全文获取类型
收费全文 | 784篇 |
免费 | 50篇 |
国内免费 | 5篇 |
专业分类
儿科学 | 21篇 |
妇产科学 | 7篇 |
基础医学 | 81篇 |
口腔科学 | 61篇 |
临床医学 | 67篇 |
内科学 | 116篇 |
皮肤病学 | 131篇 |
神经病学 | 198篇 |
特种医学 | 15篇 |
外科学 | 23篇 |
综合类 | 25篇 |
预防医学 | 29篇 |
眼科学 | 1篇 |
药学 | 46篇 |
肿瘤学 | 18篇 |
出版年
2020年 | 15篇 |
2019年 | 9篇 |
2018年 | 13篇 |
2017年 | 9篇 |
2016年 | 8篇 |
2015年 | 8篇 |
2014年 | 14篇 |
2013年 | 16篇 |
2012年 | 25篇 |
2011年 | 22篇 |
2010年 | 19篇 |
2009年 | 23篇 |
2008年 | 23篇 |
2007年 | 34篇 |
2006年 | 49篇 |
2005年 | 40篇 |
2004年 | 29篇 |
2003年 | 29篇 |
2002年 | 48篇 |
2001年 | 35篇 |
2000年 | 31篇 |
1999年 | 26篇 |
1998年 | 28篇 |
1997年 | 18篇 |
1996年 | 10篇 |
1995年 | 11篇 |
1994年 | 8篇 |
1993年 | 11篇 |
1992年 | 16篇 |
1991年 | 20篇 |
1990年 | 12篇 |
1989年 | 14篇 |
1988年 | 12篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 16篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1981年 | 4篇 |
1979年 | 12篇 |
1978年 | 7篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1973年 | 6篇 |
1972年 | 7篇 |
1970年 | 6篇 |
1968年 | 4篇 |
1967年 | 6篇 |
1966年 | 7篇 |
1940年 | 4篇 |
排序方式: 共有839条查询结果,搜索用时 31 毫秒
1.
2.
Adolf Pfefferbaum Edith V. Sullivan Margaret J. Rosenbloom Paula K. Shear Daniel H. Mathalon Kelvin O. Lim 《Psychiatry Research: Neuroimaging》1993,50(4):257-274
This cross-sectional study used a semi-automated analysis technique to quantify regional brain cerebrospinal fluid (CSF) volumes derived from computed tomography (CT) in 84 healthy men ranging from 21 to 82 years of age and 28 patients meeting Research Diagnostic Criteria for alcohol dependence. The goals were to replicate an earlier CT study of an independent sample of alcoholic and control subjects (Pfefferbaum et al., 1988a; Zipursky et al., 1988) and to compare CT assessments of brain changes with magnetic resonance imaging (MRI) assessments made in the same alcoholic patients (Pfefferbaum et al., 1992). Regional brain changes associated with normal aging were derived by regression analysis, using CT data collected from the healthy control subjects. As in the earlier CT study and in the concurrent MRI study, ventricular and sulcal CSF volumes in alcoholic patients were greater than would be expected for their age. Furthermore, the present CT study replicated the previous CT and MRI findings of a positive relationship between age and CSF volume enlargement in alcoholic patients over and above the normal age-related increase in CSF volume, suggesting greater vulnerability of the aging brain to alcohol. Comparison of CT-and MRI-derived estimates of ventricular and cortical sulcal volume revealed high correlations (>0.80). MRI and CT produced similar absolute ventricular volumes, while MRI produced larger sulcal volume estimates than did CT. The difference in sulcal volume estimate may be due to differences between CT and MRI in slice thickness and sensitivity to partial volume effects. 相似文献
3.
Disturbances in neural circuitry including the basal ganglia and prefrontal cortex have been hypothesized to be a cause of obsessive-compulsive disorder (OCD). Because eye movements are often impaired in neurologic diseases affecting these brain areas, oculomotor functioning was assessed in 17 unmedicated patients with OCD and in 25 normal controls. As compared with control subjects, patients with OCD demonstrated low-gain (slow) pursuit eye movements and an increased frequency of square wave jerk intrusions, but no increase in anticipatory saccades. In addition, several OCD patients showed an unusual pattern of intrusive, brief epochs of high-gain (fast) pursuit lasting on the order of 50 to 130 msec. These epochs of fast pursuit moved the eyes ahead of the target being tracked, and were terminated by corrective reversal saccades. Studies of eye movement abnormalities may provide an informative neurophysiologic approach for studying disturbances in basal ganglia and frontal cortical function that have been observed in functional neuroimaging and neuropsychological studies of OCD. 相似文献
4.
A. C. Leon M. Katherine Shear Laura Portera G. L. Klerman 《Social psychiatry and psychiatric epidemiology》1992,27(2):78-82
Summary The DSM-III-R incorporates both distress (symptoms) and disability (impairment) in the definition of a psychiatric disorder. In psychiatric research there is a wide array of instruments used to measure symptom severity, but a limited selection for the assessment of impairment. The psychometric properties of one such instrument, The Sheehan Disability Scale (Sheehan 1983), are evaluated in this paper. The data analyzed come from two studies of patients with panic disorder, the Cross National Collaborative Panic Study-Phase I and the Panic Depression Study. In this report both the alpha coefficients and factor analyses indicate that the reliability of the scale is acceptable. The factor structure of the items and the sensitivity to change of their composite demonstrate satisfactory construct validity. The criterion-related validity is substantiated by the significant relationship between symptomatology and impairment. These analyses were limited to patients with panic disorder. Further work is needed to evaluate the instrument in assessing patients with other disorders. 相似文献
5.
Mervyn Shear 《Journal of oral pathology & medicine》1994,23(1):1-11
This review paper reports recent advances in the subject of developmental odontogenic cysts, essentially those of the past decade, starting with reference to the new WHO classification (1). On keratocysts, the latest reported recurrence rates are assessed as are their mode of growth, immunocytochemistry, immunology, genetic studies, and work on specific keratocyst antigens. There is a critical account of the group of lesions which includes the gingival cyst of adults, lateral periodontal cyst, hotryoid odontogenic cyst and glandular odontogenic cyst, and their possible relationship to one another. On dentigerous cysts, reference is made to the relationship between them and deciduous teeth, as well as to their immunocytochemistry and immunology. Recent work on the unicystic ameloblastomas. their classification and prognosis, is assessed, as is the calcifying odontogenic cyst and its relationship with solid odontogenic tumours. 相似文献
6.
Hyponatremia and the syndrome of inappropriate secretion of antidiuretic hormone associated with the use of selective serotonin reuptake inhibitors: a review of spontaneous reports. 总被引:6,自引:1,他引:5
下载免费PDF全文
![点击此处可从《Canadian Medical Association journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
OBJECTIVE: To review reported cases of hyponatremia and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) associated with the use of selective serotonin reuptake inhibitors (SSRIs). DATA SOURCES: A search of MEDLINE for reports of hyponatremia and SIADH associated with the use of fluoxetine, fluvoxamine, paroxetine or sertraline published between January 1980 and May 1995. Unpublished reports of cases were requested from the pharmaceutical industry, the Ontario Medical Association, the Health Protection Branch of Health Canada, the US Food and Drug Administration and the World Health Organization. DATA SELECTION AND EXTRACTION: Spontaneous reports from postmarketing surveillance. DATA SYNTHESIS: A total of 736 cases of hyponatremia [corrected] and SIADH associated with SSRI use were reported. Fluoxetine was involved in 554 (75.3%) of the cases, paroxetine in 91 (12.4%), sertraline in 86 (11.7%) and fluvoxamine in 11 (1.5%). Reports of 30 cases were published. The remaining 706 cases were reported to monitoring bodies and the pharmaceutical industry. According to information in the published reports, the median time to onset of hyponatremia was 13 days (range 3 to 120 days). Most (83%) of the published cases involved patients 65 years of age or more, as compared with 74% of the unpublished cases. CONCLUSION: Elderly people may be at increased risk for hyponatremia associated with SSRI use. Physicians caring for elderly patients should be aware of this potentially serious but reversible adverse effect. Further research is required to determine the incidence of this adverse effect, the relative risk of hyponatremia and SIADH in different age groups and the risk associated with different SSRI drugs. 相似文献
7.
Relation of body fat distribution to hyperinsulinemia in children and adolescents: the Bogalusa Heart Study 总被引:2,自引:0,他引:2
D S Freedman S R Srinivasan G L Burke C L Shear C G Smoak D W Harsha L S Webber G S Berenson 《The American journal of clinical nutrition》1987,46(3):403-410
The relation of body fat distribution to plasma levels of glucose and insulin during an oral glucose tolerance test was examined in 355 Black and White school-age children. Both central and peripheral fat were similarly related to fasting, 30-min, and 1-h glucose. Unlike peripheral fat, central body fat was more strongly related to the 1-h insulin response (r = 0.35 vs 0.26); this association remained significant for central fat independent of peripheral fat (r = 0.18). The strong relation of central fat to insulin response was noted in both races and sexes but not in either sexually immature or relatively thin children. These findings indicate that, even in early life, a central body fat pattern relates positively to insulin response to glucose load. Thus, knowledge of body fat localization may help identify persons most susceptible to hyperinsulinemia in early life. 相似文献
8.
Malaria-induced lymphokines: stimulation of macrophages for enhanced phagocytosis 总被引:2,自引:1,他引:2
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Culture supernatants from antigen-pulsed spleen cells of mice infected previously with either BCG or Plasmodium chabaudi were used to study macrophage activation as judged by phagocytosis of immunoglobulin G-sensitized erythrocytes and Plasmodium berghei- and P. chabaudi-infected erythrocytes. Resident peritoneal macrophages were incubated in vitro with spleen cell factor and then assayed for ingestion of immunoglobulin G-sensitized or parasitized erythrocytes. Macrophages activated with BCG-induced lymphokine bound and ingested two- to threefold more P. berghei parasitized erythrocytes than macrophages incubated with control spleen cell factor. Similarly, Plasmodium-stimulated spleen cells from mice infected with malaria produced a lymphokine(s) capable of activating macrophages for enhanced Fc receptor-mediated phagocytosis. The stimulation of phagocytosis by the lymphokine is nonspecific in nature, since phagocytosis of parasitized erythrocytes from one species of murine malaria is enhanced by the lymphokine prepared from a heterologous species. Nylon wool-nonadherent, malaria-sensitized spleen cells elaborated a lymphokine which stimulates macrophages for enhanced phagocytosis, whereas anti-0-treated spleen cells failed to produce the phagocytosis-promoting lymphokine. Consequently, this lymphokine appears to be elaborated by sensitized T lymphocytes. Interestingly, enhanced phagocytosis of opsonized trophozoites and schizonts, but not ring stage parasites of P. chabaudi, was displayed by macrophages activated with the lymphokine(s) prepared from P. chabaudi-recovered mice. Preincubation of the malaria parasitized erythrocytes with hyperimmune serum raised against the parasites greatly facilitated both binding and ingestion by the stimulated macrophages. 相似文献
9.
10.
Extent, pattern, and correlates of remote memory impairment in Alzheimer's disease and Parkinson's disease 总被引:1,自引:0,他引:1
Fama R Sullivan EV Shear PK Stein M Yesavage JA Tinklenberg JR Pfefferbaum A 《Neuropsychology》2000,14(2):265-276
Content and contextual memory for remote public figures and events was assessed with a modified version of the Presidents Test in patients with Alzheimer's disease (AD) or Parkinson's disease (PD). Contributions of executive functioning, semantic memory, and explicit anterograde memory to remote memory abilities were also examined. The AD group had temporally extensive deficits in content and contextual remote memory not accountable for by dementia severity. The PD group did not differ from the control group in remote memory, despite anterograde memory impairment. These results support the position that different component processes characterize remote memory, various mnemonic and nonmnemonic cognitive processes contribute to remote memory performance, and anterograde and remote memory processes are dissociable and differentially disrupted by neurodegenerative disease. 相似文献