全文获取类型
收费全文 | 8938篇 |
免费 | 602篇 |
国内免费 | 65篇 |
专业分类
耳鼻咽喉 | 30篇 |
儿科学 | 265篇 |
妇产科学 | 187篇 |
基础医学 | 1335篇 |
口腔科学 | 137篇 |
临床医学 | 817篇 |
内科学 | 2278篇 |
皮肤病学 | 173篇 |
神经病学 | 979篇 |
特种医学 | 204篇 |
外科学 | 864篇 |
综合类 | 20篇 |
一般理论 | 2篇 |
预防医学 | 478篇 |
眼科学 | 129篇 |
药学 | 649篇 |
中国医学 | 22篇 |
肿瘤学 | 1036篇 |
出版年
2024年 | 5篇 |
2023年 | 74篇 |
2022年 | 162篇 |
2021年 | 319篇 |
2020年 | 176篇 |
2019年 | 222篇 |
2018年 | 302篇 |
2017年 | 218篇 |
2016年 | 237篇 |
2015年 | 319篇 |
2014年 | 386篇 |
2013年 | 418篇 |
2012年 | 712篇 |
2011年 | 741篇 |
2010年 | 403篇 |
2009年 | 364篇 |
2008年 | 620篇 |
2007年 | 641篇 |
2006年 | 572篇 |
2005年 | 570篇 |
2004年 | 515篇 |
2003年 | 503篇 |
2002年 | 415篇 |
2001年 | 84篇 |
2000年 | 41篇 |
1999年 | 52篇 |
1998年 | 60篇 |
1997年 | 59篇 |
1996年 | 58篇 |
1995年 | 43篇 |
1994年 | 35篇 |
1993年 | 28篇 |
1992年 | 28篇 |
1991年 | 29篇 |
1990年 | 25篇 |
1989年 | 25篇 |
1988年 | 21篇 |
1987年 | 15篇 |
1986年 | 7篇 |
1985年 | 11篇 |
1984年 | 13篇 |
1983年 | 6篇 |
1982年 | 14篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1975年 | 6篇 |
1969年 | 2篇 |
排序方式: 共有9605条查询结果,搜索用时 187 毫秒
1.
Danut Vai
iukynien Aras Kantautas Simona Tu
kut Fallon Manhanga Eugenijus Janavi
ius Ernestas Ivanauskas
ymantas Rudionis Aloyzas Gaudutis 《Materials》2021,14(10)
Concrete plants accumulate large amounts of concrete wash water. This water, which pH is highly alkaline, has a negative impact on the environment. Its reuse in fresh concrete slightly reduces its mechanical properties. The combination of concrete wash water and zeolitic by-product led to an increase of 4.6% in the compressive strength at 7 days hydration and up to 30% at 28 days hydration. The same combination led to the denser microstructure compared to the samples made with concrete wash water. This could be explained by the pozzolanic reaction of the zeolitic by-product. The complex chemical reactions of cement, zeolitic by-product, and fines presented in the concrete wash water occurred. Therefore, it was suggested the reusing method of concrete wash water together with zeolitic by-product in the fresh concrete mixtures by substituting some amount of tap water with concrete wash water. In this way, the consumption of tap water is possible to reduce in cement systems. 相似文献
2.
Haya Mohammed BSc MChB M. Yousuf Salmasi MRCS Massimo Caputo PhD Gianni D. Angelini PhD Hunaid A. Vohra PhD 《Journal of cardiac surgery》2020,35(6):1209-1219
Background
Limited data exists demonstrating the efficacy of minimally invasive surgery (MIS) compared to median sternotomy (MS) for multiple valvular disease (MVD). This systematic review and meta-analysis aims to compare operative and peri-operative outcomes of MIS vs MS in MVD.Methods
PubMed, Ovid, and Embase were searched from inception until August 2019 for randomized and observational studies comparing MIS and MS in patients with MVD. Clinical outcomes of intra- and postoperative times, reoperation for bleeding and surgical site infection were evaluated.Results
Five observational studies comparing 340 MIS vs 414 MS patients were eligible for qualitative and quantitative review. The quality of evidence assessed using the Newcastle-Ottawa scale was good for all included studies. Meta-analysis demonstrated increased cardiopulmonary bypass time for MIS patients (weighted mean difference [WMD], 0.487; 95% confidence interval [CI], 0.365-0.608; P < .0001). Similarly, aortic cross-clamp time was longer in patients undergoing MIS (WMD, 0.632; 95% CI, 0.509-0.755; P < .0001). No differences were found in operative mortality, reoperation for bleeding, surgical site infection, or hospital stay.Conclusions
MIS for MVD have similar short-term outcomes compared to MS. This adds value to the use of minimally invasive methods for multivalvular surgery, despite conferring longer operative times. However, the paucity in literature and learning curve associated with MIS warrants further evidence, ideally randomized control trials, to support these findings.3.
Alessia Scarselli Silvia Di Cesare Claudia Capponi Simona Cascioli Maria L. Romiti Gigliola Di Matteo Alessandra Simonetti Paolo Palma Andrea Finocchi Barbarella Lucarelli Rita M. Pinto Ippolita Rana Giuseppe Palumbo Maurizio Caniglia Paolo Rossi Rita Carsetti Caterina Cancrini Alessandro Aiuti 《Journal of clinical immunology》2015,35(4):373-383
4.
Canadian Journal of Anesthesia/Journal canadien d'anesthésie - 相似文献
5.
6.
S Simona Jakab Victor J Navarro Beth W Colombe Constantine Daskalakis Steven K Herrine Simona Rossi 《Liver transplantation》2007,13(10):1405-1413
Human leukocyte antigen (HLA) compatibility has no clinically significant impact in cadaveric liver transplantation. Less is known regarding living-donor liver transplantation (LDLT). Our prior analysis of the Organ Procurement and Transplantation Network (OPTN) database suggested a higher graft failure rate in patients who underwent LDLT from donors with close HLA match. We further investigated the effect of HLA-A, -B, and -DR matching on 5-yr graft survival in adult LDLT by analyzing OPTN data regarding adult LDLT performed between 1998 and 2005. We evaluated associations between 5-yr graft survival and total, locus-specific, and haplotype match levels. Separate analyses were conducted for recipients with autoimmune (fulminant autoimmune hepatitis, cirrhosis secondary to autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis) or nonautoimmune liver disease. Multivariable Cox proportional hazard models were used to evaluate interactions and adjust for potential confounders. Among 631 patients with available donor/recipient HLA data, the degree of HLA match had no significant effect on 5-yr graft survival, even when analyzed separately in recipients with autoimmune vs. nonautoimmune liver disease. To be able to include all 1,838 adult LDLTs, we considered a first-degree related donor as substitute for a close HLA match. We found no difference in graft survival in related vs. unrelated pairs. In conclusion, our results show no detrimental impact of close HLA matching on graft survival in adult LDLT, including in recipients with underlying autoimmune liver disease. 相似文献
7.
8.
Monica Conciatori Christopher J Stodgell Susan L Hyman Melanie O'Bara Roberto Militerni Carmela Bravaccio Simona Trillo Francesco Montecchi Cindy Schneider Raun Melmed Maurizio Elia Lori Crawford Sarah J Spence Lucianna Muscarella Vito Guarnieri Leonardo D'Agruma Alessandro Quattrone Leopoldo Zelante Daniel Rabinowitz Tiziana Pascucci Stefano Puglisi-Allegra Karl-Ludvig Reichelt Patricia M Rodier Antonio M Persico 《Neuropsychopharmacology》2004,55(4):413-419
BACKGROUND: The HOXA1 gene plays a major role in brainstem and cranial morphogenesis. The G allele of the HOXA1 A218G polymorphism has been previously found associated with autism. METHODS: We performed case-control and family-based association analyses, contrasting 127 autistic patients with 174 ethnically matched controls, and assessing for allelic transmission disequilibrium in 189 complete trios. RESULTS: A, and not G, alleles were associated with autism using both case-control (chi(2) = 8.96 and 5.71, 1 df, p <.005 and <.025 for genotypes and alleles, respectively), and family-based (transmission/disequilibrium test chi(2) = 8.80, 1 df, p <.005) association analyses. The head circumference of 31 patients carrying one or two copies of the G allele displayed significantly larger median values (95.0th vs. 82.5th percentile, p <.05) and dramatically reduced interindividual variability (p <.0001), compared with 166 patients carrying the A/A genotype. CONCLUSIONS: The HOXA1 A218G polymorphism explains approximately 5% of the variance in the head circumference of autistic patients and represents to our knowledge the first known gene variant providing sizable contributions to cranial morphology. The disease specificity of this finding is currently being investigated. Nonreplications in genetic linkage/association studies could partly stem from the dyshomogeneous distribution of an endophenotype morphologically defined by cranial circumference. 相似文献
9.
Vigilio Ballabeni Massimiliano Tognolini Simona Bertoni Renato Bruni Alessandra Guerrini Gabriela Moreno Rueda Elisabetta Barocelli 《Pharmacological research》2007,55(1):23-30
Ocotea quixos essential oil was shown to possess significant inhibitory activity of platelet aggregation and clot retraction in rodent plasma. This study is aimed at fully characterizing the antiplatelet activity of the whole essential oil and its main components trans-cinnamaldehyde and methyl cinnamate also in human plasma, at investigating the mechanism underlying such activity and at evaluating the potential antithrombotic activity of subacute treatment of mice with Ocotea essential oil. In vitro Ocotea essential oil and trans-cinnamaldehyde inhibited arachidonic acid-, U46619-, ADP-, phorbol12-myristate13-alcetate-, collagen-induced platelet aggregation and thrombin-induced clot retraction in human and rodent plasma; Ocotea oil and trans-cinnamaldehyde competitively antagonized contractions induced by thromboxane A2 receptor agonist U46619 in rat isolated aortic ring (K(B) = 18 and 3.2 microg ml(-1), respectively). In vivo Ocotea oil, orally administered in a subacute treatment (30-100 mg kg(-1) day(-1) for 5 days) to mice, prevented acute thrombosis induced by collagen-epinephrine intravenous injection. This antithrombotic activity was not accompanied by pro-haemorragic side effect, as detected by the inactivity in bleeding test, thus showing a favourable safety profile compared to the conventional antiplatelet agent, acetylsalicylic acid. Present findings indicate that Ocotea essential oil possesses potent and safe antithrombotic activity attributable to its antiplatelet and vasorelaxant effects. The main constituent trans-cinnamaldehyde seems to be the primary responsible for this activity through a putative mechanism involving the inhibition of thromboxane A2 receptors. 相似文献
10.
Luca Busetto Claudia Pisent Gianni Segato Francesco De Marchi Franco Favretti Mario Lise Giuliano Enzi 《Obesity surgery》1997,7(6):505-512
Objective: To evaluate the effects of a new timing strategy of band adjustment on the short-term outcome of obese women operated
with adjustable silicone gastric banding. Subjects: The outcome of 30 women without binge-eating disorder operated with laparoscopic
adjustable silicone gastric banding with a wider intraoperatory band calibration (LAP-BAND) was compared to that of 30 body
mass index-matched women without binge-eating disorder previously operated with adjustable silicone gastric banding (ASGB)
applied by laparotomy with the usual intraoperatory band calibration. The patients were evaluated 3, 6 and 12 months after
surgery. Measurements: (1) weight loss; (2) total daily energy intake; (3) percent as liquid, soft or solid food; (4) vomiting
frequency; (5) rate of postoperative percutaneous band adjustments; (6) rate of band-related complications. Results: Both
the weight loss and the daily energy intake did not differ between patients with LAP-BAND and patients with ASGB. After surgery,
the patients with LAP-BAND ate more solid food and less liquid food than the patients with ASGB. Vomiting frequency was higher
in patients with ASGB than in patients with LAP-BAND. The total number of percutaneous band adjustments was higher in women
with LAP-BAND than in women with ASGB. Band inflation because of weight stabilization was performed in six (20.0%) women with
ASGB and in 19 (63.3%) women with LAP-BAND. Neostoma stenosis occurred in one women with ASGB, but in none of the women with
LAP-BAND. One patient with LAP-BAND presented band slippage. Conclusions: The wider intraoperatory band calibration performed
in patients with LAP-BAND did not reduce the short-term efficacy of adjustable silicone gastric banding. This new timing strategy
of band adjustment required more postoperative percutaneous band inflations, but it improved the eating pattern of the patients
(low vomiting frequency and high intake of solid food). 相似文献