全文获取类型
收费全文 | 60917篇 |
免费 | 4530篇 |
国内免费 | 165篇 |
专业分类
耳鼻咽喉 | 590篇 |
儿科学 | 2305篇 |
妇产科学 | 1849篇 |
基础医学 | 8807篇 |
口腔科学 | 716篇 |
临床医学 | 6781篇 |
内科学 | 11356篇 |
皮肤病学 | 1264篇 |
神经病学 | 6777篇 |
特种医学 | 1896篇 |
外国民族医学 | 8篇 |
外科学 | 6928篇 |
综合类 | 525篇 |
现状与发展 | 1篇 |
一般理论 | 85篇 |
预防医学 | 6723篇 |
眼科学 | 1132篇 |
药学 | 4053篇 |
中国医学 | 93篇 |
肿瘤学 | 3723篇 |
出版年
2023年 | 712篇 |
2022年 | 1146篇 |
2021年 | 2267篇 |
2020年 | 1376篇 |
2019年 | 1977篇 |
2018年 | 2259篇 |
2017年 | 1578篇 |
2016年 | 1858篇 |
2015年 | 1919篇 |
2014年 | 2483篇 |
2013年 | 3086篇 |
2012年 | 4600篇 |
2011年 | 4540篇 |
2010年 | 2309篇 |
2009年 | 2045篇 |
2008年 | 3162篇 |
2007年 | 3334篇 |
2006年 | 2980篇 |
2005年 | 2793篇 |
2004年 | 2448篇 |
2003年 | 2127篇 |
2002年 | 1976篇 |
2001年 | 936篇 |
2000年 | 817篇 |
1999年 | 838篇 |
1998年 | 498篇 |
1997年 | 358篇 |
1996年 | 305篇 |
1995年 | 305篇 |
1994年 | 264篇 |
1993年 | 263篇 |
1992年 | 443篇 |
1991年 | 417篇 |
1990年 | 448篇 |
1989年 | 398篇 |
1988年 | 365篇 |
1987年 | 407篇 |
1986年 | 372篇 |
1985年 | 365篇 |
1984年 | 285篇 |
1983年 | 230篇 |
1979年 | 268篇 |
1978年 | 215篇 |
1977年 | 187篇 |
1974年 | 193篇 |
1973年 | 186篇 |
1972年 | 223篇 |
1971年 | 195篇 |
1969年 | 171篇 |
1967年 | 174篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
E S C Korf E C W van Straaten F-E de Leeuw W M van der Flier F Barkhof L Pantoni A M Basile D Inzitari T Erkinjuntti L-O Wahlund E Rostrup R Schmidt F Fazekas P Scheltens 《Diabetic medicine》2007,24(2):166-171
HYPOTHESIS: Based on recent findings on the association between vascular risk factors and hippocampal atrophy, we hypothesized that hypertension and diabetes mellitus (DM) are associated with medial temporal lobe atrophy (MTA) in subjects without disability, independent of the severity of white matter hyperintensities. METHODS: In the Leukoaraiosis And DISability in the elderly (LADIS) study, we investigated the relationships between DM, hypertension, blood pressure and MTA in 582 subjects, stratified by white matter hyperintensity severity, using multinomial logistic regression. MTA was visually scored for the left and right medial temporal lobe (score 0-4), and meaned. RESULTS: Mean age was 73.5 years (sd 5.1), 54% was female. Of the subjects, 15% had DM, and 70% had a history of hypertension. The likelihood of having MTA score 3 was significantly higher in subjects with DM (OR 2.9; 95% CI: 1.1-7.8) compared with an MTA score of 0 (no atrophy). The odds ratio for MTA score 2 was not significantly increased (OR 1.8; CI: 0.9-4). Systolic and diastolic blood pressure and a history of hypertension were not associated with MTA. There was no interaction between DM and hypertension. Stratification on white matter hyperintensities (WMH) did not alter the associations. CONCLUSION: Our study strengthens the observation that MTA is associated with DM, independently of the amount of small vessel disease as reflected by WMH. 相似文献
52.
Sarah J Buckley 《British medical journal》2005,331(7518):698-699
53.
Beth T McCreary Thomas E Joiner Norman B Schmidt Nicholas S Ialongo 《Journal of clinical child and adolescent psychology》2004,33(2):313-324
This study examined the structure and symptom correlates of perfectionism in a sample of 6th-grade, urban, African American children using the Child and Adolescent Perfectionism Scale (CAPS; Flett, Hewitt, Boucher, Davidson, & Munro, 2000). Confirmatory factor analysis showed inadequate fit of the original subscales. Exploratory factor analysis suggested 3 dimensions of perfectionism: A Socially Prescribed and a Self-Oriented-Critical factor were described as maladaptive, whereas a Self-Oriented-Striving factor was proposed as adaptive. Cross-sectional correlations among the perfectionism dimensions and symptoms of psychopathology fit well with the adaptive versus maladaptive model. In addition, Socially Prescribed Perfectionism showed a robust predictive relation to 7th-grade internalizing symptoms, especially depression, in boys. Results are discussed in the context of the cultural and socioeconomic characteristics of this African American sample and suggestions for future research are provided. 相似文献
54.
Amit Badhwar Thomas L Forbes Marge B Lovell Alison A Dungey Sarah D McCarter Jeffrey R Scott Guy DeRose Kenneth A Harris Richard F Potter 《Canadian journal of surgery》2004,47(5):352-358
BACKGROUND: Ischemic preconditioning (IPC) has been found in animals to have a protective effect against future ischemic injury to muscle tissue. Such injury is unavoidable during some surgical procedures. To determine whether chronic ischemia in the lower extremities would imitate IPC and reduce ischemic injury during vascular surgery, we designed a controlled clinical study. PATIENTS AND METHODS: Two groups of patients at a university-affiliated medical centre with chronic lower-extremity ischemia served as models of IPC: 6 patients awaiting femoral distal bypass (FDB) and 4 scheduled for aortobifemoral (ABF) bypass grafting for aortoiliac occlusive disease. Seven patients undergoing elective open repair of an infrarenal abdominal aortic aneurysm (AAA) were chosen as non-IPC controls. Three hematologic indicators of skeletal-muscle injury, lactate dehydrogenase (LDH), creatine kinase (CK) and myoglobin, were measured before placement of the proximal clamp, during surgical ischemia, immediately upon reperfusion, 15 minutes after and 1 hour after reperfusion, and during the first, second and third postoperative days. RESULTS: Baseline markers of skeletal-muscle injury were similar in all groups. In postreperfusion samples, concentrations of muscle-injury markers were significantly lower in the 2 PC groups than in the control group. For example, at day 2, LDH levels were increased by about 30% over baseline measures in the elective AAA (control) group, whereas levels in the FDB and ABF groups remained statistically unchanged from baseline. Myoglobin in controls had increased by 977%, but only by 160% in the FDB and 528% in the ABF groups. CK levels, in a similar trend, were 1432% higher in the control group and only 111% (FDB) and 1029% (ABF) in the study groups. Taken together, these data represent a significant level of protection. CONCLUSIONS: Patients with chronic lower-extremity ischemia suffered less severe ischemic injury after a period of acute ischemia than those with acute ischemia alone. Ischemic preconditioning is one proposed mechanism to help explain this protective effect. 相似文献
55.
56.
57.
Monica Conciatori Christopher J Stodgell Susan L Hyman Melanie O'Bara Roberto Militerni Carmela Bravaccio Simona Trillo Francesco Montecchi Cindy Schneider Raun Melmed Maurizio Elia Lori Crawford Sarah J Spence Lucianna Muscarella Vito Guarnieri Leonardo D'Agruma Alessandro Quattrone Leopoldo Zelante Daniel Rabinowitz Tiziana Pascucci Stefano Puglisi-Allegra Karl-Ludvig Reichelt Patricia M Rodier Antonio M Persico 《Neuropsychopharmacology》2004,55(4):413-419
BACKGROUND: The HOXA1 gene plays a major role in brainstem and cranial morphogenesis. The G allele of the HOXA1 A218G polymorphism has been previously found associated with autism. METHODS: We performed case-control and family-based association analyses, contrasting 127 autistic patients with 174 ethnically matched controls, and assessing for allelic transmission disequilibrium in 189 complete trios. RESULTS: A, and not G, alleles were associated with autism using both case-control (chi(2) = 8.96 and 5.71, 1 df, p <.005 and <.025 for genotypes and alleles, respectively), and family-based (transmission/disequilibrium test chi(2) = 8.80, 1 df, p <.005) association analyses. The head circumference of 31 patients carrying one or two copies of the G allele displayed significantly larger median values (95.0th vs. 82.5th percentile, p <.05) and dramatically reduced interindividual variability (p <.0001), compared with 166 patients carrying the A/A genotype. CONCLUSIONS: The HOXA1 A218G polymorphism explains approximately 5% of the variance in the head circumference of autistic patients and represents to our knowledge the first known gene variant providing sizable contributions to cranial morphology. The disease specificity of this finding is currently being investigated. Nonreplications in genetic linkage/association studies could partly stem from the dyshomogeneous distribution of an endophenotype morphologically defined by cranial circumference. 相似文献
58.
F T McDermott G Whelan D J St John G L Barnes R Elliott R Herrmann G T Schmidt R A Smallwood 《The Medical journal of Australia》1987,146(10):525, 528-525, 529
Information on the relative incidence of Crohn's disease and ulcerative colitis was obtained by a prospective investigation at six Melbourne teaching hospitals. One hundred and eleven patients who presented with chronic inflammatory bowel diseases between 1980-1981 were admitted to the study. Forty (36%) patients were diagnosed as having Crohn's disease and 63 (57%) patients as having ulcerative colitis. The type of chronic inflammatory bowel disease could not be determined in eight (7%) patients. These findings suggest that the relative frequency of Crohn's disease and ulcerative colitis in Melbourne hospitals is within the range that is reported for northern Europe and the United States. 相似文献
59.
Fifty-nine patients with chronic generalized tonic-clonic or partial seizures refractory to the maximally tolerated daily dosage of single-drug therapy with carbamazepine, phenytoin, phenobarbital, or primidone subsequently received single-drug therapy with another one of these primary anticonvulsant drugs. Alternative single-drug therapy resulted in complete seizure control or more than 75% seizure reduction for 18 patients (31%). Side effects disappeared in 16 patients (27%). Patients with a good therapeutic response often had epilepsy of recent onset. Alternative single-drug therapy is beneficial for chronic refractory epilepsy and should be considered before a second drug is permanently added. 相似文献
60.