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   361篇
  免费   22篇
  国内免费   3篇
儿科学   9篇
妇产科学   1篇
基础医学   32篇
口腔科学   8篇
临床医学   46篇
内科学   57篇
皮肤病学   11篇
神经病学   30篇
特种医学   11篇
外科学   66篇
综合类   26篇
预防医学   8篇
药学   75篇
肿瘤学   6篇
  2023年   1篇
  2021年   4篇
  2020年   1篇
  2019年   1篇
  2018年   4篇
  2017年   3篇
  2016年   4篇
  2015年   10篇
  2014年   8篇
  2013年   11篇
  2012年   5篇
  2011年   9篇
  2010年   10篇
  2009年   21篇
  2008年   22篇
  2007年   12篇
  2006年   12篇
  2005年   21篇
  2004年   9篇
  2003年   7篇
  2002年   6篇
  2001年   7篇
  2000年   13篇
  1999年   10篇
  1998年   8篇
  1997年   13篇
  1996年   10篇
  1995年   9篇
  1994年   11篇
  1993年   17篇
  1992年   16篇
  1991年   19篇
  1990年   7篇
  1989年   11篇
  1988年   4篇
  1987年   6篇
  1986年   11篇
  1985年   7篇
  1984年   3篇
  1983年   1篇
  1982年   4篇
  1981年   3篇
  1980年   2篇
  1979年   5篇
  1978年   2篇
  1977年   2篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1968年   1篇
排序方式: 共有386条查询结果,搜索用时 15 毫秒
1.
PURPOSE: To describe the management of severe acute intracardiac thrombosis in a patient who underwent redo multiple valve replacement and valvular repair. The diagnostic features, associated risk factors, and anesthetic management are reviewed. CLINICAL FEATURES: A 67-yr-old woman undergoing redo mitral and aortic mechanical valve replacement and tricuspid annuloplasty under aprotinin prophylaxis exhibited severe refractory hypotension that began immediately after protamine reversal of intraoperative heparin anticoagulation following separation from cardiopulmonary bypass. Intraoperative transesophageal echocardiography revealed severe thrombosis in the right atrium, right ventricle and pulmonary artery. The patient was managed by immediate reheparinization and return to cardiopulmonary bypass (CPB), surgical thrombectomy, and intraoperative administration of recombinant tissue-plasminogen activator. After removal of the thrombi, and separation from CPB, no further protamine was given. One hundred units of blood products and two surgical re-explorations were required to manage subsequent massive postoperative bleeding. Acute heparin-induced thrombocytopenia (HIT) was ruled out using sensitive assays for HIT antibodies. After 16 days in the intensive care unit and 30 more days in hospital, the patient was subsequently transferred to a chronic care facility and succumbed several weeks later. CONCLUSION: Acute intraoperative thrombosis is a rare and potentially fatal complication of cardiac surgery. Intraoperative transesophageal echocardiography was essential for rapid diagnosis in this case. Multiple interacting prothrombotic factors (e.g., aprotinin use, acquired antithrombin deficiency, long pump time, post-protamine status, transfusion of blood components) were likely contributing factors related to this rare complication.  相似文献   
2.
血管细胞粘附分子调控造血的研究进展   总被引:2,自引:1,他引:1  
本文简述了血管细胞粘附分子 (Vascularcelladhesionmolecule 1,VCAM 1)的结构和生物学功能 ,总结了VCAM 1在恶性血液病骨髓基质中的表达和意义 ,探讨了VCAM 1在造血干细胞动员和归巢中的作用 ,指出VCAM 1作用机制的深入研究将对恶性血液病的治疗提供更为有效的方法。  相似文献   
3.
We estimated the free fraction (fu) of cyclosporine (CyA) in the plasma from concentrations of CyA in urine (Cu) and plasma (Cp), urine flow rate (UF), and glomerular filtration rate in rabbits and in heart transplant patients. Following intravenous administration of CyA (5–30 mg kg?1) in ten NZW rabbits and oral administration of CyA (4.8–12.1 mg kg?1) in nine heart transplant patients, CyA concentrations in urine and plasma were measured by HPLC. The ratios of Cu to Cp and UF data were fitted to a physiological model of renal clearance using NONMEM. The free fraction of cyclosporine in the rabbits and the heart transplant patients was 0.0122 and 0.14, respectively. Because of the relatively low permeability of CyA across the tubular epithelium, no apparent equilibrium between Cu and Cp at any urine flow rate was reached and, therefore, the Cu to Cp ratio will not be equal to fu.  相似文献   
4.
5.
As technology continues to improve, we are increasingly able to detect the presence of HPV in both clinically diseased and histologically and clinically normal vulvar tissue. Unfortunately, the technology for effective treatment of these conditions has not advanced as rapidly. Still, fundamental information about the interaction of HPV with the host cell continues to be collected and will provide us with an increased understanding of the importance of latent infection and its progression to clinical vulvar disease. There are a host of therapeutic modalities available for the treatment of HPV-associated conditions of the vulva, ranging from simple topical medication like podophyllin to sophisticated combination therapies involving carbon dioxide laser destruction in conjunction with interferon. Regrettably, there is no "magic bullet" that is totally effective for any of the HPV-associated vulvar diseases. This makes it more important to weigh the benefits and morbidity of treatment regimens before they are used. Until the success rate of available therapies improves, it is important to have definitive goals for therapy, because it is currently impossible to completely eradicate HPV from tissues. Examples of therapeutic goals might range from removal of visible lesions or treatment of symptomatic areas to treatment of premalignant or malignant lesions. At present, perhaps the most important service we can provide for patients is close follow-up of HPV-associated vulvar diseases in an attempt to prevent the development of invasive malignancy. Regardless of the choice of treatment, the primary objective of the clinician should be to help the patient but to do no harm.  相似文献   
6.
Previous studies have suggested that human follicular fluid contains factors that reduce the zona-binding capacity of spermatozoa. The present study provides further evidence of the existence of such factors. Using the hemizona binding assay (HZA), we have shown that the inhibitory effect of human follicular fluid on the zona-binding capacity of spermatozoa is concentration-dependent, an inhibitory effect being detected when the concentration of human follicular fluid was > or = 10%. A 1% concentration of human follicular fluid did not possess this inhibitory activity. Heating human follicular fluid at 56 degrees C for 30 min did not affect its inhibitory properties; treatment with proteinase-K abolished such inhibition. Human follicular fluid was fractionated sequentially by concanavalin-A affinity chromatography, Mono Q ion-exchange chromatography and Superose-12 gel filtration. The zona binding inhibitory activity resided in the fraction which bound to the lectin and Mono Q column and contained molecules with native molecular weights of 32 and 192 kDa. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis suggested that the 192 kDa glycoprotein was a tetramer, while the 32 kDa glycoprotein remained as a single molecular species under denaturing conditions. We conclude that two glycoproteins were responsible for the zona binding inhibitory activity of human follicular fluid. The physiological role of these factors remains unclear.   相似文献   
7.
Respond on comments on Lieberman's article: Cyclosiloxanes Produce Fatal Liver and Lung Damage in Mice. Environ Health Perspect 107:161-165  相似文献   
8.
The distribution of currently available anti-HIV drugs into the CNS is reviewed with a focus on transport mechanisms. Among these drugs, nucleoside analogs are most well studied for their CNS distribution. The average reported values of the CSF/plasma steady-state concentration or corresponding AUC ratios are 0.23 (AZT), 0.06 (ddI), 0.04 (ddC), 0.49 (d4T), and 0.08 (3TC). Active efflux transport out of the CNS appears to be a predominant mechanism limiting nucleoside access to the CNS, although poor penetration may contribute to some extent for some polar nucleosides. The nature of the efflux pump for these drugs is speculated to be MRP-like transporter(s) in blood-brain and blood-CSF barriers. For non-nucleoside and protease inhibitors, much research remains to be done on the extent, time course, and mechanisms of their CNS distribution. The CNS penetration of some protease inhibitors is restricted by P-glycoprotein. A better understanding of transport mechanisms of anti-HIV drugs in the CNS is essential to develop approaches to enhance CNS delivery of available drugs and to identify new drugs less subject to active efflux transporter(s) in the CNS.  相似文献   
9.
10.
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