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   2506篇
  免费   177篇
  国内免费   8篇
耳鼻咽喉   12篇
儿科学   73篇
妇产科学   16篇
基础医学   385篇
口腔科学   70篇
临床医学   129篇
内科学   549篇
皮肤病学   36篇
神经病学   198篇
特种医学   67篇
外国民族医学   1篇
外科学   411篇
综合类   3篇
预防医学   27篇
眼科学   112篇
药学   276篇
中国医学   14篇
肿瘤学   312篇
  2023年   21篇
  2022年   29篇
  2021年   80篇
  2020年   43篇
  2019年   49篇
  2018年   71篇
  2017年   56篇
  2016年   76篇
  2015年   47篇
  2014年   71篇
  2013年   88篇
  2012年   152篇
  2011年   153篇
  2010年   92篇
  2009年   93篇
  2008年   153篇
  2007年   143篇
  2006年   115篇
  2005年   159篇
  2004年   163篇
  2003年   136篇
  2002年   130篇
  2001年   33篇
  2000年   41篇
  1999年   40篇
  1998年   23篇
  1997年   18篇
  1996年   15篇
  1995年   12篇
  1994年   6篇
  1993年   14篇
  1992年   30篇
  1991年   29篇
  1990年   24篇
  1989年   39篇
  1988年   21篇
  1987年   17篇
  1986年   20篇
  1985年   23篇
  1984年   17篇
  1983年   16篇
  1982年   8篇
  1980年   12篇
  1979年   17篇
  1978年   11篇
  1977年   9篇
  1974年   7篇
  1970年   12篇
  1969年   13篇
  1967年   11篇
排序方式: 共有2691条查询结果,搜索用时 31 毫秒
101.
102.
103.
104.
105.
Vapochromic Pt(ii) complexes that exhibit color and luminescence changes induced by the presence of vapor molecules have drawn considerable attention because of their potential use as vapor sensors. Generally, the vapochromic responsiveness of Pt(ii)-based complexes is difficult to envisage, because a typical molecular design facilitates the stabilization of a vapor-adsorbed form through weak intermolecular interactions. Herein, we investigate the vapochromic behavior of a Pt(ii) complex with potassium ions, which act as vapor coordination sites, by strongly stabilizing the vapor-adsorbed form. Upon exposure to N,N-dimethylacetamide and N,N-dimethylformamide vapors, the complex exhibits crystal structural transformation with luminescence spectral changes. Crystal structural analysis indicates that the vapor molecules are coordinated to the potassium ions after vapor exposure. This study suggests the possibility of inducing Pt(ii)-based vapochromic responsiveness through establishing potassium-ion-based vapor coordination sites.

A luminescent Pt(ii) complex with potassium ions was successfully synthesized and its coordination-based vapochromic behavior was investigated.  相似文献   
106.
The influence of the nanocrystalline structure produced by severe plastic deformation (SPD) on the corrosion behavior of CoCrFeMnNi alloys with Cr contents ranging from 0 to 20 at.% was investigated in aqueous 0.5 M H2SO4 and 3.5% NaCl solutions. The resistance to general corrosion and pitting became higher in both the solutions, with higher passivation capability observed with increasing Cr content, and it is believed that the high corrosion resistance of CoCrFeMnNi alloys can be attributed to the incorporation of the Cr element. However, the impact of the nanocrystalline structure produced by SPD on the corrosion behavior was negligibly small. This is inconsistent with reports on nanocrystalline binary Fe–Cr alloys and stainless steels processed by SPD, where grain refinement by SPD results in higher corrosion resistance. The small change in the corrosion behavior with respect to grain refinement is discussed, based on the passivation process of Fe–Cr alloys and on the influence of the core effects of HEAs on the passivation process.  相似文献   
107.
108.
Although allogeneic hematopoietic stem cell transplantation (HSCT) has been reported to provide prolonged remission of relapsed/refractory mycosis fungoides (MF) and Sézary syndrome (SS), its role has not been fully evaluated. Here, the outcomes of allogeneic HSCT for patients with MF/SS were retrospectively evaluated by using the registry database of the Japan Society for Hematopoietic Cell Transplantation. Forty-eight patients were evaluable and enrolled in the analysis. Median age was 45.5 years. Eighteen patients (38%) received myeloablative conditioning, and 33 (69%) received HSCT from an alternative donor. Disease status was complete or partial response in 25% of the patients and relapsed or refractory in the others. At the time of analysis, 18 patients were alive, with a median follow-up of 31.0 months (range, 3.8-31.1). Three-year overall survival (OS) and progression-free survival (PFS) were 30% (95%CI, 16-45%) and 19% (95%CI, 9-31%), respectively. Disease progression was not observed later than 17 months after transplantation. Both disease status and performance status at transplant significantly affected OS and PFS. Although our findings suggest that allogeneic HSCT provides long-term PFS in patients with MF/SS, the timing of transplantation should be decided carefully based on the disease status and the patient's condition in order to improve the outcome.  相似文献   
109.
110.
Extratumoral lymphatic permeation (ly‐ext) has been reported as an independent poor prognostic factor for lung adenocarcinoma, but whether or not the number of ly‐ext foci is associated with prognosis and its relationship to the immune microenvironment is unclear. We counted the number of ly‐ext foci on pathological slides from patients with completely resected lung adenocarcinoma with ly‐ext, and divided them into two groups: a group with a high number of ly‐ext foci (ly‐ext high) and one with a low number of ly‐ext foci (ly‐ext low). Among the patients with ly‐ext, only a high number of ly‐ext foci was an independent poor prognostic factor. The 3‐year recurrence‐free survival (RFS) rate of the ly‐ext high group was significantly lower than that of the ly‐ext low group (14.7% vs. 50.0%, P < 0.01). Then, we analyzed the immune microenvironment of pT1 lung adenocarcinoma with ly‐ext (13 cases of ly‐ext high and 11 cases of ly‐ext low tumor) by immunohistochemistry using antibodies for stem cell markers (aldehyde dehydrogenase 1 A1 and CD44), tumor‐promoting mucin (MUC1), tumor‐infiltrating lymphocytes (CD4, CD8, FOXP3, and CD79a), and tumor‐associated macrophages (CD204). The number of CD8+ TILs within the primary lesion was significantly lower and the number of FOXP3+ TILs within the primary lesion was significantly higher in the ly‐ext high group (P < 0.05 and P < 0.01, respectively). Our results indicated that a high number of ly‐ext foci was an independent poor prognostic factor. Moreover, tumors with high numbers of ly‐ext foci had a more immunosuppressive microenvironment.  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