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   2398篇
  免费   85篇
  国内免费   11篇
耳鼻咽喉   98篇
儿科学   161篇
妇产科学   119篇
基础医学   198篇
口腔科学   102篇
临床医学   208篇
内科学   474篇
皮肤病学   47篇
神经病学   111篇
特种医学   85篇
外科学   539篇
综合类   29篇
预防医学   58篇
眼科学   37篇
药学   76篇
中国医学   1篇
肿瘤学   151篇
  2024年   1篇
  2023年   17篇
  2022年   27篇
  2021年   49篇
  2020年   27篇
  2019年   51篇
  2018年   63篇
  2017年   60篇
  2016年   70篇
  2015年   84篇
  2014年   98篇
  2013年   148篇
  2012年   195篇
  2011年   177篇
  2010年   110篇
  2009年   84篇
  2008年   158篇
  2007年   192篇
  2006年   170篇
  2005年   193篇
  2004年   159篇
  2003年   115篇
  2002年   95篇
  2001年   29篇
  2000年   34篇
  1999年   23篇
  1998年   10篇
  1997年   10篇
  1996年   11篇
  1995年   2篇
  1994年   6篇
  1993年   6篇
  1992年   1篇
  1991年   6篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1982年   1篇
  1980年   1篇
  1972年   1篇
  1969年   2篇
  1961年   1篇
排序方式: 共有2494条查询结果,搜索用时 93 毫秒
71.
72.
73.
The aim of the study was to assess mean platelet volume (MPV) in children with systemic lupus erythematosus (SLE) at the active and inactive stages. Twenty children with SLE and 30 age- and gender-matched controls were enrolled. Demographic data, SLE disease activity index (SLEDAI), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), MPV, complement 3 (C3), complement 4 (C4), urine protein (Up), and urine creatinine (Ucr) values upon reactivation and remission phases were recorded. MPV was statistically higher in patients than in controls and significantly increased in active phase compared to inactive phase (p?=?0.001). A MPV level of 8.4 fL was determined as predictive cutoff value of activation of SLE (sensitivity 75 %, specificity 90 %). MPV was positively correlated with SLEDAI (p?=?0.01, r?=?0.55), ESR (p?=?0.01, r?=?0.45), CRP (p?=?0.04, r?=?0.24), and Up/Ucr (p?=?0.01, r?=?0.45) and negatively correlated with C3 (p?=?0.02, r?=??0.36), albumin (p?=?0.01, r?=??0.63), and Hb (p?=?0.01, r?=??0.48). There was not any significant association between MPV and the histological classification of lupus nephritis (p?=?0.65). MPV might be used as an early indicator of reactivation in children with SLE. MPV seemed to be more accurate than ESR, CRP, and C3 for monitoring the disease activity in SLE.  相似文献   
74.
The aim of this study was to evaluate the calcium, sodium, potassium, serum iron, vitamin B12, and albumin concentrations, and alkaline phosphatase (ALP) activity, in samples of serum from patients with primary trigeminal neuralgia (TN), and investigate the associations between them. Results from 73 patients who had been diagnosed with primary TN between December 2015 and 2017 were compared with those of 70 healthy subjects. Calcium (p = 0.013), iron (p = 0.004), and albumin (p = 0.001) concentrations in the primary TN group were significantly lower than those in the control group, whereas the ALP activity was significantly higher in the TN group than in the control group (p = 0.007). However, there was no significant difference in the sodium, potassium, or vitamin B12 concentrations. Biochemical variables have a role in the pathogenesis and treatment of primary TN, but there are few studies that characterise the relations between the condition and the biochemical changes. Further studies are therefore necessary to gain more information.  相似文献   
75.
76.

Introduction and hypothesis

It has been suggested that weight reduction decreases the frequency of urinary incontinence (UI) episodes. However, it is not known if this improvement is associated with anatomical changes in the pelvis. The aim of this study was to investigate the effects of weight loss on UI episodes and pelvic floor anatomy.

Methods

Three hundred seventy-eight overweight/obese women were randomly allocated either to behavioral weight loss or to structured education programs. The patients were evaluated by voiding diary, Pelvic Floor Distress Inventory (PFDI), and Pelvic Organ Prolapse Quantification (POP-Q) system at baseline and after 6 months.

Results

The women in the intervention group had a mean weight loss of 9.4 %, whereas the weight in the control group remained almost the same (P?P?Conclusions Weight reduction provides improvement in episodes of UI, decreases the incidence of drops of urine leakage, and increases quality of life related to pelvic floor symptoms. However, there are little to no changes in the parameters of the POP-Q system with weight reduction.  相似文献   
77.
78.
Covalent-organic polymer networks (COPNs) have been used as catalyst supports due to their stable and favorable structure. Herein, a simple synthetic route was applied to generate Au@COPN-1 hybrids via in situ reduction of gold ions with no additional reducing agent. Synthesized novel COPN-1 was mixed with different concentrations of HAuCl4 which resulted in Au@COPN-1 with varying sizes of Au nanoparticles in a controlled manner. The microstructural and morphological features of COPN-1 and Au@COPN-1 were characterized in detail using FT-IR, C-NMR, elemental analysis, UV-Vis, XRD, TEM, BET, and TGA. It is noteworthy that the red-shifted LSPR peaks of Au nanoparticles produced with increasing concentrations of HAuCl4 indicated an increase in the particle size of the Au nanoparticles as justified by TEM images. The optimum catalytic activity of Au@COPN-1 was obtained when 4.6 × 10−3 mM HAuCl4 was used, which led to the complete reduction of 4-nitrophenol within 16 minutes with excellent recyclability for more than 5 catalytic cycles, giving yields over 94%. Moreover, the non-aggregation of nanoparticles in the reused catalyst further confirmed the stability of the prepared catalysts. Consequently, these results indicated that in situ synthesis of AuNPs inside the COPN-1 matrix produces a promising catalyst platform for the reduction of aromatic nitro compounds, for example, for the degradation of one of the most common persistent organic pollutants 4-nitrophenol, as shown here. In addition, the Au@COPN-1 hybrid system showed good biocompatibility at appropriate doses confirmed by a dynamic real-time cell analysis system which can be used in various medical applications, such as drug delivery, in the future.

A facile synthetic route was applied to generate Au@COPN-1 hybrids via in situ reduction of Au3+ with no additional reducing agent. Au@COPN-1 is a promising catalyst platform and good biocompatibility confirmed by dynamic real-time cell analysis.  相似文献   
79.
The factor V Leiden mutation in 12 children with thrombosis and in 20 controls was investigated. Five heterozygous individuals and 1 homozygous individual among the cases with thrombosis and 1 heterozygous individual among controls were found. Central nervous system thromboses were increased in children with the factor V mutation, associated with protein S deficiency. © 1996 Wiley-Liss, Inc.  相似文献   
80.
Open in a separate window OBJECTIVESWhether acute phase and immune responses are minimally affected following minimally invasive lung surgery needs further investigation. We performed a pilot study to evaluate the immune profile of patients who underwent video-assisted thoracoscopic surgery or robot-assisted thoracic surgery lobectomies for the treatment of suspicious or known stage I non-small-cell lung cancer.METHODSBlood samples were taken preoperatively and 3 and 24 h postoperatively were analysed for C-reactive protein, glucose, cortisol, tumour necrosis factor alpha (TNF-α), interleukin 8 (IL-8) and interleukin 10 (IL-10) levels. TNF-α, IL-8 and IL-10 were also measured in lung tissues. T (CD4, CD8), B (CD19) and natural killer (CD56, CD16) cell counts and natural killer cell functions were analysed using a flow cytometry-based assay before and after surgery.RESULTSMinimally invasive surgery (robot-assisted thoracic surgery + video-assisted thoracoscopic surgery) significantly decreased IL-10 (P = 0.016) levels after surgery. No significant differences were detected in TNF-α (P = 0.48) and IL-8 (P = 0.15) levels before and after surgery. C-reactive protein (P < 0.001), cortisol (P < 0.001) and glucose levels (P < 0.001) increased significantly after surgery. Lymphocyte, total T cell, CD3+CD4+ and CD3+CD8+ CD16+CD56+ cell counts were significantly lower on postoperative day 1.CONCLUSIONThere seems to be a dynamic balance between pro- and anti-inflammatory cytokines and immune cells following minimally invasive lobectomy.  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