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   1216篇
  免费   77篇
耳鼻咽喉   5篇
儿科学   39篇
妇产科学   10篇
基础医学   177篇
口腔科学   4篇
临床医学   94篇
内科学   203篇
皮肤病学   50篇
神经病学   116篇
特种医学   79篇
外科学   115篇
综合类   44篇
预防医学   88篇
眼科学   19篇
药学   106篇
中国医学   6篇
肿瘤学   138篇
  2023年   8篇
  2022年   11篇
  2021年   25篇
  2020年   24篇
  2019年   23篇
  2018年   26篇
  2017年   11篇
  2016年   21篇
  2015年   29篇
  2014年   42篇
  2013年   34篇
  2012年   64篇
  2011年   66篇
  2010年   36篇
  2009年   47篇
  2008年   65篇
  2007年   48篇
  2006年   50篇
  2005年   47篇
  2004年   61篇
  2003年   48篇
  2002年   41篇
  2001年   36篇
  2000年   28篇
  1999年   32篇
  1998年   9篇
  1997年   10篇
  1994年   10篇
  1993年   12篇
  1992年   20篇
  1991年   16篇
  1990年   24篇
  1989年   11篇
  1988年   8篇
  1987年   15篇
  1986年   17篇
  1985年   17篇
  1984年   16篇
  1983年   14篇
  1982年   11篇
  1980年   8篇
  1978年   9篇
  1977年   8篇
  1976年   14篇
  1975年   9篇
  1974年   8篇
  1973年   11篇
  1972年   11篇
  1970年   14篇
  1967年   8篇
排序方式: 共有1293条查询结果,搜索用时 156 毫秒
1.
2.
Annals of Surgical Oncology - The role of sentinel lymph node biopsy (SLNB) when ductal carcinoma in situ with microinvasion (DCISM) is identified on core biopsy is unclear. Our aim was to assess...  相似文献   
3.
Wernicke''s encephalopathy (WE) is a potentially reversible yet serious neurological manifestation caused by vitamin B1(thiamine) deficiency. It is commonly associated with heavy alcohol consumption. Other clinical associations are with hyperemesis gravidarum (HG), starvation, and prolonged intravenous feeding. Most patients present with the triad of ocular signs, ataxia, and confusion. It can be associated with life-threatening complication like central pontine myelinolysis (CPM). We report two cases of WE following HG, with two different outcomes.  相似文献   
4.
Three metal tolerant Serratia spp. isolates from sediments of pre-mined uranium ore deposit of Domiasiat, Meghalaya, India were characterized using morphological, biochemical and molecular methods. 16S rRNA gene analysis of the isolates identified one of the isolates (DB-10) as Serratia nematodiphila with 99.33 % pairwise similarity whereas remaining two isolates (DB-11 and DB-15) showed similarity with Serratia marcescens subsp. sakuensis with similarity of 98.78 and 99.54 % respectively. Randomly amplified polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus sequence-based PCR (ERIC-PCR) studies of the isolates revealed genetic diversity among them. The isolates were found to tolerate all the five tested metals namely, uranium, cadmium, copper, zinc and lead and also could resist nine commonly used antibiotics namely, ampicillin, kanamycin, chloramphenicol, erythromycin, gentamicin, aztreonam, tetracycline, imipenem and ciprofloxin. All the three isolates were found to be superior in tolerance and resistance to the reference strain S. marcescens ATCC13880. The isolates showed high efficiency of uranium (VI) removal ranging from 90 to 92 % (21.4–21.9 mg/L) and from 65 to 70 % (309.4–333.2 mg/L) when challenged with 100 μM (23.8 mg/L) and 2 mM (476 mg/L) uranyl nitrate solutions respectively within 1 h of incubation.  相似文献   
5.

Purpose

The present work was aimed at the development of prospective positron emission tomography (PET) agents for infection imaging. Towards this aim, ubiquicidin (UBI) fragments conjugated with the macrocyclic NODAGA chelator were radiolabeled with Ga-68 and evaluated.

Procedures

Conformations of custom synthesized NODAGA-UBI (29–41) and NODAGA-UBI (31–38) conjugates were compared with UBI (29–41) by circular dichroism (CD) spectroscopy. Optimization of labeling of NODAGA conjugates of UBI peptides with Ga-68 was performed and quality control analysis was carried out by chromatography techniques. In vitro uptake of [68Ga] NODAGA-UBI (29–41) and [68Ga]NODAGA-UBI (31–38) was studied in Staphylococcus aureus cells. In vivo distribution of [68Ga]GaCl3 and [68Ga]NODAGA-UBI complexes was performed in normal Swiss mice.

Results

Conformations of NODAGA-UBI (29–41) and NODAGA-UBI (31–38) conjugates were found to be similar to UBI (29–41). NODAGA-UBI conjugates could be consistently labeled with Ga-68 in high radiochemical yields (>95 %) with high radiochemical purity (>95 %). [68Ga]NODAGA-UBI (29–41) and [68Ga]NODAGA-UBI (31–38) complexes showed retention time of 14 and 14.5 min, respectively, by HPLC radiochromatogram. Specific uptake of [68Ga]NODAGA-UBI fragments was observed in S.aureus cells. Greater than 64 % of the injected dose was cleared via the renal route at 1 h post injection, and no significant uptake in vital organs of mice was observed with both the agents.

Conclusion

This is the first report on Ga-68 labeled NODAGA-UBI fragments for infection imaging and the agents hold tremendous prospect in PET imaging.
  相似文献   
6.
We have described a 63-year-old man, taking diethylstilbestrol for adenocarcinoma of the prostate, who had papilledema. Lumbar puncture revealed intracranial hypertension without pleiocytosis. CT scan was normal, consistent with the diagnosis of pseudotumor cerebri. At craniotomy for placement of a ventriculoperitoneal shunt, the dura was found to be infiltrated with adenocarcinoma. In patients with known malignancy and elevated intracranial pressure, lumbar puncture and CT scan alone are not enough to rule out meningeal carcinomatosis; repeated lumbar puncture or cervical cisternal puncture may be necessary to document malignant cytology.  相似文献   
7.
8.
Harmful and protective roles of neutrophils in sepsis   总被引:5,自引:0,他引:5  
The current studies demonstrate protective and harmful effects of neutrophils (PMN) during experimental sepsis after cecal ligation and puncture (CLP). It is known that CLP induces signaling defects in blood PMN. When PMN were depleted 12 h after CLP, there were dramatic reductions in levels of bacteremia, evidence for reduced liver and renal dysfunction, sharp reductions in serum levels of cytokines (IL-1beta, IL-6, IL-10, TNF-alpha, and IL-2), and improved survival. In contrast, PMN depletion before CLP resulted in substantial increases in bacteremia and no evidence for attenuation of liver and renal failure dysfunction. These data suggest that at the onset of sepsis, PMN are important in regulating the levels of bacteremia, whereas after the onset of sepsis, as they lose innate immune functions, their presence is associated with higher levels of bacteremia and intensified organ dysfunction.  相似文献   
9.
AIM: To evaluate the role of fluorine-18-labeled fluorodeoxyglucose positron emission tomography (18F-FDG PET) in various rheumatic diseases and its potential in the early assessment of treatment response in a limited number of patients. METHODS: This study involved 28 newly diagnosed patients, of these 17 had rheumatoid arthritis (RA) and 11 had seronegative spondyloarthropathy (SSA). In the SSA group, 7 patients had ankylosing spondylitis, 3 had psoriatic arthritis, and one had non-specific SSA. Patients with RA were selected as per the American College of Rheumatology criteria. One hour after FDG injection, a whole body PET scan was performed from the skull vertex to below the knee joints using a GE Advance dedicated PET scanner. Separate scans were acquired for both upper and lower limbs. Post-treatment scans were performed in 9 patients in the RA group (at 6-9 wk from baseline) and in 1 patient with psoriatic arthropathy. The pattern of FDG uptake was analysed visually and quantified as maximum standardized uptake value (SUVmax) in a standard region of interest. Metabolic response on the scan was assessed qualitatively and quantitatively and was correlated with clinical assessment. RESULTS: The qualitative FDG uptake was in agreement with the clinically involved joints, erythrocyte sedimentation rate, C-reactive protein values and the clinical assessment by the rheumatologist. All 17 patients in the RA group showed the highest FDG avidity in painful/swollen/tender joints. The uptake pattern was homogeneous, intense and poly-articular in distribution. Hypermetabolism in the regional nodes (axillary nodes in the case of upper limb joint involvement and inguinal nodes in lower limb joints) was a constant feature in patients with RA. Multiple other extra-articular lesions were also observed including thyroid glands (in associated thyroiditis) and in the subcutaneous nodules. Treatment response was better appreciated using SUVmax values than visual interpretation, when compared with clinical evaluation. Four patients showed a favourable response, while 3 had stable disease and 2 showed disease progression. The resolution of regional nodal uptake (axillary or inguinal nodes based on site of joint involvement) in RA following disease modifying anti-rheumatoid drugs was noteworthy, which could be regarded as an additional parameter for identifying responding patients. In the SSA group, uptake in the affected joint was heterogeneous, low grade and nonsymmetrical. In particular, there was intense tendon and muscular uptake corresponding to symptomatic joints. The patients with psoriatic arthritis showed intense FDG uptake in the joints and soft tissue. CONCLUSION: 18F-FDG PET accurately delineates the ongoing inflammatory activity in various rheumatic diseases (both at articular and extra-articular sites) and relates well to clinical symptoms. Different metabolic patterns on FDG-PET scanning in RA and SSA can have important implications for their diagnosis and management in the future with the support of larger studies. FDG-PET molecular imaging is also a sensitive tool in the early assessment of treatment response, especially when using quantitative information. With these benefits, FDG-PET could play a pivotal clinical role in the management of inflammatory joint disorders in the future.  相似文献   
10.

Purpose:

To investigate functional changes in prostate cancer patients with three pathologically proven different Gleason scores (GS) (3+3, 3+4, and 4+3) using magnetic resonance spectroscopic imaging (MRSI) and diffusion‐weighted imaging (DWI).

Materials and Methods:

In this study MRSI and DWI data were acquired in 41 prostate cancer patients using a 1.5T MRI scanner with a body matrix combined with an endorectal coil. The metabolite ratios of (Cho+Cr)/Cit were calculated from the peak integrals of total choline (Cho), creatine (Cr), and citrate (Cit) in MRSI. Apparent diffusion coefficient (ADC) values were derived from DWI for three groups of Gleason scores. The sensitivity and specificity of MRSI and DWI in patients were calculated using receiver operating characteristic curve (ROC) analysis.

Results:

The mean and standard deviation of (Cho+Cr)/Cit ratios of GS 3+3, GS 3+4, and GS 4+3 were: 0.44 ± 0.02, 0.56 ± 0.06, and 0.88 ± 0.11, respectively. For the DWI, the mean and standard deviation of ADC values in GS 3+3, GS 3+4, and GS 4+3 were: 1.13 ± 0.11, 0.97 ± 0.10, and 0.83 ± 0.08 mm2/sec, respectively. Statistical significances were observed between the GS and metabolite ratio as well as ADC values and GS.

Conclusion:

Combined MRSI and DWI helps identify the presence and the proportion of aggressive cancer (ie, Gleason grade 4) that might not be apparent on biopsy sampling. This information can guide subsequent rebiopsy management, especially for active surveillance programs. J. Magn. Reson. Imaging 2012;36:697–703. © 2012 Wiley Periodicals, Inc.  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