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   10719篇
  免费   965篇
  国内免费   16篇
耳鼻咽喉   79篇
儿科学   250篇
妇产科学   284篇
基础医学   1563篇
口腔科学   266篇
临床医学   1245篇
内科学   2447篇
皮肤病学   84篇
神经病学   816篇
特种医学   486篇
外科学   1281篇
综合类   184篇
一般理论   6篇
预防医学   1301篇
眼科学   108篇
药学   743篇
中国医学   4篇
肿瘤学   553篇
  2021年   143篇
  2020年   92篇
  2019年   146篇
  2018年   160篇
  2017年   101篇
  2016年   149篇
  2015年   149篇
  2014年   262篇
  2013年   326篇
  2012年   457篇
  2011年   527篇
  2010年   310篇
  2009年   250篇
  2008年   509篇
  2007年   464篇
  2006年   468篇
  2005年   439篇
  2004年   368篇
  2003年   356篇
  2002年   343篇
  2001年   324篇
  2000年   321篇
  1999年   293篇
  1998年   140篇
  1997年   117篇
  1996年   127篇
  1995年   102篇
  1994年   87篇
  1992年   271篇
  1991年   251篇
  1990年   245篇
  1989年   233篇
  1988年   227篇
  1987年   195篇
  1986年   228篇
  1985年   199篇
  1984年   189篇
  1983年   177篇
  1982年   126篇
  1981年   103篇
  1980年   91篇
  1979年   163篇
  1978年   122篇
  1977年   112篇
  1976年   94篇
  1975年   87篇
  1974年   110篇
  1973年   105篇
  1972年   89篇
  1968年   88篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
82.
It was predicted, based on a mathematical model of the cortex, that early music training would enhance spatial-temporal reasoning. We have demonstrated that preschool children given six months of piano keyboard lessons improved dramatically on spatial-temporal reasoning while children in appropriate control groups did not improve. It was then predicted that the enhanced spatial-temporal reasoning from piano keyboard training could lead to enhanced learning of specific math concepts, in particular proportional math, which is notoriously difficult to teach using the usual language-analytic methods. We report here the development of Spatial-Temporal Math Video Game software designed to teach fractions and proportional math, and its strikingly successful use in a study involving 237 second-grade children (age range six years eight months-eight years five months). Furthermore, as predicted, children given piano keyboard training along with the Math Video Game training scored significantly higher on proportional math and fractions than children given a control training along with the Math Video Game. These results were readily measured using the companion Math Video Game Evaluation Program. The training time necessary for children on the Math Video Game is very short, and they rapidly reach a high level of performance. This suggests that, as predicted, we are tapping into fundamental cortical processes of spatial-temporal reasoning. This spatial-temporal approach is easily generalized to teach other math and science concepts in a complementary manner to traditional language-analytic methods, and at a younger age. The neural mechanisms involved in thinking through fractions and proportional math during training with the Math Video Game might be investigated in EEG coherence studies along with priming by specific music.  相似文献   
83.
84.
85.

Purpose

To present the first photographed bronchoscopic findings associated with negative pressure pulmonary oedema (NPPE).

Clinical features

A previously healthy patient underwent anterior C3–C4 disc removal and arthrodesis. Following tracheal extubation he developed acute respiratory distress manifested as stridor, tachypnoea, restlessness, and desaturation. Once the trachea was reintubated, he displayed the classic findings of pulmonary oedema. Bronchoscopy was performed to confirm tracheal tube position and to rule out tracheal injury secondary to surgical manipulation. Diffuse punctate haemorrhages were noted throughout the visualised tracheobronchial tree.

Conclusion

We believe that these haemorrhages represent disruption of the bronchial vasculature and may contribute to the clinical presentation of NPPE.  相似文献   
86.
Cytomegalovirus as a risk factor in renal transplantation   总被引:6,自引:0,他引:6  
A prospective study of 276 patients that were greater than 12 years old and received transplants between October 1, 1977 and September 30, 1979 has been undertaken. Any patient with clinical findings compatible with overt cytomegalovirus (CMV) disease was placed on a "CMV disease diagnostic protocol." All diagnosed cases of CMV occurring before November 15, 1979 have been analyzed. Eighty patients (29%) had overt CMV disease. Seventy-two (90%) of them contracted CMV within the first 3 months post-transplant. The incidence of overt CMV varied with donor type. Eight percent (4 of 49), 17% (8 of 48), 20% (5 of 25), 40% (46 of 115) and 43% (15 of 35) of HLA-identical (ID) siblings, non-ID siblings, child donor, cadaveric donor, and parental donor, respectively, contracted CMV disease. Overt clinical CMV disease influenced the graft function and patient survival rates significantly (P < 0.01). Several risk factors have been considered as possible indicators of CMV disease. These include age, sex, diabetic status, time of onset of CMV, donor and recipient CMV complement-fixing (CF) and indirect fluorescence (IF) titers. The same variables were analyzed to determine whether they might also predict the severity of the disease. Donor CF is the single most important risk factor. Recipient serology alone was not found to be a significant risk factor but 15 of 27 (56%) persons who had a negative titer and received a kidney from a donor with a positive CF titer contracted overt CMV. Nine of those 15 (60%) had moderate, severe, or lethal illness.  相似文献   
87.
88.
89.
90.
Peterson AM 《Hospital pharmacy》1991,26(2):110-2, 115-6, 124
Fax technology is the transmission of text and graphic data between two locations via telephone lines. The advantages of this technology include the speed with which a document can be sent anywhere in the world and the decreased cost versus traditional courier and Telex services. Several different types of machines exist, but standard operating parameters are set by the Consultative Committee for International Telephone and Telegraph (CCITT). There are four categories of machines, called Groups, which aid in classifying the various fax units. Group 3 machines are the most common comprising about 75% of the market. Standard features vary between and within groups, depending on the manufacturer and model. Features such as polling, document broadcasting, security levels, and computer linkage are discussed. The healthcare industry has been slow to adopt fax technology. Applications in hospital pharmacy are the main focus of attention of some hospital administrators and directors of pharmacy. A few studies have shown decreased medication order turnaround time after implementation of a fax-based pharmacy order system. However, problems such as order clarity and legibility, elevated nursing expectations and increased use of paper can decrease its usefulness. Overall, facsimile technology will find a place in the healthcare arena and may become an integral part of the modern pharmacy department.  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