全文获取类型
收费全文 | 2069715篇 |
免费 | 165555篇 |
国内免费 | 4799篇 |
专业分类
耳鼻咽喉 | 28889篇 |
儿科学 | 65723篇 |
妇产科学 | 60118篇 |
基础医学 | 295567篇 |
口腔科学 | 58065篇 |
临床医学 | 184326篇 |
内科学 | 405175篇 |
皮肤病学 | 46552篇 |
神经病学 | 170777篇 |
特种医学 | 80558篇 |
外国民族医学 | 626篇 |
外科学 | 313867篇 |
综合类 | 52378篇 |
现状与发展 | 4篇 |
一般理论 | 704篇 |
预防医学 | 162984篇 |
眼科学 | 48207篇 |
药学 | 148755篇 |
1篇 | |
中国医学 | 4464篇 |
肿瘤学 | 112329篇 |
出版年
2018年 | 21878篇 |
2017年 | 16795篇 |
2016年 | 19023篇 |
2015年 | 21588篇 |
2014年 | 30680篇 |
2013年 | 46181篇 |
2012年 | 62416篇 |
2011年 | 65864篇 |
2010年 | 38670篇 |
2009年 | 36866篇 |
2008年 | 61325篇 |
2007年 | 65488篇 |
2006年 | 65927篇 |
2005年 | 64083篇 |
2004年 | 61700篇 |
2003年 | 59177篇 |
2002年 | 57143篇 |
2001年 | 96826篇 |
2000年 | 99118篇 |
1999年 | 82837篇 |
1998年 | 24083篇 |
1997年 | 21808篇 |
1996年 | 21749篇 |
1995年 | 20646篇 |
1994年 | 19082篇 |
1993年 | 17893篇 |
1992年 | 64783篇 |
1991年 | 62341篇 |
1990年 | 60290篇 |
1989年 | 57636篇 |
1988年 | 53471篇 |
1987年 | 52343篇 |
1986年 | 49294篇 |
1985年 | 47301篇 |
1984年 | 36321篇 |
1983年 | 30804篇 |
1982年 | 19193篇 |
1981年 | 17330篇 |
1979年 | 34083篇 |
1978年 | 24267篇 |
1977年 | 20271篇 |
1976年 | 18915篇 |
1975年 | 19854篇 |
1974年 | 24354篇 |
1973年 | 23470篇 |
1972年 | 22189篇 |
1971年 | 20351篇 |
1970年 | 19401篇 |
1969年 | 18370篇 |
1968年 | 16953篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Johannes Brettschneider Axel Petzold Sigurd D Süssmuth Georg B Landwehrmeyer Albert C Ludolph Jan Kassubek Hayrettin Tumani 《Movement disorders》2006,21(12):2224-2227
We aimed to evaluate the potential of the cerebrospinal fluid (CSF) axonal damage biomarker NfH(SMI35) in the laboratory-supported differential diagnosis of parkinsonian syndromes. Patients with idiopathic Parkinson's disease (PD; n = 22), multiple-system atrophy (MSA; n = 21), progressive supranuclear palsy (PSP; n = 21), corticobasal degeneration (CBD; n = 6), and age-matched controls (n = 45) were included. CSF levels of NfH(SMI35) were measured using ELISA. Levels of CSF NfH(SMI35) were elevated in PSP compared to PD and controls (P < 0.05 each). They were also significantly higher in MSA than in PD and controls (P < 0.05 each). NfH(SMI35) differentiated PD from PSP with a sensitivity of 76.5% and a specificity of 94.4%. Axonal damage as measured by CSF NfH(SMI35) is most prominent in the more rapidly progressive syndromes PSP and MSA as compared to PD or CBD. CSF NfH(SMI35) may therefore be of some value for the laboratory-supported differential diagnosis of atypical parkinsonian syndromes. 相似文献
22.
J Phua E S C Koay D Zhang L K Tai X L Boo K C Lim T K Lim 《The European respiratory journal》2006,28(4):695-702
Levels of the soluble form of the triggering receptor expressed on myeloid cells (sTREM)-1 are elevated in severe sepsis. However, it is not known whether sTREM-1 measurements can distinguish milder bacterial infections from noninfectious inflammation. The present authors studied whether serum sTREM-1 levels differ in community-acquired pneumonia, exacerbations of chronic obstructive pulmonary disease (COPD), asthma and controls, and whether sTREM-1 may be used as a surrogate marker for the need for antibiotics. Serum sTREM-1 levels in 150 patients with pneumonia, COPD and asthma exacerbations and 62 healthy controls were measured. Serum sTREM-1 levels were significantly elevated in pneumonia (median 295.2 ng x mL(-1)), COPD (280.3 ng x mL(-1)) and asthma exacerbations (184.0 ng x mL(-1)) compared with controls (83.1 ng x mL(-1)). Levels were higher in pneumonia and Anthonisen type 1 COPD exacerbations than in type 2 and 3 COPD and asthma exacerbations. The area under the receiver operating characteristics curve for sTREM-1 as a surrogate marker for the need for antibiotics was 0.77. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 were elevated predominantly in pneumonia and Anthonisen type 1 COPD exacerbations versus type 2 and 3 chronic obstructive pulmonary disease exacerbations, asthma and controls. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 has moderate but insufficient accuracy as a surrogate marker for the need for antibiotics in lower respiratory tract infections. 相似文献
23.
Jonathan Halford Gandis Mazeika Susan Slifer Marcy Speer Ann M Saunders Warren J Strittmatter Joel C Morgenlander 《Movement disorders》2006,21(4):540-542
Ninety-seven inpatients with tardive dyskinesia (average AIMS score = 13), the majority of whom were schizophrenic, were studied. Forty patients were Caucasian, and 57 were African-American. The APOE genotypes of these patients were compared to previously published genotypes of controls and with previously published studies of APOE genotypes in patients with schizophrenia. There were no significant differences in APOE allele frequencies comparing the African-American tardive dyskinesia population and the African-American control groups. In contrast, significant (< 0.05) P values were obtained comparing the Caucasian tardive dyskinesia population to the Caucasian controls, when comparing allele frequencies and genotypic frequencies. This study suggests that Caucasians bearing an APOE2 allele are at increased risk of developing tardive dyskinesia, whereas African-Americans are not. APOE genotype-specific risks of both tardive dyskinesia and Alzheimer's disease that vary across populations could be due to recruitment of patients or controls or could be due to modifying effects of differing genetic or environmental backgrounds. The mechanism by which the APOE2 allele increases risk of tardive dyskinesia is not known. Further information about the mechanisms of increased risk of tardive dyskinesia could result in stratification of prescribing practices weighing the costs of medications against the relative risk of side effects. 相似文献
24.
25.
26.
27.
28.
29.
30.
C F A Peralta P Cavoretto B Csapo O Falcon K H Nicolaides 《Ultrasound in obstetrics & gynecology》2006,27(2):128-133
OBJECTIVE: To establish reference intervals for the fetal right, left and total lung volumes and heart volume between 12 and 32 weeks of gestation. METHODS: Fetal lung and heart volumes were measured using three-dimensional (3D) ultrasound in 650 normal singleton pregnancies at 12-32 weeks. The VOCAL (Virtual Organ Computer-aided AnaLysis) technique was used to obtain a sequence of six sections of each lung and the heart around a fixed axis, each after a 30 degrees rotation from the previous one. The rotation axis for the lungs extended from the apex to the upper limit of the diaphragm dome, and the rotation axis for the heart extended from its apex to its connection to the great vessels. The contour of each of these organs was drawn manually in the six different rotation planes to obtain the 3D volume measurement. In 60 cases the fetal lungs and heart volumes were measured by the same sonographer twice and also by a second sonographer once in order to compare the measurements and calculate intra- and interobserver agreement. RESULTS: The total lung volume and heart volume increased with gestation, from respective mean values of 1.6 and 0.6 mL at 12 weeks to 10.9 and 4.3 mL at 20 weeks and 49.3 and 26.6 mL at 32 weeks. The right to left lung volume ratio did not change significantly with gestation (median, 0.7), whereas the heart to total lung volume ratio increased with gestation from about 0.3 at 12 weeks to 0.5 at 32 weeks. In the Bland-Altman plot, the difference between paired measurements by two sonographers was, in 95% of the cases, less than 0.05, 0.5 and 1.9 mL for each lung at 12-13, 19-22 and 29-32 weeks, respectively, and the corresponding values for the heart volumes were 0.04, 0.4 and 2.3 mL. CONCLUSIONS: In normal fetuses the lung and heart volumes increase between 12 and 32 weeks of gestation. The extent to which in pathological pregnancies possible deviations in these measurements from normal prove to be useful in the prediction of outcome remains to be determined. 相似文献