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   2043篇
  免费   116篇
  国内免费   30篇
耳鼻咽喉   44篇
儿科学   17篇
妇产科学   49篇
基础医学   280篇
口腔科学   59篇
临床医学   139篇
内科学   689篇
皮肤病学   15篇
神经病学   87篇
特种医学   89篇
外科学   297篇
综合类   4篇
预防医学   69篇
眼科学   13篇
药学   112篇
肿瘤学   226篇
  2023年   17篇
  2022年   33篇
  2021年   71篇
  2020年   39篇
  2019年   40篇
  2018年   57篇
  2017年   48篇
  2016年   40篇
  2015年   73篇
  2014年   95篇
  2013年   91篇
  2012年   135篇
  2011年   140篇
  2010年   66篇
  2009年   58篇
  2008年   96篇
  2007年   101篇
  2006年   109篇
  2005年   102篇
  2004年   101篇
  2003年   96篇
  2002年   99篇
  2001年   57篇
  2000年   53篇
  1999年   57篇
  1998年   15篇
  1997年   12篇
  1996年   12篇
  1995年   9篇
  1994年   10篇
  1993年   8篇
  1992年   24篇
  1991年   27篇
  1990年   16篇
  1989年   22篇
  1988年   11篇
  1987年   16篇
  1986年   15篇
  1985年   17篇
  1984年   13篇
  1983年   10篇
  1982年   6篇
  1980年   6篇
  1979年   6篇
  1978年   8篇
  1977年   6篇
  1970年   5篇
  1969年   8篇
  1967年   6篇
  1965年   5篇
排序方式: 共有2189条查询结果,搜索用时 15 毫秒
1.
2.
The cardiohemodynamic effect of (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (FK409), a novel potent vasodilator, was studied in anesthetized open-chest dogs. FK409 (1 to 10 micrograms/kg, i.v.) decreased mean blood pressure, cardiac output and venous return (sum of the flow through the inferior and the superior vena cava). These changes accompanied decreases in left ventricular pressure, in its maximum rate of rise and in right atrial pressure. This cardiovascular profile of FK409 is very similar to those of classical nitrates.  相似文献   
3.
4.
We made an attempt to detect organic brain lesions in eight patients with myotonic dystrophy (MyD) using X-ray computed tomography (CT) and magnetic resonance imaging (MRI). The patients comprised seven men and one woman with ages ranging from 41 to 58 years (average 47 +/- 5.3 years). Seven patients had intellectual impairment assessed using an intelligence quotient test (WAIS-R < 70). CT scans were obtained in the axial plane with a slice thickness of 10 mm, and MRI scans were performed on a 1.5 tesla system in the axial and coronal sections with a slice thickness of 8 mm. CT scans displayed both marked sulcal and prominent ventricular enlargement in 6 of the 8 patients, indicating the presence of brain atrophy, and 3 cases had a few paraventricular low density area in the cerebral hemispheres. In contrast to CT, MRI study revealed more widespread brain parenchymatous lesions in all the 8 cases, showing the multiple foci of high signal intensity with varying size in the white matter on T2-weighted images and proton density-weighted images. No visible changes were detected on CT or MRI in the brain stem and cerebellum. The present study demonstrated that there exist organic cerebral lesions, predominantly located in the white matter in patients with MyD, regardless of focal neurological symptoms. The parenchymatous lesions in the brain can be detected with MRI, and lesser extent with CT, and are considered to be intimately correlated with intellectual deterioration commonly seen in patients with MyD.  相似文献   
5.
We report the results of reduced-intensity unrelated cord blood transplantation (RI-UCBT) in patients with advanced malignant lymphoma. Twenty patients (median age, 46.5 years; range, 27-66 years) underwent RI-UCBT with a preparative regimen consisting of fludarabine 125 mg/m2 , melphalan 80 mg/m 2 , and 4 Gy of total body irradiation. The median infused total cell dose was 2.75 x 10(7)/kg (range, 2.3-3.4 x 10(7)/kg). Graft-versus-host disease (GVHD) prophylaxis was composed of cyclosporine or tacrolimus alone. Fifteen patients achieved primary neutrophil engraftment after a median of 20 days. Eight patients developed grade II to IV acute GVHD, and 2 developed chronic GVHD. Of the 16 patients with evaluable disease, 10 achieved a complete response. Primary disease recurred in 1 patient, and transplant-related mortality within 100 days occurred in 8 of 20 patients. The estimated 1-year probability of progression-free survival was 50%. These data suggest that RI-UCBT is a feasible option for patients with refractory lymphoma who lack an HLA-matched donor.  相似文献   
6.
Cell type-specific involvement of RIG-I in antiviral response   总被引:34,自引:0,他引:34  
Toll-like receptors (TLRs) play an important role in antiviral response by recognizing viral components. Recently, a RNA helicase, RIG-I, was also suggested to recognize viral double-stranded RNA. However, how these molecules contribute to viral recognition in vivo is poorly understood. We show by gene targeting that RIG-I is essential for induction of type I interferons (IFNs) after infection with RNA viruses in fibroblasts and conventional dendritic cells (DCs). RIG-I induces type I IFNs by activating IRF3 via IkappaB kinase-related kinases. In contrast, plasmacytoid DCs, which produce large amounts of IFN-alpha, use the TLR system rather than RIG-I for viral detection. Taken together, RIG-I and the TLR system exert antiviral responses in a cell type-specific manner.  相似文献   
7.
8.
B1 cells have different origin and function from conventional B (B2) cells and are considered to be involved in autoantibody production in the development of autoimmune disease. We found that B1 cells preferentially accumulated in the target organs including thymus in aged BWF1 mice, a murine model for systemic lupus erythematosus, and that B lymphocyte chemoattractant (BLC/CXCL13) expression was increased in the thymus before the onset of lupus nephritis, while stromal cell-derived factor-1 (SDF-1/CXCL12) and secondary lymphoid tissue chemokine (SLC/CCL21) expression remained unchanged. Adhesion molecules such as peripheral node addressin (PNAd), ICAM-1, and VCAM-1 were also expressed on endothelial cells in the enlarged thymic perivascular space (PVS) in aged BWF1 mice. BLC protein and PNAd were co-localized on these high-endothelial-venules-like vessels in enlarged PVS. B1 cells expressed higher level of costimulatory molecules and showed a potent antigen-presenting activity in allogeneic mixed lymphocyte reaction comparable to splenic dendritic cells. Interestingly, B1 cells stimulated proliferation of autologous thymic CD4 T cells in the presence of IL-2. These results indicate that aberrant B1 cell trafficking into the thymus due to ectopic high expression of BLC may result in an activation of self-reactive T cells in the development of murine lupus.  相似文献   
9.
10.
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