全文获取类型
收费全文 | 16511篇 |
免费 | 1308篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 302篇 |
儿科学 | 460篇 |
妇产科学 | 234篇 |
基础医学 | 2029篇 |
口腔科学 | 215篇 |
临床医学 | 2031篇 |
内科学 | 3418篇 |
皮肤病学 | 175篇 |
神经病学 | 1548篇 |
特种医学 | 515篇 |
外国民族医学 | 7篇 |
外科学 | 2997篇 |
综合类 | 242篇 |
一般理论 | 10篇 |
预防医学 | 1568篇 |
眼科学 | 229篇 |
药学 | 990篇 |
1篇 | |
中国医学 | 23篇 |
肿瘤学 | 900篇 |
出版年
2023年 | 78篇 |
2022年 | 122篇 |
2021年 | 340篇 |
2020年 | 195篇 |
2019年 | 309篇 |
2018年 | 358篇 |
2017年 | 312篇 |
2016年 | 291篇 |
2015年 | 368篇 |
2014年 | 530篇 |
2013年 | 741篇 |
2012年 | 1069篇 |
2011年 | 1144篇 |
2010年 | 625篇 |
2009年 | 573篇 |
2008年 | 1030篇 |
2007年 | 1168篇 |
2006年 | 1074篇 |
2005年 | 1041篇 |
2004年 | 951篇 |
2003年 | 878篇 |
2002年 | 859篇 |
2001年 | 286篇 |
2000年 | 256篇 |
1999年 | 229篇 |
1998年 | 165篇 |
1997年 | 136篇 |
1996年 | 117篇 |
1995年 | 120篇 |
1994年 | 98篇 |
1993年 | 102篇 |
1992年 | 163篇 |
1991年 | 173篇 |
1990年 | 204篇 |
1989年 | 141篇 |
1988年 | 132篇 |
1987年 | 146篇 |
1986年 | 123篇 |
1985年 | 139篇 |
1984年 | 89篇 |
1983年 | 77篇 |
1982年 | 42篇 |
1981年 | 57篇 |
1979年 | 95篇 |
1978年 | 68篇 |
1977年 | 53篇 |
1976年 | 47篇 |
1974年 | 55篇 |
1973年 | 42篇 |
1972年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
11.
François Béïque Mohamed Ali Scott MacKenzie Mark Hynes 《Journal canadien d'anesthésie》2007,54(2):158-159
12.
Elizabeth A Johnson Todd S Harwell Peg M Donahue M'liss A Weisner Michael J McInerney Greg S Holzman Steven D Helgerson 《The Journal of rural health》2003,19(4):506-510
CONTEXT: Vaccine-preventable diseases among adults are major contributing causes of morbidity and mortality in the United States. However, adult immunizations continue to be underutilized in both urban and rural areas. PURPOSE: To evaluate the effectiveness of a community-wide education campaign and mailed reminders promoting pneumococcal immunizations to rural Medicare beneficiaries. METHODS: We implemented a community-wide education campaign, and mailed reminders were sent to Medicare beneficiaries in 1 media market in Montana to increase pneumococcal immunizations. In a second distinct media market, mailed reminders only were sent to beneficiaries. FINDINGS: The proportion of respondents aged 65 years and older aware of pneumococcal immunizations increased significantly from baseline to follow-up among respondents both in the education-plus-reminder (63% to 78%, P = 0.04) and the reminder-only (64% to 74%, P = 0.05) markets. Overall from 1998 to 1999, there was a 3.7-percentage-point increase in pneumococcal immunization claims for Medicare beneficiaries in the education-plus-reminder market and a 1.5-percentage-point increase in the reminder-only market. Medicare beneficiaries sent reminders in the education-plus-reminder market compared to those in the reminder-only market were more likely to have a claim for pneumococcal immunization in 1999 (odds ratio 1.18, 95% confidence interval 1.08 to 1.28). The results suggest that these quality improvement strategies (community education plus reminders and reminders alone) modestly increased pneumococcal immunization awareness and pneumococcal immunization among rural adults. Mailed reminder exposure was associated with an increased prevalence of pneumococcal immunizations between 1998 and 1999 and was augmented somewhat by the education campaign. 相似文献
13.
14.
15.
16.
Devang N Patel Francis D Pagani Todd M Koelling David B Dyke Ragavendra R Baliga Robert J Cody Kathleen D Lake Keith D Aaronson 《The Journal of heart and lung transplantation》2002,21(2):204-210
BACKGROUND: Pravastatin and simvastatin prolong survival and reduce transplant-related coronary vasculopathy, although low-density lipoprotein (LDL) lowering with these agents is only modest. The objective of this study was to assess the safety of moderate dose atorvastatin and its efficacy when prior treatment with another statin had failed to lower LDL to < 100 mg/dl. METHODS: Data from 185 patients were retrospectively evaluated for adverse events, duration of exposure (person-days), and the mean atorvastatin dose exposure. Changes in lipid parameters, and prednisone and cyclosporine doses were determined. RESULTS: Safety: 48 patients received atorvastatin for 24,240 person-days at a mean dose exposure of 21 +/- 10 mg. Rhabdomyolysis, myositis, myalgias, and hepatotoxicity occurred in 0, 2, 2, and 0 patients, respectively. All events occurred at the 10-mg dose, within the first 3 months, and were rapidly reversible with atorvastatin discontinuation. Efficacy: Thirty-four patients evaluable for efficacy analyses had a pre-atorvastatin LDL of 145 +/- 38 mg/dl on the following statins: pravastatin (n = 30, 40 +/- 0mg), fluvastatin (n = 3, 33 +/- 12 mg), simvastatin (n = 1, 40 mg). After atorvastatin (21 +/- 9 mg/day) for 133 +/- 67 days, LDL was reduced to 97 +/- 24 mg/dl (relative reduction 31 +/- 20%, p < 0.0001). At the end of the observation period (418 +/- 229 days, atorvastatin final dose 24 +/- 14 mg/day), LDL was further decreased to 88 +/- 23 mg (relative reduction 37 +/- 17%, p < 0.0001). CONCLUSION: Atorvastatin, when used at moderate doses and with close biochemical and clinical monitoring, appears to be safe and is effective in aggressively lowering LDL in heart transplant recipients when treatment with other statins has failed to achieve LDL goals. 相似文献
17.
J A Noonan E P Todd S Norman C B Bacdayan L J Swift R J Mier J F Kilner J Engelberg 《Southern medical journal》1987,80(8):1016-1023
We discuss the ethical, psychosocial, economic, and medical dimensions of the treatment and management of a child with Down's syndrome and a congenital heart defect. 相似文献
18.
Primary care referrals for lumbar spine radiography: diagnostic yield and clinical guidelines. 下载免费PDF全文
William Hollingworth Christopher J Todd Hugh King Tony Males Adrian K Dixon Kanti R Karia Ann Louise Kinmonth 《The British journal of general practice》2002,52(479):475-480
BACKGROUND: Primary care requests for radiographs of the lumbar spine have come under increasing scrutiny. Guidelines aiming to reduce unnecessary radiographs by limiting referrals to patients at high risk of serious disease have been widely distributed. Trial evidence suggests that guidelines can reduce radiography referrals. It is not clear whether this reduction has been achieved in routine practice. AIM: This study, using routine data, was conducted to measure trends in pnmary care referrals for lumbar spine radiography at two hospitals between 1994 and 1999. DESIGN OF STUDY: Analysis of primary care requests for lumbar spine radiography from computerised records. SETTING: Addenbrooke's Hospital, Cambridge (1 July 1994 to 30 June 1999), and Ipswich General Hospital (1 July 1995 to 30 June 1999), United Kingdom. METHOD: All primary care requests for lumbar radiography were identified electronically from computerised information systems. A random sample of 2100 radiography reports were classified according to clinical importance. These classifications were used to examine whether the proportion of radiographs demonstrating potentially more serious findings had increased between 1994 and 1999. RESULTS: There was no evidence that primary care referrals for radiography of the lumbar spine had decreased between 1994 and 1999 at either hospital. General practitioners did not progressively refer more high-risk patients for lumbar radiography. Only a small proportion of patients had important radiographic findings that might warrant specialist referral or specific therapy. CONCLUSION: The implementation of diagnostic guidelines offers much to the NHS. However in these two hospitals, the reduction in radiograph utilisation evident in trials was not achieved. Guideline development is a resource intensive process; distribution must be supported by more effective implementation strategies. 相似文献
19.
David W Todd 《Journal of oral and maxillofacial surgery》2002,60(1):2-4; discussion 4-5
PURPOSE: This study compared current experience with the laryngeal mask airway (LMA) to previous experience with endotracheal intubation for ambulatory patients receiving general anesthesia. PATIENTS AND METHODS: A retrospective comparison of 157 patients (50 endotracheal intubation [ET] and 107 LMA cases) was conducted. The subjects were American Association of Anesthesiologist (ASA) Class I and II patients who underwent outpatient general anesthesia for dentoalveolar surgery. Procedure time, recovery time, and cost of techniques were compared. RESULTS: The patients undergoing a variety of outpatient dentoalveolar surgical procedures under general anesthesia in the LMA group had a shorter procedure time than the ET group (40 vs 44 minutes) and had a significantly shorter recovery time (54 vs 67 minutes). In addition, compared with the cost of delivering care with ET, the LMA provided slightly lower cost per case ($20 to $30 per case compared with $35 to $80 per case), depending on the anesthetic technique used. Comparing the 2 techniques for removal of 4 impacted third molars (25 patients ET and 68 patients LMA) revealed a similar procedure time of 39 minutes for both groups, but a shorter recovery time for the LMA group (54 vs 68 minutes). CONCLUSIONS: Use of the LMA has advantages over endotracheal intubation for outpatients receiving general anesthesia for dentoalveolar surgery. 相似文献
20.
Todd W Kelley Ernest C Borden John R Goldblum 《Applied immunohistochemistry & molecular morphology》2004,12(4):338-341
The authors have noted anecdotal cases of extrauterine leiomyosarcomas (LMS) with estrogen receptor (ER) and progester-one receptor (PR) immunoreactivity. However, there are few studies that have compared ER and PR immunoexpression in LMS of uterine and extrauterine origin. The authors obtained a representative formalin-fixed, paraffin-embedded tissue block from cases of uterine LMS (n = 15) and extrauterine LMS (n = 16) from the archives of the Cleveland Clinic Foundation and performed immunohistochemical staining for ER and PR. Staining was evaluated by 2 observers in a semiquantitative manner using the following scale: 0, no nuclear staining; 1+, 1 to 25% of nuclei stained; 2+, 26 to 50% of nuclei stained; 3+, 51 to 75% of nuclei stained; 4+, 76 to 100% of nuclei stained. The majority of uterine LMS stained for ER (13 of 15, 87%), PR (12 of 15, 80%), or both ER and PR (12 of 15, 80%), with most cases showing 3+ or 4+ positive staining. For the extrauterine LMS cases, staining for ER was seen in 4 of 16 cases (25%), staining for PR was observed in 2 of 16 cases (13%), and staining for both ER and PR was seen in 2 of 16 cases (13%). One extrauterine LMS showed 4+ coexpression of ER and PR, but the remaining extrauterine cases showed only 1+ ER and/or PR immunoreactivity. These data suggest that most uterine LMS coexpress ER and PR, and most extrauterine LMS do not stain for these antigens. However, a subset of extrauterine LMS are ER and/or PR immunoreactive. This raises the possibility that hormonal manipulation may be beneficial in the treatment of these therapeutically recalcitrant tumors. 相似文献