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   909篇
  免费   38篇
  国内免费   7篇
耳鼻咽喉   2篇
儿科学   31篇
妇产科学   5篇
基础医学   63篇
口腔科学   33篇
临床医学   53篇
内科学   140篇
皮肤病学   17篇
神经病学   17篇
特种医学   112篇
外科学   300篇
综合类   24篇
预防医学   44篇
眼科学   4篇
药学   61篇
中国医学   1篇
肿瘤学   47篇
  2021年   25篇
  2020年   5篇
  2019年   5篇
  2018年   12篇
  2017年   10篇
  2016年   26篇
  2015年   21篇
  2014年   25篇
  2013年   42篇
  2012年   35篇
  2011年   26篇
  2010年   36篇
  2009年   33篇
  2008年   18篇
  2007年   25篇
  2006年   44篇
  2005年   26篇
  2004年   22篇
  2003年   33篇
  2002年   30篇
  2001年   16篇
  2000年   18篇
  1999年   27篇
  1998年   39篇
  1997年   28篇
  1996年   25篇
  1995年   15篇
  1994年   22篇
  1993年   26篇
  1992年   7篇
  1991年   11篇
  1990年   7篇
  1989年   19篇
  1988年   29篇
  1987年   14篇
  1986年   23篇
  1985年   14篇
  1984年   10篇
  1983年   8篇
  1982年   9篇
  1981年   13篇
  1980年   14篇
  1979年   5篇
  1978年   5篇
  1977年   9篇
  1976年   11篇
  1975年   7篇
  1972年   4篇
  1969年   3篇
  1965年   2篇
排序方式: 共有954条查询结果,搜索用时 15 毫秒
1.
OBJECTIVE: Nocturnal enuresis is a common pediatric problem, the etiology of which is unclear. In recent years, various studies have been published stating that children with nocturnal enuresis exhibit growth and skeletal maturation retardation. METHODS: In this cross-sectional study, we included 27 patients (16 boys, 11 girls) between the ages of 6 and 14 years who had presented with primary nocturnal enuresis (PNE) complaints. We included in the evaluation 19 healthy subjects (12 boys, 7 girls), who were the siblings of the children with PNE, as the control group. RESULTS: The patients in both groups were similar in chronological age, bone age, height and weight, with no significant difference between groups (P>0.05). CONCLUSION: The two groups in our study consisted of the same genetic background. Thus, our results were found to be different from the previous studies. We have concluded that there is no direct relationship between enuresis nocturnal and skeletal maturation.  相似文献   
2.
3.
J Dvorak  D Grob  H Baumgartner  N Gschwend  W Grauer  S Larsson 《Spine》1989,14(10):1057-1064
Thirty-four patients with atlanto-axial instability due to rheumatoid arthritis were examined with plain x-ray views and functional magnetic resonance imaging (MR), and were neurologically evaluated. Transcranial brain stimulation was performed in 25 patients. In 22 cases, the authors observed inflammatory tissue thicker than 3 mm behind the odontoid peg. The spinal canal diameter was significantly decreased in the flexed position. Nine patients showed signs of cranial migration of the axis. The diameter of the spinal cord was measured to be 7.4 mm in the neutral position, and 6.5 mm in flexion. The difference between the diameter of the neutral and flexed positions was highly significant. Twelve of the 34 patients displayed clinical signs of cervical myelopathy, and 13 showed a significant delay of central motor latency, as calculated from the motor evoked potentials. Surgical intervention, either by a posterior approach only or combined with a transoral dens and inflammatory tissue resection, is recommended in patients with progressive atlanto-axial instability, pathologic clinical and neurophysiologic findings, and a spinal cord diameter of less than 6 mm in flexion. Severe pain and cranial migration of the axis, as measured by the MRI, also justify a surgical intervention.  相似文献   
4.
Fully constrained metal-to-metal elbow prostheses are not used anymore because of a high loosening rate. Today semiconstrained or condylar prostheses are the two possibilities when replacement of a destroyed elbow joint is considered. A careful analysis of the most recent publications in the world literature reveals a high complication rate for both types of prostheses, each one having specific advantages and disadvantages. The Gschwend-Scheier-B?hler (GSB) III prosthesis is a semiconstrained prosthesis, requires little bone resection, and is therefore easily salvaged. The results in regard to pain relief and improvement in range of motion are satisfactory in a high percentage of patients. The rate of lasting complications is lower than with most of the other prostheses. The authors' transtricipital approach is also a factor that contributes to the high success rate. In case of a failed arthroplasty the authors' method of reconstructing the humeral condyles allows a better salvage.  相似文献   
5.
Pre-clerking of all patients undergoing elective general surgical operations was introduced at our hospital in an attempt to reduce an unacceptably high operation cancellation rate. A prospective audit has been performed on the effect of this policy on the cancellation rate. Before the introduction of pre-clerking there was a marked seasonal variation in the number of patients who failed to attend for surgery, which could be explained by absence on holiday. This seasonal variation disappeared after the start of pre-clerking clinics, but there has been no reduction in the number of cancellations for medical reasons.  相似文献   
6.
Summary The great number of knee-replacement systems makes a comparative study difficult. Even more confusing are the different criteria used for the evaluation of the results. After a critical review of what can be taken as proven facts, our own experience with the semiconstrained GSB-III knee prosthesis is critically analyzed. The survivorship method is used, presenting the cumulative success rate and analyzing the reasons for the failure rates. We feel that all authors presenting results of knee arthroplasty should adopt this method, using the same or at least comparable evaluation sheets (for instance, that of ERASS). Moreover, more attention should be given to bone dynamics in a prospective study using modern technology (CT densitometry). This will help to detect possible factors responsible for the failure of knee arthroplasty and possibly to prevent failure with medication.
Zusammenfassung Die große Zahl verschiedener Kniegelenks-Systeme im prothetischen Ersatz erschwert vergleichendes Studium. Zusätzliche Schwierigkeiten erwachsen aus der Verwendung verschiedener Kriterien bei der Auswertung der Ergebnisse. Wir selbst haben zur Erfahrung mit der GSB-III Knie-Endoprothese kritisch analysiert, nachdem wir versucht haben nur eindeutige Fakten miteinzubeziehen. Wir verwendeten die sogenannte survivorship Methode (Überlebenskurven) und untersuchten die cumulative Erfolgsrate und die Gründe für die Fehlschläge. Wir vertreten die Auffassung, daß alle Autoren, die Ergebnisse über Knie-Arthroplastiken vorstellen, diese Methode verwenden sollten, wenn immer möglich unter Gebrauch desselben oder mindestens vergleichbarer Erhebungsbogen (z. B.
  相似文献   
7.
X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene. Disease-associated alleles (37-66 CAGs) change in length when transmitted from parents to offspring, with a significantly greater tendency to shift size when inherited paternally. As transgenic mice carrying human AR cDNAs with 45 and 66 CAG repeats do not display repeat instability, we attempted to model trinucleotide repeat instability by generating transgenic mice with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions in their genomic context. Studies of independent lines of AR YAC transgenic mice with CAG 45 alleles reveal intergenerational instability at an overall rate of approximately 10%. We also find that the 45 CAG repeat tracts are significantly more unstable with maternal transmission and as the transmitting mother ages. Of all the CAG/CTG repeat transgenic mice produced to date the AR YAC CAG 45 mice are unstable with the smallest trinucleotide repeat mutations, suggesting that the length threshold for repeat instability in the mouse may be lowered by including the appropriate flanking human DNA sequences. By sequence-tagged site content analysis and long range mapping we determined that one unstable transgenic line has integrated an approximately 70 kb segment of the AR locus due to fragmentation of the AR YAC. Identification of the cis - acting elements that permit CAG tract instability and the trans -acting factors that modulate repeat instability in the AR YAC CAG 45 mice may provide insights into the molecular basis of trinucleotide repeat instability in humans.   相似文献   
8.

Background  

Arsenic in groundwater and its accumulation in plants and animals have assumed a menacing proportion in a large part of West Bengal, India and adjoining areas of Bangladesh. Because of the tremendous magnitude of the problem, there seems to be no way to tackle the problem overnight. Efforts to provide arsenic free water to the millions of people living in these dreaded zones are being made, but are awfully inadequate. In our quest for finding out an easy, safe and affordable means to combat this problem, a homeopathic drug, Arsenicum Album-30, appears to yield promising results in mice. The relative efficacies of two micro doses of this drug, namely, Arsenicum Album-30 and Arsenicum Album-200, in combating arsenic toxicity have been determined in the present study on the basis of some accepted biochemical protocols.  相似文献   
9.

Background

The current status of radioiodine-131 (RaI) dosimetry for Graves' hyperthyroidism is not clear. Recurrent hyperthyroidism and iatrogenic hypothyroidism are two problems which interact such that trying to solve one leads to exacerbation of the other. Optimized RaI therapy has therefore begun to be defined just in terms of early hypothyroidism (ablative therapy) as physicians have given up on reducing hypothyroidism.

Methods

Optimized therapy is evaluated both in terms of the greatest separation of cure rate from hypothyroidism rate (non-ablative therapy) or in terms of early hypothyroidism (ablative therapy) by mathematical modeling of outcome after radioiodine and critically discussing the three common methods of RaI dosing for Graves' disease.

Results

Cure follows a logarithmic relationship to activity administered or absorbed dose, while hypothyroidism follows a linear relationship. The effect of including or omitting factors in the calculation of the administered I–131 activity such as the measured thyroid uptake and effective half-life of RaI or giving extra compensation for gland size is discussed.

Conclusions

Very little benefit can be gained by employing complicated methods of RaI dose selection for non-ablative therapy since the standard activity model shows the best potential for cure and prolonged euthyroidism. For ablative therapy, a standard MBq/g dosing provides the best outcome in terms of cure and early hypothyroidism.  相似文献   
10.
Labial adhesions are usually seen in early childhood or in the postmenopausal years, but this clinical entity is rarely seen in the reproductive years. We report a case of labial adhesion with acute urinary retention secondary to Bartholin's abscess in a reproductive‐aged woman with normal menstrual periods. We emphasize the possible occurrence of labial adhesion following Bartholin's abscess in the reproductive years with normal estrogen levels.  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