全文获取类型
收费全文 | 55638篇 |
免费 | 3488篇 |
国内免费 | 110篇 |
专业分类
耳鼻咽喉 | 529篇 |
儿科学 | 2300篇 |
妇产科学 | 1521篇 |
基础医学 | 6956篇 |
口腔科学 | 539篇 |
临床医学 | 8549篇 |
内科学 | 9543篇 |
皮肤病学 | 762篇 |
神经病学 | 5335篇 |
特种医学 | 977篇 |
外科学 | 4607篇 |
综合类 | 589篇 |
一般理论 | 109篇 |
预防医学 | 7769篇 |
眼科学 | 761篇 |
药学 | 3634篇 |
中国医学 | 61篇 |
肿瘤学 | 4695篇 |
出版年
2023年 | 290篇 |
2022年 | 431篇 |
2021年 | 1016篇 |
2020年 | 693篇 |
2019年 | 1052篇 |
2018年 | 1202篇 |
2017年 | 977篇 |
2016年 | 1058篇 |
2015年 | 1237篇 |
2014年 | 1711篇 |
2013年 | 2730篇 |
2012年 | 3929篇 |
2011年 | 4243篇 |
2010年 | 2360篇 |
2009年 | 2131篇 |
2008年 | 3834篇 |
2007年 | 4079篇 |
2006年 | 3930篇 |
2005年 | 4070篇 |
2004年 | 3870篇 |
2003年 | 3639篇 |
2002年 | 3358篇 |
2001年 | 473篇 |
2000年 | 351篇 |
1999年 | 473篇 |
1998年 | 686篇 |
1997年 | 609篇 |
1996年 | 479篇 |
1995年 | 482篇 |
1994年 | 425篇 |
1993年 | 338篇 |
1992年 | 244篇 |
1991年 | 208篇 |
1990年 | 187篇 |
1989年 | 198篇 |
1988年 | 186篇 |
1987年 | 170篇 |
1986年 | 164篇 |
1985年 | 164篇 |
1984年 | 187篇 |
1983年 | 169篇 |
1982年 | 216篇 |
1981年 | 207篇 |
1980年 | 155篇 |
1979年 | 94篇 |
1978年 | 112篇 |
1977年 | 52篇 |
1976年 | 57篇 |
1975年 | 46篇 |
1974年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Maher M El-Masri Mayer M El-Masri Susan M Fox-Wasylyshyn 《Revue canadienne de recherche en sciences infirmières》2006,38(4):162-172
Knowledge of the factors that contribute to delay in seeking medical treatment for acute myocardial infarction (AMI) provides the basis for interventions that are intended to facilitate prompt care-seeking behaviour. However, operational definitions of delay time vary across research studies. The use of inconsistent cut-off times to distinguish between delayers and non-delayers is likely to compromise comparability and generalizability of the findings across studies. The purpose of this paper is to examine the impact of inconsistent operationalization of delay, in terms of cut-off times, on the validity of research findings pertaining to identifying its predictors. Secondary data analysis was performed using a sample of 73 patients who had recently experienced out-of-hospital AMI and concluded that their symptoms were related to the heart. Several regression models were built to examine the influence of using different cut-off times (1, 2, 3, 6, and 12 hours, median delay) on the number and nature of predictors ofAMI care-seeking delay.The impact of varying cut-off times on the explained variance, sensitivity, specificity, and predictive values associated with each regression model was examined. The use of different cut-off times produced different sets of independent predictors, which varied in number and nature.The variance explained by the different regression models as well as their classification indices varied. Use of different cut-off times for the definition of delay time led to inconsistent results. Thus, it is recommended that criteria be established among clinicians and researchers with regard to operationally defining care-seeking delay for AMI. 相似文献
92.
Spontaneous uterine rupture during subsequent pregnancy following non-excision of an interstitial ectopic gestation 总被引:2,自引:1,他引:1
93.
The results of external beam radiotherapy for clinically localized adenocarcinorna of the prostate in 448 patients treated in the period 1980–90 were reviewed. The average follow up was 4.9 years. The patients were aged 44–87 years (median 69 years) and all had histopathological evidence of adenocarcinoma by needle biopsy or transurethral resection of prostate. The histopathological grading was: 127 G1; 154 G2; 127 G3; 12 G4; 28 Gx. Clinical staging according to TNM (American Urological Association) was: 29 T0 (A2); 4 T1 (B1); 173 T2 (B2); 176 T3 (C1); 63 T4 (C2); 3 Tx. Routine surgical pelvic lymph node staging was not performed but patients had radiological (computerized tomography scan or lymphogram) nodal staging: 350 N0; 22 N1; 12 N2; 64 Nx. High energy linear accelerator external beam radiotherapy was given by multiple fields to total doses of 50–70 Gy (median 60 Gy). The majority of patients (307, 69%) was treated by a uniform policy under the care of one radiation oncologist (HM). The rates of local and distant failure at 5 years were 10% (s.e. = 2%) and 42% (s.e. = 3%), respectively. The late complication rate at 5 years was 25% (s.e. = 2%), comprising mild 16%, moderate 7% and severe 1.3%. The 5 year overall survival rate was 64% (s.e. = 2%) and the cancer-specific survival rate was 74% (s.e. = 3%). Both histological grade and clinical stage were strongly predictive of overall survival and distant failure. Only histological grade was predictive of local failure. Treatment with external beam radiotherapy for this common cancer resulted in survival and disease control rates that compare favourably with other published radiotherapy series and has been accompanied by acceptably low morbidity. 相似文献
94.
Identifying potential indicators of the quality of end-of-life cancer care from administrative data.
Craig C Earle Elyse R Park Bonnie Lai Jane C Weeks John Z Ayanian Susan Block 《Journal of clinical oncology》2003,21(6):1133-1138
PURPOSE: To explore potential indicators of the quality of end-of-life services for cancer patients that could be monitored using existing administrative data. METHODS: Quality indicators were identified and assessed by literature review for proposed indicators, focus groups with cancer patients and family members to assess candidate indicators and generate new ideas, and an expert panel ranking the meaningfulness and importance of each potential indicator using a modified Delphi approach. RESULTS: There were three major concepts of poor quality of end-of-life cancer care that could be examined using currently-available administrative data (such as Medicare claims): institution of new anticancer therapies or continuation of ongoing treatments very near death; a high number of emergency room visits, inpatient hospital admissions, or intensive care unit days near the end of life; and a high proportion of patients never enrolled in hospice, only admitted in the last few days of life, or dying in an acute-care setting. Concepts such as access to psychosocial and other multidisciplinary services and pain and symptom control are important and may eventually be feasible, but they cannot currently be applied in most data systems. Indicators based on limiting the use of treatments with low probability of benefit or indicators based on economic efficiency were not acceptable to patients, family members, or physicians. CONCLUSION: Several promising claims-based quality indicators were identified that, if found to be valid and reliable within data systems, could be useful in identifying health-care systems in need of improving end-of-life services. 相似文献
95.
Todd M. Koelling MD FACC Susan Joseph MD Keith D. Aaronson MD 《The Journal of heart and lung transplantation》2004,23(12):232-1422
BACKGROUND: The Heart Failure Survival Score (HFSS) has been previously shown to effectively risk-stratify patients under evaluation for heart transplantation. However, this model was developed before broad use of beta blockade. We hypothesized that the prognostic tool would retain its ability to risk stratify patients treated with beta-blockers. METHODS: We collected clinical data on 524 consecutive patients referred for heart transplantation from 1994 to 2001. Kaplan-Meier survival analysis and multivariable Cox regression analysis were performed with events defined as death, left ventricular assist device placement, or United Network of Organ Sharing 1 heart transplantation. RESULTS: Kaplan-Meier analysis of the patient population revealed effective discrimination by the survival score both for beta-blocker treated and untreated patients (both p <0.0001). Two-year event-free survival was 94% +/- 2% and 84% +/- 4% for beta-blocker and no beta-blocker patients in the low-risk HFSS strata. Cox proportional hazard modeling showed that HFSS strata (medium risk: HR 2.65, 95% CI 1.75-4.02, p <0.001; high risk: HR 5.51, 95% CI 3.64-8.33, p <0.001) and beta-blocker treatment (HR 0.45, 95% CI 0.31-0.64, p <0.001) were significant predictors of event-free survival. Receiver operating curves (area under the curve) for HFSS strata used to predict 2-year events were similar for beta-blocker treated (0.78 +/- 0.04) and untreated (0.80 +/- 0.03) patients. CONCLUSIONS: The HFSS provides effective risk stratification with or without beta-blocker therapy. Consideration of beta-blocker therapy with survival score strata improves outcome prediction in patients evaluated for heart transplantation. 相似文献
96.
97.
98.
As the nursing shortage escalates, nurse managers will continue to grapple with how to retain their most valuable asset—the talented staff they are charged to lead. Survival in the current market makes both recruitment and retention efforts critical. One primary concern is an aging workforce. The American Nursing Association projects that 65% of current nurses will retire within this decade and predicts that the supply will no longer meet the demand by the year 2010.1 In fact, by 2020, the health care industry will need 1.7 million nurses—yet only 600,000 will be available.1 The key for success is retention of your current staff. 相似文献
99.
Susan Bell 《The Journal of neuroscience nursing》2004,36(4):195-199
Germinomas are the most common type of germ cell tumor occurring commonly before the second decade of life. Because of the radiosensitivity of germinomas, traditional treatment following diagnosis has been conventional radiotherapy. The desire to defer radiotherapy to avoid the delayed neurocognitive effects has led researchers to investigate the use of up front chemotherapy. A major limitation in using chemotherapy for brain tumors has been the inability to deliver drugs across the blood brain barrier. The blood brain barrier consortium has developed chemotherapy protocols for patients with malignant brain tumors through the use of reversible osmotic opening of the blood brain barrier. While the patient is under general anesthesia, osmotic opening or disruption is achieved by a 30-second intracarotid infusion of mannitol. The mannitol infusion is followed by both intraarterial and intravenous chemotherapy. By administering chemotherapy in conjunction with blood brain barrier disruption, drug delivery to the tumor and the brain around tumor is increased. 相似文献
100.
Hugh Devlin Kety Karayianni Anastasia Mitsea Reinhilde Jacobs Christina Lindh Paul van der Stelt Elizabeth Marjanovic Judith Adams Susan Pavitt Keith Horner 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(6):821-828
OBJECTIVES: Measurement of cortical thickness and subjective assessment of cortical porosity on panoramic radiographs are methods previously reported for diagnosing osteoporosis. The aims of this study were to determine the relative efficacy of the mandibular cortical index and cortical width in detecting osteoporosis, both alone and in combination, and to determine the optimal cortical width threshold for referral for additional osteoporosis investigation. STUDY DESIGN: Six hundred seventy-one postmenopausal women 45 to 70 years of age were recruited for this study. They received dual energy x-ray absorptiometry (DXA) scans of the left hip and lumbar spine (L1 to L4), and dental panoramic radiographic examinations of the teeth and jaws. Three observers separately assessed the mandibular cortical width and porosity in the mental foramen region of the mandible. Cortical width was corrected for magnification errors. Chi-squared automatic interaction detection analysis (CHAID) software was used (SPSS AnswerTree, version 3.1, SPSS Inc., Chicago, IL). RESULTS: Chi-squared automatic interaction detection analysis showed that the cortical porosity was a poorer predictor of osteoporosis than mandibular cortical width. For the 3 observers, a mandibular cortical width of <3 mm provided diagnostic odds ratios of 6.51, 6.09, and 8.04. The test is therefore only recommended in triage screening of individuals by using radiographs made for purposes other than osteoporosis. CONCLUSION: When evaluating panoramic radiographs, only those patients with the thinnest mandibular cortices (i.e., <3 mm) should be referred for further osteoporosis investigation. 相似文献