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   1376篇
  免费   100篇
  国内免费   12篇
耳鼻咽喉   3篇
儿科学   45篇
妇产科学   18篇
基础医学   164篇
口腔科学   37篇
临床医学   150篇
内科学   334篇
皮肤病学   19篇
神经病学   75篇
特种医学   20篇
外科学   176篇
综合类   59篇
预防医学   168篇
眼科学   44篇
药学   68篇
中国医学   12篇
肿瘤学   96篇
  2024年   3篇
  2023年   21篇
  2022年   67篇
  2021年   77篇
  2020年   46篇
  2019年   61篇
  2018年   89篇
  2017年   50篇
  2016年   51篇
  2015年   40篇
  2014年   73篇
  2013年   68篇
  2012年   104篇
  2011年   91篇
  2010年   55篇
  2009年   37篇
  2008年   59篇
  2007年   80篇
  2006年   58篇
  2005年   44篇
  2004年   25篇
  2003年   35篇
  2002年   27篇
  2001年   24篇
  2000年   18篇
  1999年   17篇
  1998年   15篇
  1997年   6篇
  1996年   10篇
  1995年   7篇
  1994年   5篇
  1993年   4篇
  1992年   16篇
  1991年   13篇
  1990年   10篇
  1989年   16篇
  1988年   12篇
  1987年   16篇
  1986年   8篇
  1985年   7篇
  1984年   5篇
  1983年   2篇
  1979年   3篇
  1978年   3篇
  1976年   1篇
  1975年   2篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
  1966年   2篇
排序方式: 共有1488条查询结果,搜索用时 573 毫秒
121.
Hepatic vena cava disease: Etiologic relation to bacterial infection   总被引:2,自引:0,他引:2  
Aim: Hepatic vena cava disease is a primary obliterative disease of the hepatic portion of the inferior vena cava (IVC) that often causes liver cirrhosis and hepatocellular carcinoma. Its geographic prevalence is inversely related to the standard of community hygiene. The disease is endemic in Nepal and is commonly associated with bacterial infection. The cause of the disease is not known. It was previously thought to be congenital. Thrombosis due to hypercoagulable condition is suggested as a possible cause of the disease. This study looks at the relation of the disease to bacterial infection. Methods: Ultrasonography is sensitive and specific for the diagnosis of acute and chronic lesions of hepatic vena cava disease. Patients attending the Liver Clinic with pyrexia with and without bacteremia were examined by ultrasonography for acute "thrombophlebitic" lesion of the IVC, and five patients with bacterial infection with acute lesion in the hepatic portion of the IVC were followed. Results: Sixty eight percent of the patients with bacteremia had ultrasonographic evidence of acute lesion in the hepatic portion of the IVC, compared to 18% patients without bacteremia. A follow-up study of five patients showed transformation of the acute lesion into chronic obliterative lesion - stenosis or complete obstruction. Conclusion: Bacterial infection is probably the cause of hepatic vena cava disease seen in developing countries.  相似文献   
122.
The safety of total arterial revascularization with a left internal thoracic artery-radial artery T-graft was evaluated in patients with at least two-vessel coronary artery disease and aortic valve stenosis requiring concomitant aortic valve replacement. From June 2001 to January 2005, 18 patients underwent aortic valve replacement and total arterial revascularization, while 101 had aortic valve replacement and conventional grafting. By matching age, sex, left ventricular ejection fraction, and number of distal anastomoses, 1:2 matched groups were generated: 15 patients with a left internal thoracic-radial artery T-graft, and 30 with left internal thoracic artery and additional vein grafts. Aortic cross clamp and cardiopulmonary bypass times were similar in both groups. There were no significant differences in postoperative data between the groups. Early mortality was 0% in the T-graft group and 2% in those with conventional grafts. Follow-up ranged from 2 to 50 months. Event-free survival was 100% in the T-graft group and 90% in the conventional graft group. Total arterial grafting with a left internal thoracic-radial artery T-graft can be performed in selected patients with aortic valve stenosis requiring simultaneous aortic valve replacement.  相似文献   
123.
RATIONALE AND OBJECTIVES: Most health care facilities currently struggle with protecting medical data privacy, misidentification of patients, and long patient waiting times. This article demonstrates a novel system for a clinical environment using wireless tracking and facial biometric technologies to automatically monitor and identify staff and patients to address these problems. MATERIALS AND METHODS: The design of the location tracking and verification system (LTVS) was based on a workflow study which was performed to observe the physical location and movement of patient and staff at the Healthcare Consultation Center II (HCC II) running hospital information systems, radiology information systems, picture archive and communication systems, and a voice recognition system. Based on the results from this workflow study, the LTVS was designed using a wireless real-time location system and a facial biometric system integrated with the radiology information system. The LTVS was tested for its functionality in a laboratory environment, then evaluated at HCC II. RESULTS: Experimental results in the laboratory and clinical environments demonstrated that patient and staff real-time location information and identity verification can be obtained from LTVS. Warning messages can immediately be sent to alert staff when patient's waiting time is over a predefined limit, and unauthorized access to a security area can be audited. Additionally, patient misidentification can be prevented during the course of examinations. CONCLUSIONS: The system enabled health care providers to streamline the patient workflow, protect against erroneous examinations and create a security zone to prevent, and audit unauthorized access to patient health care data required by the Health Insurance Portability and Accountability Act mandate.  相似文献   
124.
After isoniazid and rifampin (rifampicin), the next pivotal drug class in Mycobacterium tuberculosis treatment is the fluoroquinolone class. Mutations in resistance-determining regions (RDR) of the rpoB, katG, and gyrA genes occur with frequencies of 97%, 50%, and 85% among M. tuberculosis isolates resistant to rifampin, isoniazid, and fluoroquinolones, respectively. Sequences are highly conserved, and certain mutations correlate well with phenotypic resistance. We developed a pyrosequencing assay to determine M. tuberculosis genotypic resistance to rifampin, isoniazid, and fluoroquinolones. We characterized 102 M. tuberculosis clinical isolates from the Philippines for susceptibility to rifampin, isoniazid, and ofloxacin by using the conventional submerged-disk proportion method and validated our pyrosequencing assay using these isolates. DNA was extracted and amplified by using PCR primers directed toward the RDR of the rpoB, katG, and gyrA genes, and pyrosequencing was performed on the extracts. The M. tuberculosis H37Rv strain (ATCC 25618) was used as the reference strain. The sensitivities and specificities of pyrosequencing were 96.7% and 97.3%, 63.8% and 100%, and 70.0% and 100% for the detection of resistance to rifampin, isoniazid, and ofloxacin, respectively. Pyrosequencing is thus a rapid and accurate method for detecting M. tuberculosis resistance to these three drugs.Rifampin (rifampicin), isoniazid, and the fluoroquinolones are the most important initial drug markers for extensively drug-resistant Mycobacterium tuberculosis strains, defined as multidrug-resistant (MDR) isolates (resistant to both isoniazid and rifampin) with additional resistance to a fluoroquinolone and to one of the injectable drugs (2). The fluoroquinolones have become an essential part of treatment regimens for MDR tuberculosis (7, 25). Due to their potency and safety, the new-generation fluoroquinolones are now even being evaluated as first-line medications for tuberculosis (3, 13, 20). Wang et al. further suggested that routine fluoroquinolone resistance testing may have a clinical impact by showing a significant correlation between development of fluoroquinolone and first-line M. tuberculosis drug resistance in an area in which resistant strains are highly endemic (28).The spontaneous acquisition of DNA sequence mutations is the primary genetic basis for the development of M. tuberculosis drug resistance (14). Since sequences are highly conserved, certain mutations correlate well with phenotypic resistance, and a limited number of mutations account for the majority of phenotypic resistance to the important antituberculosis medications, various methods of genotypic testing have successfully been used for the rapid detection of M. tuberculosis resistance (16, 22). The sites that most frequently contain mutations associated with phenotypic resistance, called resistance-determining regions (RDR), differ depending on the drug tested. Among rifampin-resistant isolates worldwide, 95 to 97% harbor mutations in the rifampin RDR, an 81-bp target encompassing codons 507 to 533 of the 3,519-bp rpoB gene (17). Isoniazid resistance has a more complex mechanism, involving several gene targets, the most important of which is codon 315 of the 2,223-bp katG gene, in which mutations are found in up to 50% of resistant isolates (18). Likewise, M. tuberculosis has a quinolone RDR which spans codons 88 to 94 of the 2,517-bp gyrA gene. Mutations in this region, particularly in codon 88, 90, 91, or 94, correlate with high-level resistance and are seen in 42 to 85% of resistant clinical isolates (6).Pyrosequencing, a method of DNA sequencing by synthesis, has been applied to the rapid detection of M. tuberculosis resistance to rifampin, isoniazid, and ethambutol (9, 29). Its main advantage is a much shorter turnaround time than that of conventional drug susceptibility testing, the latter taking 2 to 4 weeks from the time an isolate is obtained in pure culture.After isoniazid and rifampin, the next pivotal drug class in M. tuberculosis treatment is the fluoroquinolone class, as previously discussed (3, 7, 13, 20, 25, 28). Given that most resistance to the latter is determined by mutations that are generally limited to the quinolone RDR of the gyrA gene, it should be feasible and clinically more relevant to develop an assay for rapid resistance testing which includes fluoroquinolone resistance in addition to rifampin and isoniazid resistance.We developed a pyrosequencing assay to determine M. tuberculosis genotypic resistance to rifampin, isoniazid, and fluoroquinolones, which we validated against the conventional submerged-disk proportion method. We also improved on the previously reported pyrosequencing assay by reducing the number of primers required to sequence for rifampin resistance (9).  相似文献   
125.
Status epilepticus (SE) is one of the most serious manifestations of epilepsy. Systemic inflammation and damage of blood-brain barrier (BBB) are etiologic cofactors in the pathogenesis of pilocarpine SE while acute osmotic disruption of the BBB is sufficient to elicit seizures. Whether an inflammatory-vascular-BBB mechanism could apply to the lithium–pilocarpine model is unknown. LiCl facilitated seizures induced by low-dose pilocarpine by activation of circulating T-lymphocytes and mononuclear cells. Serum IL-1β levels increased and BBB damage occurred concurrently to increased theta EEG activity. These events occurred prior to SE induced by cholinergic exposure. SE was elicited by lithium and pilocarpine irrespective of their sequence of administration supporting a common pathogenetic mechanism. Since IL-1β is an etiologic trigger for BBB breakdown and its serum elevation occurs before onset of SE early after LiCl and pilocarpine injections, we tested the hypothesis that intravenous administration of IL-1 receptor antagonists (IL-1ra) may prevent pilocarpine-induced seizures. Animals pre-treated with IL-1ra exhibited significant reduction of SE onset and of BBB damage. Our data support the concept of targeting systemic inflammation and BBB for the prevention of status epilepticus.  相似文献   
126.

Aims

Axillary nodal status is the most important prognostic indicator which in turn influences adjuvant therapy and long term outcomes. The aim of this study was to compare total nodal yields from primary axillary lymph node dissection (pALND) with completion ALND after a cancer positive SLNB: either concurrently (cALND) following intra-operative assessment (IOA) of the SLN’s or as a delayed procedure (dALND) when the SLN was found to be cancer positive on post-operative histological examination.

Methods

All axillary procedures performed between May 2006 and September 2009 were identified from a prospective database and categorised into four groups: SLNB with no further axillary surgery, pALND, cALND and dALND. Total nodal yield was the sum of SLN/s and ALND yields.

Results

Of 1025 axillary procedures, ALND accounted for 332 (32.4%) of which 207 (62.3%) underwent pALND, 43 (12.9%) cALND, and 82 (24.6%) dALND. Median nodal yields were 15.0, 16.0 and 14.5 respectively (p = 0.3).

Conclusion

Total nodal yields for primary, concurrent and delayed ALND were comparable suggesting completion dALND performed as a second operation does not compromise axillary staging.  相似文献   
127.
In a lethal West Nile virus (WNV) model, central nervous system infection triggered a threefold increase in CD45(int)/CD11b(+)/CD11c(-) microglia at days 6-7 postinfection (p.i.). Few microglia were proliferating, suggesting that the increased numbers were derived from a migratory precursor cell. Depletion of "circulating" (Gr1(-)(Ly6C(lo))CX3CR1(+)) and "inflammatory" (Gr1(hi)/Ly6C(hi)/CCR2(+)) classical monocytes during infection abrogated the increase in microglia. C57BL/6 chimeras reconstituted with cFMS-enhanced green fluorescent protein (EGFP) bone marrow (BM) showed large numbers of peripherally derived (GFP(+)) microglia expressing GR1(+)(Ly6C(+)) at day 7 p.i., suggesting that the inflammatory monocyte is a microglial precursor. This was confirmed by adoptive transfer of labeled BM (Ly6C(hi)/CD115(+)) or circulating inflammatory monocytes that trafficked to the WNV-infected brain and expressed a microglial phenotype. CCL2 is a chemokine that is highly expressed during WNV infection and important in inflammatory monocyte trafficking. Neutralization of CCL2 not only reduced the number of GFP(+) microglia in the brain during WNV infection but prolonged the life of infected animals. Therefore, CCL2-dependent inflammatory monocyte migration is critical for increases in microglia during WNV infection and may also play a pathogenic role during WNV encephalitis.  相似文献   
128.
Penetrating chest trauma involving the heart is usually known with a high mortality rate. Neither the absence of hemodynamic depression nor ECG changes exclude a potential fatal injury to the heart. We report on the diagnosis and definitive treatment of a stab wound injury with transected coronary artery, concomittant ventricular penetration, and pulmonary injury.A 37-year-old female was admitted to our emergency room with multiple left-sided gashes (cheek, neck, upper extremity) and a single stab wound in the left thorax. At the scene of the accident the patient's hemodynamic condition was stable with no signs of shock or shortness of breath. Auscultation revealed regular respiratory sound on both lung sides. Hospital transfer by ground was uneventful. Chest X-ray showed left pleural effusion with no signs of pneumothorax. ECG demonstrated regular sinus rhythm without repolarization changes or low voltage. Transthoracic echocardiography revealed pericardial effusion with a swinging heart. The patient was electively intubated in the emergency room and transferred to the operating room for pericardial paracentesis. Median sternotomy was necessary due to extensive bleeding in the drain. Examination of the heart showed a laceration of the left coronary artery (LAD), left ventricle, and upper lobe of the left lung. Cardiopulmonary bypass was instituted and the LAD was ligated proximal to the penetration. The left internal thoracic artery was used for coronary revascularization of the LAD. Postoperative ECG and creatine kinase evaluations excluded myocardial ischemia. The patient was discharged from hospital at POD 10 fully recovered. Transthoracic echocardiography in the emergency room is the diagnostic tool of choice to exclude/confirm a potential cardiac injury. In the case of pericardial effusion, paracentesis sometimes followed by thoracotomy should be performed. The importance of rapid diagnosis and intervention should be emphasized to reduce mortality due to cardiac tamponade or acute myocardial infarction as illustrated by this case.  相似文献   
129.
130.
BACKGROUND: The morbidity and mortality from donation of a right hepatic lobe for living donor liver transplantation (LDLT) is an important issue for this procedure. We report the prevalence of severe psychiatric postoperative complications from the Adult-to-Adult Living Donor Liver Transplantation Cohort study (A2ALL), which was established to define the risks and benefits of LDLT for donors and recipients. METHODS: Severe psychiatric complications were evaluated in all donors from the A2ALL study who were evaluated between 1998 and February 2003. RESULTS: Of the 392 donors, 16 (4.1%) had one or multiple psychiatric complications, including three severe psychiatric complications (suicide, accidental drug overdose, and suicide attempt). CONCLUSIONS: Despite extensive preoperative screening, some donors experience severe psychiatric complications, including suicide, after liver donation. Psychiatric assessment and monitoring of liver donors may help to understand and prevent such tragic events.  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