全文获取类型
收费全文 | 28674篇 |
免费 | 2245篇 |
国内免费 | 84篇 |
专业分类
耳鼻咽喉 | 221篇 |
儿科学 | 922篇 |
妇产科学 | 629篇 |
基础医学 | 4295篇 |
口腔科学 | 637篇 |
临床医学 | 2695篇 |
内科学 | 6349篇 |
皮肤病学 | 726篇 |
神经病学 | 2411篇 |
特种医学 | 953篇 |
外国民族医学 | 1篇 |
外科学 | 3881篇 |
综合类 | 300篇 |
一般理论 | 24篇 |
预防医学 | 2424篇 |
眼科学 | 785篇 |
药学 | 1667篇 |
中国医学 | 12篇 |
肿瘤学 | 2071篇 |
出版年
2022年 | 253篇 |
2021年 | 489篇 |
2020年 | 237篇 |
2019年 | 416篇 |
2018年 | 534篇 |
2017年 | 357篇 |
2016年 | 402篇 |
2015年 | 455篇 |
2014年 | 616篇 |
2013年 | 944篇 |
2012年 | 1417篇 |
2011年 | 1466篇 |
2010年 | 807篇 |
2009年 | 749篇 |
2008年 | 1357篇 |
2007年 | 1420篇 |
2006年 | 1332篇 |
2005年 | 1441篇 |
2004年 | 1272篇 |
2003年 | 1216篇 |
2002年 | 1234篇 |
2001年 | 748篇 |
2000年 | 849篇 |
1999年 | 708篇 |
1998年 | 359篇 |
1997年 | 312篇 |
1996年 | 254篇 |
1995年 | 283篇 |
1994年 | 245篇 |
1993年 | 253篇 |
1992年 | 588篇 |
1991年 | 601篇 |
1990年 | 520篇 |
1989年 | 529篇 |
1988年 | 484篇 |
1987年 | 497篇 |
1986年 | 455篇 |
1985年 | 438篇 |
1984年 | 419篇 |
1983年 | 295篇 |
1982年 | 217篇 |
1981年 | 208篇 |
1980年 | 238篇 |
1979年 | 291篇 |
1978年 | 245篇 |
1977年 | 199篇 |
1976年 | 197篇 |
1975年 | 189篇 |
1974年 | 235篇 |
1973年 | 223篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Denis Nissim-Sabat William H. Farr Kathleen McCune Melanie Stith 《Community mental health journal》1986,22(2):160-165
This study represents the first of a two-stage project. The first phase of the study examined the funding sources for the 40 Community Services Boards in Virginia. Data provided from the Department of Mental Health and Mental Retardation in Virginia examined fee collections which are comprised of direct client, commercial insurance, Medicaid and Medicare. An analysis of quarterly reports from 1982 to 1984 revealed that Medicaid collections have decreased significantly, while commercial insurance reimbursements have increased significantly. These results, although limited to data from Virginia, point to the need to examine if these shifts are occurring nation-wide, and to determine if the shift toward commercial insurance is impacting upon the delivery of services in Community Mental Health Centers. 相似文献
22.
Leslee J. Shaw Romalisa Miranda-Peats Piotr Slomka John Friedman Sean W. Hayes Daniel S. Berman Gary V. Heller Marcin Dada William E. Boden Paul Casperson Robert A. O’Rourke Ronald Schwartz William S. Weintraub David J. Maron Spencer King Koon Teo Pamela Hartigan 《Journal of nuclear cardiology》2006,13(5):685-698
Background Stress gated myocardial perfusion single photon emission computed tomography (gSPECT) is increasingly used before and after
intercurrent therapeutic intervention and is the basis for ongoing evaluation in the Department of Veterans Affairs clinical
outcomes utilizing revascularization and aggressive drug evaluation (COURAGE) trial.
Methods and Results The COURAGE trial is a North American multicenter randomized clinical trial that enrolled 2287 patients to aggressive medical
therapy vs percutaneous coronary intervention plus aggressive medical therapy. Three COURAGE nuclear substudies have been
designed. The goals of substudy 0 are to examine the diagnostic accuracy of the extent and severity of inducible ischemia
at baseline in COURAGE patients compared with patient symptoms and quantitative coronary angiography and to explore the relationship
between inducible ischemia and the benefit from revascularization when added to medical therapy. Substudy 1 will correlate
the extent and severity of provocative ischemia with the frequency, quality, and instability of recurrent symptoms in postcatheterization
patients. Substudy 2 (n _ 300) will examine the usefulness of sequential gSPECT monitoring 6 to 18 months after therapeutic
intervention. Together, these nuclear substudies will evaluate the role of gSPECT to determine the effectiveness of aggressive
risk-factor modifications, lifestyle interventions, and anti-ischemic medical therapies with or without revascularization
in reducing patients’ ischemic burdens.
Conclusions The unfolding of evidence on the application of gSPECT in trials such as COURAGE defines a new era for nuclear cardiology.
We hope the evidence that emerges from the COURAGE trial will further establish the role of nuclear imaging in the evidence-based
management of patients with stable coronary disease.
The COURAGE trial was supported by the Cooperative Studies Program of the Department of Veterans Affairs Office of Research
and Development in collaboration with the Canadian Institutes of Health Research. Unrestricted research grants were obtained
from Merck & Co; Pfizer Pharmaceuticals; Bristol-Myers Squibb Medical Imaging; Astellas Pharma; Kos Pharmaceuticals; Data
Scope; Astra Zeneca Pharmaceuticals; Astra-Zeneca-Canada; Schering-Plough Coorporation, Ltd; Sanofi-Aventis, Inc; First Horizon;
and GE Healthcare. All industrial funding for this trial was directed through the Department of Veterans Affairs. Additional
funding for this substudy was provided by grants to the Department of Veterans Affairs and Canadian Institutes of Health Research
from Astellas Pharma and Bristol-Myers-Squibb Medical Imaging. 相似文献
23.
24.
J A Gottridge B R Meyer N S Schwartz R S Lesser 《Archives of internal medicine》1989,149(7):1660-1662
To determine the value of chest roentgenograms in the management of asymptomatic persons with positive tuberculin skin test results, we undertook a retrospective review of all tests administered by our Employee Health Service, North Shore University Hospital, Manhasset, NY, between July 1, 1983 and November 1, 1987. Of 5200 tests, 247 results were positive. Two hundred twenty-one of these charts were reviewed for roentgenographic results and the presence of symptoms. All persons were asymptomatic. Chest roentgenograms revealed the following: normal, 188; unrelated abnormalities, 24; apical pleural thickening, 5; granulomas, 2; calcified hilar node, 1; and calcified node plus granuloma, 1. We noted no active tuberculosis, nor did the chest roentgenographic results influence recommendations for isoniazid prophylaxis. We conclude that chest roentgenograms are of value in 0% to 1.3% of asymptomatic people with positive tuberculin test results. A larger study should be undertaken to further define the usefulness of chest roentgenograms in this population. 相似文献
25.
Oren S Cohen Eli Vakil David Tanne Zeev Nitsan Roseline Schwartz Sharon Hassin-Baer 《Cognitive and behavioral neurology》2007,20(1):68-72
OBJECTIVES: To test a possible association between the educational level (EL), cognitive performance, and neuropsychiatric features in Parkinson disease (PD). BACKGROUND: An inverse association has been reported between EL and cognitive dysfunction in patients with senile dementia of Alzheimer type but it is yet unsettled whether education has a similar effect on cognition in PD. METHODS: Seventy-two PD patients (45 males, mean age 68.7+/-11.6 y) underwent a detailed neurologic examination, a battery of neuropsychologic tests, and questionnaires for the evaluation of psychosis, sleep disturbances, and depression. According to the number of educational years, patients were divided into 3 groups: low EL (0 to 8 y), (15 patients), intermediate EL (9 to 12 y) (28 patients), and high EL (>/=13 y) (29 patients). RESULTS: Patients with a higher EL had a better cognitive function and an association was found between the patients' EL and their scores in various neuropsychologic tests mainly those sensitive to frontal lobe dysfunction. Low education was associated with an increased risk for hallucinations and a trend for more depression, delusions, and sleep disturbances. CONCLUSIONS: The association between high educational attainment and the lower risk of cognitive dysfunction suggest that education might modulate cognitive performance in PD. 相似文献
26.
Denis Mariano-Goulart Laurent Déchaux Fran?ois Rouzet Eric Barbotte Charles Caderas de Kerleau Michel Rossi Dominique Le Guludec 《Journal of nuclear medicine》2007,48(9):1416-1423
This study aimed to assess the ability of global and local systolic parameters measured with gated blood-pool SPECT (GBPS) to diagnose and characterize the severity of diffuse or localized arrhythmogenic right ventricular dysplasia (ARVD). METHODS: Fifty-nine subjects with symptomatic ventricular arrhythmias were prospectively included in the study. With the International Society and Federation of Cardiology criteria for ARVD as a gold standard, these subjects were classified as subjects without ARVD (21 control subjects) and patients with localized ARVD (16 patients) or diffuse ARVD (22 patients). Right ventricular volumes, right ventricular ejection fractions (EF), the SD of local EF (sigma-EF), and the SD of the local times of end systole (sigma-TES) were computed from GBPS data and compared among the groups in the study population. RESULTS: sigma-EF did not differ between control subjects and patients with diffuse or localized ARVD. Right ventricular EF and volumes differed between patients with diffuse ARVD and control subjects, with similar areas under the receiver-operating-characteristic curves, but right ventricular EF and volumes failed to differentiate patients with localized ARVD. In contrast, sigma-TES differed between patients with diffuse or localized ARVD and control subjects. Regression analysis showed that the systolic parameter most strongly associated with the diagnosis of ARVD was sigma-TES. The probabilities of a randomly chosen patient in the diffuse ARVD group and of a randomly chosen patient in the localized ARVD group having sigma-TES values greater than that of a randomly chosen control subject were 98.5% and 96.7%, respectively. For the diagnosis of localized ARVD, a threshold of 80 ms for sigma-TES corresponded to sensitivity, specificity, and positive and negative predictive values of 100%, 81%, 80%, and 100%, respectively. CONCLUSION: With GBPS, both diffuse ARVD and localized ARVD can be accurately diagnosed by computing sigma-TES for all of the pixels on the surface of the right ventricle. 相似文献
27.
Enhanced chronic inflammation and reduced insulin sensitivity are often present in chronic kidney disease (CKD). Cardiovascular disease remains a major cause of morbidity and mortality in end-stage renal patients. Adiponectin (ADP) is a hormone exclusively produced by adipocytes and possesses anti-inflammatory and cardioprotective properties. Despite the high prevalence of insulin resistance and cardiovascular disease, levels of ADP are increased among end-stage renal disease patients on hemo or peritoneal dialysis but also among patients with moderate renal failure or with the nephrotic syndrome. Furthermore, lower ADP levels are associated with poor cardiovascular outcome. In this review, we examine ADP modifications in CKD and discuss the different factors that may have an impact on this adipokine metabolism in renal failure. 相似文献
28.
Margaret J Bowers Nick J Orr Si Dempsey H Denis Alexander 《Blood coagulation & fibrinolysis》2006,17(5):409-411
We present a case of Bernard Soulier syndrome in a 9-year-old boy caused by a novel genetic mutation. This child was shown to be homozygous for a single nucleotide deletion (c.1077delG) in the GP1BA gene not previously reported. Clinically, the boy has become refractory to platelet transfusions with both allo-antibodies and iso-antibodies and a massive transfusion requirement for ongoing haemorrhage. We describe the critical role that the blood product transfusion continues to play in the management of Bernard Soulier syndrome and discuss therapeutic options in these patients. 相似文献
29.
Brain morphology in first-episode schizophrenic-like psychotic patients: a quantitative magnetic resonance imaging study 总被引:5,自引:0,他引:5
L E DeLisi A L Hoff J E Schwartz G W Shields S N Halthore S M Gupta F A Henn A K Anand 《Neuropsychopharmacology》1991,29(2):159-175
Brain morphology was examined using magnetic resonance imaging in 30 first-episode patients with a schizophreniclike psychosis, 15 chronic schizophrenics, and 20 neurological controls. Statistical analyses of computer-generated measurements of regions of interest were controlled for gender, age, social class, and total brain volume. Lateral ventricular size was increased in both first-episode and chronic schizophrenic patients, with greater significance on the left than on the right side. Only the chronic patients, however, had reduced temporal lobe size, which also was greater on the left side. No major correlations of regional brain morphological measurements with cognitive functioning were found, although some measurements of verbal memory were correlated with parahippocampal size. This is a report of a preliminary study that suggests that some morphological brain changes may be present at the time of first treatment for a psychotic illness, whereas others may occur later in the course of illness. Future prospective studies may determine the clinical significance of these changes and whether they progress with the development of illness chronicity. 相似文献
30.
Computer software developed in our laboratory (CMATRIX) was used to design a physiological pharmacokinetic model of nicotine absorption, distribution, metabolism and excretion in man. The model accommodates inhalation of nicotine from various environmental settings and physiological conditions in man. It was also used to predict pharmacokinetic behavior of cotinine arising from nicotine metabolism. Model-predicted variations in body-fluid nicotine levels confirm that nicotine is not an acceptable quantitative marker of environmental tobacco smoke (ETS) exposure. Though cotinine provides a more stable pattern, predicted interindividual variation suggests the need for specific strict sampling and monitoring guidelines for cotinine to be a reliable quantitative marker. 相似文献