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   2550篇
  免费   161篇
  国内免费   8篇
耳鼻咽喉   18篇
儿科学   153篇
妇产科学   43篇
基础医学   283篇
口腔科学   55篇
临床医学   144篇
内科学   598篇
皮肤病学   81篇
神经病学   82篇
特种医学   100篇
外科学   549篇
综合类   39篇
预防医学   95篇
眼科学   119篇
药学   194篇
中国医学   12篇
肿瘤学   154篇
  2023年   33篇
  2022年   37篇
  2021年   119篇
  2020年   71篇
  2019年   92篇
  2018年   125篇
  2017年   67篇
  2016年   50篇
  2015年   85篇
  2014年   128篇
  2013年   107篇
  2012年   175篇
  2011年   175篇
  2010年   124篇
  2009年   95篇
  2008年   143篇
  2007年   186篇
  2006年   136篇
  2005年   117篇
  2004年   76篇
  2003年   94篇
  2002年   74篇
  2001年   38篇
  2000年   41篇
  1999年   45篇
  1998年   24篇
  1997年   13篇
  1996年   12篇
  1994年   11篇
  1993年   5篇
  1992年   17篇
  1991年   13篇
  1990年   8篇
  1989年   14篇
  1988年   10篇
  1987年   5篇
  1986年   6篇
  1985年   6篇
  1984年   10篇
  1979年   13篇
  1978年   11篇
  1977年   5篇
  1976年   11篇
  1975年   5篇
  1973年   10篇
  1972年   5篇
  1971年   7篇
  1970年   11篇
  1969年   13篇
  1963年   5篇
排序方式: 共有2719条查询结果,搜索用时 15 毫秒
61.
Surgical emphysema is defined as gas or air trapped in the subcutaneous tissue plane. Here, we report a rare case of bilateral periorbital and cervicofacial subcutaneous emphysema following a vitreoretinal surgery for inadvertent globe perforation during the administration of peribulbar anesthesia. This condition, although self-resolving when restricted to the subcutaneous plane has the potential to spread into deeper tissue planes such as the retropharyngeal space. The presence of crepitus helps to distinguish it from angioneurotic edema. Ophthalmologists must be sensitive to the fact that surgical emphysema can be a very rare, but possible complication of an intraocular surgery following globe perforation.  相似文献   
62.
Schwannomas are benign, encapsulated, primary neurilemmal tumors composed of proliferating Schwann cells. Schwannomas are commonly seen in the orbit, but are rare on the epibulbar surface. Herein, we report a case of a 12-year-old boy who presented to us with a slow-growing painless subconjunctival mass in the left eye. There was no intraocular extension of the mass and intra-operatively, the mass could be clearly delineated and was excised off the underlying sclera. Histopathological examination of the mass showed typical features of schwannoma and immunohistochemistry helped to confirm the diagnosis. There was no recurrence of the lesion observed at follow-up 26 months after surgery. Here, we describe this uncommon tumor and review the available literature. Although rare, an epibulbar schwannoma should be considered in the differential diagnosis of an amelanotic, painless subconjunctival nodular mass. Excision of the lesion is the recommended treatment.  相似文献   
63.
Early mixed chimerism (MC) can lead to secondary graft rejection post allogeneic hematopoietic stem cell transplantation in transfusion dependent thalassemia (TDT) patients. Reduction of immunosuppression and donor lymphocyte infusions is the mainstay for treating MC. We report our experience of administering unmanipulated stem cell boost (SCB) in reversing progressive early MC. There were 70 transplants done for 69 TDT patients at our center between September 2005 and January 2020. Mixed chimerism was defined by > 5% recipient cells and the severity was assigned according to the proportion of recipient cells as level 1 =  < 10%, level 2 = 10–25%, level 3 =  > 25%. For patients developing MC level 2 and 3, we administered unmanipulated SCB and analyzed its safety and efficacy. Out of 70 transplants 7 (10%) had MC level 2 (3/7) and 3 (4/7). These patients received unmanipulated SCB at a median CD34 cell dose of 4.5 × 106/kg (range—3.5 × 106/kg–5.5 × 106/kg). Overall Response (stable MC and/or transfusion independency) to unmanipulated SCB was seen in 5 patients (71.4%). Five patients (71.4%) developed acute graft versus host disease (GVHD) of which 1 patient expired due to severe GVHD. SCB infusion was well tolerated by majority of our patients. The 3 year overall survival and thalassemia free survival was 85.7% (6/7) and 57.1% (4/7) respectively. Timely monitoring of chimerism is important for detecting early MC. Development of acute GVHD is common after administration of unmanipulated SCB and requires vigilance and prompt management. Unmanipulated SCB is a feasible modality for treating progressive MC and salvaging the graft especially in resource-constrained settings.  相似文献   
64.
We undertook a prospective study to test Simoons' hypothesis that in certain susceptible races milk exerts a cataractogenic effect. Overall milk intake in low lactase deficiency areas did not correlate with cataract occurrence. Subgrouping of cataract patients revealed that greater milk intake did show positive correlation with cortical cataracts. Cortical cataracts were also markedly more common in females. Analysis of data from three different regions showed greater milk intake in cortical cataract patients only. Our data indicate the importance of specifying cataract type in cataract studies and highlight the problem this approach brings forth. We noted no different trends in subjects from northwest and southeast India, although the number of subjects from the southeast was considerably less. Patients with early cortical cataracts may be advised to restrict milk intake.Part of this material was presented at second cataract epidemiology meeting at Bonn in March 1988. A brief report has been accepted for publication in the proceedings of the meeting to be published inDevelopment of Ophthalmology, Vol. 17, 1988.  相似文献   
65.
BACKGROUND: Comparative trials of ursodeoxycholic acid (UDCA), vitamin E and weight management programs among patients with nonalcoholic fatty liver disease (NAFLD) are lacking. AIM: To find an effective single agent or combination of agents for management of NAFLD. METHODS: In this retrospective study, consecutive patient with histologically confirmed NAFLD with raised ALT were included. The patients received either weight management (exercise and therapeutic lifestyle changes [TLC] diet with a target to reduce body weight 10% in 6 months) (group I) ; weight management + UDCA (300 mg BID) (group II); or weight management + UDCA + vitamin E (400 mg OD) (group III). Outcome measure was normalization of ALT. RESULTS: 42 patients (18, 12 and 12 in groups I, II and III, respectively) were included between 1996 and 2004. All patients in group III normalized their ALT levels, which was significantly higher than numbers in group I (8/18) and group II (5/12); (p=0.003). Post treatment ALT was significantly lower in group III (28.6 [9.3]) as compared to group I (59.3 [32.2]) and group II (49.0[31.8]); (p=0.01). Type of therapy received was the only factor predictive of ALT normalization. CONCLUSION: Combination regimen containing vitamin E appears to be effective in normalizing ALT among NAFLD patients.  相似文献   
66.
Cardiac G alpha(q)-coupled receptors (such as endothelin, angiotensin, and alpha1-adrenergic receptors) mediate cardiac inotropy and chronotropy, as well as the development of hypertrophy. These receptors signal through protein kinase C (PKC), a family of 12 isozymes including PKC alpha, beta I, beta II, gamma, delta, epsilon, theta, eta, lambda, iota, zeta, and mu. Of these PKC isozymes, alpha, beta II, gamma, epsilon, delta, and zeta have been implicated in signaling through cardiac G alpha(q)-coupled receptors in various animal models. However, the profile of which isozymes are activated by a given G alpha(q)-coupled receptor varies among animal species. Thus, these results can not be extrapolated to human heart. In this study, we examine PKC isozymes activated by three different G alpha(q)-coupled receptors in human atrial tissue. Live atrial appendages obtained from the operating room were sliced and treated with agonists of G alpha(q)-coupled receptors, and cellular redistribution of PKC isozymes was examined by immunoblotting. We find that stimulation of G alpha(q)-coupled receptors in human atrium activates PKC epsilon and delta only, under both acute (5 min) and longer (35 min) stimulations. Further, PKC epsilon and delta exhibit distinct subcellular redistribution patterns; while both translocate to the plasma membrane upon G alpha(q) stimulation, PKC delta also redistributes to mitochondria. We conclude that PKC epsilon and delta are the main PKC isozymes involved in G alpha(q)-mediated signaling in human atria.  相似文献   
67.
Implantable cardioverter-defibrillators (ICDs) are an important nonpharmacological option in the treatment of malignant ventricular arrhythmias. Technological advances in current devices permit nonthoracotomy implantation with transvenous lead systems using biphasic shocks. Decreasing device size has resulted in pectoral implantation. Battery longevity is still short in comparison with that of pacemakers. Lead failure rates as well as pacing thresholds are significantly higher than those for cardiac pacing lead systems. Other complications of ICD systems include infection, perforation, and thrombosis. The long-term performance of nonthoracotomy lead systems for ICD devices has now been extensively studied. Sudden death recurrence rates for these systems are less than 2% in 3 years and less than 5% at 5 years. Clinical trials with both monophasic and biphasic systems show a high degree of prevention of sudden death. Comparison of ICD outcome with that of drug therapy in three large retrospective studies and two small prospective randomized trials favors improved survival and sudden death prevention with device therapy. However, these studies need corroboration from large prospective trials. Two large prospective trials, CIDS and the AVID study, are now in progress to address this issue.  相似文献   
68.
In the study carried out from, February, 1996 to January, 1999. 42 (33.9%) a typical variants of S typhi which fermented sucrose were encountered. This variant was identified as of antigenic structure 9, 12, v1, d1 and typed as phage type E1 and Bio type I.  相似文献   
69.
70.
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