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   377篇
  免费   24篇
  国内免费   2篇
儿科学   6篇
基础医学   74篇
口腔科学   3篇
临床医学   31篇
内科学   92篇
皮肤病学   14篇
神经病学   19篇
特种医学   11篇
外科学   22篇
综合类   1篇
现状与发展   1篇
预防医学   18篇
眼科学   1篇
药学   31篇
中国医学   7篇
肿瘤学   72篇
  2023年   8篇
  2022年   30篇
  2021年   22篇
  2020年   10篇
  2019年   10篇
  2018年   11篇
  2017年   5篇
  2016年   11篇
  2015年   21篇
  2014年   18篇
  2013年   18篇
  2012年   29篇
  2011年   20篇
  2010年   22篇
  2009年   11篇
  2008年   17篇
  2007年   20篇
  2006年   16篇
  2005年   25篇
  2004年   16篇
  2003年   17篇
  2002年   18篇
  2001年   4篇
  2000年   1篇
  1999年   3篇
  1998年   4篇
  1997年   5篇
  1996年   2篇
  1995年   4篇
  1994年   1篇
  1993年   3篇
  1990年   1篇
排序方式: 共有403条查询结果,搜索用时 0 毫秒
91.
We aimed to assess the effect of oral probiotics containing the Streptococcus salivarius K12 strain on the salivary level of secretory immunoglobulin A, salivation rate, and oral biofilm. Thirty-one consenting patients meeting the inclusion criteria were recruited in this double-blind, placebo-controlled, two-arm, parallel-group study and randomly divided into probiotic (n = 15) and placebo (n = 16) groups. Unstimulated salivation rate, concentration of salivary secretory immunoglobulin A, Turesky index, and Papillary-Marginal-Attached index were assessed after 4 weeks of intervention and 2 weeks of washout. Thirty patients completed the entire study protocol. We found no increase in salivary secretory immunoglobulin A levels and salivary flow rates in the probiotic group compared with placebo. Baseline and outcome salivary secretory immunoglobulin A concentrations (mg/L) were 226 ± 130 and 200 ± 113 for the probiotic group and 205 ± 92 and 191 ± 97 for the placebo group, respectively. A significant decrease in plaque accumulation was observed in the probiotic group at 4 and 6 weeks. Within the limitations of the present study, it may be concluded that probiotic intake (Streptococcus salivarius K12) does not affect salivation rates and secretory immunoglobulin A salivary levels but exhibits a positive effect on plaque accumulation. Trial registration NCT05039320. Funding: none.  相似文献   
92.
In this work, nanoporous antireflective coatings on silicate glass were obtained from silicon dioxide sol compositions by the sol-gel method in the presence of quaternary ammonium salt (tetrabutylammonium bromide) at different annealing temperatures (200–250 °C). Varying the salt concentration from 3 to 5 wt.%, we achieved the transmittance of the coatings of about 97% at 250 °C in comparison with 91% for clean glass in the wavelength range from 400 to 1100 nm. The addition of gold nanoparticles to the composition containing 5 wt.% tetrabutylammonium bromide allowed us to decrease the annealing temperature to 200 °C, preserving the transmittance at the level of 96.5%. For this case, the optimal concentration of gold nanoparticles is determined (2.6 × 10−9 mol/mL). According to the SEM analysis, the obtained antireflective coatings contain pores with a minimum area size up to 4 nm2.  相似文献   
93.
94.
This article describes a technology for the thermomechanical treatment of stainless-steel piston rings. This technology makes it possible to obtain rings with an optimal combination of plastic and strength properties that is essential for piston rings. The following thermomechanical treatment is suggested for piston rings manufacturing: quenching at 1050 °C, holding for 30 min and cooling in water, then straining by the HPT method for eight cycles at cryogenic temperature and annealing at a temperature up to 600 °C. The resulting microstructure consisted of fine austenite grains sized 0.3 μm and evenly distributed carbide particles. Annealing above this temperature led to the formation of ferrite in the structure; however, preserving the maximum fraction of austenitic component is very important, since the reduction of austenite in the structure will cause a deterioration of corrosion resistance. The strength properties of steel after such treatment increased by almost two times compared with the initial ones: microhardness increased from 980 MPa to 2425 MPa, relative elongation increased by 20%. The proposed technology will improve the strength and performance characteristics of piston rings, as well as increase their service life, which will lead to significant savings in the cost of repair, replacement and downtime.  相似文献   
95.
Background Recent evidence implicates smoking as a risk factor for cervical cancer (CC), but the confounding from high-risk human papillomavirus (HPV) infections is not clear. Objectives To analyse the role of smoking as an independent predictor of CIN2+ and HR-HPV infections in a population-based prospective (NIS, New Independent States of former Soviet Union) cohort study. Study design and Methods A cohort of 3,187 women was stratified into three groups according to their smoking status: (i) women who never smoked; (ii) those smoking in the past; and (iii) women who are current smokers. These groups were analysed for predictors of (a) HR-HPV; (b) high-grade CIN, and (c) outcome of HR-HPV infections and cytological abnormalities during prospective follow-up (n = 854). Results The three groups were significantly different in all major indicators or risk sexual behaviour (or history) implicating strong confounding. There was no increase in HSIL/LSIL/ASC-US cytology or CIN1+/CIN2+/CIN3+ among current smokers. Only few predictors of HR-HPV and CIN2+ were common to all three groups, indicating strong interference of the smoking status. There was no difference in outcomes of cervical disease or HR-HPV infections between the three groups. In multivariate model, being current smoker was one of the five independent predictors of HR-HPV (P = 0.014), with adjusted OR = 1.52 (95%CI 1.09–2.14). In addition to age, HR-HPV was the only independent predictor of CIN2+ in multivariate model (OR = 14.8; 95%CI 1.72–127.31). Conclusions These data indicate that cigarette smoking is not an independent risk factor of CIN2+, but the increased risk ascribed to smoking is mediated by acquisition of HR-HPV, of which current smoking was an independent predictor in multivariate model.  相似文献   
96.
Catheter‐based renal denervation (RDN) is a novel invasive approach in the treatment of resistant hypertension. It is considered a minimally invasive and safe procedure which, as shown by initial experimental and clinical trials, is able not only to reduce blood pressure but also to modify its risk factors by modulation of autonomic nervous system. Recently published results of a randomized Symplicity HTN‐3 trial, which failed to demonstrate RDN‐induced reduction of blood pressure at six months, decreased the initial enthusiasm regarding RDN and raised a question about real efficacy of this procedure. Nevertheless, still there are some other conditions characterized by increased sympathetic tone such as heart failure, atrial fibrillation, or ventricular arrhythmias that may benefit from RDN. Furthermore, novel therapeutical approach toward RDN using adapted electrophysiological or new specially designed electrodes may improve effectiveness of RDN procedure.  相似文献   
97.
98.
Rationale:The use of cisplatin in patients with chronic kidney disease (CKD) is risky and depends on a number of factors. The optimal procedure in stage I of a non seminomatous germ cell tumor without proven lymphangioinvasion after orchiectomy is controversial and is the subject of a number of discussions due to the lack of randomized studies assessing individual treatment options. The adjuvant method of choice is surveillance or application of cisplatin-based chemotherapy with the risk of treatment related nephrotoxicity. Information about cisplatin safety in renal transplant patients is particularly limited. The aim of this paper is to share the experience with the application of adjuvant chemotherapy Bleomycin, Etoposide, Cisplatin (BEP) in high-risk patient with nonseminoma after kidney transplantation.Patient concerns:We report a case report of rare group of high-risk patient with non-seminomatous germ cell testicular tumor (NSGCT) after kidney transplantation before application of adjuvant chemotherapy BEP. Patient presented with month-long discomfort in the scrotal area. Previously, he was treated with chronic kidney disease based on chronic glomerulonephritis, which was treated with repeated kidney transplantation.Diagnosis:The ultrasound examination for a month-long discomfort in the scrotal area found a solid mass of the left testis. Radical inguinal orchiectomy confirmed NSGCT with the presence of lymphovascular invasion (LVI). Postoperative staging with computed tomography of the chest and abdomen did not show obvious dissemination of the disease.Interventions:Reducing original dose of chemotherapeutics according to the recommendations of the summary of product characteristics led to only a transient increase in creatinine levels.Outcomes:The 5-year risk of relapse in surveillance was reduced to around 3% by applying cisplatin-based chemotherapy.Lessons:Application of cisplatin-based chemotherapy is safe and effective in patients with CKD and in patients with a kidney transplant.  相似文献   
99.
A taxonomically unique bacterial strain, Acinetobacter sp. A47, has been recovered from several soft tissue samples from a patient undergoing reconstructive surgery owing to a traumatic amputation. The results of 16S rRNA, rpoB, and gyrB gene comparative sequence analyses showed that A47 does not belong to any of the hitherto-known taxa and may represent an as-yet-unknown Acinetobacter species. The recognition of this novel organism contributes to our knowledge of the taxonomic complexity underlying infections caused by Acinetobacter.  相似文献   
100.
Intramyocardial transplantation of autologous bone marrow mononuclear cells (BMMC) is believed to be a promising method for the treatment of patients with chronic ischemic heart disease. The aim of this study was to evaluate long-term results of intramyocardial bone marrow cell transplantation in patients with severe ischemic heart failure. One hundred nine patients with chronic myocardial infarction and end-stage chronic heart failure were randomized into two groups: 55 patients received intramyocardial BMMC injection and 54 received optimal medical therapy. The NOGA system (Biosense-Webster) was used to administer 41?±?16?×?106 BMMC into the border zone of myocardial infarction. None of the patients developed periprocedural complications following BMMC injections. The injections led to improvement of CCS class (3.1?±?0.4 to 1.6?±?0.6 after 6 months and 1.6?±?0.4 after 12 months; p?=?0.001) and NYHA functional class (3.3?±?0.2 to 2.3?±?0.2 after 6 months and 2.5?±?0.1 after 12 months; p?=?0.006). Left ventricular ejection fraction increased significantly in the BMMC group (27.8?±?3.4% vs 32.3?±?4.1%; p?=?0.04) while it tended to decrease in the control group (26.8?±?3.8% to 25.2?±?4.1%; p?=?0.61). Summed rest score improved in the BMMC group after 12 months (30.2?±?5.6 to 27.8?±?5.1; p?=?0.032). The improvement of stress score was more noticeable (34.5?±?5.4 to 28.1?±?5.2; p?=?0.016). Neither stress nor rest score changed in patients numbers on medical therapy. In BMMC group 6 (10.9%) patients died at 12-month follow-up compared with 21 (38.9%) in control group (log-rank test, p?=?0.0007). Intramyocardial bone marrow cell transplantation to patients with ischemic heart failure is safe and improved survival, clinical symptoms, and has beneficial effect on LV function  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