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   638篇
  免费   36篇
  国内免费   5篇
耳鼻咽喉   11篇
儿科学   14篇
妇产科学   9篇
基础医学   67篇
口腔科学   29篇
临床医学   61篇
内科学   145篇
皮肤病学   4篇
神经病学   43篇
特种医学   16篇
外科学   116篇
综合类   14篇
一般理论   1篇
预防医学   26篇
眼科学   37篇
药学   49篇
中国医学   5篇
肿瘤学   32篇
  2024年   2篇
  2023年   10篇
  2022年   29篇
  2021年   39篇
  2020年   20篇
  2019年   38篇
  2018年   37篇
  2017年   23篇
  2016年   35篇
  2015年   18篇
  2014年   22篇
  2013年   23篇
  2012年   35篇
  2011年   45篇
  2010年   21篇
  2009年   11篇
  2008年   33篇
  2007年   39篇
  2006年   39篇
  2005年   31篇
  2004年   35篇
  2003年   26篇
  2002年   21篇
  2001年   4篇
  2000年   3篇
  1999年   3篇
  1998年   3篇
  1997年   2篇
  1996年   3篇
  1995年   2篇
  1992年   2篇
  1991年   2篇
  1988年   2篇
  1986年   4篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1978年   3篇
  1974年   4篇
  1972年   1篇
  1969年   1篇
  1968年   1篇
排序方式: 共有679条查询结果,搜索用时 15 毫秒
1.
Malignant schwannoma (malignant peripheral nerve sheath tumour, MPNST) is a rare high-grade tumour arising from peripheral nerves. We report the case of a 3-year-old male who presented with a non-tender lesion on the dorsum of his penis. The lesion was excised and a formal circumcision performed. Histology of the lesion revealed a spindle cell tumour. Immunohistochemistry showed the tumour cells to be strongly positive for S100 and Vimentin. A diagnosis of intermediate grade malignant peripheral nerve sheath tumour was made. Malignant schwannoma is rare in children and is previously unreported in the penis in the paediatric age group without evidence of neurofibromatosis.  相似文献   
2.
3.
This study was aimed to evaluate the efficacy of crude aqueous-methanol and aqueous extracts of neem (Azadirachta indica) seed kernel against sarcoptic mange of sheep. Crude aqueous-methanol (AME) and aqueous extracts (AE) of neem seed kernel (NSK) were prepared and formulated as 10% and 20% ointments (w/w), using Vaseline as vehicle. Forty-two lambs of Pak Karakul breed, having natural infection of sarcoptic mange were divided into seven experimental groups. Skin scrapings and clinical examination were carried out at scheduled intervals after treatment. Ivermectin (positive control) completely cleared infesting mites from animals after 10 days and 20% AME after 16 days. While, clinical mange was completely cured after 16 and 20 days with ivermectin and 20% AME, respectively, under field conditions. Only the higher concentration (20% AME) of NSK extracts completely cured the clinical mange, suggesting a dose-dependent response. Our results consolidate the belief that use of folk remedies can provide an effective and economic way of combating sarcoptic mange in sheep.  相似文献   
4.
Breast cancer is one of the leading causes of cancer-related deaths in women worldwide. It is a cancer that originates from the mammary ducts and involves mutations in multiple genes. Recently, the treatment of breast cancer has become increasingly challenging owing to the increase in tumor heterogeneity and aggressiveness, which gives rise to therapeutic resistance. Epidemiological, population-based, and hospital-based case-control studies have demonstrated an association between high intake of certain Allium vegetables and a reduced risk in the development of breast cancer. Diallyl disulfide (DADS) and diallyl trisulfide (DATS) are the main allyl sulfur compounds present in garlic, and are known to exhibit anticancer activity as they interfere with breast cancer cell proliferation, tumor metastasis, and angiogenesis. The present review highlights multidrug resistance mechanisms and their signaling pathways in breast cancer. This review discusses the potential anticancer activities of DADS and DATS, with emphasis on drug resistance in triple-negative breast cancer (TNBC). Understanding the anticancer activities of DADS and DATS provides insights into their potential in targeting drug resistance mechanisms of TNBC, especially in clinical studies.  相似文献   
5.
6.
7.
Nickel(ii)dibenzotetramethyltetraaza[14]annulene complex (Nitmtaa) was synthetized and immobilized on post amino-functionalized SBA-15 (N-SBA-15) to obtain a stable and reusable nanocatalyst named as Nitmtaa@N-SBA-15. Here (3-aminopropyl)triethoxysilane (APTES) was first grafted on the surface SBA-15, then Nitmtaa was added and coordinated on the silica surface via APTES amine groups. The structure and morphology, and thermal stability of the prepared nanocatalyst was investigated using SEM, HR-TEM, BET, FT-IR, powder XRD, and TGA. HR-TEM and XRD results revealed a high dispersion of Nitmtaa on the SBA-15 surface. The catalytic activity of this nanocatalyst was evaluated in the epoxidation of styrene, under ambient conditions, using meta-chloroperoxybenzoic acid (m-CPBA) as the oxygen donor. This nanocatalyst showed an immediate and quantitative epoxidation of styrene with high turn-over-frequency ∼31.58 s−1. Moreover, the superior catalytic activity and high stability of Nitmtaa@N-SBA-15 could be maintained after four successive cycles. A possible reaction mechanism is also proposed.

Immediate and quantitative epoxidation of styrene under ambient conditions catalyzed by new nanocatalyst obtained by immobilizing nickel(ii)dibenzotetramethyltetraaza[14]annulene in amino-functionalized SBA-15.  相似文献   
8.
9.
Composite resin is used extensively for restoration of teeth with vital pulps. Although cell culture studies have disclosed harmful effects on pulpal cells, any untoward clinical effects, manifest as adverse pulpal responses, have yet to be determined. This study comprises a systematic review, designed to address the question of whether the risk of endodontic complications is greater with composite resin restorations than with other restorative materials, such as amalgam. The study methodology involved (i) formulation of the research question, (ii) construction and conduct of an extensive literature search with (iii) interpretation and assessment of the retrieved literature. A search of the medical database PubMed was complemented with a search of the Controlled Trials Register (CENTRAL). The initial search yielded 1043 publications, the abstracts of which were read independently by the authors. After additional searches, 10 studies were included in the review. In all the included studies, the level of evidence was assessed as low. No conclusions could therefore be drawn. The included studies reported few, if any, endodontic complications. Little or no differences emerged between teeth restored with composite resins and those restored with amalgam. To determine whether composite resin restorations of teeth with vital pulps are associated with an increased risk for development of endodontic complications such as apical periodontitis, further evidence is needed, from well‐constructed studies with a large number of participants.  相似文献   
10.
A total of 149 patients with multiple myeloma (MM) who received allogeneic hematopoietic stem cell transplantation (allo-HCT) with myeloablative (MAC; n = 38) or reduced-intensity conditioning (RIC; n = 110) regimens at MD Anderson Cancer Center were evaluated. Of the total, 120 (81%) patients had relapsed or had refractory disease. Median age of MM patients was 50 (28-70) years with a followup time of 28.5 (3-164) months. The 100-day and 5-year treatment related mortality (TRM) rates were 17% and 47%, respectively. TRM was significantly lower with RIC regimens (13%) vs. 29% for MAC at 100 days (P = 0.012). The cumulative incidence of Grade II-IV acute graft-versus-host disease (GVHD) was 35% and chronic GVHD was 46%. PFS and OS at 5 years were 15% and 21%, respectively. In multivariate analysis, allo-HCT for primary remission consolidation was associated with longer PFS (HR 0.35; 95% CI, 0.18-0.67) and OS (HR 0.29; 95% CI 0.15-0.55), while absence of high-risk cytogenetics was associated with longer PFS only (HR 0.59; 95% CI 0.37-0.95). We observe that TRM has decreased with the use of RIC regimens, and long-term disease control can be expected in a subset of MM patients undergoing allo-HCT. Further studies should be conducted in carefully designed clinical trials in this patient population.  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