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   44725篇
  免费   5413篇
  国内免费   159篇
耳鼻咽喉   312篇
儿科学   1045篇
妇产科学   621篇
基础医学   3323篇
口腔科学   1592篇
临床医学   4229篇
内科学   5967篇
皮肤病学   490篇
神经病学   3622篇
特种医学   1325篇
外国民族医学   3篇
外科学   3634篇
综合类   4767篇
一般理论   2篇
预防医学   7676篇
眼科学   587篇
药学   3413篇
  25篇
中国医学   4422篇
肿瘤学   3242篇
  2024年   11篇
  2023年   1034篇
  2022年   986篇
  2021年   1720篇
  2020年   1981篇
  2019年   1861篇
  2018年   1800篇
  2017年   1790篇
  2016年   1559篇
  2015年   1409篇
  2014年   3328篇
  2013年   3343篇
  2012年   2655篇
  2011年   2820篇
  2010年   2156篇
  2009年   2117篇
  2008年   2376篇
  2007年   2412篇
  2006年   2180篇
  2005年   1754篇
  2004年   1476篇
  2003年   1404篇
  2002年   1095篇
  2001年   999篇
  2000年   788篇
  1999年   679篇
  1998年   471篇
  1997年   481篇
  1996年   379篇
  1995年   428篇
  1994年   372篇
  1993年   308篇
  1992年   301篇
  1991年   266篇
  1990年   228篇
  1989年   212篇
  1988年   197篇
  1987年   160篇
  1986年   128篇
  1985年   119篇
  1984年   102篇
  1983年   72篇
  1982年   66篇
  1981年   63篇
  1980年   59篇
  1979年   32篇
  1978年   30篇
  1977年   27篇
  1976年   18篇
  1975年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Introduction: The aim of this study was to assess the reliability of a near‐nerve needle recording technique in lateral femoral cutaneous nerve (LFCN) sensory nerve conduction studies (NCS). Methods: Bilateral LFCN sensory nerve action potentials (SNAPs) were recorded from 10 healthy volunteers using surface and near‐nerve needle recording electrodes. Absolute amplitudes were compared side‐to‐side in each subject and between the 2 techniques. Results: Near‐nerve needle electrode recording amplitude was significantly higher when compared with surface electrode recording (surface 9 μV, needle 58 μV; P < 0.0001), whereas side‐to‐side variability did not differ (surface 37%, needle 37%; P = 0.94). Conclusions: We propose that near‐nerve needle recording is a simple technique to employ for clinicians with experience in ultrasound‐guided needle placement, especially when evaluation is critical and responses are difficult to obtain. However, given the degree of side‐to‐side variability in healthy subjects, we recommend caution when interpreting side‐to‐side differences. Muscle Nerve, 2013  相似文献   
5.
Introduction: The aim of this study was to make correlations between ultrasonographic measurements of thenar muscle and flexor retinaculum and nerve conduction studies (NCS) in carpal tunnel syndrome (CTS). Methods: Ultrasound and NCS were performed on 92 wrists with CTS and on 40 wrists from healthy individuals. Ultrasound of thenar and hypothenar muscles, flexor retinaculum, and median nerve were assessed. The ultrasonographic findings were compared between the 2 groups, and correlation analyses between median latency and ultrasonographic findings were performed. Results: Motor latency correlated positively with flexor retinaculum thickness (FRT) and negatively with the ratio of thenar to hypothenar muscle. FRT and motor latency were found to be increased significantly in CTS. The ratio of thenar to hypothenar muscle was found to be decreased significantly in CTS compared with controls. Conclusions: The ultrasonographic findings of FRT and thenar muscle reflect the severity of disease in patients with CTS and are valuable for the diagnosis of CTS. Muscle Nerve 48 : 905–910, 2013  相似文献   
6.
7.
The aims of our meta‐analysis were (i) to quantify the predictability of childhood overweight and obesity on the risk of incident asthma; and (ii) to evaluate the gender difference on this relationship. The selection criteria included prospective cohort paediatric studies which use age‐ and sex‐specific body mass index (BMI) as a measure of childhood overweight and the primary outcome of incident asthma. A total of 1,027 studies were initially identified through online database searches, and finally 6 studies met the inclusion criteria. The combined result of reported relative risk from the 6 included studies revealed that overweight children conferred increased risks of incident asthma as compared with non‐overweight children (relative risk, 1.19; 95% confidence interval [CI], 1.03–1.37). The relationship was further elevated for obesity vs. non‐obesity (relative risk, 2.02; 95% CI, 1.16–3.50). A dose–responsiveness of elevated BMI on asthma incidence was observed (P for trend, 0.004). Obese boys had a significantly larger effect than obese girls (relative risk, boys: 2.47; 95% CI, 1.57–3.87; girls: 1.25; 95% CI, 0.51–3.03), with significant dose‐dependent effect. Proposed mechanisms of gender difference could be through pulmonary mechanics, sleep disordered breathing and leptin. Further research might be needed to better understand the exact mechanism of gender difference on the obesity–asthma relationship.  相似文献   
8.
Training volume and body composition have been suggested as risk factors for jumper's knee among athletic youth, but research is lacking. The aim of this 4‐year prospective cohort study was to examine the relationship between training and competition load, body composition, and risk for developing jumper's knee. Participants are elite volleyball players, aged 16–18 years. Training and competition load was recorded continuously and body composition semiannually. Jumper's knee was diagnosed on a standardized clinical examination. We recruited 141 healthy students (69 males and 72 females), and 28 developed jumper's knee (22 boys and six girls). In a multivariate analyses, boys had three to four times higher risk compared with girls. Volleyball training had an odds ratio (OR) 1.72 (1.18–2.53) for every extra hour trained, and match exposure was the strongest sports‐related predictor for developing jumper's knee with an OR of 3.88 (1.80–8.40) for every extra set played per week. We did not detect any significant differences between the groups in body composition at the time of inclusion or in the change of body composition during the study period. Conclusion, male gender, a high volume of volleyball training and match exposure were risk factors for developing jumper's knee.  相似文献   
9.
To assess, using clinical cases, the potential of a hybrid technique for the treatment of non–small cell lung cancer (NSCLC)-blending volumetric-modulated arc therapy (VMAT) and conformal radiation therapy (CRT) fields, and to consider potential issues with implementation of such a technique. Eight clinical cases already treated with CRT were used for a planning study comparing target coverage and organs at risk (OAR) sparing between CRT and hybrid VMAT (VMATh). Quality assurance (QA) implications of the resultant hybrid plans are discussed. The hybrid technique resulted in superior target conformity or improved sparing of OAR or both. The hybrid technique shows promise, but the QA implications of motion at treatment need careful consideration.  相似文献   
10.
PurposeTo investigate prevalence of extracranial abnormalities in azygos and internal jugular (IJ) veins using conventional venography and intravascular ultrasound (IVUS) in patients with multiple sclerosis (MS) being evaluated for chronic cerebrospinal venous insufficiency, a condition of vascular hemodynamic dysfunction.Materials and MethodsPREMiSe (Prospective Randomized Endovascular therapy in Multiple Sclerosis) is a venous angioplasty study that enrolled 30 patients with relapsing MS. The patients fulfilled two or more venous hemodynamic extracranial Doppler sonography screening criteria. Phase I of the study included 10 patients and was planned to assess safety and standardize venography, IVUS, and angioplasty and blinding procedures; phase II enrolled 20 patients and further validated diagnostic assessments using the two invasive techniques. Venography was considered abnormal when ≥ 50% lumen-diameter restriction was detected. IVUS was considered abnormal when ≥ 50% lumen-diameter restriction, intraluminal defects, or reduced pulsatility was detected.ResultsNo venography-related or IVUS-related complications, including vessel rupture, thrombosis, or side effects of contrast media were recorded among the 30 study patients. IVUS-detected venous abnormalities, including chronic, organized, thrombus-like inclusions were observed in 85% of azygos, 50% of right IJ, and 83.3% of left IJ veins, whereas venography demonstrated stenosis of ≥ 50% in 50% of azygos, 55% of right IJ, and 72% of left IJ veins. Sensitivity of venography for detecting IVUS abnormalities was 52.9%, 73.3%, and 80% for the azygos, left IJ, and right IJ veins, respectively.ConclusionsIVUS assessment of azygos and IJ veins showed a higher rate of venous abnormalities than venography. IVUS provides a diagnostic advantage over conventional venography in detecting extracranial venous abnormalities indicative of chronic cerebrospinal venous insufficiency.  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