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   484篇
  免费   40篇
  国内免费   2篇
耳鼻咽喉   1篇
儿科学   13篇
妇产科学   15篇
基础医学   57篇
口腔科学   10篇
临床医学   43篇
内科学   170篇
皮肤病学   7篇
神经病学   26篇
特种医学   25篇
外科学   53篇
综合类   18篇
预防医学   23篇
眼科学   2篇
药学   33篇
中国医学   2篇
肿瘤学   28篇
  2024年   1篇
  2023年   6篇
  2022年   12篇
  2021年   19篇
  2020年   7篇
  2019年   17篇
  2018年   17篇
  2017年   10篇
  2016年   16篇
  2015年   15篇
  2014年   18篇
  2013年   20篇
  2012年   26篇
  2011年   37篇
  2010年   18篇
  2009年   22篇
  2008年   17篇
  2007年   27篇
  2006年   19篇
  2005年   25篇
  2004年   14篇
  2003年   20篇
  2002年   28篇
  2001年   10篇
  2000年   12篇
  1999年   14篇
  1998年   5篇
  1997年   13篇
  1996年   4篇
  1995年   4篇
  1994年   3篇
  1993年   2篇
  1992年   5篇
  1991年   3篇
  1990年   3篇
  1989年   5篇
  1988年   7篇
  1987年   5篇
  1986年   3篇
  1985年   5篇
  1984年   4篇
  1983年   1篇
  1982年   3篇
  1981年   2篇
  1980年   1篇
  1976年   1篇
排序方式: 共有526条查询结果,搜索用时 15 毫秒
61.
A monoclonal antibody, designated BM-1, which is reactive in B5 formalin-fixed, paraffin-embedded tissues, has been generated against a cytoplasmic and nuclear antigen expressed in human myeloid precursor cells and derived leukemias. Using the avidin-biotin-complex immunoperoxidase procedure, BM-1 was found to stain selectively myeloid precursor cells in normal bone marrow and mature granulocytes in the blood. In a screen of 26 normal adult and fetal human organs fixed in B5 formalin, BM-1 was negative in all nonhematopoietic tissues with the exception of tissue granulocytes and scattered cells in the peripheral cortex of the thymus. Likewise a screen of 30 solid tumor cell lines including a spectrum of carcinomas, sarcomas, and neural-derived tumors was negative. BM-1 was also negative with 21 T and B cell lymphomas and 11 Hodgkin's disease tumors. A preliminary study of tumors of the hematopoietic system revealed that BM-1 was reactive with M2 and M3 acute myelogenous leukemias (AML), chronic myelogenous leukemias (CML) and myelomonocytic leukemias, and granulocytic sarcomas. M1, M4, M5, and M6 AML clot preparations were negative in this study, indicating that BM-1 may have a role in the histopathologic diagnosis of myelogenous leukemia. Myeloid leukemic cell lines HL-60, ML-2, KG1, and TPH-1-O showed BM-1 nuclear and/or cytoplasmic reactivity in a subpopulation of cells, but erythroid and lymphoid leukemias and all lymphoma cell lines were negative. Immunoperoxidase studies of a panel of fetal tissues showed BM-1 positive cells in the peripheral cortex of the thymus and portal myelopoietic regions of the liver at 18 weeks gestation. Finally, DNA-cellulose and solid phase radioimmunoassay (RIA) techniques developed in our laboratory demonstrate that the BM-1 antigenic domain is reactive only after binding to eukaryotic but not prokaryotic single- or double-stranded DNA. Immunoblot techniques using a DNA-cellulose purified protein sample revealed that BM-1 recognizes a 183 kD protein. These studies indicate that BM-1 is recognizing a myeloid-specific antigen that, because of its DNA binding characteristics, may have an important role in the differentiation of myeloid cells at the molecular level.  相似文献   
62.
63.
In the current study, polymer-based composites, consisting of Acrylonitrile Butadiene Styrene (ABS) and Bismuth Antimony Telluride (BixSb2−xTe3), were produced using mechanical mixing and hot pressing. These composites were investigated regarding their electrical resistivity and Seebeck coefficient, with respect to Bi doping and BixSb2-xTe3 loading into the composite. Experimental results showed that their thermoelectric performance is comparable—or even superior, in some cases—to reported thermoelectric polymer composites that have been produced using other complex techniques. Consequently, mechanically mixed polymer-based thermoelectric materials could be an efficient method for low-cost and large-scale production of polymer composites for potential thermoelectric applications.  相似文献   
64.
The isolation of the aneurysm sac from systemic pressure and its consequent shrinkage are considered criteria of success after endovascular repair (EVAR). However, the process of shrinkage does not solely depend on the intrasac pressure, the predictive role of which remains ambiguous. This brief review summarizes the additional pathophysiological mechanisms that regulate the biomechanical properties of the aneurysm wall and may interfere with the process of aneurysm sac shrinkage.  相似文献   
65.
ObjectiveThe effect of IGF-1 in the human pleural permeability and the underlying mechanisms involved were investigated.DesignSpecimens from thoracic surgical patients were mounted in Ussing chambers. Solutions containing IGF-1 (1 nM–100 nM) and IGF-1 Receptor Inhibitor (1 μΜ), amiloride 10 μM (Na+ channel blocker) and ouabain 1 mM (Na+–K+ pump inhibitor) were used in order to investigate receptor and ion transporter involvement respectively. Trans-mesothelial Resistance (RTM) across the pleural membrane was determined as a permeability indicator. Immunohistochemistry for IGF-1 receptors was performed.ResultsIGF-1 increased RTM when added on the interstitial surface for all concentrations (p = .008, 1 nM–100 nM) and decreased it on the mesothelial surface for higher concentrations (p = .046, 100 nM). Amiloride and ouabain inhibited this effect. The IGF-1 Receptor Inhibitor also totally inhibited this effect. Immonuhistochemistry demonstrated the presence of IGF-1 receptors in the pleura.ConclusionsIt is concluded that IGF-1 changes the electrophysiology of the human parietal pleura by hindering the normal ion transportation and therefore the pleural fluid recycling process. This event is achieved after IGF-1 interaction with its receptor which is present in the human pleura.  相似文献   
66.
OBJECTIVE: To assess the true incidence, the reflux patterns and the mechanisms responsible for recurrent varicose vein disease according to current definitions and guidelines. PATIENTS AND METHODS: Ninety-three patients (69 female, 24 male, mean age: 48 years) were prospectively evaluated pre- and postoperatively (1 month and 5 years), using clinical and colour duplex examination of both lower limbs. The CEAP score and its modification for recurrence (REVAS) were used for classification. RESULTS: In 113 operated lower limbs, 28 (25%) were found to have a recurrence, 20 of which were symptomatic (20/28, 72%). However, in this group, the mean severity score decreased significantly from 6.5 (SD 3.1) to 5.2 (SD 2.8) (p<0.001, paired t-test). The correlation between the type and cause of recurrence revealed: (1) true recurrent varices in eight limbs (8/28, 29%), primarily caused by neovascularisation, (2) new varicose veins as a consequence of disease progression in seven limbs (7/28, 25%), (3) residual veins in three limbs (3/28, 11%) mainly due to tactical errors (e.g. failure to strip the GSV), (4) complex patterns in 10 limbs (10/28, 36%). In the limbs with recurrence, 42 sources of venous reflux were identified: (1) 19 new sites of venous reflux were due to disease progression (15% of the operated limbs), (2) 13 were caused by neovascularisation (11.5% of the operated limbs), (3) six resulted from tactical failures (5.3% of the operated limbs) and (4) four were due to technical failures (3.5% of the operated limbs). CONCLUSIONS: This study shows that the recurrence of varicose veins after surgery is not uncommon. However, the clinical condition of most affected limbs remains improved. Progression of the disease and neovascularisation are responsible for more than half of the recurrences. Rigorous evaluation of patients and assiduous surgical technique might reduce recurrence due to technical and tactical failures.  相似文献   
67.
Rupture of abdominal aortic aneurysms (AAA) is a life-threatening condition and a leading cause of death in various countries. In spite of increased awareness of most physicians for an early diagnosis of the rupture, the performance of surgery in an early stage and special care in the Intensive Care Unit, postoperative mortality is still high in most medical centers as well as in our Clinic. Two series of patients operated in our Clinic during the last 17 years are analysed. The applied surgical technics are presented and morbidity and mortality are analysed. A distinction between the general mortality was made based on all the inhospital deaths and the postoperative mortality rate including only the deaths after the operation during the postoperative period. Among the other conclusions it is also stressed that a real improvement in the mortality rate depends on elective surgery of all the disclosed AAA larger than 4 cm in diameter.  相似文献   
68.
Gene therapy has become the next frontier in the treatment and potential cure of many disorders that are refractive to current therapies. The lysosomal storage disorders (LSDs) collectively constitute one of the largest groups of inherited metabolic disorders. Propelled by the exciting success of enzyme replacement therapies applied to LSDs without neuropathology, the development of effective gene therapy protocols for the LSDs is underway. For the LSDs with neuropathology, in particular, it has become clear that gene therapy is at present one of only a few therapeutic options with the potential for success. Studies summarised in this review indicate that gene therapy using a variety of vectors both in vivo and ex vivo have shown great promise for the treatment of these diseases. However, several problems require serious attention before it will be feasible to embark on human gene therapy trials.  相似文献   
69.
70.
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