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   7652篇
  免费   350篇
  国内免费   78篇
耳鼻咽喉   72篇
儿科学   133篇
妇产科学   158篇
基础医学   841篇
口腔科学   134篇
临床医学   474篇
内科学   2085篇
皮肤病学   154篇
神经病学   468篇
特种医学   268篇
外科学   1512篇
综合类   18篇
一般理论   1篇
预防医学   191篇
眼科学   188篇
药学   356篇
中国医学   14篇
肿瘤学   1013篇
  2024年   9篇
  2023年   70篇
  2022年   130篇
  2021年   199篇
  2020年   119篇
  2019年   142篇
  2018年   215篇
  2017年   147篇
  2016年   171篇
  2015年   201篇
  2014年   253篇
  2013年   314篇
  2012年   537篇
  2011年   626篇
  2010年   347篇
  2009年   305篇
  2008年   554篇
  2007年   569篇
  2006年   509篇
  2005年   497篇
  2004年   450篇
  2003年   452篇
  2002年   389篇
  2001年   71篇
  2000年   51篇
  1999年   66篇
  1998年   103篇
  1997年   64篇
  1996年   65篇
  1995年   43篇
  1994年   55篇
  1993年   38篇
  1992年   37篇
  1991年   31篇
  1990年   27篇
  1989年   32篇
  1988年   35篇
  1987年   22篇
  1986年   12篇
  1985年   10篇
  1984年   17篇
  1983年   12篇
  1982年   14篇
  1981年   12篇
  1980年   8篇
  1978年   14篇
  1977年   10篇
  1976年   3篇
  1975年   7篇
  1974年   3篇
排序方式: 共有8080条查询结果,搜索用时 15 毫秒
81.
Pulmonary artery obstruction is a rare complication of acute thoracic aortic dissection. A 74-year-old woman was admitted to hospital with respiratory distress. Computed tomography scan showed right pulmonary artery occlusion and a thoracic aortic dissection of the Stanford A type. Lung perfusion scan revealed a defect in the entire right lung field. These findings mimicked acute pulmonary thromboembolism accompanying aortic dissection. On the other hand, pulmonary angiography revealed a round smooth defect of the right pulmonary artery, indicating an extrinsic compression. The patient finally died of cardiac tamponade. Autopsy disclosed that the right pulmonary artery was compressed by a hematoma in the adventitial space around the pulmonary artery. Such a mechanism of pulmonary artery obstruction caused by acute aortic dissection is unique, and is distinct from that caused by chronic non-dissecting aortic aneurysms, which themselves compress the pulmonary arteries. This complication inevitably follows aortic rupture; therefore, emergency operation to repair the dissected aorta must be performed to avoid the following catastrophic event.  相似文献   
82.
A 73-year-old woman was admitted with consciousness disturbance following a fever. Abdominal computed tomography revealed a large liver abscess with which the presence of Desulfovibrio desulfuricans and Escherichia coli was confirmed by thorough blood and abscess content culture. Empiric meropenem treatment was switched to cefoperazone/sulbactam, followed by ampicillin/sulbactam based on susceptibility testing. Desulfovibrio desulfuricans is a common bacterium that rarely causes liver abscess and may be overlooked during co-infection due to overgrowth of the accompanying bacteria. Clinicians should bear Desulfovibrio desulfuricans in mind and select the appropriate antibiotics according to susceptibility testing when anaerobic bacteria are detected in a liver abscess.  相似文献   
83.
It has been suggested that pain control during intracavitary brachytherapy for cervical cancer is insufficient in most hospitals in Japan. Our hospital began using caudal epidural anesthesia during high-dose-rate (HDR) intracavitary brachytherapy in 2011. The purpose of the present study was to retrospectively investigate the effects of caudal epidural anesthesia during HDR intracavitary brachytherapy for cervical cancer patients. Caudal epidural anesthesia for 34 cervical cancer patients was performed during HDR intracavitary brachytherapy between October 2011 and August 2013. We used the patients'' self-reported Numeric Rating Scale (NRS) score at the first session of HDR intracavitary brachytherapy as a subjective evaluation of pain. We compared NRS scores of the patients with anesthesia with those of 30 patients who underwent HDR intracavitary brachytherapy without sacral epidural anesthesia at our hospital between May 2010 and August 2011. Caudal epidural anesthesia succeeded in 33 patients (97%), and the NRS score was recorded in 30 patients. The mean NRS score of the anesthesia group was 5.17 ± 2.97, significantly lower than that of the control group''s 6.80 ± 2.59 (P = 0.035). The caudal epidural block resulted in no side-effects. Caudal epidural anesthesia is an effective and safe anesthesia option during HDR intracavitary brachytherapy for cervical cancer.  相似文献   
84.
To monitor the development of specific and cross-reactive antibody response in twenty Japanese volunteers after vaccination with live yellow fever vaccine. Serum samples were collected on various days after vaccination and examined for hemagglutination inhibition (HI) antibodies against yellow fever virus (YFV), Japanese encephalitis virus (JEV) and dengue virus (DV), neutralizing antibodies against YFV and JEV, and IgM antibodies against YFV. None of the volunteers had been previously immunized with this vaccine. Fifteen of 20 had pre-vaccinated with JEV 7 to 40 years before. Ten of the 20 had neutralizing antibodies against JEV before immunization. None of the 20 had detectable antibodies against YFV or DV before vaccination. On day 10th after the vaccination, neutralizing antibodies to YFV were detected in 6 of 19 volunteers and IgM antibodies against YFV were detected in 7 of 19. On day 14th, HI, neutralizing, and IgM antibodies against YFV were detected in all the tested sera. Neutralizing antibodies against JEV were developed in 2 volunteers and HI antibodies against JEV were increased in 3 of 6 volunteers respectively. On day 29th, cross-reactive HI antibodies for JEV and DV were detected in all the tested sera. The results indicate that YF vaccine induces YFV-specific antibodies in all the tested volunteers and that it also induces HI antibodies cross-reactive for JEV and DV. The YF vaccine has a strong immunogenicity because it is a live vaccine, and induces antibody against YFV predominantly. The international certificate of yellow fever vaccination becomes valid 10 days after vaccination. On day 14th after vaccination, we detected neutralizing antibodies against YFV from all tested volunteers, however, only 6 of 19 volunteers had detectable neutralizing antibody on the 10th day after vaccination. Therefore, the vaccine may not be perfectly effective on day 10th after the vaccination.  相似文献   
85.
In the narrowed upper airway of patients with obstructive sleep apnea (OSA), a neuromuscular compensatory mechanism augments the activity of the upper airway dilator muscles in defense of upper airway patency, particularly during inspiration. We hypothesized that mechanical enlargement of the upper airway by a mandibular advancement oral appliance would permit a reduction in this neuromuscular compensation during wakefulness. To test this hypothesis, we focused on changes in the cross-sectional (CS) area of the upper airway before and after emplacement of a ventrally titrated oral appliance in 12 awake OSA patients. The CS areas at the end of tidal expiration (CS area-EET) and at the nadir of intraluminal pressure during inspiration (CS area-IN) were obtained using videoendoscopy. The median apnea–hypopnea index decreased with mandibular advancement. Before mandibular advancement, there was no difference between CS area-EET and CS area-IN in the velopharynx, oropharynx, and hypopharynx. This indicates that upper airway dilator muscle activity increased during inspiration to counteract the intraluminal negative pressure of the upper airway. After mandibular advancement, CS area-EET increased in the velopharynx, oropharynx, and hypopharynx, but CS area-IN was unchanged at any level and was less than CS area-EET in the velopharynx and oropharynx. These findings suggest that mandibular advancement enlarges the upper airway and may reduce upper airway dilator muscle activity during inspiration. We conclude that oral appliances act to return the upper airway towards a normal configuration and pattern of muscle function in OSA patients.  相似文献   
86.
BACKGROUND: The small dense low-density lipoprotein (LDL) phenotype (pattern B), high concentrations of remnant-like particles (RLPs), and postprandial lipemia are newly recognized risk factors for coronary heart disease (CHD). However, the associations of these lipoprotein abnormalities remain unclear. The aim of this study was to investigate the relationships among LDL phenotype, very-low-density lipoprotein (VLDL) subclasses, and postprandial lipoprotein metabolism in CHD patients. METHOD: We performed an oral fat tolerance test in 32 patients with acute myocardial infarction and compared the following parameters between patients characterized by either large buoyant LDL (pattern A) versus pattern B: lipids and apolipoproteins (apo) in the plasma and Svedberg flotation rates (Sf) >400 (chylomicron), Sf 60-400 (large VLDL), and Sf 20-60 (small VLDL) fractions. RESULT: Fasting levels of triglyceride, RLP-cholesterol and RLP-triglyceride were slightly higher in the pattern B patients. Postprandial increases of RLP-cholesterol and the cholesterol and triglyceride of large VLDL fractions were significantly greater in the pattern B patients. The areas under the curves of cholesterol, triglyceride, and apo-B in large VLDL fractions were significantly higher in pattern B, while those in small VLDL were not. RLP-cholesterol and RLP-triglyceride in fasting and fed states correlated very highly with the corresponding cholesterol and triglyceride concentrations in large VLDL fractions. CONCLUSION: These results suggest that postprandial increase of large VLDL fractions and RLPs contribute to the formation of small dense LDL in CHD patients.  相似文献   
87.
A 54-year-old woman had an episode of sudden oral bleeding and generalized petechiae 1 week after a sore throat and diarrhea. On admission, the platelet count was 0.1 x 10(4)/microl, and the platelet-associated IgG level was elevated. Hyperplasia of megakaryocytes in a bone marrow specimen and aberrant Epstein-Barr virus (EBV) antibody patterns led to a diagnosis of EBV-associated idiopathic thrombocytopenic purpura (ITP). Prednisolone (PSL) promptly restored her platelet count; however, she developed disorientation and affective lability soon after PSL was tapered. Subsequently, she ran a high fever and developed convulsive seizures. T2-weighted MRI demonstrated a high signal area in the subcortical white matter, and no abnormal findings were found on examination of the cerebrospinal fluid. The diagnosis of acute disseminated encephalomyelitis (ADEM) was made and steroid pulse therapy was started, which resulted in remission of the symptoms without recurrence in the following months. This is the first reported case of ADEM following EBV infection during treatment for ITP. Administration of PSL for ITP might mask the presenting clinical picture of ADEM. The possibility of ADEM should be investigated in patients of ITP following viral infection who develop acute encephalopathy.  相似文献   
88.
89.
90.
A 45-year-old man with intestinal Behçet's disease noticed an enlarged right cervical lymph node, and was diagnosed with diffuse large cell type, non-Hodgkin's lymphoma. The intrapelvic lymph tract was markedly deformed because of recurrent ileocecal ulceration, and conventional lymphoscintigraphy with a common tracer did not abolish the suspicion that lymphoma cells may have invaded the lymph nodes. Dynamic lymphoscintigraphy with a new tracer,99mtechnetium-diethylene triamine pentaacetic acid-human serum albumin, because of its high detection sensitivity, was very useful for excluding this suspicion, and for determining the clinical stage of lymphoma. Combination induction chemotherapy led to complete remission without any adverse effects, but subsequent supportive therapy with same protocol could not be completed because of progression of the intestinal lesions. Special management for the intestinal lesions, such as bowel rest, may be essential with chemotherapy for patients with intestinal Behçet'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