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   515篇
  免费   34篇
  国内免费   3篇
耳鼻咽喉   3篇
儿科学   4篇
妇产科学   9篇
基础医学   45篇
口腔科学   2篇
临床医学   62篇
内科学   125篇
皮肤病学   5篇
神经病学   28篇
特种医学   24篇
外科学   106篇
综合类   5篇
预防医学   44篇
眼科学   20篇
药学   38篇
中国医学   6篇
肿瘤学   26篇
  2024年   1篇
  2023年   10篇
  2022年   17篇
  2021年   30篇
  2020年   13篇
  2019年   21篇
  2018年   17篇
  2017年   9篇
  2016年   13篇
  2015年   20篇
  2014年   25篇
  2013年   22篇
  2012年   43篇
  2011年   48篇
  2010年   23篇
  2009年   17篇
  2008年   22篇
  2007年   39篇
  2006年   21篇
  2005年   15篇
  2004年   17篇
  2003年   22篇
  2002年   22篇
  2001年   9篇
  2000年   4篇
  1999年   4篇
  1998年   3篇
  1997年   3篇
  1995年   4篇
  1994年   1篇
  1993年   2篇
  1992年   4篇
  1991年   4篇
  1990年   2篇
  1989年   4篇
  1988年   4篇
  1987年   4篇
  1986年   6篇
  1985年   2篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1977年   1篇
  1974年   1篇
排序方式: 共有552条查询结果,搜索用时 15 毫秒
11.
A patient with renal cell carcinoma, recurrent in the renal bed and metastatic to the lung parenchyma, hilar lymph nodes, and ilium bone, showed a complete response to 12 months of treatment with human diploid fibroblast interferon. However, concurrently with clinical and pathologic resolution of the metastatic and recurrent tumor at known sites, a brain metastasis developed, which was not clinically or radiologically apparent during his lifetime. At autopsy, there was no evidence of metastatic renal cell carcinoma at the known sites of disease. In the brain, there was a massive fresh intracerebral hemorrhage originating in a small focus of metastatic renal cell carcinoma. Possible explanations for these mixed responses to interferon and this curious phenomenon are discussed.  相似文献   
12.
Dendritic cells (DCs) are the most potent antigen-presenting cells, yet little data are available on the differential characteristics of donor and recipient DCs (dDCs and rDCs, respectively) during the process of islet allograft rejection. DTR-GFP-DC mice provide a novel tool to monitor DC trafficking and characteristics during allograft rejection. We show rapid migration of dDCs to recipient lymphoid tissues as early as 3 h post-islet allotransplantation. Compared with rDCs, dDCs express different patterns of chemokine receptors, display differential proliferative capacity, and exhibit a higher level of maturity; these findings could be attributed to the effects of injury that dDCs undergo during islet cell preparation and engraftment. Intriguingly, we detected dDCs in the spleen of recipients long after rejection of islet allografts. Given that dDCs express high levels of CCR7, islets were cultured before transplant with the ligand for CCR7 (CCL21). This novel method, which enabled us to enhance the efflux of dDCs from islet preparations, resulted in a prolongation of islet allograft survival in immunocompetent recipients. This study introduces dDCs and rDCs as two distinct types of DCs and provides novel data with clinical implications to use chemokine-based DC-depleting strategies to prolong islet allograft survival.  相似文献   
13.
14.
15.

Objective

The use of preparations based on minerals extracts of Calicotome villosa and butter is born from the misuse of drugs without specific microbiological analyzes. Seventeen different preparations were performed. The antibacterial and antifungal activities were determined on five bacteria and two fungi strains respectively.

Material and methods

C.villosa ashes are obtained by incineration of roots plant at 498 °C for 4 hours. They are analyzed to determine the shape of the particles and the mineral constituents by scanning electronic microscopy (SEM) and energy dispersive X-ray spectrometry (EDX) techniques respectively. The effectiveness of preparations or tablets is measured in solid medium. It allows to calculating the diameter of the inhibition zone for the antibacterial activity as well as the diameter of mycelia growth and the critical values (MIC, MFC, IC50 and IC90) for the antifungal activity. Finally, the results are compared to the activity of a commercial positive control aiming to give value of the observed activity.

Results

SEM observations reveal the presence of nanoparticles agglomerated with size of about 50 nm. The EDX analyzes indicate the presence of Fe, Na, Al, Mg, Si, K, Ca, O2 and C. Among all the results, the preparation (Bs + A) or (Bsd + A) can completely inhibit the growth of two fungal pathogens. The activity of the preparation is faced with the activity of the synthetic fungicide nystatin.

Conclusion

The efficacy of the preparation (Bs + A) or (Bsd + A) is larger than that of nystatin against Aspergillus sp. and Fusarium sp. The preparation could serve as natural antifungal for the pharmaceutical industry.  相似文献   
16.
17.
BACKGROUND: The purpose of this study was to evaluate the incidence rate of endometrial disease, particularly endometrial carcinoma, in patients with primary peritoneal serous papillary carcinoma (PSPC). METHODS: Retrospective review of clinical and histological data from 32 women undergoing surgery (with hysterectomy) for stage III or IV PSPC. RESULTS: Six patients underwent primary debulking surgery and 26 underwent interval debulking surgery after 3 or 4 courses of platinum-based chemotherapy. Six patients (18%) had endometrial disease (hyperplasia in four). Two patients had endometrioid adenocarcinoma of the uterine body (stage IA grade 1 in one case, and stage IB grade 1 in the other) associated with the PSPC. CONCLUSIONS: Endometrial carcinoma of the uterine body may be associated with PSPC (6% cases in the present series). This result suggests that systematic hysterectomy should be performed at the time of debulking surgery in PSPC, even in the absence of peritoneal spread within pelvic cavity.  相似文献   
18.
ABSTRACT

Mast cells (MCs) are well known for their role in allergic conditions. This cell can be activated by various types of secretagogues, ranging from a small chemical to a huge protein. Mast cell activation by secretagogues triggers the increase in intracellular calcium (iCa2+) concentration, granule trafficking, and exocytosis. Activated mast cells release their intra-granular pre-stored mediator or the newly synthesized mediator in the exocytosis process, in the form of degranulation or secretion. There are at least three types of exocytosis in mast cells, which are suggested to contribute to the release of different mediators, i.e.,, piecemeal, kiss-and-run, and compound exocytosis. The status of mast cells, i.e., activated or resting, is often determined by measuring the concentration of the released mediator such as histamine or β-hexosaminidase. This review summarizes several mast cell components that have been and are generally used as mast cell activation indicator, from the classical histamine and β-hexosaminidase measurement, to eicosanoid and granule trafficking observation. Basic principle of the component determination is also explained with their specified research application and purpose. The information will help to predict the experiment results with a certain study design.  相似文献   
19.
Group A Streptococcus (GAS) expresses cell surface proteins that mediate important biological functions such as resistance to phagocytosis, adherence to plasma and extracellular matrix proteins, and degradation of host proteins. An open reading frame encoding a protein of 348 amino acid residues was identified by analysis of the genome sequence available for a serotype M1 strain. The protein has an LPATGE sequence located near the carboxy terminus that matches the consensus sequence (LPXTGX) present in many gram-positive cell wall-anchored molecules. Importantly, the central region of this protein contains 50 contiguous Gly-X-X triplet amino acid motifs characteristic of the structure of human collagen. The structural gene (designated scl for streptococcal collagen-like) was present in all 50 GAS isolates tested, which together express 21 different M protein types and represent the breadth of genomic diversity in the species. DNA sequence analysis of the gene in these 50 isolates found that the number of contiguous Gly-X-X motifs ranged from 14 in serotype M6 isolates to 62 in a serotype M41 organism. M1 and M18 organisms had the identical allele, which indicates very recent horizontal gene transfer. The gene was transcribed abundantly in the logarithmic but not stationary phase of growth, a result consistent with the occurrence of a DNA sequence with substantial homology with a consensus Mga binding site immediately upstream of the scl open reading frame. Two isogenic mutant M1 strains created by nonpolar mutagenesis of the scl structural gene were not attenuated for mouse virulence as assessed by intraperitoneal inoculation. In contrast, the isogenic mutant derivative made from the M1 strain representative of the subclone most frequently causing human infections was significantly less virulent when inoculated subcutaneously into mice. In addition, both isogenic mutant strains had significantly reduced adherence to human A549 epithelial cells grown in culture. These studies identify a new extracellular GAS virulence factor that is widely distributed in the species and participates in adherence to host cells and soft tissue pathology.  相似文献   
20.
To assess the influence of incubation conditions on the resistance of Helicobacter pylori this study compared the effect of micro-aerophilic and anaerobic incubation followed by micro-aerophilic incubation on the measurement of metronidazole resistance of 102 H. pylori isolates, by both disk diffusion and Epsilometer (E)-tests. Anaerobic incubation for 24 h before micro-aerophilic incubation for 48 h consistently increased metronidazole activity in both assay methods. Although statistically significant, this was microbiologically less significant, as only 4 of 102 isolates gave discrepant readings (all four were resistant in micro-aerophilic conditions but susceptible in anaerobic/micro-aerophilic conditions). In all four cases variation was by a few millimeters in zone size (i.e., all were close to the cut-off point). There was 100% agreement between disk diffusion and E-test results. Of 104 observations (52 duplicate assays: 13 strains, two atmospheric conditions, two methods of determining resistance) there was 100% intra-observer and inter-observer agreement with regard to susceptibility and resistance status for both E-test and disk diffusion methods. Anaerobic incubation followed by micro-aerophilic incubation had little effect on the estimation of prevalence of metronidazole resistance and seemed to add little, if any, significant advantage over micro-aerophilic incubation alone.  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