全文获取类型
收费全文 | 2874篇 |
免费 | 286篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 76篇 |
妇产科学 | 31篇 |
基础医学 | 306篇 |
口腔科学 | 70篇 |
临床医学 | 371篇 |
内科学 | 473篇 |
皮肤病学 | 47篇 |
神经病学 | 387篇 |
特种医学 | 141篇 |
外科学 | 399篇 |
综合类 | 88篇 |
一般理论 | 2篇 |
预防医学 | 230篇 |
眼科学 | 89篇 |
药学 | 214篇 |
中国医学 | 2篇 |
肿瘤学 | 251篇 |
出版年
2023年 | 15篇 |
2022年 | 33篇 |
2021年 | 39篇 |
2020年 | 23篇 |
2019年 | 48篇 |
2018年 | 70篇 |
2017年 | 36篇 |
2016年 | 55篇 |
2015年 | 53篇 |
2014年 | 80篇 |
2013年 | 85篇 |
2012年 | 115篇 |
2011年 | 111篇 |
2010年 | 80篇 |
2009年 | 79篇 |
2008年 | 126篇 |
2007年 | 152篇 |
2006年 | 136篇 |
2005年 | 141篇 |
2004年 | 130篇 |
2003年 | 114篇 |
2002年 | 108篇 |
2001年 | 121篇 |
2000年 | 128篇 |
1999年 | 85篇 |
1998年 | 45篇 |
1997年 | 45篇 |
1996年 | 42篇 |
1995年 | 50篇 |
1994年 | 42篇 |
1993年 | 25篇 |
1992年 | 57篇 |
1991年 | 51篇 |
1990年 | 61篇 |
1989年 | 66篇 |
1988年 | 59篇 |
1987年 | 58篇 |
1986年 | 60篇 |
1985年 | 56篇 |
1984年 | 28篇 |
1983年 | 17篇 |
1982年 | 23篇 |
1981年 | 20篇 |
1980年 | 15篇 |
1979年 | 31篇 |
1978年 | 17篇 |
1977年 | 14篇 |
1974年 | 15篇 |
1973年 | 22篇 |
1972年 | 17篇 |
排序方式: 共有3192条查询结果,搜索用时 15 毫秒
1.
Mani N Pavuluri Megan Marlow O'Connor Erin M Harral Melissa Moss John A Sweeney 《Neuropsychopharmacology》2006,60(9):951-956
BACKGROUND: Previous research has demonstrated that academic and neuropsychological functions are compromised in pediatric bipolar disorder (PBD). Investigation of the degree to which neuropsychological deficits might contribute to those academic problems is needed to aid in the recognition and intervention for school achievement difficulties in PBD. METHODS: A sample of 55 children and adolescents with PBD with and without attention-deficit/hyperactivity disorder (ADHD) (PBD group, n = 28; PBD+ADHD group, n = 27) were tested with a computerized neurocognitive battery and standardized neuropsychological tests. Age range of subjects was 7-17 years, with the mean age of 11.97 (3.18) years. Parents completed a structured questionnaire on school and academic functioning. RESULTS: Logistic regression analyses indicated that executive function, attention, working memory, and verbal memory scores were poorer in those with a history of reading/writing difficulties. A separate logistic regression analysis found that attentional dysfunction predicted math difficulties. These relationships between neuropsychological function and academic difficulties were not different in those with PBD+ADHD than in those with PBD alone. CONCLUSIONS: In PBD neuropsychological deficits in the areas of attention, working memory, and organization/problem solving skills all contribute to academic difficulties. Early identification and intervention for these difficulties might help prevent lower academic achievement in PBD. 相似文献
2.
3.
Changes to the ocular biota with time in extended- and daily-wear disposable contact lens use. 总被引:3,自引:0,他引:3
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)
F Stapleton M D Willcox C M Fleming S Hickson D F Sweeney B A Holden 《Infection and immunity》1995,63(11):4501-4505
Gram-negative bacteria may play a role in the etiology of certain soft contact lens (SCL)-related diseases. Contact lens (CL) wear may modify the normal ocular biota, providing a more favorable environment for potential pathogens. This study reports temporal changes in ocular biota in daily-wear (DW) and extended-wear (EW) disposable SCL use in experienced and neophyte wearers. Lid margin and bulbar conjunctival biota were sampled prior to CL fitting in 26 previous DW SCL users, 18 previous EW SCL users, and 26 neophytes. Wearers were fitted with an etafilcon A CL in one eye and a polymacon CL in the fellow eye. Lenses were worn on a daily basis by the 26 previous DW SCL wearers and on an EW basis by the remaining 44 subjects. The ocular biota was further sampled after 1, 3, 6, 9, and 12 months of wear. The ocular biota consisted of coagulase-negative staphylococci, Corynebacterium spp., Micrococcus spp., and Propionibacterium spp. Potential pathogens were rarely isolated at baseline. No significant trend of increasing ocular colonization was shown for extended CL wear. Lid and conjunctival colonization increased with DW SCL use (P < 0.001), although this increase occurred for nonpathogenic species only. Fewer potential pathogens were isolated from DW SCL than from EW SCL users (P < 0.05). The lid margin consistently showed greater colonization than the conjunctiva and may be a source of potential pathogens during CL wear. Hydrogel CL wear appears to modify the ocular biota. An increased number of commensal organisms were present in DW SCL use. EW SCL use altered the spectrum of organisms isolated. These alterations may suppress the normal ocular defense mechanisms and may be relevant in the pathogenesis of CL-related disease. 相似文献
4.
Sun Weidong Hansell Stedman Chen Xiaoli Wei Yu Liu Meizhen Xu Chengbin H. Lee Sweeney 《中华医学杂志(英文版)》1998,(6):495
LigasechainreactionfordiagnosisoffamilialhypertrophiccardiomyopathySunWeidong孙维东,HanselStedman,ChenXiaoli,WeiYu,LiuMeizhen,Xu... 相似文献
5.
W K Chong M Paley I D Wilkinson M A Hall-Craggs B Sweeney M J Harrison R F Miller B E Kendall 《AJNR. American journal of neuroradiology》1994,15(1):21
PURPOSETo document differences in the cerebral proton MR spectra of patients with early and late stages of human immunodeficiency virus (HIV) infection.METHODWe studied the relative N-acetyl-aspartate (NAA) levels by localized proton spectroscopy of the parietooccipital region of the brain in 43 HIV-seropositive patients, including 26 with an acquired immunodeficiency syndrome (AIDS)-defining diagnosis, and in eight control subjects.RESULTSReduced relative NAA levels were shown in those HIV-1-seropositive patients: 1) with AIDS against HIV-1-seropositive patients without AIDS (P < .04); 2) with HIV-1-associated cognitive/motor complex against neurologically healthy patients (P < .007); 3) with encephalopathic changes on MR against those with normal imaging (P < .001); and 4) on follow-up against their results on initial study (P < .03).CONCLUSIONSBy clinical (Centers for Disease Control classification) and radiologic (MR evidence of white-matter disease) criteria indicating late-stage HIV infection, reduced relative levels of NAA have been demonstrated. Spectroscopic abnormalities can be quantitatively tracked with time. This paper demonstrates the clinical use of detecting NAA as a putative in vivo measure of the neuronal loss that has been demonstrated in postmortem studies of patients with AIDS. This neuronal loss, which is believed to underlie the HIV-1-associated cognitive/motor complex, is thought to be attributable directly or indirectly to the presence of HIV in the brain. Proton spectroscopy may serve as a quantitative noninvasive indicator of this aspect of cerebral involvement in HIV disease. 相似文献
6.
Levels of plasma Von Willebrand Factor (vWF) are known to be influenced by ABO Blood Group but such an influence on platelet vWF is not known. Forty-three healthy donors had blood drawn for measurement of plasma and platelet vWF, both antigenic (vWF:Ag) and functional (RCo). Twenty-six were Group O and seventeen were Group A. Groups did not differ in age, platelet count, hemoglobin, white cell counts, platelet rich plasma counts nor length of in vitro storage of samples prior to assay. Plasma levels of vWF:Ag and RCo was lower in Group O as expected. Platelet RCo was lower in Group O and such a trend was present for vWF:Ag. This influence of ABO Groups on platelet vWF was modest compared to that on plasma vWF. 相似文献
7.
8.
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
9.
Alcohol versus Mnemosyne--blackouts 总被引:1,自引:0,他引:1
D F Sweeney 《Journal of substance abuse treatment》1989,6(3):159-162
Blackouts induced by alcohol, in spite of their frequent occurrence, remain something of an enigma. This article reviews the knowledge of the blackout and of memory theory to date, and proposes a definition for this amnestic event. After establishing a definition, the article comments on the clinical significance, both from a medical and a medical-legal perspective. 相似文献
10.
Anal fissure in Crohn's disease 总被引:7,自引:0,他引:7
There is little information on the natural history of anal fissure in Crohn's disease. The case notes of all new patients with Crohn's disease attending one hospital between 1977 and 1983 were reviewed: there were 61 patients with this diagnosis and an unhealed anal fissure as the only anal lesion. Of these 61 patients the fissure healed in 42 (69 per cent) during medical treatment of the intestinal disease. Ten patients (16 per cent) developed other anal lesions and in the remaining nine patients the fissure remained unhealed at the time of rectal excision (six) or last out-patient attendance (three). Activity of the fissure did not reflect disease activity elsewhere in 11 cases in whom healing of the fissure occurred despite progressive intestinal disease subsequently requiring resection. This study validates the policy of conservative management of anal fissure in Crohn's disease with anal surgery (required in 9.8 per cent of patients in this series) being reserved for the development of other anal disease. 相似文献