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   1432篇
  免费   195篇
  国内免费   2篇
耳鼻咽喉   3篇
儿科学   48篇
妇产科学   20篇
基础医学   214篇
口腔科学   20篇
临床医学   121篇
内科学   369篇
皮肤病学   8篇
神经病学   80篇
特种医学   146篇
外科学   93篇
综合类   77篇
预防医学   139篇
眼科学   157篇
药学   95篇
中国医学   1篇
肿瘤学   38篇
  2021年   16篇
  2019年   16篇
  2017年   18篇
  2016年   15篇
  2015年   21篇
  2014年   28篇
  2013年   43篇
  2012年   41篇
  2011年   40篇
  2010年   43篇
  2009年   38篇
  2008年   58篇
  2007年   80篇
  2006年   74篇
  2005年   62篇
  2004年   69篇
  2003年   64篇
  2002年   47篇
  2001年   39篇
  2000年   35篇
  1999年   36篇
  1998年   24篇
  1997年   28篇
  1996年   26篇
  1995年   21篇
  1994年   28篇
  1993年   12篇
  1992年   40篇
  1991年   34篇
  1990年   44篇
  1989年   28篇
  1988年   37篇
  1987年   35篇
  1986年   49篇
  1985年   31篇
  1984年   13篇
  1983年   17篇
  1982年   11篇
  1981年   19篇
  1980年   16篇
  1979年   15篇
  1978年   17篇
  1977年   22篇
  1976年   19篇
  1975年   14篇
  1974年   14篇
  1973年   18篇
  1972年   16篇
  1971年   15篇
  1970年   14篇
排序方式: 共有1629条查询结果,搜索用时 9 毫秒
81.
Laser Doppler perfusion imaging (LDI) is an established technique for early assessment of burn depth to help determine a course of treatment. Laser speckle perfusion imaging (LSPI) is an alternative laser based, non-invasive perfusion monitoring technique that offers rapid and high resolution images of tissue. We have evaluated the ability of the LSPI instrument in determining and monitoring burn scar perfusion over time and compared it with the LDI instrument as a standard. METHODS: Ten patients with hypertrophic burn scars (time since injury: 1-8 months) were recruited. Burn scars were scanned with both instruments (LSPI and LDI) monthly over a period of 11 months. Clinical grading of the burn scars was assessed on every scan date using the Vancouver burn scar scale. RESULTS: Comparison of the perfusion values determined by each instrument shows a strong positive correlation, r2=0.86 (n=63). Each instrument's output also correlated significantly with the clinical grading of the scar, indicating the expected decrease in perfusion as the clinical condition of the scars improved with time. SIGNIFICANCE: The new LSPI instrument compared favorably with the established LDI instrument, yielding similar results. The considerably faster scan time and higher resolution of the LSPI method provides a distinct clinical advantage, both in terms of patient comfort and for reliably matching perfusion characteristics to their associated anatomical features. The fast temporal response of the LSPI instrument could be used to monitor near real-time responses to mechanical or pharmacological interventions to study dynamic vascular changes to burn damaged tissues.  相似文献   
82.
Using data from a birth defects registry, this study examined the epidemiology of hydrocephaly in Hawaii during 1986--2000. There were 294 cases of hydrocephaly, resulting in a rate of 10.4 per 10,000 live births. The hydrocephaly rate was lower with increased maternal age and female sex and higher with lower birth weight, lower gestational age, and multiple gestation pregnancy.  相似文献   
83.
84.
G S Sidhu  E M Forrester 《Cancer》1977,40(5):2209-2215
A clear cell type of bronchiolo-alveolar carcinoma removed from the lung of a 63-year-old man was studied by light and electron microscopy. The tumor was composed exclusively of Clara cells identified by the presence of secretory granules, an abundance of granular endoplasmic reticulum, a moderate number of mitochondria and prominent Golgi complexes. The tumor cells were tall columnar and had clear cytoplasm due to the presence of large pools of intracytoplasmic glycogen. This feature has not heretofore been described. Ultrastructural features distinguishing this tumor from benign clear cell tumors of the lung and clear cell carcinomas of the kidney are described.  相似文献   
85.
In an effort to clarify the conformational requirements, if any, of agents producing adrenergic neuronal blockade through mechanisms similar to guanethidine, the synthesis and pharmacological evaluation of 15 analogues of cinnamylguanidine are described. These analogues represent derivatives in which the distance between the center of the ring system and the guanidinium nitrogen atom varies from 3.9 to 6.2 A. While conformational relationships could not be defined in this study, three analogues (3, 4, and 5) were apparently more potent than guanethidine in the in vitro assay employed.  相似文献   
86.
87.
As an alternative to performing interventional radiology on inpatients under the care of internists and surgeons, the authors have established a cardiovascular radiology admitting service for well-screened, elective patients. The patients are admitted under the care of a cardiovascular radiology fellow and a staff physician. From April 1982 to December 1983, 133 patients were admitted to the service. Patients are cared for in a surgical ward or in an intermediate unit, as determined by the clinical situation. Advantages of this approach include a broader patient referral base, improved rapport with clinical colleagues and patients, improved follow-up data, and rapid evaluation and treatment, resulting in short hospital stays. The major disadvantages involve the commitment of time and staff necessary to provide quality care. The concept of the interventional radiologist in the role of admitting physician has important implications in terms of negotiations for additional financial compensation, commensurate with the skill and time required for performing these procedures and caring for the patient.  相似文献   
88.
OBJECTIVES: This field study tested the feasibility and benefits of a program to promote 6 targeted parental behaviors to prevent obesity in children served by the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). METHODS: Two WIC sites participated in a nonrandomized, controlled 1-year prospective study to assess parents' self-reported behavior changes. RESULTS: Statistical analyses of preintervention and postintervention assessments of parental behavior demonstrated significant changes in 2 behaviors: frequency of offering the child water and frequency of engaging in active play with the child. In both cases, the intervention proved effective in increasing the desired behavior. CONCLUSIONS: The findings demonstrate the feasibility of changing parental behaviors through multidimensional education in a WIC clinic setting.  相似文献   
89.
Harnessing the power of the immune system to eliminate infection and cancer is a long-standing goal in clinical immunology. The development of a robust immune response to foreign antigen relies, in part, on communication between cellular components of the immune system. The proteins involved in governing the magnitude and longevity of an immune response are collectively called cytokines. Cytokines act directly on immune cells to induce proliferation, differentiation and tolerance, and signaling errors can lead to autoimmune disease or immune deficiency. Identification of the molecules involved in these signaling processes has allowed investigators to manipulate immune cells for therapeutic effect, both in vivo and ex vivo. While in vivo immune modulation using cytokines has produced some exciting results, the toxicity involved with systemic administration has limited their broad use in the clinic. Therefore, research has been focused on the ex vivo manipulation of immune cells for adoptive transfer to treat cancer and infection. This review will focus on the ex vivo manipulation of immune cells with particular emphasis on stimulating cytotoxic T cell responses. Adoptive transfer of ex vivo generated cell types may then be used to treat malignant and viral disease.  相似文献   
90.
TRANSLATIONAL RESEARCH IN PRACTICE: a PKC-beta inhibitor for diabetic retinopathy  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