全文获取类型
收费全文 | 4521篇 |
免费 | 331篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 169篇 |
妇产科学 | 97篇 |
基础医学 | 522篇 |
口腔科学 | 69篇 |
临床医学 | 616篇 |
内科学 | 827篇 |
皮肤病学 | 50篇 |
神经病学 | 436篇 |
特种医学 | 100篇 |
外科学 | 685篇 |
综合类 | 68篇 |
一般理论 | 26篇 |
预防医学 | 535篇 |
眼科学 | 32篇 |
药学 | 276篇 |
中国医学 | 8篇 |
肿瘤学 | 315篇 |
出版年
2023年 | 69篇 |
2022年 | 119篇 |
2021年 | 278篇 |
2020年 | 124篇 |
2019年 | 236篇 |
2018年 | 248篇 |
2017年 | 150篇 |
2016年 | 132篇 |
2015年 | 134篇 |
2014年 | 183篇 |
2013年 | 260篇 |
2012年 | 340篇 |
2011年 | 401篇 |
2010年 | 174篇 |
2009年 | 150篇 |
2008年 | 246篇 |
2007年 | 214篇 |
2006年 | 198篇 |
2005年 | 202篇 |
2004年 | 175篇 |
2003年 | 133篇 |
2002年 | 120篇 |
2001年 | 40篇 |
2000年 | 32篇 |
1999年 | 24篇 |
1998年 | 27篇 |
1997年 | 17篇 |
1996年 | 18篇 |
1995年 | 17篇 |
1994年 | 13篇 |
1993年 | 17篇 |
1992年 | 28篇 |
1991年 | 27篇 |
1990年 | 35篇 |
1989年 | 20篇 |
1988年 | 21篇 |
1987年 | 28篇 |
1986年 | 23篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 8篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 9篇 |
1979年 | 19篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1976年 | 12篇 |
1971年 | 10篇 |
1970年 | 10篇 |
排序方式: 共有4866条查询结果,搜索用时 15 毫秒
91.
92.
Courtney Pendleton Shaan M. Raza Gary L. Gallia Alfredo Quinones-Hinojosa 《Skull base》2014,75(1):27-34
Objectives To review Dr. Harvey Cushing''s early surgical cases at the Johns Hopkins Hospital, revealing details of his operative approaches to fractures of the skull base.
Design Following institutional review board approval and through the courtesy of the Alan Mason Chesney Archives, we reviewed the Johns Hopkins Hospital surgical files.
Setting The Johns Hopkins Hospital, 1896 to 1912.
Participants A total of 24 patients underwent operative treatment for suspected fractures of the skull base.
Main Outcome Measures The main outcome measure was operative approach, postoperative mortality, and condition recorded at the time of discharge.
Results Overall, 23 patients underwent operative treatment for suspected skull base fractures. The mechanisms of injury were known for 22 patients and included work-related injuries (41%), falls (23%), vehicle injuries (32%), and other trauma (5%). One patient had no mechanism of injury specified in the file. The outcome at the time of discharge from the hospital was “well” or “improved” in 12 patients (52%). The remaining 11 patients died during their admission.
Conclusions Although Cushing''s experience with selected skull base pathology has been previously reported, the breadth of his contributions to operative approaches to the skull base has been neglected. 相似文献
93.
The Role of the Neurokinin-1 Receptor in Stress-Induced Reinstatement of Alcohol and Cocaine Seeking
Jesse R Schank Courtney E King Hui Sun Kejun Cheng Kenner C Rice Markus Heilig David Weinshenker Jason P Schroeder 《Neuropsychopharmacology》2014,39(5):1093-1101
Neurokinin-1 receptors (NK1Rs) have been shown to mediate alcohol and opiate, but not cocaine reward in rodents. We recently reported that NK1R antagonism also blocks stress-induced reinstatement of alcohol seeking in rats, but it is presently unknown whether these antirelapse properties extend to other drug classes. Although some work has suggested that intracranial substance P (SP) infusion reinstates cocaine seeking following extinction, no studies have indicated a direct role for the NK1R in reinstatement of cocaine seeking. Here, we explored the effect of the NK1R antagonist L822429 on yohimbine-induced reinstatement of alcohol or cocaine seeking in Long–Evans rats. Consistent with our previous findings with footshock-induced reinstatement of alcohol seeking in Wistar rats, we found that L822429 attenuates yohimbine-induced reinstatement of alcohol seeking, but does not affect baseline alcohol self-administration. We observed a similar suppression of yohimbine-induced reinstatement of cocaine seeking by L822429, and found that Long–Evans rats exhibit greater sensitivity to NK1R antagonism than Wistar rats. Accordingly, Long–Evans rats exhibit differences in the expression of NK1Rs in some subcortical brain regions. Combined, our findings suggest that while NK1R antagonism differentially influences alcohol- and cocaine-related behavior, this receptor mediates stress-induced seeking of both drugs. 相似文献
94.
Jacob C. Jentzer Nandan S. Anavekar Jorge A. Brenes-Salazar Brandon Wiley Dennis H. Murphree Courtney Bennett Joseph G. Murphy Mark T. Keegan Gregory W. Barsness 《Mayo Clinic proceedings. Mayo Clinic》2019,94(10):1994-2003
ObjectiveTo determine whether a low Braden skin score (BSS), reflecting increased risk for skin pressure injury, would predict lower survival in cardiac intensive care unit (CICU) patients after adjustment for illness severity and comorbidities.Patients and MethodsThis retrospective cohort study included consecutive unique adult patients admitted to a single tertiary care referral hospital CICU from January 1, 2007, through December 31, 2015, who had a BSS documented on CICU admission. The primary outcome was all-cause hospital mortality, using elastic net penalized logistic regression to determine predictors of hospital mortality. The secondary outcome was all-cause post-discharge mortality, using Cox proportional hazards models to determine predictors of post-discharge mortality.ResultsThe study included 9552 patients with a mean age of 67.4±15.2 years (3589 [37.6%] were females) and a hospital mortality rate of 8.3%. Admission BSS was inversely associated with hospital mortality (unadjusted odds ratio, 0.70; 95% CI, 0.68-0.72; P<.001; area under the receiver operator curve, 0.80; 95% CI, 0.78-0.82), with increased short-term mortality as a function of decreasing admission BSS. After adjustment for illness severity and comorbidities using multivariable analysis, admission BSS remained inversely associated with hospital mortality (adjusted odds ratio, 0.88; 95% CI, 0.85-0.92; P<.001). Among hospital survivors, admission BSS was inversely associated with post-discharge mortality after adjustment for illness severity and comorbidities (adjusted hazard ratio, 0.89; 95% CI, 0.88-0. 90; P<.001).ConclusionThe admission BSS, a simple inexpensive bedside nursing assessment potentially reflecting frailty and overall illness acuity, was independently associated with hospital and post-discharge mortality when added to established multiparametric illness severity scores among contemporary CICU patients. 相似文献
95.
Danielle M. McCarthy Laura M. Curtis D. Mark Courtney Kenzie A. Cameron Patrick M. Lank Howard S. Kim Lauren A. Opsasnick Abbie E. Lyden Stephanie J. Gravenor Andrea M. Russell Morgan R. Eifler Scott I. Hur Megan E. Rowland Surrey M. Walton Enid Montague Kwang‐Youn A. Kim Michael S. Wolf 《Academic emergency medicine》2019,26(12):1311-1325
96.
Sympathoadrenal imbalance before neurocardiogenic syncope 总被引:2,自引:0,他引:2
Goldstein DS Holmes C Frank SM Naqibuddin M Dendi R Snader S Calkins H 《The American journal of cardiology》2003,91(1):53-58
Neurocardiogenic syncope is the most common cause of acute loss of consciousness in adults. The present study attempted to identify neuroendocrine and hemodynamic changes before syncope that could therefore play a pathophysiologic role. Twenty-five patients referred for chronic orthostatic intolerance had plasma catecholamines measured serially; 21 patients during tilt-table testing (evoking syncope in 13) and 4 others with spontaneous syncope while supine. Forearm blood flow was measured by impedance plethysmography. All 12 patients with blood sampled before tilt-induced syncope had progressive, marked increases in plasma epinephrine levels (mean 11 times baseline, p <0.0001) before syncope. Simultaneously obtained norepinephrine levels increased to a much smaller extent than did epinephrine levels ("sympathoadrenal imbalance"). In the same patients, forearm vascular resistance decreased by 21% before syncope. Proportionate changes in forearm vascular resistance before syncope correlated negatively with those in the epinephrine:norepinephrine ratio (r = -0.75, p = 0.005). Patients without syncope had forearm vasoconstriction and no sympathoadrenal imbalance during tilt. Patients with syncope while supine also had sympathoadrenal imbalance before loss of consciousness. Sympathoadrenal imbalance precedes tilt-evoked and spontaneous neurocardiogenic syncope and correlates with concurrent skeletal muscle vasodilation. Sympathoadrenal imbalance may contribute to hemodynamic derangements precipitating neurocardiogenic syncope. 相似文献
97.
98.
Kyongshin Cho Woo-Sik Choi Courtney L. Crane Chung S. Park 《European journal of nutrition》2014,53(4):1139-1143
Purpose
The time from puberty to the first pregnancy is known to be important for a woman’s life-time breast cancer risk. Recent studies suggest that epigenetic mechanisms may involve pubertal maturation processes, which can affect the risk of breast cancer in later life. Epigenetic alterations are related to lipotropes (methionine, choline, folate, and vitamin B12), which are methyl donors and cofactors. However, the effects of pubertal supplementation of lipotropes in breast cancer remain largely unknown.Methods
Twenty female Sprague–Dawley rats, aged 6 weeks, were divided into two groups and fed a normal control diet or a lipotrope-fortified diet formulated to provide five times basal levels of lipotropes during puberty. All rats were injected intraperitoneally with N-nitroso-N-methylurea at 50 days of age to induce mammary tumors.Results
Tumor multiplicity and tumor volume decreased significantly as a result of lipotrope supplementation. Interestingly, quantitative RT-PCR revealed significantly decreased expression of histone deacetylase 1 (Hdac1) and DNA methyltransferase 1 (Dnmt1) genes in tumor tissues of the rats supplemented with lipotrope-fortified diet, suggesting that reduced risk of breast cancer can be attributed, at least in part, to decreased expression of these two genes.Conclusions
This study demonstrates that supplementation of lipotrope-fortified diet during puberty suppresses tumor growth, potentially through down-regulating Hdac1 and Dnmt1 gene expression. Our findings suggest that pubertal methyl diet plays an important role in the etiology of breast cancer, and further studies are warranted to develop preventative strategies against breast cancer. 相似文献99.
Courtney K. Brown Brynne Stainsby Guy Sovak 《The Journal of the Canadian Chiropractic Association》2014,58(4):413-420
Objective:
To present the clinical diagnostic features including management of Guyon canal syndrome in a case with unresolved sensory deficits in a young female cyclist.Clinical Presentation:
After 14 days of cycling across Canada, a 23-year old female experienced sensory loss, followed by atrophy and a “claw” hand appearance of her left hand.Intervention and Outcome:
Treatment included cervical chiropractic manipulation, soft tissue therapy and the use of cycling gloves. Seven years after the initial injury a lack of sensation in the ulnar nerve distribution of her left hand has persisted.Discussion:
This case demonstrates that a lack of proper management can lead to permanent sensory loss and is worth highlighting. Various therapists evaluated the patient’s symptoms and provided minimal care. No diagnosis was given, nor were appropriate measures taken for her to understand the risks of continuing to ride.Summary:
Although treatment for Guyon Canal Syndrome can be as easy as cessation from cycling until symptoms subside, other treatment options could be utilized to help manage ulnar nerve compression injuries in cyclists. 相似文献100.