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   3979篇
  免费   209篇
  国内免费   14篇
耳鼻咽喉   38篇
儿科学   286篇
妇产科学   208篇
基础医学   401篇
口腔科学   125篇
临床医学   366篇
内科学   891篇
皮肤病学   157篇
神经病学   275篇
特种医学   185篇
外国民族医学   2篇
外科学   528篇
综合类   50篇
预防医学   201篇
眼科学   140篇
药学   189篇
  1篇
中国医学   7篇
肿瘤学   152篇
  2023年   26篇
  2022年   47篇
  2021年   101篇
  2020年   93篇
  2019年   123篇
  2018年   133篇
  2017年   117篇
  2016年   143篇
  2015年   145篇
  2014年   178篇
  2013年   232篇
  2012年   281篇
  2011年   277篇
  2010年   145篇
  2009年   158篇
  2008年   244篇
  2007年   280篇
  2006年   235篇
  2005年   225篇
  2004年   196篇
  2003年   173篇
  2002年   128篇
  2001年   47篇
  2000年   46篇
  1999年   49篇
  1998年   26篇
  1997年   19篇
  1996年   20篇
  1995年   14篇
  1994年   19篇
  1993年   18篇
  1992年   40篇
  1991年   28篇
  1990年   18篇
  1989年   12篇
  1988年   13篇
  1987年   13篇
  1986年   10篇
  1985年   16篇
  1984年   13篇
  1983年   12篇
  1982年   7篇
  1981年   9篇
  1980年   10篇
  1979年   8篇
  1978年   10篇
  1976年   6篇
  1974年   5篇
  1973年   7篇
  1969年   4篇
排序方式: 共有4202条查询结果,搜索用时 15 毫秒
1.
Low molecular weight heparins are widely used in the prophylaxis and treatment of thrombotic disorders. The effect of low molecular weight heparins on coagulation was examined ultrastructurally in an animal model. A test and a control group was formed, each consisting of five rabbits. Nadroparine (225 Institute of Chaoy Unit/kg twice daily) was applied to the test group for 10 days. The control group received 1 ml saline solution subcutaneously. Blood and vascular tissue samples collected at the end of the 10th day were evaluated under a JEM 100 B electron microscope. Platelet degranulation and agglutination was observed in the control group. Fibrin materials were detected in the cytoplasms and surroundings of degranulated platelets. Erythrocyte accumulation was remarkable on the vascular endothelium with intact coagulation periods. In the test group, outer membranes of platelets, hyalomere, and granular structures in the granulomeres were detected to be nearly intact. There were rare erythrocytes in the large vascular lumens. The aggregation phase had occurred but no agglutination was detected. Nadroparine seems to preserve consistency of lipoprotein membranes of platelets and granular structures containing enzymes, which contribute to the coagulation mechanisms.  相似文献   
2.
In living donor liver transplantation (LDLT), obtaining the precise volume of the graft is very important to decrease volume-related postoperative complications, especially in cases with suspected small-for size grafts. We used stereology based on the Cavalieri method (CM), a new method to measure liver graft volume, and compared the results with those obtained through intraoperative measurement (IOM) and through multidetector computed tomography (MDCT) measurement. Liver volumes estimated using the 3 methods were well-correlated with each other (r(2) = 0.94 and P < 0.001 for IOM and CM; r(2) = 0.91 and P < 0.001 for IOM and MDCT, and r(2) = 0.95 and P < 0.001 for CM and MDCT); however, they were different from each other (in descending order, 908 +/- 124 cm(2), 861 +/- 121 cm(2), and 777 +/- 168 cm(2) for MDCT, CM, and IOM, respectively). Although MDCT and CM overestimated the volumes, the results of CM were almost similar to those obtained via IOM. In conclusion, our results suggest that CM measured the liver graft volume more reliably. Thus, its use, particularly in cases with suspected small-for-size graft, may prove useful.  相似文献   
3.
4.
5.
A 19-year-old immunocompetent man was admitted to hospital with diplopia, nausea, vomiting and change in mental status. The patient had a history of tuberculous meningitis that was diagnosed at another hospital 6 months before the present admission, and at that time anti-tuberculosis treatment was initiated using a first-line drug combination. A computed tomography (CT) scan of the brain revealed non-communicating hydrocephalus. A ventriculo-peritoneal shunt was inserted surgically. Two months later, the patient was hospitalized again for fever, dysphagia and left hemiparesis. At that time, his cranial CT findings were within normal limits; however, magnetic resonance imaging (MRI) revealed an irregular multilocular peripheral contrast-enhancing lesion in the posterior fossa. The abscess was surgically drained. The presence of acid-fast bacilli in the abscess material was demonstrated by Ziehl-Neelsen staining. Mycobacterium tuberculosis grew on Lowenstein-Jensen culture medium, and the strain was found to be resistant to isoniazid. One month after the operation, the patient became quadriparetic. Cervical MRI revealed a cervico-thoracic syringomyelitic cavity, after which a syringoperitoneal shunt was placed. Treatment with four drugs was continued for 10 months, and then treatment with three drugs for a total period of 18 months. The patient recovered, with residual quadriparesis. Even though very rare, isoniazid-resistant M. tuberculosis may be the causative agent of progressive tuberculosis.  相似文献   
6.
We investigated the neurobiological basis of variation in sensitization between three aplysiid species: Aplysia californica , Phyllaplysia taylori and Dolabrifera dolabrifera . We tested two different forms of sensitization induced by a noxious tail shock: local sensitization, expressed near the site of shock, and general sensitization, tested at remote sites. Aplysia showed both local and general sensitization, whereas Phyllaplysia demonstrated only local sensitization, and Dolabrifera lacked both forms of learning. We then investigated a neurobiological correlate of sensitization, heterosynaptic modulation of sensory neuron excitability by tail-nerve stimulation. We found (1) an increase in sensory neuron (SN) excitability after both ipsilateral and contralateral nerve stimulation in Aplysia , (2) a smaller and shorter-lasting increase in Phyllaplysia , and (3) no effect in Dolabrifera . Because sensitization in Aplysia is strongly correlated with serotonergic (5-HT) neuromodulation, we hypothesized that the observed interspecific variation in sensitization and SN neuromodulation might be correlated with variation in the anatomy and/or functional response of the serotonergic system. However, using immunohistochemistry, we found that all three species showed a similar pattern of 5-HT innervation. Furthermore, they also showed comparable 5-HT release evoked by tail-nerve shock, as measured with chronoamperometry. These observations indicate that interspecific variation in learning is correlated with differences in SN heterosynaptic plasticity within a backgound of evolutionary conservation in the 5-HT neuromodulatory pathway. We thus hypothesize that evolutionary changes in learning phenotype do not involve modifications of the 5-HT pathway per se , but rather, changes in the response of SNs to the activation of this or other neuromodulatory pathways upon noxious stimulation.  相似文献   
7.
8.
SUMMARY: Renal involvement is not uncommon in rheumatoid arthritis (RA). Many RA patients have renal dysfunction either secondary to the drugs used to treat arthritis or because of the chronic inflammation. Renal pathologies have often included amyloidosis, drug-related renal disease and mesangial glomerulonephritis. However, membranoproliferative glomerulonephritis has only been rarely reported. We report a case of rheumatoid arthritis associated with membranoproliferative glomerulonephritis that rapidly progressed to end-stage renal disease.  相似文献   
9.
10.
We present a new case of Pilomatrix Carcinoma after having review the 22 cases previously published. The tumor arisen in a 74 years old male, in the left preauricular region. The lesion was excised with wide margins. A year after there is not any evidence of recurrence or metastases.  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