全文获取类型
收费全文 | 5625篇 |
免费 | 635篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 250篇 |
妇产科学 | 244篇 |
基础医学 | 868篇 |
口腔科学 | 128篇 |
临床医学 | 584篇 |
内科学 | 986篇 |
皮肤病学 | 153篇 |
神经病学 | 506篇 |
特种医学 | 347篇 |
外科学 | 614篇 |
综合类 | 148篇 |
一般理论 | 5篇 |
预防医学 | 615篇 |
眼科学 | 145篇 |
药学 | 332篇 |
中国医学 | 20篇 |
肿瘤学 | 320篇 |
出版年
2021年 | 69篇 |
2019年 | 65篇 |
2018年 | 93篇 |
2017年 | 75篇 |
2016年 | 87篇 |
2015年 | 77篇 |
2014年 | 110篇 |
2013年 | 143篇 |
2012年 | 204篇 |
2011年 | 195篇 |
2010年 | 155篇 |
2009年 | 161篇 |
2008年 | 209篇 |
2007年 | 229篇 |
2006年 | 240篇 |
2005年 | 178篇 |
2004年 | 187篇 |
2003年 | 190篇 |
2002年 | 208篇 |
2001年 | 191篇 |
2000年 | 192篇 |
1999年 | 181篇 |
1998年 | 116篇 |
1997年 | 97篇 |
1996年 | 118篇 |
1995年 | 88篇 |
1994年 | 88篇 |
1993年 | 102篇 |
1992年 | 140篇 |
1991年 | 119篇 |
1990年 | 134篇 |
1989年 | 148篇 |
1988年 | 124篇 |
1987年 | 140篇 |
1986年 | 133篇 |
1985年 | 123篇 |
1984年 | 102篇 |
1983年 | 85篇 |
1982年 | 76篇 |
1981年 | 50篇 |
1980年 | 58篇 |
1979年 | 69篇 |
1978年 | 56篇 |
1977年 | 58篇 |
1976年 | 55篇 |
1975年 | 57篇 |
1974年 | 53篇 |
1973年 | 52篇 |
1972年 | 45篇 |
1967年 | 35篇 |
排序方式: 共有6276条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
T al-Shawaf A Nolan J Harper P Serhal I Craft 《Human reproduction (Oxford, England)》1991,6(3):365-366
Cryopreserved spermatozoa from men having treatment for lymphoma or testicular tumour have been reported to function sub-optimally. We report on three successful pregnancies following gamete intra-Fallopian transfer (GIFT) using such cryopreserved sperm samples. In one case, ovum donation was required since the woman had premature ovarian failure. 相似文献
35.
N. Y. Calingasan S. E. Gandy H. Baker K. F. Sheu J. D. Smith B. T. Lamb J. D. Gearhart J. D. Buxbaum C. Harper D. J. Selkoe D. L. Price S. S. Sisodia G. E. Gibson 《The American journal of pathology》1996,149(3):1063-1071
Experimental thiamine deficiency (TD) is a classical model of a nutritional deficit associated with a generalized impairment of oxidative metabolism and selective cell loss in the brain. In rats, TD-induced cell degeneration is accompanied by an accumulation of amyloid precursor protein (APP)/amyloid precursor-like protein 2 (APLP2) immunoreactivity in abnormal neurites and perikarya along the periphery of, or scattered within, the lesion. Prompted by these data and our previous findings of a genetic variation in the development of TD symptoms, we extended our studies to mice. C57BL/6, ApoE knockout, and APP YAC transgenic mice received thiamine-deficient diet and pyrithiamine injections. Unlike rats, APP/APLP2-immunoreactive neurites in all strains of mice were sparsely scattered within damaged areas and did not delimit the thalamic lesion. In addition, abnormal clusters of intensely immunoreactive neurites occurred only in areas of damage including the thalamus, mammillary body, and inferior colliculus. The clusters appeared as either irregular clumps or round or oval rosettes that strikingly resembled the neuritic component of Alzheimer amyloid plaques. However, immunostaining using various antisera to synthetic amyloid beta-protein (A beta 1-40) and thioflavine S histochemistry failed to show evidence of a component of A beta Neither APP/APLP2-immunoreactive clusters nor amyloid plaques were observed in the brain from patients with Wernicke-Korsakoff syndrome, the clinical manifestation of TD in man. Our results demonstrate species (i.e., genetic) differences in the response to TD-induced damage and support a role for APP and APLP2 in the response to brain injury. This is the first report that chronic oxidative deficits can lead to this novel pathology. 相似文献
36.
Henderson LA Macey PM Macey KE Frysinger RC Woo MA Harper RK Alger JR Yan-Go FL Harper RM 《Journal of neurophysiology》2002,88(6):3477-3486
The Valsalva maneuver, a test frequently used to evaluate autonomic function, recruits discrete neural sites. The time courses of neural recruitment relative to accompanying cardiovascular and breathing patterns are unknown. We examined functional magnetic resonance imaging signal changes within the brain to repeated Valsalva maneuvers and correlated these changes with physiological trends. In 12 healthy subjects (age, 30-58 yr), a series of 25 volumes (20 gradient echo echo-planar image slices per volume) was collected using a 1.5-Tesla scanner during a 60-s baseline and 90-s challenge period consisting of three Valsalva maneuvers. Regions of interest were examined for signal intensity changes over baseline and challenge conditions in cardiorespiratory-related regions. In addition, whole brain correlations between signal intensity and heart rate and airway load pressure were performed on a voxel-by-voxel basis. Significant signal changes, correlated with the time course of load pressure and heart rate, emerged within multiple areas, including the amygdala and hippocampus, insular and lateral frontal cortices, dorsal pons, dorsal medulla, lentiform nucleus, and fastigial and dentate nuclei of the cerebellum. Signal intensities peaked early in the Valsalva maneuver within the hippocampus and amygdala, later within the dorsal medulla, pons and midbrain, and deep cerebellar nuclei, and last within the lentiform nuclei and the lateral prefrontal cortex. The ventral pontine signals increased during the challenge, but not in a fashion correlated to load pressure or heart rate. Sites showing little or no correlation included the vermis and medial prefrontal cortex. These data suggest an initiating component arising in rostral brain areas, a later contribution from cerebellar nuclei, basal ganglia, and lateral prefrontal cortex, and a role for the ventral pons in mediating longer term processes. 相似文献
37.
Media coverage of psychiatric issues will reflect or influence public perceptions of the mentally ill. In order to explore the relationship between psychiatry and the media, an attitudinal questionnaire was administered to a systematic sample of 20 reporters, 20 psychiatrists, 20 medical outpatients with no psychiatric history, and 40 psychiatric inpatients. In addition, 4 psychiatric patients who had personal experience with media coverage were interviewed to determine the impact. Their stories are presented as clinical vignettes. The results of the questionnaire survey show that media reporters are no less accepting of mental illness than the other groups. A regression analysis of attitudinal predictors elicit education as more significant than age and media exposure. Yet low scores for the coverage by the media of mental illness were given by all groups with psychiatrists tending to be most critical. Reasons offered by reporters included "sensationalism sells" along with cost and time factors. Recommendations for both reporters and psychiatrists groups were collated, aiming at improving communication and ensuring a more positive emphasis and greater accuracy of media coverage of mental health issues. 相似文献
38.
Clinical signs in the Wernicke-Korsakoff complex: a retrospective analysis of 131 cases diagnosed at necropsy. 总被引:9,自引:0,他引:9 下载免费PDF全文
C G Harper M Giles R Finlay-Jones 《Journal of neurology, neurosurgery, and psychiatry》1986,49(4):341-345
A recent necropsy study has shown that 80% of patients with the Wernicke-Korsakoff syndrome were not diagnosed as such during life. Review of the clinical signs of these cases revealed that only 16% had the classical clinical triad and 19% had no documented clinical signs. The incidence of clinical signs in this and other retrospective pathological studies is very different from that of prospective clinical studies. This discrepancy may relate to "missed" clinical signs but the magnitude of the difference suggests that at least some cases of the Wernicke-Korsakoff syndrome may be the end result of repeated subclinical episodes of vitamin B1 deficiency. In order to make the diagnosis, clinicians must maintain a high index of suspicion in the "at risk" group of patients, particularly alcoholics. Investigations of thiamine status may be helpful and if the diagnosis is suspected, parenteral thiamine should be given. 相似文献
39.
Dennis C. Harper 《Journal of autism and developmental disorders》1984,14(2):165-182
The current study evaluated the generalizability of a parent-child rearing inventory designed for normal children and parents to a group of parents of disabled children. A total of 101 mothers of multihandicapped children completed a questionnaire (Parent Report of Child Behavior) reporting their child's behavior toward them in five areas: Positive Relationship, Detachment, Obedience, Independence, and Control Problems. Factor analysis of these mothers' responses revealed a qualitatively different set of underlying factors as contrasted to the original normative group. For mothers in this study, a positive relationship with their disabled child was contingent upon a combination of compliant behaviors (obeying rules, doing things independently, actively trying to please), all of which are likely associated with general child competence. The disabled child's age, intellectual level, degree of physical impairment, and number of nonhandicapped sibs influenced maternal report of child behavior. 相似文献
40.