全文获取类型
收费全文 | 10567篇 |
免费 | 735篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 95篇 |
儿科学 | 427篇 |
妇产科学 | 156篇 |
基础医学 | 1484篇 |
口腔科学 | 166篇 |
临床医学 | 964篇 |
内科学 | 1987篇 |
皮肤病学 | 213篇 |
神经病学 | 1147篇 |
特种医学 | 644篇 |
外国民族医学 | 5篇 |
外科学 | 1517篇 |
综合类 | 75篇 |
一般理论 | 6篇 |
预防医学 | 533篇 |
眼科学 | 233篇 |
药学 | 969篇 |
中国医学 | 4篇 |
肿瘤学 | 722篇 |
出版年
2021年 | 117篇 |
2019年 | 100篇 |
2018年 | 152篇 |
2017年 | 97篇 |
2016年 | 149篇 |
2015年 | 183篇 |
2014年 | 196篇 |
2013年 | 288篇 |
2012年 | 383篇 |
2011年 | 439篇 |
2010年 | 239篇 |
2009年 | 222篇 |
2008年 | 358篇 |
2007年 | 426篇 |
2006年 | 419篇 |
2005年 | 381篇 |
2004年 | 441篇 |
2003年 | 405篇 |
2002年 | 332篇 |
2001年 | 345篇 |
2000年 | 338篇 |
1999年 | 283篇 |
1998年 | 193篇 |
1997年 | 174篇 |
1996年 | 171篇 |
1995年 | 129篇 |
1994年 | 115篇 |
1993年 | 133篇 |
1992年 | 228篇 |
1991年 | 226篇 |
1990年 | 223篇 |
1989年 | 274篇 |
1988年 | 238篇 |
1987年 | 233篇 |
1986年 | 208篇 |
1985年 | 234篇 |
1984年 | 154篇 |
1983年 | 108篇 |
1982年 | 104篇 |
1981年 | 103篇 |
1980年 | 110篇 |
1979年 | 145篇 |
1978年 | 107篇 |
1977年 | 98篇 |
1976年 | 126篇 |
1975年 | 114篇 |
1974年 | 96篇 |
1972年 | 74篇 |
1971年 | 87篇 |
1970年 | 84篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
J S Weissman J Z Ayanian S Chasan-Taber M J Sherwood C Roth A M Epstein 《Medical care》1999,37(5):490-501
BACKGROUND: Readmission rates are often proposed as markers for quality of care. However, a consistent link between readmissions and quality has not been established. OBJECTIVE: To test the relation of readmission to quality and the utility of readmissions as hospital quality measures. SUBJECTS: One thousand, seven hundred and fifty-eight Medicare patients hospitalized in four states between 1991 to 1992 with pneumonia or congestive heart failure (CHF). DESIGN: Case control. MEASURES: Related adverse readmissions (RARs), defined as readmissions that indicate potentially sub-optimal care during initial hospitalization, were identified from administrative data using readmission diagnoses and intervening time periods designated by physician panels. We used linear regression to estimate the association between implicit and explicit quality measures and readmission status (RARs, non-RAR readmissions, and nonreadmissions), adjusting for severity. We tested whether RARs were associated with inferior care and performed simulations to determine whether RARs discriminated between hospitals on the basis of quality. RESULTS: Compared with nonreadmitted pneumonia patients, patients with RARs had lower adjusted quality measured both by explicit (0.25 standardized units, P = 0.004) and implicit methods (0.17, P = 0.047). Adjusted differences for CHF patients were 0.17 (P = 0.048) and 0.20 (P = 0.017), respectively. In some analyses, patients with non-RAR readmissions also experienced lower quality. However, rates of inferior quality care did not differ significantly by readmission status, and simulations identified no meaningful relationship between RARs and hospital quality of care. CONCLUSIONS: RARs are statistically associated with lower quality of care. However, neither RARs nor other readmissions appear to be useful tools for identifying patients who experience inferior care or for comparing quality among hospitals. 相似文献
993.
Evaluation of a reporting system for bacterial contamination of blood components in the United States 总被引:6,自引:0,他引:6
Virginia R. Roth Matthew J. Kuehnert N. Rebecca Haley Kay R. Gregory George B. Schreiber Matthew J. Arduino Stacey C. Holt Loretta A. Carson Kathleen V. Elder William R. Jarvis 《Transfusion》2001,41(12):1486-1492
BACKGROUND: The transfusion of blood components contaminated with bacteria may have serious clinical consequences, but few data are available on the incidence of these events. A national effort to assess the frequency of blood component bacterial contamination associated with transfusion reaction (the BaCon Study) was initiated to better estimate their occurrence. STUDY DESIGN AND METHODS: Standard reporting criteria, data collection forms, and a standardized reporting protocol were developed in collaboration with the American Red Cross, AABB, and the Department of Defense. Episodes reported to the BaCon Study were compared with those reported to the FDA's national reporting systems to estimate the extent to which all serious reactions associated with bacterial contamination were captured. RESULTS: During the first 2 years, 38 episodes meeting study criteria were reported; 21 were laboratory-confirmed. The estimated proportion of episodes reported to the BaCon Study (i.e., completeness of coverage) was lower than that reported to the FDA during the same period (0.33 vs. 0.68), but the positive predictive value was higher (0.66 vs.0.28). CONCLUSION: Despite the complexity of obtaining reports from a large number of United States hospitals and transfusion centers, the feasibility and usefulness of the BaCon Study were shown. This study was the only national study in the United States to monitor adverse clinical events associated with bacterial contamination of blood components. By building on hospital-based reporting of transfusion-related adverse events, the BaCon Study serves as a model for the study of other complications associated with blood and blood components. 相似文献
994.
H Kaube YE Knight RJ Storer KL Hoskin A May PJ Goadsby 《Cephalalgia : an international journal of headache》1999,19(6):592-597
It remains an open question as to whether cortical spreading depression (CSD) is the pathophysiological correlate of the neurological symptoms in migraine with aura. In the experimental animal, CSD is an electrophysiological phenomenon mainly mediated via NMDA receptors. However, according to case reports in humans, visual aura in migraine can be alleviated by vasodilator substances, such as amyl nitrite and isoprenaline. There is also circumstantial evidence that brainstem nuclei (dorsal raphe nucleus and locus coeruleus) may play a pivotal role in the initiation of aura. In this study, CSD was elicited in alpha-chloralose anesthetized cats by cortical needle stab injury and monitored by means of laser Doppler flowmetry. Topical application of isoprenaline (0.1-1%) and amyl nitrite (0.05%) onto the exposed cortex had no effect on the elicitation or propagation of CSD. Also, after supracollicular transection, subsequent CSDs showed no differences in the speed of propagation and associated flow changes. We conclude from these data that--given CSD probably exists in humans during migraine--spreading neurological deficits during migraine aura are independent of brainstem influence and have a primarily neuronal rather than vascular mechanism of generation. 相似文献
995.
996.
A. Kobayashi P. T. Brey K. Katsube A. della Torre C. W. Roth S. Natori R. Ollo 《Insect molecular biology》1999,8(2):277-285
Tyrosine kinase sequences were identified and characterized in Anopheles gambiae, the major vector of malaria in subsaharan Africa. One of these sequences has the characteristics expected for a homologue of the Drosophila sevenless gene, which is necessary for R7 photoreceptor cell fate determination in the developing compound eye. The putative Anopheles seven-less gene homologue is located in a telomeric region of the X chromosome and is expressed in the head of late larval and pupal stage mosquitoes. Identification of the Anopheles homologue of the sevenless gene is a first step towards the development of a dominant phenotypic marker that could be used for detecting transformed Anopheles mosquitoes in a wide variety of genetic backgrounds and, as such, could be used in the development of transgenic mosquitoes for the control of parasite transmission. Preliminary evidence for sevenless sequences were also found in DNA from blackfly, Mediterranean fruit fly and the honeybee. 相似文献
997.
Jens Blechert Frank H. Wilhelm Alicia E. Meuret Walton T. Roth 《Biological psychology》2010,84(1):104-111
Inhalation of carbon dioxide (CO2) enriched air triggers anxiety in panic disorder (PD) patients, which is often interpreted as a sign of biological vulnerability. However, most studies have not measured respiration in these tasks. We compared patients with PD (n = 20) and social phobia (SP, n = 19) to healthy controls (n = 18) during eight inhalations of 20% CO2, preceded and followed by two inhalations of room air, while continuously measuring subjective anxiety and dyspnea as well as autonomic and respiratory variables. PD patients showed increased reactivity and delayed recovery during CO2 inhalations for most measures. Unlike both other groups, the PD group's tidal volume responses did not habituate across CO2 inhalations. However, PD patients did not differ from SP patients on most other measures, supporting a continuum model of CO2 sensitivity across anxiety disorders. Both patient groups showed continued reactivity during the last air inhalations, which is unlikely to be due to a biological sensitivity. 相似文献
998.
Jennifer S Mindell Sarah Tipping Kevin Pickering Steven Hope Marilyn A Roth Bob Erens 《BMC medical research methodology》2010,10(1):83
Background
There is a need for local level health data for local government and health bodies, for health surveillance and planning and monitoring of policies and interventions. The Health Survey for England (HSE) is a nationally-representative survey of the English population living in private households, but sub-national analyses can be performed only at a regional level because of sample size. A boost of the HSE was commissioned to address the need for local level data in London but a different mode of data collection was used to maximise participant numbers for a given cost. This study examines the effects on survey and item response of the different survey modes. 相似文献999.
Röhner E Hoff P Winkler T von Roth P Seeger JB Perka C Matziolis G 《Journal of histotechnology》2011,34(1):35-39
The use of local antiseptics is a common method in septic joint surgery. We tested polyhexanide and hydrogen peroxide, two of the most frequently used antiseptics with high efficacy and low toxicity. The purpose of this study was to evaluate the effects of both antiseptics on the extracellular cartilaginous matrix synthesis of human chondrocytes. Chondrocytes were isolated from donated human knee joints, embedded in alginate beads, and incubated for 10 and 30 minutes with polyhexanide (0.04%), hydrogen peroxide (3%), or phosphate-buffered saline (PBS) for control. Cartilaginous matrix production was quantified through light microscopic analysis of Alcian blue staining. Cell number and morphology were detected by histological analysis. Chondrocytes showed a decreased intensity of blue colouring after antiseptic treatment versus PBS. In contrast to that, neither the cell number per view field nor the cell morphology differed between the groups. Polyhexanide has more toxic potential than hydrogen peroxide. Based on the fact that the cell number and morphology was not altered by the substances at the examined concentrations, the lower intensity of Alcian blue staining of treated chondrocytes indicates a decreased cartilage-specific matrix synthesis by polyhexanide more than by hydrogen peroxide and control. 相似文献
1000.
Lupus nephritis: a clinical review for practicing nephrologists 总被引:3,自引:0,他引:3
The renal manifestations in systemic lupus erythematosus (SLE) are protean and difficult to categorize into clinical syndromes and histologic classes. Lupus nephritis is frequently unrecognized until full-blown nephritic and/or nephrotic syndrome with renal failure emerge. Epidemiologically, approximately one third of SLE patients from unselected populations have renal involvement early during the disease. Most renal abnormalities emerge within the first few years of SLE diagnosis. Currently, most nephrologists agree that an early renal biopsy is worthwhile in those SLE patients with abnormal urinalysis and/or reduced renal function. First, it provides a histologic categorization of the glomerulonephritis as well as an assessment of the degree of activity and chronicity. Second, it provides vital prognostic information. Third, it is beneficial in planning a more rational therapy with or without potentially toxic immunosuppressive agents. Over the last 3 decades, many controlled clinical trials for treatment of lupus nephritis have been completed with a few therapeutic immunosuppressive regimens. Among those agents used. cyclophosphamide and azathioprine provide a reduction of morbidity in those patients afflicted with proliferative forms of lupus glomerulonephritis. A new immunosuppressive agent, mycophenolate mofetil, is being studied for treatment of proliferative forms of lupus glomerulonephritis in a controlled clinical trial at our institution. Immunosuppressive agents and the availability of dialysis and transplantation have improved the survival of patients with lupus nephritis, in particular those with proliferative forms. 相似文献