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   433篇
  免费   21篇
  国内免费   12篇
耳鼻咽喉   4篇
儿科学   14篇
妇产科学   33篇
基础医学   43篇
口腔科学   7篇
临床医学   33篇
内科学   88篇
皮肤病学   9篇
神经病学   9篇
特种医学   24篇
外科学   40篇
综合类   27篇
预防医学   41篇
眼科学   33篇
药学   46篇
肿瘤学   15篇
  2022年   6篇
  2021年   11篇
  2020年   7篇
  2019年   13篇
  2018年   13篇
  2017年   11篇
  2016年   13篇
  2015年   9篇
  2014年   11篇
  2013年   22篇
  2012年   28篇
  2011年   37篇
  2010年   16篇
  2009年   18篇
  2008年   22篇
  2007年   18篇
  2006年   18篇
  2005年   13篇
  2004年   14篇
  2003年   11篇
  2002年   7篇
  2001年   8篇
  2000年   5篇
  1999年   12篇
  1998年   4篇
  1997年   8篇
  1996年   4篇
  1995年   6篇
  1994年   4篇
  1993年   3篇
  1992年   3篇
  1990年   5篇
  1989年   5篇
  1988年   4篇
  1986年   3篇
  1985年   4篇
  1983年   6篇
  1982年   4篇
  1981年   3篇
  1980年   5篇
  1978年   6篇
  1977年   6篇
  1976年   5篇
  1975年   2篇
  1974年   2篇
  1973年   6篇
  1971年   6篇
  1970年   6篇
  1968年   2篇
  1965年   3篇
排序方式: 共有466条查询结果,搜索用时 15 毫秒
161.
162.
The prevalence of hepatitis C virus (HCV) infection and hepatitis G virus (HGV) RNA were studied in 50 adult haemophilic patients who had received commercial clotting factors prior to 1980. HGV RNA was detectable in 6/50 patients (12%); 49/50 (98%) had antibody to HCV and 40/49 (82%) of these were viraemic with detectable HCV RNA; 5/6 patients with detectable HGV RNA had co-existing HCV infection and viraemia. The HGV PCR products from all six patients were directly sequenced and all were shown to be similar to that of HGV but more diverse from that of GB virus C. One patient who had persistent abnormal liver function tests had detectable HGV RNA but no evidence of hepatitis B or C. The presence of HGV RNA in the absence of hepatitis B and C infection indicates that this virus is capable of independent transmission. Independent response to interferon was demonstrated in one patient with co-infection who lost HGV but not HCV after interferon therapy.  相似文献   
163.
The aim of this study was to investigate under in vitro conditions the influence of ethanol on acid resistance of four commercially-available enteric polymers (Acryl-EZE®, AQOAT®, Hypromellose phthalate, and Sureteric®). For this purpose, custom-prepared paracetamol tablets were coated with the enteric polymers and tested for release using the buffer-addition method. Ten different hydro-ethanolic media were used in the acid stage corresponding to five levels of ethanol (0, 5, 10, 20, and 40% v/v) in two acidic solutions representing low and high gastric pH (0.1?N HCl pH 1.2, LGpH, and phosphate buffer pH 4.0, HGpH, respectively). The coats were found to resist both types of acidic solution with ethanol percentages up to 10% leading to release profiles that conformed with the pharmacopeial requirements (<10% release after 2?h in acid stage) except for Acryl-EZE®, which showed a premature release in HGpH media. At the higher ethanol levels (20 and 40%), premature release associated with increased acid uptake by coated tablets was noticed for all polymers and more remarkably in HGpH media. ANOVA tests revealed significant effects of polymer type, acidic solution type, and ethanol level on the onset and extent of premature release.  相似文献   
164.
165.
The aim of the study was to examine whether weight reduction can result in improvement of fibromyalgia impact questionnaire (FIQ) in the patients with fibromyalgia syndrome (FMS). This study was a randomized controlled trial. Obese patients with fibromyalgia were randomly assigned to 6-month dietary weight loss (n?=?41) and no weight loss (n?=?42) groups. Patients were assessed at baseline and at 6?months. The primary outcome measure was FIQ. Secondary measures included the tender point (TP) examination, Beck Depression Inventory-II, and Pittsburg Sleep Quality Index. Compared to the control group, patients who underwent weight reduction obtained significantly better FIQ (p?=?0.007), lower mean TP count (p?=?0.015), and lower mean TP pain rating in the lower body (p?<?0.001). Patients who lost weight had less depression and better sleep quality than the controls. Patients who lost weight had significantly lower interleukin 6 and C-reactive protein levels than those in the control group (p?=?0.034 and p?=?0.007, respectively). Weight loss in obese patients with FMS leads to significant improvement in the quality of life as shown by the decrease in the FIQ score. Depression, sleep quality, and tender point count are also significantly improved by weight loss in obese patients with fibromyalgia. Our results suggest that weight reduction should be a part of fibromyalgia treatment.  相似文献   
166.
167.

Objectives

To assess the feasibility and safety of transulnar approach whenever transradial access fails.

Background

Radial access for coronary procedures has gained sound recognition. However, the method is not always successful.

Methods

Between January 2010 and June 2013, diagnostic with or without percutaneous coronary intervention (PCI) was attempted in 2804 patients via the radial approach. Transradial approach was unsuccessful in 173 patients (6.2%) requiring crossover to either femoral (128 patients, 4.6%) or ulnar approach (45 patients, 1.6%). Patients who had undergone ulnar approach constituted our study population. Selective forearm angiography was performed after ulnar sheath placement. We documented procedural characteristics and major adverse cardio-cerebrovascular events.

Results

Radial artery spasm was the most common cause of crossover to the ulnar approach (64.4%) followed by failure to puncture the radial artery (33.4%). Out of 45 patients (82.2%), 37 underwent successful ulnar approach. The eight failed cases (17.8%) were mainly due to absent or weak ulnar pulse (75%). PCI was performed in 17 cases (37.8%), of which 8 patients underwent emergency interventions. Complications included transient numbness, non-significant hematoma, ulnar artery perforation, and minor stroke in 15.5%, 13.3%, 2.2% and 2.2%, respectively. No major cardiac-cerebrovascular events or hand ischemia were noted.

Conclusion

Ulnar approach for coronary diagnostic or intervention procedures is a feasible alternative whenever radial route fails. It circumvents crossover to the femoral approach. Our study confirms satisfactory success rate of ulnar access in the presence of adequate ulnar pulse intensity and within acceptable rates of complications.  相似文献   
168.
169.
Please cite this paper as: WHO/OIE/FAO. (2012) Continued evolution of highly pathogenic avian influenza A(H5N1): Updated nomenclature. Influenza and Other Respiratory Viruses 6(1), 1–5. Background Continued evolution of highly pathogenic avian influenza A (H5N1) throughout many regions of the eastern hemisphere has led to the emergence of new phylogenetic groups. A total of 1637 new H5N1 hemagglutinin (HA) sequences have become available since the previous nomenclature recommendations described in 2009 by the WHO/OIE/FAO H5N1 Evolution Working Group. A comprehensive analysis including all the new data is needed to update HA clade nomenclature. Methods Phylogenetic trees were constructed from data sets of all available H5N1 HA sequences. New clades were designated on the basis of phylogeny and p‐distance using the pre‐established nomenclature system (Emerg Infec Dis 2008; 14:e1). Each circulating H5N1 clade was subjected to further phylogenetic analysis and nucleotide sequence divergence calculations. Results All recently circulating clades (clade 1 in the Mekong River Delta, 2.1.3 in Indonesia, 2.2 in India/Bangladesh, 2.2.1 in Egypt, 2.3.2, 2.3.4 and 7 in Asia) required assignment of divergent HA genes to new second‐, third‐, and/or fourth‐order clades. At the same time, clades 0, 3, 4, 5, 6, 8, 9, and several second‐ and third‐order groups from clade 2 have not been detected since 2008 or earlier. Conclusions New designations are recommended for 12 HA clades, named according to previously defined criteria. In addition, viruses from 13 clades have not been detected since 2008 or earlier. The periodic updating of this dynamic classification system allows continued use of a unified nomenclature in all H5N1 studies.  相似文献   
170.
Prostaglandin A1 is a potent hypotensive, peripheral vasodilator, a weak oxytocic, antiplatelet aggregator. It improves the renal hemodynamics. Its effect on placental circulation was evaluated (expressed as systolic/diastolic ratio and umbilical artery resistance index) in 20 women with severe pre-eclampsia and 10 normotensive pregnant women, by using the Doppler technique. Moreover, another 10 women with severe pre-eclampsia received dextrose 5% as a placebo for comparative purposes. Significant improvements in both parameters studied were observed in the women with severe pre-eclampsia. The beneficial changes differed significantly from the recorded values when using dextrose in pre-eclampsia or prostaglandin A1 in normotensive subjects. Such promising data add another important perspective to prostaglandin A1 in severe pre-eclampsia and may open up new avenues for its use in other situations with compromised placental flow.  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