全文获取类型
收费全文 | 19143篇 |
免费 | 1627篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 229篇 |
儿科学 | 597篇 |
妇产科学 | 419篇 |
基础医学 | 2539篇 |
口腔科学 | 643篇 |
临床医学 | 1899篇 |
内科学 | 3586篇 |
皮肤病学 | 184篇 |
神经病学 | 1532篇 |
特种医学 | 693篇 |
外国民族医学 | 3篇 |
外科学 | 2829篇 |
综合类 | 378篇 |
一般理论 | 29篇 |
预防医学 | 1958篇 |
眼科学 | 610篇 |
药学 | 1304篇 |
中国医学 | 33篇 |
肿瘤学 | 1356篇 |
出版年
2022年 | 123篇 |
2021年 | 251篇 |
2020年 | 147篇 |
2019年 | 241篇 |
2018年 | 294篇 |
2017年 | 221篇 |
2016年 | 237篇 |
2015年 | 287篇 |
2014年 | 389篇 |
2013年 | 598篇 |
2012年 | 844篇 |
2011年 | 948篇 |
2010年 | 603篇 |
2009年 | 558篇 |
2008年 | 897篇 |
2007年 | 1028篇 |
2006年 | 953篇 |
2005年 | 994篇 |
2004年 | 953篇 |
2003年 | 824篇 |
2002年 | 848篇 |
2001年 | 574篇 |
2000年 | 598篇 |
1999年 | 491篇 |
1998年 | 226篇 |
1997年 | 206篇 |
1996年 | 173篇 |
1995年 | 169篇 |
1994年 | 179篇 |
1993年 | 174篇 |
1992年 | 439篇 |
1991年 | 395篇 |
1990年 | 371篇 |
1989年 | 355篇 |
1988年 | 331篇 |
1987年 | 316篇 |
1986年 | 296篇 |
1985年 | 293篇 |
1984年 | 239篇 |
1983年 | 241篇 |
1982年 | 160篇 |
1981年 | 146篇 |
1980年 | 130篇 |
1979年 | 192篇 |
1978年 | 180篇 |
1977年 | 115篇 |
1976年 | 134篇 |
1975年 | 118篇 |
1974年 | 139篇 |
1973年 | 151篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
K.A. Eaton F.M. Rimini E. Zak D.J. Brookman L.M.A. Hopkins P. J. Carmell LG. Yates C. A. Morrice B.A. Lall H. N. Newman 《Journal of clinical periodontology》1997,24(3):189-197
Abstract Several previous studies have evaluated the effects of 0.12% chlorhexidine digluconate (ChD) mouthrinses on plaque and gingival inflammation. However, previously, none have been based in general dental practices. The aim of this study was to evaluate the potential to conduct controlled periodontal clinical trials in co-operation with general dental practitioners (gdps). The project took place in 5 general dental practices in the South of England. 121 healthy subjects (24 at 4 sites and 25 at the 5th). aged 18-65 years, mean 35 ± 12) years participated in a double-blind, randomised study during which they received full mouth assessments for plaque and gingival bleeding at baseline, 6 and 12 weeks. 60 subjects were randomly asigned to use the 0.12% ChD mouth wash and 6i the placebo. The assessments were carried out by 5 gpds, who had previously achieved inter-examiner κ scores of 0.78–0.85 (mean 0.81) for the plaque index (PlI), and of 0.73–0.94 (mean 0.87) for a modified gingival index (mGI), and who maintained κ scores of 0.51–0.90 for PII and of 0.73–1.00 for mGI during the 12 months required to complete the study. 98 subjects (48 ChD and 50 placebo) completed the study. Even though the baseline levels of plaque and gingivitis were low, by week 12, mean whole mouth piaque score of the ChD mouthwash users had fallen from 1.33 at baseline to 0.96 and was significantly lower (p < 0.001) than for the placebo users, 1.31 at baseline to 1.13. Whole-mouth gingival bleeding score fell from 0.56 to 0.42 in the ChD mouthwash group but was unchanged (0.54–0.55) in the placebo group. A subsidiary data analysis which considered the effects at sites indicated that within these overall differences, the ChD users experienced almost 2× the reduction from plaque score 2 at baseline at proximal molar sites over a 12-week period (50.6% ChD versus 27.6% placebo). It was concluded that 0.12% ChD mouthwash reduced plaque accumulation fay 28% and gingival inflammation by 25% over a 12–week period, that it is feasible for a group of gdps to maintain high levels of inter–examiner consistency in the use of PlI and mGI, that it is also feasible to carry out such a multicentre study in general dental practice, and that the use of mean mouth scores per subject to analyse the effects of mouthrinses may well mask variations in response throughout the mouth. 相似文献
32.
33.
Pharmacokinetics of high-dose etoposide 总被引:1,自引:0,他引:1
E M Newman J H Doroshow S J Forman K G Blume 《Clinical pharmacology and therapeutics》1988,43(5):561-564
The pharmacokinetics of etoposide at doses of 1 gm/m2 to 3 gm/m2 were studied in patients with hematologic malignancies. The noncompartmental systemic clearance, mean residence time, steady-state volume of distribution, and elimination half-life were independent of the dose of etoposide, whereas the AUC was proportional to the dose. Comparison of these results with those reported previously indicates that etoposide exhibits linear pharmacokinetics over a thirtyfold range in doses (0.1 to 3 gm/m2). 相似文献
34.
S P Newman G Woodman F Morén S W Clarke 《British journal of diseases of the chest》1988,82(3):262-267
Metered dose inhalers are sometimes used in conjunction with NebuhalerR, a 750 ml holding chamber, but the permissible delay time between actuating the aerosol into Nebuhaler and commencing inhalation is unknown. We have compared in 10 asthmatic patients the bronchodilator responses following inhalations of terbutaline sulphate from Nebuhaler after delays of 1, 5 and 30 seconds and following placebo inhalation. Terbutaline sulphate was administered as 2 puffs, each of 250 micrograms, separated by approximately 15 minutes. After each delay time, terbutaline produced increases in forced expiratory volume in one second (FEV1), peak expiratory flow rate (PEFR) and maximum expiratory flow following exhalation of 75% of the forced vital capacity (V max25) significantly greater than those after placebo (P less than 0.01). Changes in PEFR did not vary significantly among the three delay times, but the increases in FEV1 and in V max25 were significantly reduced with 30 seconds' delay. It is concluded that the delay between actuation into Nebuhaler and commencing inhalation can be extended from 1 second to 5 seconds without significant loss of drug efficacy, and that further extension to 30 seconds causes only a small loss of bronchodilatation: hence the delay time is unlikely to be of major importance in clinical practice. 相似文献
35.
J G Williams B M Newman J L Sutphen J Madison H Frierson J McIlhenny 《Journal of pediatric surgery》1990,25(12):1250-1252
This report describes a 3-year-old child with a hepatobiliary cystadenoma. Cystadenomas are benign, multilocular, cystic neoplasms that usually occur in middle-aged women. The patients may be asymptomatic, but often there are vague abdominal complaints related to extrinsic compression of the stomach, duodenum, or biliary tree. Recurrence following incomplete excision and the presence of carcinoma within otherwise benign cysts has been documented. Complete resection is the therapy of choice, and thorough histopathologic evaluation is imperative. 相似文献
36.
Choc Miles G. Hsuan Francis Honigfeld Gilbert Robinson William T. Ereshefsky Larry Crismon Miles L. Saklad Stephen R. Hirschowitz Jack Wagner Richard 《Pharmaceutical research》1990,7(4):347-351
Clozapine plasma levels were monitored in 16 patients during a series of three consecutive treatments (single dose-multiple dose-single dose). Each patient received a single 75-mg dose (3 x 25 mg) with clozapine tablets, and serial plasma samples were collected over 48 hr after the dose. At 48 hr, a multiple-dose regimen was started, consisting of an initial dose escalation period followed by dosing at a constant regimen for at least 6 days. After the last dose, serial plasma samples were again obtained over 72 hr. Drug was then withheld for at least 7 days, a final single 75-mg dose was given, and plasma sampling was repeated. A subset of the patient population (N = 7) was used to test for a food effect during the single-dose treatments. The pharmacokinetic parameters between the initial and the final single dose periods were not significantly different. Similarly, there were no differences within patients when given the dose after fasting (fed 1 hr after dose) or with a meal. In contrast, the terminal elimination rate differed between the single-dose and the multiple-dose treatments (t1/2 m3 = 7.9 hr single dose and 14.2 hr multiple dose) (P less than 0.05) and the dose-normalized area under the plasma concentration/time curves increased 27% with multiple dosing. Since a previous study in patients (Choc et al., Pharm. Res. 4:402-405, 1987) showed dose proportionality of clozapine plasma concentrations during multiple-dose regimens, the present results cannot be described by Michaelis-Menten kinetics. 相似文献
37.
Perioperative cardiac events in patients undergoing noncardiac surgery: a review of the magnitude of the problem, the pathophysiology of the events and methods to estimate and communicate risk 总被引:5,自引:0,他引:5 下载免费PDF全文
P.J. Devereaux Lee Goldman Deborah J. Cook Ken Gilbert Kate Leslie Gordon H. Guyatt 《Canadian Medical Association journal》2005,173(6):627-634
THIS IS THE FIRST OF 2 ARTICLES EVALUATING cardiac events in patients undergoing noncardiac surgery. In this article, we review the magnitude of the problem, the pathophysiology of these events, approaches to risk assessment and communication of risk. The number of patients undergoing noncardiac surgery worldwide is growing, and annually 500 000 to 900 000 of these patients experience perioperative cardiac death, nonfatal myocardial infarction (MI) or nonfatal cardiac arrest. Although the evidence is limited, a substantial proportion of fatal perioperative MIs may not share the same pathophysiology as nonoperative MIs. A clearer understanding of the pathophysiology is needed to direct future research evaluating prophylactic, acute and long-term interventions. Researchers have developed tools to facilitate the estimation of perioperative cardiac risk. Studies suggest that the Lee index is the most accurate generic perioperative cardiac risk index. The limitations of the studies evaluating the ability of noninvasive cardiac tests to predict perioperative cardiac risk reveals considerable uncertainty as to the role of these popular tests. Similarly, there is uncertainty as to the predictive accuracy of the American College of Cardiology / American Heart Association algorithm for cardiac risk assessment. Patients are likely to benefit from improved estimation and communication of cardiac risk because the majority of noncardiac surgeries are elective and accurate risk estimation is important to allow informed patient and physician decision-making. 相似文献
38.
Pleural cryptococcosis is extremely rare. We report the first case of cryptococcal pleural effusion in association with the acquired immune deficiency syndrome. Pleural effusion without the evidence of pulmonary parenchymal involvement was the initial and only clinical finding leading to the diagnosis of disseminated cryptococcosis. The pleural effusion resolved spontaneously prior to amphotericin B therapy. 相似文献
39.
J W Shore C T Westfall C R Leone R K Newman F W Shagets 《Ophthalmic plastic and reconstructive surgery》1987,3(1):13-15
A 38-year-old man presented with hyperophthalmia, enophthalmos, and upper eyelid retraction 18 months following an osteoplastic flap and frontal sinus obliteration for mucocele. Computerized tomography confirmed the presence of frontal bone absorption in the roof of the orbit with traction and elevation of the orbital contents into the obliterated frontal sinus. A fracture of the orbital roof with penetration of periorbita at the time of original surgery was the suspected precipitating cause of the complication. Surgical management included lysis of the cicatrix between the orbit and frontal sinus and interposition of a silicone sheet between the orbit and sinus, which restored the appropriate anatomic relationships and prevented recurrence. 相似文献
40.
Chain transfer constants (Ctr) for three phosphonated thiols in methyl methacrylate (MMA) polymerization at 60°C were determined from measurements of the degree of polymerization. These thiols were: diethyl 2-mercaptoethyl phosphate ( 1 ), diethyl 2-mercaptoethylamidophosphate ( 2 ), and tetraethyl mercaptomethylethylene bis(phosphate) ( 3 ). Transfer efficiencies of the thiols were found to be dependent upon their structures. The Ctr value of thiol 2 with MMA was the lowest in the present series, which can be attributed to a possible charged tautomeric form which eventually may reduce the electron density on the thiol, thus rendering the chain transfer reaction with the PMMA radical less feasible. Ctr values of thiol 1 were evaluated at 55, 60, 65, 70 and 75°C. This thiol behaves as an “azeotropic” transfer agent for MMA at 96°C. 相似文献