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   2590篇
  免费   215篇
  国内免费   91篇
耳鼻咽喉   22篇
儿科学   68篇
妇产科学   29篇
基础医学   266篇
口腔科学   120篇
临床医学   306篇
内科学   480篇
皮肤病学   69篇
神经病学   195篇
特种医学   155篇
外科学   305篇
综合类   155篇
预防医学   181篇
眼科学   179篇
药学   154篇
  1篇
中国医学   8篇
肿瘤学   203篇
  2023年   26篇
  2022年   45篇
  2021年   89篇
  2020年   61篇
  2019年   79篇
  2018年   117篇
  2017年   85篇
  2016年   80篇
  2015年   87篇
  2014年   118篇
  2013年   133篇
  2012年   147篇
  2011年   188篇
  2010年   99篇
  2009年   86篇
  2008年   129篇
  2007年   177篇
  2006年   141篇
  2005年   105篇
  2004年   110篇
  2003年   84篇
  2002年   61篇
  2001年   46篇
  2000年   45篇
  1999年   43篇
  1998年   36篇
  1997年   44篇
  1996年   33篇
  1995年   31篇
  1994年   23篇
  1993年   24篇
  1992年   21篇
  1991年   25篇
  1990年   22篇
  1989年   24篇
  1988年   37篇
  1987年   19篇
  1986年   20篇
  1985年   19篇
  1984年   9篇
  1983年   12篇
  1982年   15篇
  1981年   12篇
  1980年   12篇
  1979年   9篇
  1978年   7篇
  1977年   7篇
  1976年   13篇
  1975年   14篇
  1970年   4篇
排序方式: 共有2896条查询结果,搜索用时 15 毫秒
991.
The effect of leucine5 -enkephalin on angiotensin II (AII)-stimulated release of oxytocin and vasopressin (VP) was investigated in the conscious male rat. Changes in the plasma concentration ([]) of both oxytocin and VP were measured in animals: (1) 60 s after intracerebroventricular (i.v.t.) administration of either artificial cerebrospinal fluid (CSF) or CSF with AII (10, 50, 100 ng/5 microliter); (2) 30, 60, 90 and 300 s after single injection of AII (50 ng/5 microliter; i.v.t.) or CSF and (3) 60 s after AII (50 ng/5 microliter) or CSF in animals pretreated with leucine5 -enkephalin (100 ng/5 microliter; i.v.t.) or CSF (5 microliter). Oxytocin and VP were quantified by radioimmunoassay and values corrected for 100% recovery. The development of a sensitive radioimmunoassay for oxytocin is described. The antiserum for oxytocin enabled detection of greater than or equal to 0.8 pg/ml oxytocin with cross-reactivity of 0.01% with arginine vasopressin and 0.10% with arginine vasotocin. The inter- and intra-assay coefficients of variation were 3-9% and 3.2%, respectively. The hypotheses being tested were that i.v.t. injection of AII stimulates release of both neurohypophysial hormones non-selectively and that leucine5 -enkephalin inhibits both AII-stimulated oxytocin and VP release. Angiotensin II at doses ranging from 10 to 100 ng/5 microliter, i.v.t. increased the plasma concentration of both oxytocin and VP. Plasma levels of both neurohypophysial hormones were elevated 30 s after AII administration i.v.t. and remained elevated 300 sec later.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
992.
The Ministry of Health (MOH) has developed the clinical practice guidelines on Prevention, Diagnosis and Management of Tuberculosis to provide doctors and patients in Singapore with evidence-based treatment for tuberculosis. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Prevention, Diagnosis and Management of Tuberculosis, for the information of SMJ readers. The chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website: http://www.moh.gov.sg/content/moh_web/healthprofessionalsportal/doctors/guidelines/cpg_medical.html. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.  相似文献   
993.
The aim of this study was to investigate whether there is a reduction in radiation dose and improvement in image quality of pediatric cardiac computed tomography scans performed using the high-pitch spiral technique on a new third-generation dual-source 2 × 192-slice scanner (group B) compared with scans performed using the sequential technique on a single-source 256-slice scanner (group A). We performed a retrospective observational study on 40 patients aged ≤18 years who underwent prospectively electrocardiogram-triggered cardiac computed tomography. Image quality was assessed by pre-defined objective indices and a four-point subjective score. Apart from a higher mean heart rate in group A (P = 0.016), there were otherwise no significant inter-group differences in patient characteristics. The median effective dose was 4.41 mSv (interquartile range 2.58–5.90 mSv) in group A and 0.52 mSv (interquartile range 0.39–0.59 mSv) in group B (P < 0.001), representing a 88 % reduction. Subjective image quality score was significantly better in group B (4 = excellent with no artifact, mode 57.1 %) than in group A (3 = good with mild artifact, mode 57.9 %) (P < 0.001). Noise index, signal-to-noise ratio and contrast-to-noise ratio between both groups were not statistically significant. New third-generation dual-source high-pitch spiral scan technique can deliver excellent image quality with low radiation dose. Our results suggest that it should be considered as a first-choice technique for performing cardiac computed tomography in the pediatric population.  相似文献   
994.
995.
996.
The practice of implant dentistry requires an interdisciplinary approach that integrates the knowledge, skills, and experience of all the disciplines of dentistry into a comprehensive treatment plan. The team must examine the anticipated restorative site to determine the suitability of the existing hard and soft tissues for implant placement. Deficiencies in hard and soft tissue, which prevent ideal implant placement, must be recognized and addressed to ensure a more predictable esthetic outcome. This article outlines a comprehensive interdisciplinary treatment philosophy designed for developing the foundation of optimal esthetics in implant dentistry. Cases are presented to illustrate the utility of interdisciplinary treatment in which specialists are recruited to enhance and improve a patient's dental function and esthetics.  相似文献   
997.
998.
Liu TQ  Ng C  Ma H  Castle D  Hao W  Li LJ 《中华医学杂志(英文版)》2008,121(14):1331-1338
Mental illness is recognized as a significant social and public health problem in China, with approximately 16 million people affected with mental illness according to a report in 2002.^1 In addition, approximately 30 million children and young adolescents are suffering from mood and/or behavioral disorders. Drug and alcohol problems and other psychosocial disorders affecting women, elders and survivors of disasters are also important problems adding to the overall national mental health burden. Research from both China and abroad indicate that mental and behavioral problems will continue to increase in the future. The World Health Organization (WHO) has warned that the financial burden from mental disorders in China will constitute 1/4 of total burden from various diseases in 2020.^1  相似文献   
999.
When multiple anterior teeth are missing, many options of replacement are available. Traditionally, the choice was between a fixed or removable prostheses. Today, with the predictability of dental implants, the options of tooth replacement range from removable partial dentures to implant-supported fixed prostheses. The choice of which restoration that will best provide occlusion and esthetics depends on multiple factors including the number and location of missing teeth, the residual ridge form in relation to the replacement teeth, the relationship of the maxillary and mandibular anterior teeth, the condition of teeth adjacent to the edentulous span, the amount of bone available for implant placement, the patients "smile line" and display of teeth, lip support, and financial constraints. When there is minimal loss of the ridge contour, restorations that emerge from the ridge are the most functional and esthetic restorations, adhesive-type fixed partial dentures, conventional fixed partial dentures, and implant-supported restorations can be indicated with the choice of restoration dependent on a risk benefit and cost benefit analysis. When there is a loss of ridge contour due to residual ridge resorption or trauma, the decision becomes more complex as not only does the tooth structure need to be replaced, the ridge form also has to be replaced. (Figures 1 and 2). This can be assessed clinically as illustrated by Figures 1 and 2 where a dis crepancy in arch form and ridge form in relation to the adjacent teeth and/or opposing arch can be observed. Other considerations are lip support and display of the teeth when smiling. This article presents a case and rationale for implant-supported par tial overdentures. Many authors have written on the merits of com plete overdentures. The complete overdenture has proven to be an improvement over conventional complete prostheses with respect to chewing efficiency, patient comfort and satisfaction. In partial edentulism, the implant-supported overdenture has several advantages, some in common with a removable partial denture.  相似文献   
1000.
To test whether the language we speak influences our behavior even when we are not speaking, we asked speakers of four languages differing in their predominant word orders (English, Turkish, Spanish, and Chinese) to perform two nonverbal tasks: a communicative task (describing an event by using gesture without speech) and a noncommunicative task (reconstructing an event with pictures). We found that the word orders speakers used in their everyday speech did not influence their nonverbal behavior. Surprisingly, speakers of all four languages used the same order and on both nonverbal tasks. This order, actor-patient-act, is analogous to the subject-object-verb pattern found in many languages of the world and, importantly, in newly developing gestural languages. The findings provide evidence for a natural order that we impose on events when describing and reconstructing them nonverbally and exploit when constructing language anew.  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