全文获取类型
收费全文 | 676篇 |
免费 | 59篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 10篇 |
妇产科学 | 26篇 |
基础医学 | 122篇 |
口腔科学 | 32篇 |
临床医学 | 41篇 |
内科学 | 109篇 |
皮肤病学 | 6篇 |
神经病学 | 44篇 |
特种医学 | 21篇 |
外科学 | 99篇 |
综合类 | 10篇 |
预防医学 | 44篇 |
眼科学 | 6篇 |
药学 | 28篇 |
肿瘤学 | 133篇 |
出版年
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 6篇 |
2018年 | 12篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 16篇 |
2012年 | 27篇 |
2011年 | 15篇 |
2010年 | 17篇 |
2009年 | 15篇 |
2008年 | 39篇 |
2007年 | 33篇 |
2006年 | 36篇 |
2005年 | 40篇 |
2004年 | 21篇 |
2003年 | 26篇 |
2002年 | 29篇 |
2001年 | 27篇 |
2000年 | 27篇 |
1999年 | 18篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 9篇 |
1994年 | 4篇 |
1992年 | 13篇 |
1991年 | 11篇 |
1990年 | 27篇 |
1989年 | 17篇 |
1988年 | 15篇 |
1987年 | 15篇 |
1986年 | 24篇 |
1985年 | 30篇 |
1984年 | 7篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1979年 | 4篇 |
1978年 | 10篇 |
1977年 | 6篇 |
1976年 | 9篇 |
1974年 | 7篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1969年 | 3篇 |
排序方式: 共有735条查询结果,搜索用时 0 毫秒
1.
Harvey A. Siegal PhD ; Paul J. Draus PhD ; Robert G. Carlson PhD ; Russel S. Falck MA ; Jichuan Wang PhD 《The Journal of rural health》2006,22(2):169-173
CONTEXT: Although the nonmedical use of stimulant drugs such as cocaine and methamphetamine is increasingly common in many rural areas of the United States, little is known about the health beliefs of people who use these drugs. PURPOSE: This research describes illicit stimulant drug users' views on health and health-related concepts that may affect their utilization of health care services. METHODS: A respondent-driven sampling plan was used to recruit 249 not-in-treatment, nonmedical stimulant drug users who were residing in 3 rural counties in west central Ohio. A structured questionnaire administered by trained interviewers was used to collect information on a range of topics, including current drug use, self-reported health status, perceived need for substance abuse treatment, and beliefs about health and health services. FINDINGS: Participants reported using a wide variety of drugs nonmedically, some by injection. Alcohol and marijuana were the most commonly used drugs in the 30 days prior to the interview. Powder cocaine was used by 72.3% of the sample, crack by 68.3%, and methamphetamine by 29.7%. Fair or poor health status was reported by 41.3% of the participants. Only 20.9% of the sample felt they needed drug abuse treatment. Less than one third of the sample reported that they would feel comfortable talking to a physician about their drug use, and 65.1% said they preferred taking care of their problems without getting professional help. CONCLUSIONS: Stimulant drug users in rural Ohio are involved with a range of substances and hold health beliefs that may impede health services utilization. 相似文献
2.
EFNS Guidelines on diagnosis and treatment of brain metastases: report of an EFNS Task Force 总被引:2,自引:0,他引:2
R. Soffietti P. Cornu J. Y. Delattre R. Grant F. Graus W. Grisold J. Heimans J. Hildebrand P. Hoskin M. Kalljo P. Krauseneck C. Marosi T. Siegal C. Vecht 《European journal of neurology》2006,13(7):674-681
The objectives have been to establish evidence-based guidelines and identify controversies regarding the management of patients with brain metastases. The collection of scientific data was obtained by consulting the Cochrane Library, bibliographic databases, overview papers and previous guidelines from scientific societies and organizations. A tissue diagnosis is necessary when the primary tumor is unknown or the aspect on computed tomography/magnetic resonance imaging is atypical. Dexamethasone is the corticosteroid of choice for cerebral edema. Anticonvulsants should not be prescribed prophylactically. Surgery should be considered in patients with up to three brain metastases, being effective in prolonging survival when the systemic disease is absent/controlled and the performance status is high. Stereotactic radiosurgery should be considered in patients with metastases of 3–3.5 cm of maximum diameter. Whole-brain radiotherapy (WBRT) after surgery or radiosurgery is debated: in case of absent/controlled systemic cancer and Karnofsky Performance score of 70 or more, one can either withhold initial WBRT or deliver early WBRT with conventional fractionation to avoid late neurotoxicity. WBRT alone is the treatment of choice for patients with single or multiple brain metastases not amenable to surgery or radiosurgery. Chemotherapy may be the initial treatment for patients with brain metastases from chemosensitive tumors. 相似文献
3.
Experimental neoplastic spinal cord compression: effect of ketamine and MK-801 on edema and prostaglandins 总被引:2,自引:0,他引:2
Excitotoxin-induced neural tissue damage is mediated through specific receptors. We studied the in vivo effect of two selective N-methyl-D-aspartate receptor antagonists on the compressed spinal cord segments of rats harboring a thoracolumbar epidural tumor. The effect of a single intramuscular treatment with either MK-801 (3 mg/kg) or ketamine (110 mg/kg) given at the onset of paraplegia was evaluated 30 hours later. In saline-treated control animals, significant increases in water content, prostaglandin E2, and 6-keto-prostaglandin F1 alpha were evident. Treatment with either agent resulted in a normal water content in the compressed segments but had no effect on prostaglandin synthesis. Evaluation of the effect of treatment on the course of the disease required dose reduction by 45% for ketamine and by 30% for MK-801, to avoid the excessive sedative effect. Treatment was started at the first appearance of neurological dysfunction (Grade 1) and continued to paraplegia (Grade 5). The mean time interval between Grades 1 and 5 was 2.1 +/- 0.3 days in saline-treated control animals, and it was not significantly altered by either ketamine or MK-801. Our study indicates that in the end stage of epidural compression, when ischemia is present, excitotoxins probably participate in the evolution of a cytotoxic edema. It is suggested that treatment initiated at the onset of paraplegia may still reduce the cytotoxic edema, but its potential clinical value requires further investigations. 相似文献
4.
Histopathological changes of three types of vein grafts were studied. Freeze-preserved, fresh human grafts and autografts were inserted as patches in the aorta of rabbits on regular and variable cholesterol diets. In all grafts the endothelium and adventitia were reconstituted after a few months. In the wall, smooth muscle and elastic tissue were markedly diminished and poorly oriented with accompanied collagenisation. Cholesterol diet led to progressive fat and/or calcium deposition with subintimal proliferation in the autografts and fresh xenografts. In contrast this was seen to a much lesser degree and later in freeze preserved xenografts, even on higher cholesterol diets. Deep freezing considerably reduces the cellularity of the graft and its metabolic ability to accumulate lipids. Freeze-preserved veins seem to be a suitable graft for vascular reconstructions in severely atherosclerotic patients and compare favorably with vein autografts. 相似文献
5.
Deepali Kumar Dean Erdman Shaf Keshavjee Teresa Peret Raymond Tellier Denis Hadjiliadis Grant Johnson Melissa Ayers Deborah Siegal Atul Humar 《American journal of transplantation》2005,5(8):2031-2036
Community-acquired viral respiratory tract infections (RTI) in lung transplant recipients may have a high rate of progression to pneumonia and can be a trigger for immunologically mediated detrimental effects on lung function. A cohort of 100 patients was enrolled from 2001 to 2003 in which 50 patients had clinically diagnosed viral RTI and 50 were asymptomatic. All patients had nasopharyngeal and throat swabs taken for respiratory virus antigen detection, culture and RT-PCR. All patients had pulmonary function tests at regular intervals for 12 months. Rates of rejection, decline in forced expiratory volume (L) in 1 s (FEV-1) and bacterial and fungal superinfection were compared at the 3-month primary endpoint. In the 50 patients with RTI, a microbial etiology was identified in 33 of 50 (66%) and included rhinovirus (9), coronavirus (8), RSV (6), influenza A (5), parainfluenza (4) and human metapneumovirus (1). During the 3-month primary endpoint, 8 of 50 (16%) RTI patients had acute rejection versus 0 of 50 non-RTI patients (p=0.006). The number of patients experiencing a 20% or more decline in FEV-1 by 3 months was 9 of 50 (18%) RTI versus 0 of 50 non-RTI (0%) (p=0.003). In six of these nine patients, the decline in FEV-1 was sustained over a 1-year period consistent with bronchiolitis obliterans syndrome (BOS). Community-acquired respiratory viruses may be associated with the development of acute rejection and BOS. 相似文献
6.
Hagood JS Prabhakaran P Kumbla P Salazar L MacEwen MW Barker TH Ortiz LA Schoeb T Siegal GP Alexander CB Pardo A Selman M 《The American journal of pathology》2005,167(2):365-379
Fibroblasts consist of heterogeneous subpopulations that have distinct roles in fibrotic responses. Previously we reported enhanced proliferation in response to fibrogenic growth factors and selective activation of latent transforming growth factor (TGF)-beta in fibroblasts lacking cell surface expression of Thy-1 glycoprotein, suggesting that Thy-1 modulates the fibrogenic potential of fibroblasts. Here we report that compared to controls Thy-1-/- C57BL/6 mice displayed more severe histopathological lung fibrosis, greater accumulation of lung collagen, and increased TGF-beta activation in the lungs 14 days after intratracheal bleomycin. The majority of cells demonstrating TGF-beta activation and myofibroblast differentiation in bleomycin-induced lesions were Thy-1-negative. Histological sections from patients with idiopathic pulmonary fibrosis demonstrated absent Thy-1 staining within fibroblastic foci. Normal lung fibroblasts, in both mice and humans, were predominantly Thy-1-positive. The fibrogenic cytokines interleukin-1 and tumor necrosis factor-alpha induced loss of fibroblast Thy-1 surface expression in vitro, which was associated with Thy-1 shedding, Smad phosphorylation, and myofibroblast differentiation. These results suggest that fibrogenic injury promotes loss of lung fibroblast Thy-1 expression, resulting in enhanced fibrogenesis. 相似文献
7.
Eltoum IA Eloubeidi MA Chhieng DC Tamhane A Crowe R Jhala D St John KD Wilcox CM Siegal GP Vickers S Jhala NC 《American journal of clinical pathology》2005,124(5):697-707
Our objectives were to devise a cytologic grading system and determine whether it would predict survival of patients with solid-type pancreatic adenocarcinoma. We evaluated 116 consecutive patients from July 2000 to November 2002; they were followed up until September 2003. We scored the following features on rapid Romanowsky-stained endoscopic ultrasound-guided fine-needle aspiration smears: cell group architecture, single cells, nuclear grade, mucus, bizarre cells, and necrosis. A cytologic grade (low vs high) was assigned. The Kaplan-Meier estimate of 6-month survival was 76% (SE, 7%) for patients with low-grade tumors vs 50% (SE, 6%) for patients with high-grade carcinoma. The median survival for patients with low-grade vs high-grade tumors was 1 year vs 6 months, respectively (chi2 = 4.45; P = .035). Cox proportional hazards regression showed tumor stage, cancer-specific treatment, and cytologic grade to be independent predictors of survival (P = .001). No other factors (age, mass location, placement of stent, presence of concomitant chronic pancreatitis, race, sex) predicted survival. We devised a grading system that independently predicted survival in patients with pancreatic adenocarcinoma. 相似文献
8.
Tea Kalebic Jeannette E. Williams James E. Talmadge Chien-Song Kao-Shan Betsy Kravitz Kimberly Locklear Gene P. Siegal Lance A. Liotta Mark E. Sobel Patricia S. Steeg 《Clinical & experimental metastasis》1988,6(4):301-318
Tumor cell invasion of basement membranes is required at several steps in the process of metastasis. To study the genetic and biochemical events mediating invasion, a variant cell line (TK) was selected from the metastatic M2 K1735 murine melanoma cell line. A novel selection procedure was used, based onin vitro andin vivo invasion and growth upon basement membrane and stroma. Additionally, two extrapulmonary metastases of the TK cell line, TK-Eve and TK-Liver, were established as cell lines and characterized. The TK cell line demonstrates greater metastatic potentialin vivo and invasive abilityin vitro than the parent M2 cell line, confirming the validity of the selection procedure. In addition, the M2 and TK cell lines were examined for other cell functions involved in the metastatic process. Cellular growth rates and sensitivity to T lymphocyte and natural killer cell lysis were not determining factors in the metastatic potentials of the M2 and selected cell lines; possible macrophage contribution to metastatic behavior was noted. [35S]methionine pulse labeling of protein synthesis and karyotypic analysis confirm the close relationship of parental and selected cell lines.Supported by contract NDI-23910.Supported by ACS Institution Grant IN-15-Y and NIH Grant MRC-5T34-GM08037.Was a fellow of the Jane Coffin Childs Memorial Fund for Medical Research. This investigation has been aided by a grant from the Jane Coffin Childs Memorial Fund for Medical Research. Also supported by NIH Postdoctoral Fellowship #HD06423. 相似文献
9.
Effect of hyperthermia and thermochemotherapy on primary and metastatic tumour cells of AKR lymphoma
G Klorin A Siegal B Bar-Shira-Maymon O Klein J Leibovici 《International journal of experimental pathology》1990,71(4):469-477
The cure of metastatic disease constitutes a serious problem. Recent findings showed cell membrane differences between slightly and highly metastasizing tumour cells, suggesting that since this cell organelle determines the metastatic phenotype, it might serve as a target for future drugs programmed against advanced cancer. The cell membrane has also been shown to be involved in the evolution of drug resistance which often accompanies tumour progression. In the present study, the effect of hyperthermia--an antitumoral treatment modality partly exerting its effect on the cell membrane--on primary and metastatic AKR lymphoma cells was compared. The effect of hyperthermia in conjunction with adriamycin (ADR) on the two cell types was also tested. Hyperthermic treatment, alone and in combination with ADR, was more effective in reducing the tumorigenicity of cells derived from metastatic tumours than of the primary tumour cells. Fluorescent microscopy and cytofluorometry showed that the increased effect of ADR by hyperthermia was due to an increased drug uptake at the supranormal temperature. 相似文献
10.
The purpose of this investigation was to determine whether paraplegia induced by neoplastic cord compression affects the pharmacodynamics of phenobarbital general anesthesia or of pentylenetet-razol (PTZ)-induced convulsions. Paraplegic rats harboring a thora-columbar epidural tumor, or an identical hindlimb tumor mass, received an i.v. infusion of phenobarbital until the onset of anesthesia. At that point, the phenobarbital concentrations in the CSF and serum were measured. Similarly, PTZ was infused until the onset of maximal seizures. It was found that changes related to systemic tumor growth and newly developed paraplegia due to neoplastic spinal cord compression did not attenuate the pharmacodynamics of phenobarbital. However, sustained paraplegia of 4 days duration reduced CNS sensitivity to the hypnotic action of the barbiturate as evidenced by the higher cerebrospinal fluid phenobarbital concentration required to induce anesthesia (170 ± 31 vs 125 ± 20 mg/L; P < 0.05). On the other hand, sustained paraplegia did not affect brain threshold concentration for PTZ-induced seizures. 相似文献