when or which antifibrinolytics should be used in liver transplantation. Although these drugs appear to reduce blood loss and decrease transfusion requirements during liver transplantation, their use is not supported uniformly in clinical trials. Aprotinin has been studied more extensively in clinical trials and appear to offer more advantages compared to two other antifibrinolytics. Because of the diverse population of liver transplant recipients and the potential adverse effects of antifibrinolytics, especially life-threatening thromboembolism, careful patient selection and close monitoring is prudent. Further studies addressing the risks and benefits of antifibrinolytics in the setting of liver transplantation are warranted. 相似文献
46.
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
47.
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
48.
49.
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
50.
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