全文获取类型
收费全文 | 16205篇 |
免费 | 1142篇 |
国内免费 | 64篇 |
专业分类
耳鼻咽喉 | 143篇 |
儿科学 | 470篇 |
妇产科学 | 411篇 |
基础医学 | 2143篇 |
口腔科学 | 228篇 |
临床医学 | 2630篇 |
内科学 | 2787篇 |
皮肤病学 | 403篇 |
神经病学 | 1593篇 |
特种医学 | 418篇 |
外国民族医学 | 1篇 |
外科学 | 1505篇 |
综合类 | 123篇 |
一般理论 | 18篇 |
预防医学 | 2063篇 |
眼科学 | 331篇 |
药学 | 901篇 |
1篇 | |
中国医学 | 17篇 |
肿瘤学 | 1225篇 |
出版年
2023年 | 62篇 |
2022年 | 122篇 |
2021年 | 364篇 |
2020年 | 182篇 |
2019年 | 371篇 |
2018年 | 345篇 |
2017年 | 272篇 |
2016年 | 341篇 |
2015年 | 406篇 |
2014年 | 593篇 |
2013年 | 766篇 |
2012年 | 1258篇 |
2011年 | 1232篇 |
2010年 | 649篇 |
2009年 | 578篇 |
2008年 | 1092篇 |
2007年 | 1152篇 |
2006年 | 1104篇 |
2005年 | 1034篇 |
2004年 | 1000篇 |
2003年 | 866篇 |
2002年 | 924篇 |
2001年 | 171篇 |
2000年 | 129篇 |
1999年 | 167篇 |
1998年 | 204篇 |
1997年 | 177篇 |
1996年 | 145篇 |
1995年 | 124篇 |
1994年 | 94篇 |
1993年 | 108篇 |
1992年 | 80篇 |
1991年 | 99篇 |
1990年 | 76篇 |
1989年 | 88篇 |
1988年 | 56篇 |
1987年 | 50篇 |
1986年 | 70篇 |
1985年 | 56篇 |
1984年 | 79篇 |
1983年 | 61篇 |
1982年 | 74篇 |
1981年 | 53篇 |
1980年 | 54篇 |
1979年 | 62篇 |
1978年 | 58篇 |
1977年 | 37篇 |
1975年 | 34篇 |
1974年 | 41篇 |
1973年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Stress Testing Versus CT Angiography in Patients With Diabetes and Suspected Coronary Artery Disease
Abhinav Sharma Adrian Coles Nishant K. Sekaran Neha J. Pagidipati Michael T. Lu Daniel B. Mark Kerry L. Lee Hussein R. Al-Khalidi Udo Hoffmann Pamela S. Douglas 《Journal of the American College of Cardiology》2019,73(8):893-902
Background
The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.Objectives
The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.Methods
PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.Results
Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).Conclusions
In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550) 相似文献2.
3.
PURPOSE: Concern over stigma as a consequence of genetic testing has grown in response to the recent increase in genetic research and testing resulting from the Human Genome Project. However, whether a genetic or hereditary basis necessarily confers a stigma to a condition remains unexamined. METHODS: We performed a qualitative interview study with 86 individuals with one of four conditions: deafness or hearing loss, breast cancer, sickle cell disease, and cystic fibrosis. The first two groups were divided approximately between people who ascribed their conditions to a genetic or hereditary cause and those who did not. RESULTS: Respondents interpreted genetic or hereditary causes and nongenetic causes in a variety of ways. Subjects with breast cancer reported the most consistently negative interpretation of genetic cause. This response concerned future ill health, not an enduring sense of stigma. Deaf and hard of hearing subjects provided the most consistently positive comments about a genetic or hereditary basis to their condition, casting familial hearing loss as a vital component of group and individual identity. Respondents with sickle cell disease and cystic fibrosis offered similar and positive interpretations of the genetic cause of their condition insofar as it meant their conditions were not contagious. CONCLUSIONS: Although some subjects report feeling stigmatized as a result of their condition, this stigmatization is not uniformly associated with the condition's cause, genetic or otherwise. Instead, stigma emerges from a variety of sources in the context of the lived experience of a particular condition. 相似文献
4.
A worldwide survey of the use of simulation in anesthesia 总被引:6,自引:0,他引:6
PURPOSE: To gather information regarding the global use of simulation technology in education, evaluation and research in anesthesia. METHODS: The WorldWide Web was searched and located sites with simulation centres (n = 158) were mailed a 67-item questionnaire requesting information regarding demographics, personnel, education use and research involvement. Comments were solicited. Medical school data only are reported in this article. RESULTS: Two web sites were used to generate the list of simulation centres. Sixty responses were received (38%), with 41 emanating from medical schools. Seventy-seven percent of centres were involved in undergraduate education and 85% in postgraduate education. Few centres were involved in evaluation and/or competency assessments. Sixty-one percent of centres indicated ongoing research with a further 25% interested in international collaboration. University or university departmental-based funding largely supported simulation technology used in medical schools. The lack of financial and human resources was the single most common problem identified by respondents. CONCLUSIONS: From the survey responses received, opportunities for the simulator to be used for the assessment of performance appear to be under-utilized. This may be due to the lack of research in this area, lack of standardized, valid and reliable tests and the fact that most centres have only recently acquired this technology. Further research supporting the use of the simulator in education and evaluation is required. 相似文献
5.
6.
7.
An unusual, elongated, refractile cell morphology was observed in keratinocytes cultured from three patients with non-lethalis forms of junctional epidermolysis bullosa (JEB). To determine whether these changes might be related to altered cell adhesion, keratinocyte strains established from one patient were examined for adhesive, structural, and functional characteristics. JEB keratinocytes expressed keratin tonofilaments, as determined by staining with AE1 monoclonal antibodies and direct observation of tonofilaments by electron microscopy. JEB keratinocytes showed diminished cell-substratum adhesions, judged by interference reflection microscopy. Areas of diminished cell-substratum adhesion corresponded to F-actin-rich cell adhesions (focal adhesions) and not to cellular areas that abundantly express hemidesmosomal antigens. Analysis of cell-substratum adhesion by electron microscopy revealed extensive areas of cell-substratum separation in JEB keratinocytes that were not present in normal keratinocytes maintained in serum-free medium. Normal keratinocytes displayed numerous regions of focal contact between the ventral plasma membrane and the culture substratum, but these structures were not seen in JEB keratinocytes. Bundled actin filaments (stress fibers) were greatly diminished in expected regions of cell-substratum adhesion in JEB keratinocytes and, instead, displayed disorganized individual filaments. The growth rate of JEB keratinocytes was quite slow in culture, with a population doubling time of 2.7 d versus 1.5 d for normal keratinocytes under identical conditions. JEB keratinocytes also displayed a reduced ability to aggregate into colonies upon exposure to medium with increased extracellular calcium. JEB keratinocytes thus display adhesive, structural, and functional abnormalities that suggest this cell type may be central to the pathogenesis of junctional epidermolysis bullosa. Study of affected keratinocytes could be important to characterize associated molecular pathologies. 相似文献
8.
Pamela D Reiter Adam A Rosenberg Robert Valuck Kathryn Novak 《Journal of perinatology》2005,25(2):125-129
OBJECTIVE: To determine the effectiveness of a 10-day subcutaneous erythropoietin (rHuEpo) course of 300 units per kg per dose plus oral iron compared to oral iron alone in anemic infants during their convalescent phase of illness. STUDY DESIGN: Prospective, randomized trial performed at a 40-bed, teaching, referral, level III, neonatal intensive care unit. Infants with a gestational age at birth of less than 32 weeks, hematocrit of less than or equal to 28% with a corrected reticulocyte count of less than or equal to 5%, postconceptual age of less than 48 weeks or 5 months chronological age, and a diagnosis of anemia of prematurity were considered for inclusion. Major outcome parameters included hematocrit, corrected reticulocyte count and red cell transfusion requirements. RESULTS: A total of 60 infants were enrolled (n=30 per group). Infants randomized to rHuEpo had a significantly higher post-treatment hematocrit and corrected reticulocyte count than infants in the iron only group (p<0.001). There was a trend towards fewer red cell requirements in the rHuEpo group. CONCLUSIONS: The rHuEpo regimen studied here was associated with an acute improvement in hematocrit and corrected reticulocyte counts. This study did not demonstrate a statistically significant decrease in transfusion therapy, in part related to increased subsequent use of rHuEpo in the control group. Taken together, these data demonstrate that this regimen can effectively treat anemia in convalescent premature infants. 相似文献
9.
10.
Michael D. Lara M.D. Matthew T. Baker M.D. Christopher J. Larson PA-C R.D. Michelle A. Mathiason M.S. Pamela J. Lambert R.N. Shanu N. Kothari M.D. 《Surgery for obesity and related diseases》2005,1(1):597-21
BACKGROUND: There is no consensus regarding the optimal rate of follow-up in the post-bariatric surgery patient population. METHODS: The records of all patients who underwent laparoscopic Roux-en-Y gastric bypass from 2001 to 2003 were reviewed. Using patient zip codes, travel distances were calculated between the patients' places of residence and our clinic. Patients were then assigned to 1 of 3 cohorts according to the following distances: (1) < 50 miles, (2) 50 to 100 miles, and (3) > 100 miles. Patient compliance with follow-up appointments at 3 weeks, 3 months, 6 months, 9 months, and 12 months was analyzed. Linear trends were identified using the Mantel-Haenszel test. Age and sex were analyzed as possible predictors of compliance using the chi(2) test. P values < .05 were considered statistically significant. RESULTS: The study group comprised 150 patients (127 females and 23 males). The 3 cohorts contained 115, 21, and 14 patients, respectively. All patients in each cohort were compliant with the 3-week follow-up appointment. Although there were differences in compliance between cohorts at each of the remaining appointments, only the 9-month (70.3% vs 61.9% vs 35.7%) visit showed statistical significance (P = .035). The 6-month visit trended toward significance (85.2% vs 76.2% vs 64.3%; P = .088). Males were more likely to be compliant with the 12-month follow-up (P = .040). When controlling for sex, travel distance was also a predictor of compliance at this follow-up visit (P = .024). Age was not predictive of compliance (P = .827). CONCLUSION: Based on our findings, we conclude that travel distance from the clinic does not significantly affect compliance at the initial follow-up, 3-month, and 12-month appointments. However, distance does tend to affect compliance at the 6-month appointment and significantly affects compliance at the 9-month appointment. Males are more likely to be compliant at the 12 month follow-up visit. We must continue to strive for 100% follow-up in our post-bariatric surgery patients. 相似文献