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   3436篇
  免费   318篇
  国内免费   9篇
耳鼻咽喉   61篇
儿科学   79篇
妇产科学   25篇
基础医学   452篇
口腔科学   33篇
临床医学   360篇
内科学   782篇
皮肤病学   45篇
神经病学   296篇
特种医学   235篇
外科学   481篇
综合类   68篇
一般理论   2篇
预防医学   278篇
眼科学   102篇
药学   219篇
中国医学   1篇
肿瘤学   244篇
  2023年   28篇
  2022年   36篇
  2021年   73篇
  2020年   58篇
  2019年   81篇
  2018年   110篇
  2017年   65篇
  2016年   72篇
  2015年   75篇
  2014年   102篇
  2013年   136篇
  2012年   196篇
  2011年   227篇
  2010年   125篇
  2009年   135篇
  2008年   199篇
  2007年   195篇
  2006年   209篇
  2005年   194篇
  2004年   186篇
  2003年   163篇
  2002年   127篇
  2001年   64篇
  2000年   54篇
  1999年   47篇
  1998年   34篇
  1997年   17篇
  1996年   18篇
  1995年   24篇
  1994年   21篇
  1992年   38篇
  1991年   39篇
  1990年   50篇
  1989年   40篇
  1988年   37篇
  1987年   33篇
  1986年   45篇
  1985年   23篇
  1984年   22篇
  1983年   20篇
  1979年   21篇
  1978年   19篇
  1976年   15篇
  1973年   21篇
  1972年   23篇
  1971年   19篇
  1969年   18篇
  1968年   24篇
  1967年   24篇
  1966年   15篇
排序方式: 共有3763条查询结果,搜索用时 15 毫秒
1.
2.
Human butyrylcholinesterase is the enzyme responsible of mivacurium and succinylcholine metabolism, which may be significantly impaired when mutation Asp70Gly is found in patients. We describe a simple PCR method for the detection of this variant. Thirteen out of sixteen patients tested after prolonged apnea were positive for the presence of this mutation (50.0% homozygotes and 31.3% heterozygotes), suggesting that this test contributes to the explanation of some clinical events and to their prevention in relatives of these patients.  相似文献   
3.
Viral infection of the heart is increasingly recognized as animportant cause of both acute and chronic heart failure. Enterovirusesand adenoviruses have been considered the most common pathogensof viral cardiomyopathy (CMP), but parvovirus B19 (PVB19) isincreasingly found in endomyocardial biopsies of patients withacute myocarditis or idiopathic dilated cardiomyopathy (ICM).1,2In addition to direct cytopathic effects of these cardiotropicviruses, there is convincing evidence that autoimmune responsesinduced by viruses contribute to the heart disease in a significantsubset of patients with myocarditis.3 Caforio et al.4 present a prospective study in 174 consecutivepatients with myocarditis included between 1992 and 2005.  相似文献   
4.
BACKGROUND: Brachial artery reactivity (BAR), carotid intima-media thickness (IMT), and applanation tonometry for evaluation of total arterial compliance may provide information about preclinical vascular disease. We sought to determine whether these tests could be used to identify patients with coronary artery disease (CAD) without being influenced by their ability to identify those at risk for CAD developing. METHODS: We studied 100 patients and compared 3 groups: 35 patients with known CAD; 34 patients with symptoms and risk factors but no CAD identified by stress echocardiography (risk group); and 31 control subjects. BAR and IMT were measured using standard methods, and total arterial compliance was calculated by the pulse-pressure method from simultaneous radial applanation tonometry and pulsed wave Doppler of the left ventricular outflow. Ischemia was identified as a new or worsening wall-motion abnormality induced by stress. RESULTS: In a comparison between the control subjects and patients either at risk for developing CAD or with CAD, the predictors of risk for CAD were: age (P =.01); smoking history (P =.002); hypercholesterolemia (P =.002); and hypertension (P =.004) (model R = 0.82; P =.0001). The independent predictors of CAD were: IMT (P =.001); BAR (P =.04); sex (P =.005); and hypertension (P =.005) (model R = 0.80; P =.0001). CONCLUSION: IMT, BAR, and traditional cardiovascular risk factors appear to identify patients at risk for CAD developing. However, only IMT was significantly different between patients at risk for developing CAD and those with overt CAD.  相似文献   
5.
Phospholipidosis (PLD) is characterized by an intracellular accumulation of phospholipids in lysosomes and the concurrent development of concentric lamellar bodies. Recently, H. Sawada et al. (2005, Toxicol. Sci. 83, 282-292) identified 17 genes as potential biomarkers of PLD in HepG2 cells. The present study was undertaken to determine if this set of genes measured by quantitative PCR could be validated in the same cell line. The objective was also to investigate the dose-response relationship to further validate the assay and to select the concentrations to use for screening activities. In a first experiment (one concentration tested), out of the 17 genes, the best gene biomarkers of PLD (i.e., 11 genes) were selected for practical screening reasons. Based on these genes, 91.6% (i.e., 11 of 12) of the compounds known to induce PLD were identified as positive and all the negative compounds (i.e., five of five) were also confirmed. When the data obtained in the first experiment were compared to the data by Sawada et al., (2005) the coefficient of correlation calculated was slightly higher than 75%. In the second experiment (26 compounds [all 17 compounds from the first experiment plus 9 other compounds] tested at a minimum of three concentrations), 93.3% (14/15) of the compounds known to induce PLD were identified as such and all the negative controls (six compounds) were also confirmed. Three compounds likely to induce PLD were identified as positive in our assay. Finally, two compounds for which no data are available were also tested. When both experiments 1 and 2 were compared, the coefficient of correlation for 16 compounds tested at the same concentrations reached 87.7%. In conclusion, the present study further confirms the utility of gene expression in HepG2 cells to identify a potential to induce PLD. Finally, based on the data presented, researchers are encouraged to use a range of minimum three concentrations (e.g., 12.5, 25, and 50 microM) to screen for PLD in the human HepG2 cell line.  相似文献   
6.
Vasopressin (AVP) receptor binding within hypothalamic sites was compared between cycling and lactating female golden hamsters. The density of AVP receptor binding was analyzed by quantitative autoradiography within the ventrolateral hypothalamus and dorsomedial hypothalamic nucleus. Lactation was correlated with a disappearance of AVP receptor binding within the ventrolateral hypothalamus. In contrast, lactation was associated with a two- to three-fold increase in the density of AVP receptor binding within the dorsomedial hypothalamic nucleus. These results suggest that AVP receptor binding within the ventrolateral hypothalamus is responsive to gonadal hormones in female golden hamsters. However, the increase in binding observed within the dorsomedial hypothalamus may be related to other neurobiological changes associated with lactation.  相似文献   
7.
Early glottic carcinoma, specifically stage I or II, can be treated with endoscopic excision, radiation therapy, or open partial laryngectomy. Over the past two decades, this topic has received intensive interest, and controversies have often focused on techniques and outcomes comparing the use of endoscopic excision versus radiation therapy. This article will discuss philosophy, techniques, and outcomes of resection using the endoscopic approach to early glottic carcinoma. Optimization through appropriate instrumentation, staging, and technical details are critical to postoperative oncologic and vocal outcomes. The reader must remember that over 90% of T1 lesions and approximately 75% of T2 lesions are curable, and therefore adherence to the principles described below is important to achieve these outcomes.  相似文献   
8.
The objective of this study was to develop and verify a new technique for monitoring the progression of osteoarthritis (OA) by combining a rat model with the imaging modality optical coherence tomography (OCT). Time-sequential, in vivo, OCT imaging was performed on the left femoral condyles of 12 Wistar rats following sodium-iodoacetic acid-induced OA progression. The right femoral condyles (untreated) were also imaged and served as controls. Imaging was performed on days 0, 10, 20, 30, and 60 with an OCT system capable of acquiring images at four frames per second and an axial resolution of 5 microm. Progressive changes were analyzed using an OA scoring system. OCT successfully identified progressive cartilage degeneration as well as alteration of the cartilage/bone interface. Significant changes to both of these structures were observed in the sodium-iodoacetic acid-injected condyles. Structural changes detected with OCT were confirmed histologically. OCT in combination with a well-known model used in arthritis research represents a powerful tool for following degenerative joint disease progression in a given animal by detecting changes to the cartilage/bone interface and articular cartilage.  相似文献   
9.
Background: A quantitative scale of intubation difficulty would be useful for objectively comparing the complexity of endotracheal intubations. The authors have developed a quantitative score that can be used to evaluate intubating conditions and techniques with the aim of determining the relative values predictive factors of intubation difficulty and of the techniques used to decrease such difficulties.

Methods: An Intubation Difficulty Scale (IDS) was developed, based on parameters known to be associated with difficult intubation. It was then evaluated prospectively in a group of 311 consecutive prehospital intubations and 315 intubations in an operating room. In the operating room, the IDS was compared with two other parameters: the time to completion of intubation and the visual analog scale (VAS). Time was measured by an independent observer. Operators in both groups completed a checklist regarding the conditions of intubation.

Results: There is a good correlation between the IDS scale and the VAS assessment of difficulty and time to completion of intubation. VAS and time to completion have a significant but lesser correlation to each other. Comparison of IDS with operator-assessed subjective categorical impression of difficulty by Kruskall-Wallis was statistically significant.  相似文献   

10.
An unusual case of sundown syndrome is here reported, in which a bilingual patient would involuntarily change languages at sunset. Numerous theories have been advanced in attempting to account for sundowning. Cameron [1] has suggested that nocturnal delirium was based on an inability to maintain a spatial image without the assistance of repeated visualization. Krai [2] and Wolanin and Phillips [3] have argued for a more psychogenic account, by stating that psychosocial stressors may, in concert with impaired cognitive functioning, account for sundowning. The present case concerns a 42-year-old white male who in January 1989 suffered a closed head injury. A thorough personal history as well as a detailed examination of the patient's daily activities allowed us to account for the unusual manner in which the sundowning manifested itself. The uniqueness of this case allows us to underscore both the psychological as well as environmental and neurological factors involved in sundowning. Thus, we have as a consequence been able to synthesize the seemingly disparate accounts of both Cameron and more recent published literature [2, 3].  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