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   10512篇
  免费   428篇
  国内免费   83篇
耳鼻咽喉   116篇
儿科学   252篇
妇产科学   157篇
基础医学   1419篇
口腔科学   264篇
临床医学   640篇
内科学   2608篇
皮肤病学   192篇
神经病学   1183篇
特种医学   313篇
外科学   1855篇
综合类   31篇
一般理论   1篇
预防医学   199篇
眼科学   240篇
药学   533篇
中国医学   26篇
肿瘤学   994篇
  2022年   65篇
  2021年   156篇
  2020年   108篇
  2019年   167篇
  2018年   211篇
  2017年   135篇
  2016年   166篇
  2015年   171篇
  2014年   237篇
  2013年   321篇
  2012年   506篇
  2011年   558篇
  2010年   298篇
  2009年   280篇
  2008年   478篇
  2007年   555篇
  2006年   491篇
  2005年   611篇
  2004年   533篇
  2003年   517篇
  2002年   536篇
  2001年   270篇
  2000年   283篇
  1999年   250篇
  1998年   128篇
  1997年   114篇
  1996年   83篇
  1995年   103篇
  1994年   96篇
  1993年   92篇
  1992年   197篇
  1991年   188篇
  1990年   165篇
  1989年   192篇
  1988年   178篇
  1987年   147篇
  1986年   140篇
  1985年   141篇
  1984年   122篇
  1983年   99篇
  1982年   47篇
  1979年   81篇
  1978年   52篇
  1977年   58篇
  1976年   54篇
  1974年   54篇
  1973年   59篇
  1972年   56篇
  1970年   53篇
  1969年   55篇
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
991.
Divided attention (DA) impairment may be the most salient and commonly reported cognitive dysfunction following traumatic brain injury (TBI). Even so, DA impairment is sometimes overlooked during hospitalization. Our group experienced two TBI patients with selective deficits of DA recognized after their return-to-work. Neither patient showed abnormalities in standard tests for higher brain dysfunction. Both, however, performed poorly in a newly developed dual-task test. DA should be assessed more thoroughly and carefully in TBI patients. Dual-task testing may be sensitive in the detection of DA disturbances.  相似文献   
992.
Multi-walled carbon nanotubes (MWCNTs), dispersed in suspensions consisting mainly of individual tubes, were used for intratracheal instillation and inhalation studies. Rats intratracheally received a dose of 0.2 mg, or 1 mg of MWCNTs and were sacrificed from 3 days to 6 months. MWCNTs induced a pulmonary inflammation, as evidenced by a transient neutrophil response in the low-dose groups, and presence of small granulomatous lesion and persistent neutrophil infiltration in the high-dose groups. In the inhalation study, rats were exposed to 0.37 mg/m(3) aerosols of well-dispersed MWCNTs (>70% of MWCNTs were individual fibers) for 4 weeks, and were sacrificed at 3 days, 1 month, and 3 months after the end of exposure. The inhalation exposures delivered less amounts of MWCNTs into the lungs, and therefore less pulmonary inflammation responses was observed, as compared to intratracheal instillation. The results of our study show that well-dispersed MWCNT can produce pulmonary lesions, including inflammation.  相似文献   
993.
A family of Bcl-2/adenovirus E1B 19 kDa-interacting proteins (BNIPs) plays critical roles in several cellular processes such as cellular transformation, apoptosis, neuronal differentiation, and synaptic function, which are mediated by the BNIP2 and Cdc42GAP homology (BCH) domain. Prune homolog 2 (Drosophila) (PRUNE2) and its isoforms - C9orf65, BCH motif-containing molecule at the carboxyl terminal region 1 (BMCC1), and BNIP2 Extra Long (BNIPXL) - have been shown to be a susceptibility gene for Alzheimer's disease, a biomarker for leiomyosarcomas, a proapoptotic protein in neuronal cells, and an antagonist of cellular transformation, respectively. However, precise localization of PRUNE2 in the brain remains unclear. Here, we identified the distribution of Prune2 mRNA in the adult mouse brain. Prune2 mRNA is predominantly expressed in the neurons of the cranial nerve motor nuclei and the motor neurons of the spinal cord. The expression in the dorsal root ganglia (DRG) is consistent with the previously described reports. In addition, we observed the expression in another sensory neuron in the mesencephalic trigeminal nucleus. These results suggest that Prune2 may be functional in these restricted brain regions.  相似文献   
994.
The aquaporin-4 (AQP4) water channel antibody is used in the diagnosis of neuromyelitis optica (NMO) due to its high sensitivity and high specificity. However, some patients are reported to have neither optic neuritis nor myelitis despite being positive for the AQP4-autoantibody (AQP4-Ab). Therefore, recent reports suggest that such patients should be diagnosed as having 'AQP4-autoimmune syndrome'. In this study, we quantified the levels of glial fibrillar acidic protein (GFAP) and S100B by enzyme-linked immunosorbent assay (ELISA) in CSF and serum samples simultaneously obtained in the acute phase of ten AQP4-autoantibody (AQP4Ab)-positive and seven AQP4Ab-negative patients. Serum levels of S100B were significantly higher in the acute phase of the AQP4Ab-positive patients (2.92±1.22pg/ml) than in the AQP4Ab-negative patients (0.559±0.180pg/ml, p=0.0250), while serum levels of GFAP were not different between the two groups (AQP4Ab-positive vs. AQP4Ab-negative: 0.120±0.113ng/ml vs. 0.00609±0.00609ng/ml, p=0.193). Furthermore, the CSF and serum levels of S100B had a significant positive correlation in AQP4Ab-positive patients (n=10, r=0.673, p=0.0390). Our results raise the possibility that serum levels of S100B, but not GFAP, examined in the acute phase of the disease might be a useful biomarker for the relapse of AQP4 autoimmune syndrome.  相似文献   
995.
Gingival response to periodontal inflammation generates excessive lipid peroxide and such a condition may augment systemic health through increased circulating lipid peroxide. The purpose of the present study was to investigate whether the generation of lipid peroxide in periodontal inflammation could induce tissue injury in the liver, heart, kidney and brain using a rat model. Twelve Wistar rats (8 week-old male) were divided into 2 groups: the periodontal inflammation group, receiving topical application of lipopolysaccharide and proteases to the gingival sulcus for 4 weeks, and the control group using instead pyrogen-free water. After blood samples were collected, specimens from the brain, heart, liver and kidney were resected to determine the concentration of 8-hydroxydeoxyguanosine (an indicator of oxidative DNA damage). Gingival and serum levels for hexanoyl-lysine were measured to evaluate lipid peroxide. Administration of lipopolysaccharide and proteases induced periodontal inflammation, with increasing gingival and serum levels of hexanoyl- lysine. The level of 8-hydroxydeoxyguanosine increased 2.27, 2.01, 1.49 and 1.40 times in mitochondrial DNA from the liver, heart, kidney and brain of rats with periodontal inflammation, respectively. The results reveal that excessive production of lipid peroxide following periodontal inflammation is involved in oxidative DNA damage of the brain, heart, liver and kidney.  相似文献   
996.

Background  

The coracoclavicular joint has been described as an articulation found inconstantly between the coracoid process and clavicle. We often observe a small space bordered by the fascia which covers the anterior surface of the subclavius muscle and the coracoclavicular ligament. The aim of this study was to observe the space in detail and to discuss the functional role of the coracoclavicular joint.  相似文献   
997.
Among bullous impetigo isolates, exfoliative toxin (ET) gene carriage was found in 61.5% of methicillin-resistant Staphylococcus aureus (MRSA) isolates versus 90.6% of methicillin-susceptible S. aureus (MSSA) isolates. MRSA-only cases were ETB or ETA positive, while MRSA/MSSA coinfection cases were ET negative for MRSA but ETA positive for MSSA. Collagen adhesin may facilitate some MRSA infections.  相似文献   
998.
Endoscopists seek to conduct more aggressive surgical procedures that surpass the limitations of existing endoscopic procedures. Endoscopic pancreatic necrosectomy and natural orifice transluminal endoscopic surgery (NOTES) are typical examples of this new trend; both are performed through the gastrointestinal wall without a skin incision. Endoscopic necrosectomy is effective for managing organized pancreatic necrosis and abscesses. The necrotic tissues are removed endoscopically by directly entering the cavity of the organized pancreatic necrosis. NOTES is a possible advance over surgical intervention, as it is a less invasive, more cosmetic, and effective procedure. There are various approaches, including the esophagus, stomach, colon, and vagina; Various procedures are possible using NOTES, such as cholecystectomy, appendectomy, full-thickness stomach resection, splenectomy, gastrointestinal (GI) anastomosis, and peritoneoscopy. The requirements for NOTES include high proficiency in endoscopic techniques, including knowledge of various devices, anatomy, and surgical procedures. Since most GI endoscopists have no surgical background, to increase the usage of NOTES, GI endoscopists should form and lead teams that include various specialists. We believe that endoscopic necrosectomy and NOTES represent a major shift in the treatment paradigm because physicians can treat beyond the gastrointestinal wall and endoscopic procedures will replace surgical treatment.  相似文献   
999.
The high‐flow management of cardiopulmonary bypass (CPB; ≥2.4 L/min/m2) is a standard strategy used at this institute for children with pulmonary atresia (PA) due to a fear that the blood flow may be diverted by the major/minor aortopulmonary‐collateral‐arteries and hypervascularization due to long‐term hypoxia. The purpose of this study was to describe the validity of high‐flow management in children with PA. The CPB records of 23 children with PA who underwent a definitive biventricular repair between Feb 2006 and Nov 2008 were retrospectively reviewed. The mean age at the operation was 33 ± 22 months. The blood‐pressure during bypass was controlled with the same protocol. The mean cooling‐temperature was 28.4 ± 3.7°C. The mean minimum hematocrit was 25.0 ± 3.4%. The mean maximum bypass flow index at the initiation, the mean maximum flow index during aortic cross‐clamping, the mean minimum flow index during aortic cross‐clamping, and the mean maximum flow index after rewarming were 3.1 ± 0.5, 3.1 ± 0.5, 2.6 ± 0.4, and 3.2 ± 0.4 L/min/m2, respectively. The higher bypass flow indexes significantly correlated with the lower serum lactate levels. The lowest oxygen delivery during CPB had significant influences on the urine output during bypass (R = 0.547, P = 0.007), the serum lactate levels at the end of CPB (R = ?0.442, P = 0.035), and the postoperative thoracic effusion (R = ?0.459, P = 0.028). A bypass flow index of 2.4 L/min/m2 may not be sufficient and the maximum requirement of bypass flow index may be 3.2 L/min/m2 or more in this patient population.  相似文献   
1000.
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