全文获取类型
收费全文 | 3390篇 |
免费 | 187篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 116篇 |
妇产科学 | 39篇 |
基础医学 | 279篇 |
口腔科学 | 114篇 |
临床医学 | 277篇 |
内科学 | 836篇 |
皮肤病学 | 54篇 |
神经病学 | 152篇 |
特种医学 | 178篇 |
外科学 | 679篇 |
综合类 | 102篇 |
一般理论 | 1篇 |
预防医学 | 268篇 |
眼科学 | 60篇 |
药学 | 219篇 |
中国医学 | 16篇 |
肿瘤学 | 187篇 |
出版年
2023年 | 30篇 |
2022年 | 54篇 |
2021年 | 108篇 |
2020年 | 61篇 |
2019年 | 77篇 |
2018年 | 104篇 |
2017年 | 61篇 |
2016年 | 69篇 |
2015年 | 64篇 |
2014年 | 142篇 |
2013年 | 161篇 |
2012年 | 187篇 |
2011年 | 236篇 |
2010年 | 153篇 |
2009年 | 143篇 |
2008年 | 168篇 |
2007年 | 188篇 |
2006年 | 170篇 |
2005年 | 166篇 |
2004年 | 145篇 |
2003年 | 155篇 |
2002年 | 152篇 |
2001年 | 66篇 |
2000年 | 74篇 |
1999年 | 56篇 |
1998年 | 35篇 |
1997年 | 18篇 |
1996年 | 30篇 |
1995年 | 27篇 |
1994年 | 27篇 |
1993年 | 17篇 |
1992年 | 35篇 |
1991年 | 38篇 |
1990年 | 37篇 |
1989年 | 28篇 |
1988年 | 36篇 |
1987年 | 38篇 |
1986年 | 31篇 |
1985年 | 30篇 |
1984年 | 16篇 |
1983年 | 12篇 |
1981年 | 10篇 |
1979年 | 15篇 |
1978年 | 14篇 |
1977年 | 9篇 |
1973年 | 11篇 |
1970年 | 9篇 |
1969年 | 13篇 |
1968年 | 9篇 |
1966年 | 9篇 |
排序方式: 共有3601条查询结果,搜索用时 15 毫秒
81.
McDonald JR Olaison L Anderson DJ Hoen B Miro JM Eykyn S Abrutyn E Fowler VG Habib G Selton-Suty C Pappas PA Cabell CH Corey GR Marco F Sexton DJ 《The American journal of medicine》2005,118(7):759-766
PURPOSE: To describe clinical features and outcomes of enterococcal left-sided native valve endocarditis and to compare it to endocarditis caused by other pathogens. SUBJECTS AND METHODS: Patients in the International Collaboration on Endocarditis-Merged Database were included if they had left-sided native valve endocarditis. Demographic characteristics, clinical features, and outcomes were analyzed. Multivariable analysis evaluated enterococcus as a predictor of mortality. RESULTS: Of 1285 patients with left-sided native valve endocarditis, 107 had enterococcal endocarditis. Enterococcal endocarditis was most frequently seen in elderly men, frequently involved the aortic valve, tended to produce heart failure rather than embolic events, and had relatively low short-term mortality. Compared to patients with non-enterococcal endocarditis, patients with enterococcal endocarditis had similar rates of nosocomial acquisition, heart failure, embolization, surgery, and mortality. Compared to patients with streptococcal endocarditis, patients with enterococcal endocarditis were more likely to be nosocomially acquired (9 of 59 [15%] vs 2 of 400 [1%]; P <.0001) and have heart failure (49 of 107 [46%] vs 234 of 666 [35%]; P = 0.03). Compared to patients with S. aureus endocarditis, patients with enterococcal endocarditis were less likely to embolize (28 of 107 [26%] vs 155 of 314 [49%]; P <.0001) and less likely to die (12 of 107 [11%] vs 83 of 313 [27%]; P = 0.001). Multivariable analysis of all patients with left-sided native valve endocarditis showed that enterococcal endocarditis was associated with lower mortality (odds ratio [OR] 0.49; 95% confidence interval [CI] 0.24 to 0.97). CONCLUSIONS: Enterococcal native valve endocarditis has a distinctive clinical picture with a good prognosis. 相似文献
82.
General and specific brain regions involved in encoding and retrieval of events: what, where, and when. 总被引:9,自引:0,他引:9
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
L Nyberg A R McIntosh R Cabeza R Habib S Houle E Tulving 《Proceedings of the National Academy of Sciences of the United States of America》1996,93(20):11280-11285
Remembering an event involves not only what happened, but also where and when it occurred. We measured regional cerebral blood flow by positron emission tomography during initial encoding and subsequent retrieval of item, location, and time information. Multivariate image analysis showed that left frontal brain regions were always activated during encoding, and right superior frontal regions were always activated at retrieval. Pairwise image subtraction analyses revealed information-specific activations at (i) encoding, item information in left hippocampal, location information in right parietal, and time information in left fusiform regions; and (ii) retrieval, item in right inferior frontal and temporal, location in left frontal, and time in anterior cingulate cortices. These results point to the existence of general encoding and retrieval networks of episodic memory whose operations are augmented by unique brain areas recruited for processing specific aspects of remembered events. 相似文献
83.
Huseyin Begenik Mehmet Aslan Ahmet Cumhur Dulger Habib Emre Ahu Kemik Ozgur Kemik Ramazan Esen 《Archives of Medical Science》2015,11(2):346-352
Introduction
Serum leptin levels have been examined in various cancers, with conflicting results. However, there is limited information regarding serum leptin levels and insulin resistance in gastric cancer patients. Therefore, we aimed to investigate serum leptin levels, performance status, insulin levels and insulin resistance in patients with gastric cancer. In addition, we examined the relationship between these measurements and leptin levels.Material and methods
Thirty-nine patients with gastric cancer and 30 control subjects were enrolled in the study. Serum leptin, total protein, albumin, growth hormone, insulin and glucose levels were measured. The homeostasis model assessment (HOMA) was used to assess insulin resistance.Results
Serum levels of insulin, glucose and growth hormone and insulin resistance were significantly lower in gastric cancer patients than controls (p < 0.05 for all). In the Pearson correlation analysis, insulin resistance was found to be significantly correlated with serum leptin levels in gastric cancer patients (r = 0.320, p = 0.047). We observed a significant negative correlation between performance status and insulin resistance in patients with cachexia (r = –0.512, p = 0.030), while no association was found in non-cachectic patients.Conclusions
We concluded that serum leptin levels are significantly lower in gastric cancer patients. In addition, gastric cancer patients have decreases in insulin levels, insulin resistance and growth hormone levels. This study found a positive association between serum leptin levels and insulin resistance. Moreover, there is a negative association between serum leptin levels and growth hormone levels. Thus, low insulin and growth hormone levels may suppress the production of leptin in gastric cancer patients. 相似文献84.
Habib Bouazzi Gaetan Lesca Carlos Trujillo Mohammad Khalid Alwasiyah Arnold Munnich 《Clinical Case Reports》2015,3(7):604-609
X‐linked intellectual deficiency (XLID) is a large group of genetic disorders. MED12 gene causes syndromic and nonsyndromic forms of XLID. Only seven pathological mutations have been identified in this gene. Here, we report a novel mutation segregating with XLID phenotype. This mutation could be in favor of genotype–phenotype correlations. 相似文献
85.
Nooraldaem Yousif Suddharsan Subbramaniyam Babu Thevan Mohammad Amin Leena Sulaibikh Nazar Bukamal Habib Tareif Sadananda Shivappa Haitham Amin Husam A. Noor 《Journal of the Saudi Heart Association》2020,32(3):434
BACKGROUNDTranscatheter aortic valve implantation (TAVI) is a minimally invasive procedure that is considered a good alternative to surgical aortic valve replacement (sAVR) in selected patients. Our aim is to determine the baseline, procedural characteristics and one-year clinical outcomes of our TAVI registry.METHODSThis study is a retrospective observational analysis of a prospectively designed cohort comprising 81 consecutive patients treated at Mohammed bin Khalifa Cardiac Centre (MKCC) who were enrolled in Bahrain TAVI registry from February 2014 to February 2019. The clinical endpoints were defined according to the updated Valve Academic Research Consortium-2 (VARC-2) consensus document.RESULTSOut of the 81 patients included in our study, there were 37 (45.7%) males. The mean age was 76.4 ± 8.9 years with a mean Logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE II) of 4.1 ± 2.5 and a mean Society of Thoracic Surgery (STS) Risk Score of 4.2 ± 3.5. Evolute-R valve was used for 36 (44.4%) patients, Edward Sapien for 26 patients (32.1%), and Core valve for 19 patients (23.5%). At one year follow up, all-cause death was reported in three (3.7%) patients; none of them was cardiovascular mortality. As per VARC-II criteria, no cases fulfilled the criteria of valve dysfunction but TAVI-related complications (i.e., TAV-in-TAV deployment) were reported in four (4.9%) cases. One (1.2%) case of major bleeding was encountered but no patient experienced life-threatening bleeding. Major vascular complications were documented in two patients (2.5%) only. Significant Acute Kidney Injury (AKI) occurred in two (2.5%) patients, both classified as stage-2 but no one deteriorated to stage-3 or hemodialysis. Seven (8.6%) patients required permanent pacemakers, and all were implanted during the index admission for TAVI. One patient (1.2%) had stroke and all survivors completed one-year follow up.CONCLUSIONThe TAVI program in Bahrain is encouraging and corresponds to the finest international centers outcomes in terms of procedural success and complications rate. 相似文献
86.
87.
88.
Variceal bleeding is one of the most dreaded complications of cirrhosis and its occurrence is associated with significant morbidity and mortality. During the past 30 years preventative therapies have reduced the risk of the first variceal bleed. Once variceal bleeding occurs use of pharmacologic and endoscopic therapies prevent rebleeding in most patients. The existing recommendations are that TIPS only be used in those patients who fail medical therapy. We reviewed recent literature focusing on the role of early TIPS in management of acute variceal hemorrhage and prevention of re-bleeding. 相似文献
89.
Mahim Khan Waqar Rauf Fazal-e- Habib Moazur Rahman Mazhar Iqbal 《World journal of hepatology》2020,12(11):976-992
BACKGROUNDHepatitis C virus genotype 3a (HCV G3a) is highly prevalent in Pakistan. Due to the elevated cost of available Food and Drug Administration-approved drugs against HCV, medicinal natural products of potent antiviral activity should be screened for the cost-effective treatment of the disease. Furthermore, from natural products, active compounds against vital HCV proteins like non-structural protein 3 (NS3) protease could be identified to prevent viral proliferation in the host.AIMTo develop cost-effective HCV genotype 3a NS3 protease inhibitors from citrus fruit extracts.METHODSFull-length NS3 without co-factor non-structural protein 4A (NS4A) and codon optimized NS3 protease in fusion with NS4A were expressed in Escherichia coli. The expressed protein was purified by metal ion affinity chromatography and gel filtration. Citrus fruit extracts were screened using fluorescence resonance energy transfer (FRET) assay against the protease and polyphenols were identified as potential inhibitors using electrospray ionization-mass spectrometry (MS)/MS technique. Among different polyphenols, highly potent compounds were screened using molecular modeling approaches and consequently the most active compound was further evaluated against HCV NS4A-NS3 protease domain using FRET assay.RESULTSNS4A fused with NS3 protease domain gene was overexpressed and the purified protein yield was high in comparison to the lower yield of the full-length NS3 protein. Furthermore, in enzyme kinetic studies, NS4A fused with NS3 protease proved to be functionally active compared to full-length NS3. So it was concluded that co-factor NS4A fusion is essential for the purification of functionally active protease. FRET assay was developed and validated by the half maximal inhibitory concentration (IC50) values of commercially available inhibitors. Screening of citrus fruit extracts against the native purified fused NS4A-NS3 protease domain showed that the grapefruit mesocarp extract exhibits the highest percentage inhibition 91% of protease activity. Among the compounds identified by LCMS analysis, hesperidin showed strong binding affinity with the protease catalytic triad having S-score value of -10.98.CONCLUSIONFused NS4A-NS3 protease is functionally more active, which is effectively inhibited by hesperidin from the grapefruit mesocarp extract with an IC50 value of 23.32 µmol/L. 相似文献
90.
Omar A. Hussein Khairul Habib R. Saidur Ali S. Muhsan Syed Shahabuddin Omer A. Alawi 《RSC advances》2019,9(66):38576
Covalent functionalization (CF-GNPs) and non-covalent functionalization (NCF-GNPs) approaches were applied to prepare graphene nanoplatelets (GNPs). The impact of using four surfactants (SDS, CTAB, Tween-80, and Triton X-100) was studied with four test times (15, 30, 60, and 90 min) and four weight concentrations. The stable thermal conductivity and viscosity were measured as a function of temperature. Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), X-ray diffraction (XRD) and Raman spectroscopy verified the fundamental efficient and stable CF. Several techniques, such as dispersion of particle size, FESEM, FETEM, EDX, zeta potential, and UV-vis spectrophotometry, were employed to characterize both the dispersion stability and morphology of functionalized materials. At ultrasonic test time, the highest stability of nanofluids was achieved at 60 min. As a result, the thermal conductivity displayed by CF-GNPs was higher than NCF-GNPs and distilled water. In conclusion, the improvement in thermal conductivity and stability displayed by CF-GNPs was higher than those of NCF-GNPs, while the lowest viscosity was 8% higher than distilled water, and the best thermal conductivity improvement was recorded at 29.2%.Covalent functionalization (CF-GNPs) and non-covalent functionalization (NCF-GNPs) approaches were applied to prepare graphene nanoplatelets (GNPs). 相似文献