全文获取类型
收费全文 | 50044篇 |
免费 | 3513篇 |
国内免费 | 1427篇 |
专业分类
耳鼻咽喉 | 385篇 |
儿科学 | 1661篇 |
妇产科学 | 1685篇 |
基础医学 | 5268篇 |
口腔科学 | 1546篇 |
临床医学 | 7583篇 |
内科学 | 5897篇 |
皮肤病学 | 609篇 |
神经病学 | 2200篇 |
特种医学 | 2351篇 |
外国民族医学 | 20篇 |
外科学 | 3476篇 |
综合类 | 10889篇 |
现状与发展 | 11篇 |
一般理论 | 2篇 |
预防医学 | 3166篇 |
眼科学 | 1069篇 |
药学 | 2252篇 |
79篇 | |
中国医学 | 1376篇 |
肿瘤学 | 3459篇 |
出版年
2024年 | 79篇 |
2023年 | 629篇 |
2022年 | 1120篇 |
2021年 | 1911篇 |
2020年 | 2052篇 |
2019年 | 1470篇 |
2018年 | 1427篇 |
2017年 | 1497篇 |
2016年 | 1879篇 |
2015年 | 1648篇 |
2014年 | 3116篇 |
2013年 | 3234篇 |
2012年 | 2854篇 |
2011年 | 3075篇 |
2010年 | 2493篇 |
2009年 | 2445篇 |
2008年 | 2351篇 |
2007年 | 2628篇 |
2006年 | 2467篇 |
2005年 | 2175篇 |
2004年 | 1937篇 |
2003年 | 1703篇 |
2002年 | 1401篇 |
2001年 | 1287篇 |
2000年 | 956篇 |
1999年 | 821篇 |
1998年 | 708篇 |
1997年 | 690篇 |
1996年 | 619篇 |
1995年 | 553篇 |
1994年 | 500篇 |
1993年 | 448篇 |
1992年 | 370篇 |
1991年 | 352篇 |
1990年 | 299篇 |
1989年 | 243篇 |
1988年 | 281篇 |
1987年 | 236篇 |
1986年 | 184篇 |
1985年 | 184篇 |
1984年 | 115篇 |
1983年 | 78篇 |
1982年 | 92篇 |
1981年 | 81篇 |
1980年 | 75篇 |
1979年 | 62篇 |
1978年 | 41篇 |
1977年 | 24篇 |
1976年 | 27篇 |
1975年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
91.
Objective: To study the diagnostic value of T2^*-weighted first-pass perfusion imaging in breast tumors. Methods: We analyzed the magnetic resonance imaging (MRI) information along with the pathological and immunohistochemistry results. Magnetic resonance imaging was performed in 28 patients with breast tumor. The time to signal intensity curves were generated according to the T2^*-weighted first-pass perfusion imaging. The curve's maximal signal intensity drop rate and maximal signal intensity decrease time were analyzed and compared with the pathological diagnoses after surgery. Results: Malignant breast lesions showed higher maximal signal intensity drop rate (44.69% ± 17.07 vs. 17.22% ±7.49, P 〈 0.001) than benign lesions, but there was no significant difference of maximal signal decrease time between those two lesions (23.94 s ± 4.92 vs. 20.02 s ± 6.83, P 〉 0.05). Conclusion: The T2^*-weighted first-pass perfusion imaging has enough sensitivity and specificity in breast tumor diagnosis. 相似文献
92.
心血管疾病并发焦虑抑郁症状2050例心理干预治疗分析 总被引:13,自引:1,他引:12
目的:了解心血管疾病并发焦虑抑郁症状的情况并探讨心理干预等对焦虑抑郁症状的影响。方法:对住院的2050例心血管疾病并发焦虑抑郁症状的患者进行回顾性分析。结果:心血管疾病患者中并发有焦虑抑郁症状者占56%;其常表现为类似心绞痛、左心衰竭症状,可并发有心律失常;高血压病并发有焦虑抑郁患者对血压升高的耐受性差,动态血压检查以非勺型改变者居多;单纯使用心血管药物治疗效果欠佳,心理干预,焦虑抑郁症状严重者结合抗焦虑抑郁药物疗效显著。结论:心血管疾病患者常并发焦虑抑郁症状,心理干预治疗等可有效改善患者的症状。 相似文献
93.
本文报道用二维超声心动图对主动脉瓣关闭不全124例进行病变鉴别诊断。就其图象特征结合X线所见,心音图等进行了鉴别诊断的探讨。其中,有风湿性心脏病111例;感染性心内膜炎4例;冠状动脉粥样硬化性心脏病5例;马凡氏综合征2例;左室假腱索2例。认为此项检查对主动脉瓣关闭不全病变鉴别诊断有一定的价值。 相似文献
94.
The clinical and ultrasonographic (US) features of 15 cases of mesenteric or omental cyst are herein described. This series included seven male and eight female patients, whose age ranged from 2–89 years. Correct clinical diagnosis was made in two children only, but preoperative US examination accurately demonstrated the lesion in 11 of 13 patients (85%). These cystic lesions usually had a thin wall, internal septations, and fluid content with sedimentation. Enteric duplication cysts had a relatively thick wall merging with the muscle layer of bowel loop, and multiloculation was noted mainly with cystic lymphangiomas or pseudocysts. The diagnostic and surgical management of these lesions are briefly reviewed and their US appearance is illustrated. 相似文献
95.
AIM: To undertake a systematic review of the diagnostic performance of clinical examination, sample acquisition and sample analysis in infected foot ulcers in diabetes. METHODS: Nineteen electronic databases plus other sources were searched. To be included, studies had to fulfil the following criteria: (i) compare a method of clinical assessment, sample collection or sample analysis with a reference standard; (ii) recruit diabetic individuals with foot ulcers; (ii) present 2 x 2 diagnostic data. Studies were critically appraised using a 12-item checklist. RESULTS: Three eligible studies were identified, one each on clinical examination, sample collection and sample analysis. For all three, study groups were heterogeneous with respect to wound type and a small proportion of participants had foot ulcers due to diabetes. No studies identified an optimum reference standard. Other methodological problems included non-blind interpretation of tests and the time lag between index and reference tests. Individual signs or symptoms of infection did not prove to be useful tests when assessed against punch biopsy as the reference standard. The wound swab did not perform well when assessed against tissue biopsy. Semiquantitative analysis of wound swab might be a useful alternative to quantitative analysis. The limitations of these findings and their impact on recommendations from relevant clinical guidelines are discussed. CONCLUSION: Given the importance of this topic, it is surprising that only three eligible studies were identified. It was not possible to describe the optimal methods of diagnosing infection in diabetic patients with foot ulceration from the evidence identified in this systematic review. 相似文献
96.
97.
The objective of this study is to determine whether a normal fetal morphology ultrasound scan in women older than 35 years reduces the risk of aneuploidy. We reviewed the results of amniocentesis and second trimester sonogram in all women older than 35 years from 1991 to 1995. None had prior screening. We excluded fetuses with structural anomalies. We determined the sensitivity and specificity of minor markers in detecting Down syndrome and also determined the reduction in risk of a normal sonogram. Among the 2060 women older than 35 years giving birth during the study period, 16 (0.78%) delivered an infant with Down syndrome. Of the 16 fetuses, two had no prenatal testing or ultrasound, two had invasive testing but no second trimester sonogram, five had a normal sonogram and seven had one or more sonographic markers of Down syndrome. At least 17% of women older than 35 years did not participate in prenatal testing or ultrasound. Ultrasound detected Down syndrome with a sensitivity of 59% (95% confidence interval: 45–72%), a false‐positive rate of 10.6% (9.4–11.8%) and a positive predictor value of 1 in 9. The likelihood of having normal karyotype if the sonogram was normal was 0.46 (0.31–0.61). In women older than 35 years, a normal second trimester sonogram reduces the risk of Down syndrome by more than 50%. At least 17% of women older than 35 years do not participate in prenatal testing or ultrasound. 相似文献
98.
99.
烧伤后机体应激导致代谢紊乱,表现为严重高分解代谢,机体损耗和抵抗力下降,严重影响患者预后。临床上主要采用生理营养指标、实验室诊断指标和能量消耗测定3类检测指标对机体代谢状况进行诊断评估,继而通过药物治疗结合非药物治疗手段加以调理支持,促进烧伤修复。目前,仍有多种诊断治疗方法尚未普及或有待完善。 相似文献
100.
多层螺旋CT(MSCT)使扫描速度,薄层,覆盖范围达到了很好的统一,是胰腺癌最佳的单项检查手段。本文介绍了MSCT运用于胰腺的技术优势以及具体检查方法,重点叙述其在胰腺癌的诊断,术前可切除性的评估等方面的应用。 相似文献