全文获取类型
收费全文 | 1008篇 |
免费 | 43篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 18篇 |
妇产科学 | 2篇 |
基础医学 | 86篇 |
口腔科学 | 16篇 |
临床医学 | 64篇 |
内科学 | 177篇 |
皮肤病学 | 4篇 |
神经病学 | 256篇 |
特种医学 | 209篇 |
外科学 | 83篇 |
综合类 | 17篇 |
预防医学 | 78篇 |
眼科学 | 11篇 |
药学 | 28篇 |
肿瘤学 | 27篇 |
出版年
2023年 | 7篇 |
2022年 | 14篇 |
2021年 | 16篇 |
2020年 | 9篇 |
2019年 | 14篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 15篇 |
2015年 | 26篇 |
2014年 | 26篇 |
2013年 | 38篇 |
2012年 | 52篇 |
2011年 | 47篇 |
2010年 | 29篇 |
2009年 | 35篇 |
2008年 | 36篇 |
2007年 | 59篇 |
2006年 | 55篇 |
2005年 | 29篇 |
2004年 | 32篇 |
2003年 | 30篇 |
2002年 | 28篇 |
2001年 | 27篇 |
2000年 | 21篇 |
1999年 | 15篇 |
1998年 | 30篇 |
1997年 | 10篇 |
1996年 | 25篇 |
1995年 | 21篇 |
1994年 | 25篇 |
1993年 | 11篇 |
1992年 | 25篇 |
1991年 | 30篇 |
1990年 | 24篇 |
1989年 | 25篇 |
1988年 | 29篇 |
1987年 | 24篇 |
1986年 | 17篇 |
1985年 | 23篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1969年 | 3篇 |
排序方式: 共有1077条查询结果,搜索用时 15 毫秒
71.
Sequential magnetic resonance imaging in Perthes' disease 总被引:1,自引:0,他引:1
C F Bos J L Bloem R M Bloem 《The Journal of bone and joint surgery. British volume》1991,73(2):219-224
Forty-eight images using magnetic resonance imaging (MRI) in 16 hips with Perthes' disease were evaluated over a mean period of two years. MRI depicted exactly the infarcted zone in the femoral head before typical radiological changes were evident. Early determination of the extent of the infarcted bone on MRI benefits those patients who require treatment. Follow-up MRI scans at six-monthly intervals, reflected the chronological stages of the repair process in each group classified according to Catterall. 相似文献
72.
Accuracy of fetal echocardiography 总被引:6,自引:0,他引:6
The reliability of prenatal ultrasound (US) for the detection of structural heart defects was investigated in a consecutive population of patients referred for prenatal US. Twenty-eight of 49 fetuses (57%) shown to have one or more heart defects with physical examination or autopsy were found to have congenital heart disease with prenatal US. There were 66 cardiac defects in 49 fetuses, 33 of which were entirely or partly identified (50%). Defects correctly diagnosed included hypoplasia of either ventricle, common atrioventricular canal, tetralogy of Fallot, transposition of the great vessels, and Ebstein anomaly. Defects rarely diagnosed correctly included semilunar valve stenosis, total anomalous pulmonary venous drainage, coarctation of the aorta, pulmonic atresia, atrioseptal defect, and ventricular septal defect. Many types of heart defects can be diagnosed accurately with prenatal US in a general population of patients not at high risk for congenital heart disease. Some lesions, however, were difficult to detect. 相似文献
73.
Delayed hepatic CT scanning: increased confidence and improved detection of hepatic metastases 总被引:1,自引:0,他引:1
Bernardino ME; Erwin BC; Steinberg HV; Baumgartner BR; Torres WE; Gedgaudas- McClees RK 《Radiology》1986,159(1):71-74
Fifty oncologic patients with suspected hepatic metastases were prospectively evaluated by dynamic sequential hepatic computed tomography (DSHCT) and by delayed iodine hepatic computed tomography (DICT) scanning. DICT scanning was performed 4-6 hours following administration of 60 g of intravenous iodine. Both techniques were evaluated for lesion definition relative to the adjacent hepatic parenchyma and for numbers of metastases detected. Metastases were detected by both techniques in 26 patients. Fifteen patients (58%) had lesions better defined by DICT. DICT scanning detected more metastases in seven of these 15 patients. In eight patients (31%), there was no difference between the two techniques in numbers of masses detected or lesion definition. In three cases (11%), metastases were more confidently identified on the initial or DSHCT scan. DICT scanning, as described, is useful in defining and detecting hepatic metastases, especially where there is questionable hepatic involvement or better quantification of size is necessary. 相似文献
74.
Assessment of interpersonal problem-solving skills 总被引:3,自引:0,他引:3
A new instrument for assessing social skills of schizophrenic patients, Assessment of Interpersonal Problem-Solving Skills (AIPSS), is a videotaped-based test with an examiner's administration and scoring manual. The test measures an examinee's ability to describe an interpersonal social problem, to derive a solution to the problem, and to enact a solution in a role-played simulation test. In a study using a sample of schizophrenic outpatients and a comparison group of nonpatients, we found that the test had adequate psychometric properties, and the patients demonstrated deficits on all scales relative to the nonpatients. The results of the study also provided partial support for the validity of an information-processing model of social skills, which was used as a basis for constructing the AIPSS. Thus, the AIPSS represents a departure from previous methods of assessing social skills. 相似文献
75.
目的探讨医源性脾脏损伤脾切除对结直肠癌切除患者术后长期生存的影响。方法对1990年1月1日至1999年12月31日10年间行结直肠癌手术切除并附带脾切除患者进行病例配对回顾研究。分析患者年龄、性别、依据美国麻醉学医师协会(ASA)标准评估的身体状况、疾病分期、手术类型及预后等资料。配对病例来自同一医疗中心,性别、年龄、疾病分期及手术类型完全相同。手术附带脾切除患者为试验组,未切脾者为对照组。结果55例患者行医源性脾切除术,对照组在年龄、性别、身体状况、疾病分期及手术类型上与之匹配。随访时间(从手术开始到患者死亡或者最后一次随访1为2~205个月(中位随访时间为43个月)。Cox比例危险度模型进行Kaplan-Meier法生存分析发现两组间差异有显著性意义,不切除脾脏对患者生存有利(危险度1.8,95%可信区间为1-3.3,P=0.0399),未切脾组与切脾组5年生存率分别为70%和47%,10年生存率分别为55%和38%。结论结直肠癌患者在行结肠或直肠切除时,因医源性脾脏损伤而切除脾脏者,预后较差。 相似文献
76.
对人流感病毒A/Udorn/72(H_3N_2)株与禽类流感病毒A/Mallard/NY/78/(H_2N_2)重组后的重组株分析表明,仅含禽类病毒的核蛋白(NP)或膜蛋白(M)的RNA片段的重组株,在松鼠猴的呼吸道繁殖是受限制的。另外。仅有禽类的RNAl和NS基因的重组株(Clone 12)在松鼠猴的气管内的繁殖也明显受限制,而只具有其中一个基因的Clone 9, Clone 2, 则限制就不明显。由此表明,禽类流感病毒的NP和M基因在宿主范围的繁殖限制中起主要作用,而RNAI和SN基因的结合,同样起着繁殖受限制作用。 相似文献
77.
Richard Sinert DO Shahriar Zehtabchi MD Christina Bloem MD Michael Lucchesi MD 《Academic emergency medicine》2006,13(12):1269-1274
Background
Base deficit (BD) is a reliable marker of metabolic acidosis and is useful in gauging hemorrhage after trauma. Resuscitation with chloride-rich solutions such as normal saline (NS) can cause a dilutional acidosis, possibly confounding the interpretation of BD.
Objectives
To test the diagnostic utility of BD in distinguishing minor from major injury after administration of NS.
Methods
This was a prospective observational study at a Level 1 trauma center. The authors enrolled patients with significant mechanism of injury and measured BD at triage (BD-0) and at four hours after triage (BD-4). Major injury was defined by any of the following: injury severity score of ≥15, drop in hematocrit of ≥10 points, or the patient requiring a blood transfusion. Patients were divided into a low-volume (NS < 2L) and a high-volume (NS ≥ 2L) group. Data were reported as mean (±SD). Student's t- and Wilcoxon tests were used to compare data. Receiver operating characteristic (ROC) curves tested the utility of BD-4 in differentiating minor from major injury in the study groups.
Results
Four hundred eighty-nine trauma patients (mean age, 36 [± 18] yr) were enrolled; 82% were male, and 34% had penetrating injury. Major-(20%) compared with minor-(80%) injury patients were significantly (p = 0.0001) more acidotic (BD-0 mean difference: −3.3 mmol/L; 95% confidence interval [CI] =−2.5 to −4.2). The high-volume group (n = 174) received 3,342 (±1,821) mL, and the low-volume group (n = 315) received 621 (±509) mL of NS. Areas under the ROC curves for the high-volume (0.63; 95% CI = 0.52 to 0.74) and low-volume (0.73; 95% CI = 0.60 to 0.86) groups were not significantly different from each other.
Conclusions
Base deficit was able to distinguish minor from major injury after four hours of resuscitation, irrespective of the volume of NS infused. 相似文献
Base deficit (BD) is a reliable marker of metabolic acidosis and is useful in gauging hemorrhage after trauma. Resuscitation with chloride-rich solutions such as normal saline (NS) can cause a dilutional acidosis, possibly confounding the interpretation of BD.
Objectives
To test the diagnostic utility of BD in distinguishing minor from major injury after administration of NS.
Methods
This was a prospective observational study at a Level 1 trauma center. The authors enrolled patients with significant mechanism of injury and measured BD at triage (BD-0) and at four hours after triage (BD-4). Major injury was defined by any of the following: injury severity score of ≥15, drop in hematocrit of ≥10 points, or the patient requiring a blood transfusion. Patients were divided into a low-volume (NS < 2L) and a high-volume (NS ≥ 2L) group. Data were reported as mean (±SD). Student's t- and Wilcoxon tests were used to compare data. Receiver operating characteristic (ROC) curves tested the utility of BD-4 in differentiating minor from major injury in the study groups.
Results
Four hundred eighty-nine trauma patients (mean age, 36 [± 18] yr) were enrolled; 82% were male, and 34% had penetrating injury. Major-(20%) compared with minor-(80%) injury patients were significantly (p = 0.0001) more acidotic (BD-0 mean difference: −3.3 mmol/L; 95% confidence interval [CI] =−2.5 to −4.2). The high-volume group (n = 174) received 3,342 (±1,821) mL, and the low-volume group (n = 315) received 621 (±509) mL of NS. Areas under the ROC curves for the high-volume (0.63; 95% CI = 0.52 to 0.74) and low-volume (0.73; 95% CI = 0.60 to 0.86) groups were not significantly different from each other.
Conclusions
Base deficit was able to distinguish minor from major injury after four hours of resuscitation, irrespective of the volume of NS infused. 相似文献
78.
N Minato L Reid H Cantor P Lengyel BR Bloom 《The Journal of experimental medicine》1980,152(1):124-137
Whereas xenogeneic tumors such as baby hamster kidney or HeLa cells grow in nude mice, the same cells persistently infected with a variety of viruses are rejected. Spleen cells from normal nude mice were found to be induced to produce interferon and to exert natural killer (NK) activity on virus persistently infected (PI) tumor cells, and not on uninfected parental cells in vitro. The phenotype of the interferon-producing cells and the NK effector cells was found to be the same namely, Qa 5(+), Ly 5(+), ganglio-N- tetraosylceramide, with 35 percent of the NK cells also expressing Thy 1.2. NK activity against virus PI tumor cell lines could be nonspecifically augmented both in vivo and in vitro by prior contact with virus PI tumor cells. It was unambiguously demonstrated with chemically homogeneous mouse interferon that interferon, and not a contaminant, was responsible for the augmentation of NK activity in vitro. Studies on the mode of interferon action in augmenting NK activity revealed that the target cell for interferon action was serologically distinct from the NK effector cell. Anti-Ly 5 + complement (C)-treated spleen cells were depleted of NK activity and the ability to produce interferon, but, upon incubation with interferon for 1-3 h, regained both NK activity and susceptibility to anti-Ly 5 + C. Treatment with anti-Qa 5 + C eliminated NK activity, which could not be restored by the addition of interferon. We conclude that interferon produced by Ly 5(+) cells in response to virus PI tumor cells acts on Ly 5(-) precursor cells and induces their differentiation into functional Ly 5(+) NK effector cells. 相似文献
79.
80.
The value of medical imaging in detection, staging, grading, and tissue-specific diagnosis has been substantially increased, especially after the introduction of magnetic resonance imaging, the combined use of cytogenetic and molecular techniques and the refinement of biopsy techniques. In this paper, we will focus on the combination of parameters including clinical information, prevalence, age, location, and findings on medical imaging, yielding the highest diagnostic sensitivity and specificity. An imaging prototype of a malignant soft tissue tumor will be proposed. In a second part, we will present an overview of most common soft tissue tumors, especially focusing on these tumors having more characteristic imaging features that allow to make a more detailed tissue-specific diagnosis. Finally, we will give the radiologist a short list of important things to take home. 相似文献