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   107781篇
  免费   11327篇
  国内免费   3368篇
耳鼻咽喉   750篇
儿科学   1708篇
妇产科学   1217篇
基础医学   20167篇
口腔科学   2858篇
临床医学   6767篇
内科学   16356篇
皮肤病学   1916篇
神经病学   11513篇
特种医学   2885篇
外国民族医学   27篇
外科学   8600篇
综合类   10692篇
现状与发展   14篇
预防医学   4408篇
眼科学   1109篇
药学   17330篇
  34篇
中国医学   4121篇
肿瘤学   10004篇
  2024年   309篇
  2023年   1957篇
  2022年   4404篇
  2021年   4961篇
  2020年   4206篇
  2019年   4455篇
  2018年   4252篇
  2017年   4220篇
  2016年   3944篇
  2015年   4475篇
  2014年   6492篇
  2013年   6722篇
  2012年   5971篇
  2011年   7091篇
  2010年   5698篇
  2009年   5724篇
  2008年   5639篇
  2007年   4796篇
  2006年   4132篇
  2005年   3794篇
  2004年   3200篇
  2003年   2864篇
  2002年   2148篇
  2001年   1803篇
  2000年   1507篇
  1999年   1425篇
  1998年   1371篇
  1997年   1332篇
  1996年   1223篇
  1995年   1122篇
  1994年   1027篇
  1993年   979篇
  1992年   768篇
  1991年   689篇
  1990年   594篇
  1989年   507篇
  1988年   484篇
  1987年   478篇
  1986年   573篇
  1985年   787篇
  1984年   756篇
  1983年   600篇
  1982年   597篇
  1981年   504篇
  1980年   465篇
  1979年   381篇
  1978年   233篇
  1977年   196篇
  1976年   205篇
  1975年   127篇
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
81.
目的探讨重睑术中采用经重睑切口的上睑旋转皮瓣矫正轻、中度内眦赘皮的疗效。方法回顾分析 2016 年 7 月—2017 年 10 月,重睑术中采用经重睑切口的上睑旋转皮瓣矫正轻、中度睑板型内眦赘皮合并单睑的 34 例患者(试验组)临床资料;以同期 38 例接受传统“Z”成形内眦开大术联合重睑术患者为对照(对照组)。两组患者年龄及内侧赘皮分度比较,差异无统计学意义(P>0.05)。于术前及术后 6 d、6 个月测量眼裂长度,计算眼裂长度改善程度;参照内眦赘皮矫正标准评价手术疗效。 结果两组患者切口均Ⅰ期愈合,并获随访 6 个月。两组内眦赘皮明显矫正。试验组内眦处无切口;对照组遗留瘢痕,其中 6 例增生明显。术后 6 d 试验组及对照组眼裂长度改善程度分别为 3.63%±0.07%、3.70%±0.05%;术后 6 个月分别为 4.64%±0.09%、4.46%±0.10%;两组比较差异均无统计学意义(t=0.005,P=0.996;t=0.287,P=0.871)。术后 6 个月疗效评价,试验组优 20 例、良 12 例、差 2 例,优良率 94.12%;对照组优 16 例、良 16 例、差 6 例,优良率 84.21%;差异无统计学意义(χ2=0.796,P=0.372)。 结论经重睑切口的上睑旋转皮瓣矫正轻、中度内眦赘皮手术操作简便、效果满意,内眦处无瘢痕形成。  相似文献   
82.
《Injury》2022,53(8):2725-2733
BackgroundPrioritising patients in mass casualty incidents (MCI) can be extremely difficult. Therefore, triage systems are important in every emergency medical service. This study reviews the accuracy of primary triage systems for MCI in trauma register studies.MethodsWe registered a protocol at PROSPERO ID: CRD42018115438. We searched MEDLINE, EMBASE, Central, Web of Science, Scopus, Clinical Trials, Google Scholar, and reference lists for eligible studies. We included studies that both examined a primary triage system for MCI in trauma registers and provided sensitivity and specificity for critically injured vs non-critically injured as results. We excluded studies that used paediatric, chemical, biological, radiological or nuclear MCIs populations or triage systems. Finally, we calculated intra-study relative sensitivity, specificity and diagnostic odds ratio for each triage system.ResultsTriage Sieve (TS) significantly underperformed in relative diagnostic odds ratio (DOR) when compared to START and CareFlight (CF) (START vs TS: 19.85 vs 13.23 (p<0.0001)│CF vs TS: 23.72 vs 12.83 (p<0.0001)). There was no significant difference in DOR between TS and Military Sieve (MS) (p<0.710). Compared to START, MS and CF TS had significantly higher relative specificity (START vs TS: 93.6% vs 96.1% (p=0.047)│CF vs TS: 96% vs 95.3% (p=0.0006)│MS vs TS: 94% vs 88.3% (p=0.0002)) and lower relative sensitivity (START vs TS: 57.8% vs 34.8% (p<0.0001)│CF vs TS: 53.9% vs 34.7% (p<0.0001)│MS vs TS: 51.9% vs 35.2% p<0.0001)).CF had significantly better relative DOR than START (CF vs START: 23.56 vs 27.79 (p=0.043)). MS had significantly better relative sensitivity than CF and START (MS vs CF: 49.5% vs 38.7% (p<0.0001)│MS vs START: 49.4% vs 43.9% (p=0.01)). In contrast, CF had significantly better relative specificity than MS (MS vs CF: 91.3% vs 93.3% (p<0.0001)). The remaining comparisons did not yield any significant differences.ConclusionAs the included studies were at risk of bias and had heterogenic characteristics, our results should be interpreted with caution. Nonetheless, our results point towards inferior accuracy of Triage Sieve compared to START and CareFlight, and less firmly point towards superior accuracy of Military Sieve compared to START, CareFlight and Triage Sieve  相似文献   
83.
Among the numerous signaling pathways involved in tumorigenesis, PI3K‐AKT‐mTOR is a key one that regulates diverse cellular functions. However, its prognostic value in esophageal carcinoma remains unclear. In our study, we examined the immunohistochemical expression of phosphorylated (p‐) AKT, mTOR, p70S6K and 4E‐BP1 along with the mutational status of PIK3CA and AKT1 genes by High Resolution Melting Analysis and Pyrosequencing in 44 esophageal carcinomas. The results were correlated with the clinicopathological characteristics of the patients in an effort to define their possible prognostic significance. Total p‐mTOR cytoplasmic expression, assessed in 10 random areas, was positively correlated with tumor stage (Kruskal–Wallis ANOVA, I/II vs III/IV, p = 0.0500). Μoreover, maximum p‐mTOR cytoplasmic immunoexpression, estimated in hot spot areas, was positively associated with tumor grade (Mann–Whitney U test, I/II vs III, p = 0.0565). Interestingly, p‐4E‐BP1 immunoreactivity was negatively correlated with tumor histological grade (Mann–Whitney U test, I/II vs III, p = 0.0427). No mutation was observed in exons 9 and 20 of PIK3CA gene and in exon 4 of AKT1 gene. In conclusion, our findings depict the presence of activated PI3K/AKT/mTOR pathway in esophageal cancer bringing forward p‐mTOR and p‐4E‐BP1 for their potential role in esophageal carcinogenesis. Additional studies are warranted to validate our findings.  相似文献   
84.
85.
《Vaccine》2015,33(43):5861-5867
River blindness, caused by the filarial parasite Onchocerca volvulus, is a major socio-economic and public health problem in Sub-Saharan Africa. In January 2015, The Onchocerciasis Vaccine for Africa (TOVA) Initiative has been launched with the aim of providing new tools to complement mass drug administration (MDA) of ivermectin, thereby promoting elimination of onchocerciasis in Africa. In this context we here present Onchocerca volvulus glyceraldehyde-3-phosphate dehydrogenase (Ov-GAPDH) as a possible DNA vaccine candidate. We report that in a laboratory model for filariasis, immunization with Ov-GAPDH led to a significant reduction of adult worm load and microfilaraemia in BALB/c mice after challenge infection with the filarial parasite Litomosoides sigmodontis. Mice were either vaccinated with Ov-GAPDH.DNA plasmid (Ov-pGAPDH.DNA) alone or in combination with recombinantly expressed Ov-GAPDH protein (Ov-rGAPDH). During the following challenge infection of immunized and control mice with L. sigmodontis, those formulations which included the DNA plasmid, led to a significant reduction of adult worm loads (up to 57% median reduction) and microfilaraemia (up to 94% reduction) in immunized animals. In a further experiment, immunization with a mixture of four overlapping, synthetic Ov-GAPDH peptides (Ov-GAPDHpept), with alum as adjuvant, did not significantly reduce worm loads. Our results indicate that DNA vaccination with Ov-GAPDH has protective potential against filarial challenge infection in the mouse model. This suggests a transfer of the approach into the cattle Onchocerca ochengi model, where it is possible to investigate the effects of this vaccination in the context of a natural host–parasite relationship.  相似文献   
86.
87.
BackgroundTakotsubo syndrome (TTS) is an acquired form of cardiomyopathy. National Brazilian data on this condition are scarce. The Takotsubo Multicenter Registry (REMUTA) is the first to include multicenter data on this condition in Brazil.ObjectiveTo describe the clinical characteristics, prognosis, in-hospital treatment, in-hospital mortality, and mortality during 1 year of follow-up.MethodsThis is an observational, retrospective registry study including patients admitted to the hospital with diagnosis of TTS and patients admitted for other reasons who developed this condition. Evaluated outcomes included triggering factor, analysis of exams, use of medications, complications, in-hospital mortality, and mortality during 1 year of follow-up. A significance level of 5% was adopted.ResultsThe registry included 169 patients from 12 centers in the state of Rio de Janeiro, Brazil. Mean age was 70.9 ± 14.1 years, and 90.5% of patients were female; 63% of cases were primary TTS, and 37% were secondary. Troponin I was positive in 92.5% of patients, and median BNP was 395 (176.5; 1725). ST-segment elevation was present in 28% of patients. Median left ventricular ejection fraction was 40 (35; 48)%. We observed invasive mechanical ventilation in 25.7% of cases and shock in 17.4%. Mechanical circulatory support was used in 7.7%. In-hospital mortality was 10.6%, and mortality at 1 year of follow-up was 16.5%. Secondary TTS and cardiogenic shock were independent predictors of mortality.ConclusionThe results of the REMUTA show that TTS is not a benign pathology, as was once thought, especially regarding the secondary TTS group, which has a high rate of complications and mortality. (Arq Bras Cardiol. 2020; 115(2):207-216)  相似文献   
88.
Additive manufacturing is a rapidly emerging technology which is being successfully implemented in the various field of medicine as well as in orthopaedics, where it has applications in reducing cartilage defects and treatments of bones. The technology helps through systematic collection of information about the shape of the "defects" and precise fabrication of complex 3D constructs such as cartilage, heart valve, trachea, myocardial bone tissue and blood vessels. In this paper, a large number of the relevant research papers on the additive manufacturing and its application in medical specifically orthopaedics are identified through Scopus had been studied using Bibliometric analysis and application analysis is undertaken. The bibliometric analysis shows that there is an increasing trend in the research reports on additive manufacturing applications in the field of orthopaedics. Discussions are on using technological advancement like scanning techniques and various challenges of the orthopaedic being met by additive manufacturing technology. For patient-specific orthopaedic applications, these techniques incorporate clinical practice and use for effective planning. 3D printed models printed by this technology are accepted for orthopaedic surgery such as revision of lumbar discectomy, pelvic surgery and large scapular osteochondroma. The applications of additive manufacturing in orthopaedics will experience a rapid translation in future. An orthopaedic surgeon can convert need/idea into a reality by using computer-aided design (CAD) software, analysis software to facilitate the manufacturing. Thus, AM provides a comprehensive opportunity to manufacture orthopaedic implantable medical devices.  相似文献   
89.
The development and use of the tumour necrosis factor (TNF) antagonists is a major breakthrough in the treatment of many rheumatic diseases. Although these novel agents are undoubtedly superior to conventional therapeutic modalities, their costs and potential adverse effects are of concern. The current consensus statements were developed in early 2005 to help practicing rheumatologists identify which adult patients may benefit from anti‐TNF therapies and highlight their potential toxicities. The Hong Kong Society of Rheumatology has developed a registry on the use of the biologics in our local patients with chronic rheumatic disorders. Because the indications and novel data regarding the TNF inhibitors are ever changing, this consensus will be updated regularly.  相似文献   
90.
A method is presented for 3D MRI in an extended field of view (FOV) based on continuous motion of the patient table and an efficient acquisition scheme. A gradient-echo MR pulse sequence is applied with lateral (left-right (L/R)) frequency-encoding direction and slab selection along the direction of motion. Compensation for the table motion is achieved by a combination of slab tracking and data alignment in hybrid space. The method allows fast k-space coverage to be achieved, especially when a short sampling FOV is chosen along the direction of table motion, as is desirable for good image quality. The method can be incorporated into different acquisitions schemes, including segmented k-space scanning, which allows for contrast variation with the use of magnetization preparation. Head-to-toe images of volunteers were obtained with good quality using 3D spoiled gradient-echo sequences. As an example of magnetization-prepared imaging, fat/water separated images were acquired using chemical shift selective (CHESS) presaturation pulses.  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