全文获取类型
收费全文 | 26156篇 |
免费 | 2582篇 |
国内免费 | 96篇 |
专业分类
耳鼻咽喉 | 380篇 |
儿科学 | 1066篇 |
妇产科学 | 758篇 |
基础医学 | 3541篇 |
口腔科学 | 713篇 |
临床医学 | 3683篇 |
内科学 | 4686篇 |
皮肤病学 | 295篇 |
神经病学 | 1691篇 |
特种医学 | 886篇 |
外科学 | 3388篇 |
综合类 | 561篇 |
一般理论 | 29篇 |
预防医学 | 3000篇 |
眼科学 | 510篇 |
药学 | 1977篇 |
中国医学 | 100篇 |
肿瘤学 | 1570篇 |
出版年
2022年 | 172篇 |
2021年 | 395篇 |
2020年 | 218篇 |
2019年 | 345篇 |
2018年 | 453篇 |
2017年 | 339篇 |
2016年 | 366篇 |
2015年 | 407篇 |
2014年 | 645篇 |
2013年 | 914篇 |
2012年 | 1353篇 |
2011年 | 1425篇 |
2010年 | 825篇 |
2009年 | 635篇 |
2008年 | 1271篇 |
2007年 | 1381篇 |
2006年 | 1373篇 |
2005年 | 1323篇 |
2004年 | 1201篇 |
2003年 | 1176篇 |
2002年 | 1137篇 |
2001年 | 754篇 |
2000年 | 711篇 |
1999年 | 698篇 |
1998年 | 319篇 |
1997年 | 312篇 |
1996年 | 266篇 |
1995年 | 259篇 |
1994年 | 233篇 |
1993年 | 187篇 |
1992年 | 505篇 |
1991年 | 477篇 |
1990年 | 440篇 |
1989年 | 409篇 |
1988年 | 421篇 |
1987年 | 391篇 |
1986年 | 388篇 |
1985年 | 392篇 |
1984年 | 298篇 |
1983年 | 274篇 |
1982年 | 196篇 |
1981年 | 201篇 |
1979年 | 277篇 |
1978年 | 234篇 |
1977年 | 204篇 |
1975年 | 170篇 |
1974年 | 217篇 |
1973年 | 233篇 |
1972年 | 185篇 |
1971年 | 170篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Juri V. Kaude M.D. James D. McDowall Charles L. Neustein Edward R. Woodward Patricia G. Wright 《Abdominal imaging》1981,6(1):135-140
Eighty patients who had undergone jejunoileal bypass for morbid obesity were examined by ultrasound at their routine follow-up visits to the clinic. Ultrasonographic evidence of intestinal intussusception was found in 15 patients (19%). Two of these patients were asymptomatic. Ultrasonographic findings were confirmed by operation in 6 patients (5 with intussusception, 1 negative). 相似文献
102.
Binding, degradation and pressor activity of angiotensins II and III after aminopeptidase inhibition with amastatin and bestatin 总被引:3,自引:0,他引:3
R H Abhold M J Sullivan J W Wright J W Harding 《The Journal of pharmacology and experimental therapeutics》1987,242(3):957-962
In the metabolism of angiotensin peptides by tissue angiotensinases, aminopeptidases A, B, M and leucine aminopeptidase have been identified as being particularly effective. Because the inhibitory actions of amastatin (AM) and bestatin (BE) are relatively specific for these aminopeptidases, we have examined the effects of these inhibitors on the binding, degradation and pressor activity of angiotensin II (AII) and angiotensin III (AIII). Within 30 min at 37 degrees C, significant metabolism of 125I-AII and 125I-AIII by homogenates of a block of tissue containing hypothalamus, thalamus, septum and anteroventral third ventricle regions of the brain was observed. A majority of 125I-AIII metabolism was due to soluble peptidases, whereas that of 125I-AII primarily resulted from membrane-bound peptidases. AM, BE and reduced incubation temperatures significantly decreased the metabolism of 125I-AII and 125I-AIII. After appropriate adjustments to reflect the proportion of intact radioligand bound, temperature- or inhibitor-induced decreases in metabolism were matched by corresponding increases in specific binding. Heat-treated bovine serum albumin, as a nonspecific peptidase inhibitor, had no effect on either the metabolism or binding of the ligands used. In accordance with their actions in vitro, i.c.v. administration of AM and BE prolonged the pressor activity of subsequently applied AII and AIII. Unexpectedly, the amplitude of the pressor response to AIII was increased by BE, whereas that to AII was decreased by AM. The results of this study indicate that the metabolism of AII and AIII by aminopeptidases is relatively specific and acts to modulate the actions of these peptides.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
103.
The purpose of this study was to determine the histologic findings at the bone-cement interface in successful asymptomatic total hip replacements (THR) retrieved from patients at autopsy. The criteria for a successful hip arthroplasty were clinical, radiologic, and direct examination of the prosthesis at the time of harvesting. Twelve patients with a total of 14 cemented hip arthroplasties came to autopsy at a mean of 4.7 years after implantation. A detailed histomorphometric objective means of assessing the tissue response was applied to the membrane. The density of histiocytes correlated with the thickness of the membrane, the density of polyethylene particles, and the time after implantation. The fibrohistiocytic membrane in this group of patients was similar to that described in the literature in cases of loose THRs. These findings advance current understanding of transcellular particle transportation (directional exocytosis) in tissue reactions to endoprostheses of THR. 相似文献
104.
105.
A R Wright P T English H M Cameron J B Wilsdon 《Acta radiologica (Stockholm, Sweden : 1987)》1992,33(6):582-587
Pelvimetry remains a useful technique as part of the assessment of the term breech pregnancy where vaginal delivery is planned. MR pelvimetry is accurate, well tolerated and shows soft-tissue structures as well as bone. It avoids the potentially carcinogenic effects of ionising radiation and is thought to be completely safe for mother and fetus. A technique of MR pelvimetry is described which uses gradient-echo sequences. This quick, practical method makes minimal inroads into valuable scanning time, and may therefore be considered a potentially cost-effective alternative to conventional pelvimetry. 相似文献
106.
Elizabeth Rosyold Russell Schilder Judy Walczak S. M. DiFino P. J. Flynn T. K. Banerjee W. J. Heim Paul E. Engstrom Robert F. Ozols Peter J. O'Dwyer 《Cancer chemotherapy and pharmacology》1992,29(4):305-308
Summary Phosphonacetyl-l-aspartate (PALA), an inhibitor of aspartate transcarbamylase that depletes uridine nucleotide pools, selectively potentiates the antitumor activity of 5-fluorouracil (5-FU) in preclinical models. Due to the promising results we obtained using PALA/5-FU in colorectal cancer, we performed a phase II trial in patients presenting with advanced pancreatic cancer. PALA was given intravenously at 250 mg/m2 on day 1, followed 24 h later by 2,600 mg/m2 5-FU given by 24-h infusion. Treatments were repeated weekly. A total of 41 patients who had not previously undergone chemotherapy were entered in the trial; of these, 35 were evaluable for response. Toxicity was generally mild to moderate; neurotoxicity (13/35) and diarrhea (8/35) predominated. Among the 35 patients, 1 achieved a complete response and 4, a partial remission, for an overall response rate of 14%. The median survival was 5.1 months. Pretreatment with PALA alone was not sufficient to enhance the activity of 5-FU in pancreatic cancer.Supported in part by grant CA 06927 from the National Cancer Institute 相似文献
107.
Kenneth P Wright Jr. Pietro Badia Bryan L Myers Steven C Plenzler Milton Hakel 《Brain research》1997,747(1):654
The effects of caffeine ingestion and exposure to bright light, both separately and in combination, on salivary melatonin and tympanic temperature were assessed in humans. Four treatments during a 45.5 h sleep deprivation period were compared: Dim Light-Placebo, Dim Light-Caffeine, Bright Light-Placebo and Bright-Light Caffeine. The Dim Light-Caffeine condition (200 mg twice each night) relative to the Dim Light-Placebo condition suppressed nighttime melatonin levels and attenuated the normal decrease in temperature. Combining caffeine ingestion with bright light exposure (≥2000 lux) suppressed melatonin and attenuated the normal nighttime drop in temperature to a larger degree than either condition alone; i.e. effects were additive. Circadian effects were also observed in that the amplitude and phase of the temperature rhythm were altered during treatment. These findings establish that the human melatonin system is responsive to caffeine. Other evidence suggests that caffeine may influence melatonin and temperature levels through antagonism of the neuromodulator adenosine. 相似文献
108.
Sneyd J. R.; Wright PMC.; Cross M.; Thompson P.; Voortman G.; Weideman M. M.; Andrews CJH.; Daniell C. J. 《British journal of anaesthesia》1997,79(4):427-432
Ten male volunteers received a 1-min i.v. infusion of a new water soluble
steroid anaesthetic agent, ORG 21465. Individuals received doses ranging
from 0.8 to 1.8 mg kg-1. All subjects experienced venous pain at the site
of injection; those receiving 1.0 mg kg-1 or more became anaesthetized.
There was no evidence of histamine release and apnoea did not occur.
Excitatory phenomena were observed in all subjects and were dose related;
no spikes were seen on the EEG. Pharmacokinetic analysis supported a
three-compartment (non-weight- related) model with compartmental volumes
V1, V2 and V3 of 4.31, 14.2 and 89.4 litre, respectively. Clearance from
the central compartment V1 was 1.55 litre min-1. Inter-compartmental
clearances Q1 and Q2 were 2.54 and 1.79 litre min-1. We found that ORG
21465 was an effective anaesthetic in humans. The relationship between
sedation, anaesthesia and excitation requires further exploration.
相似文献
109.
K L Dawson-Falk A M Wright B Bakker P T Pitlick D M Wilson R G Rosenfeld 《Australasian radiology》1992,36(3):204-209
Forty patients with karyotypically proven Turner syndrome were prospectively studied using magnetic resonance imaging (MRI) and echocardiography in order to determine the frequency of cardiovascular anomalies and to assess the utility of both imaging modalities as methods for cardiovascular evaluation in Turner syndrome. Cardiovascular anomalies were found in 45% of patients. A high absolute prevalence of bicuspid aortic valve (17.5%) and aortic coarctation (12.5%) were observed relative to comparable series. Of clinically significant abnormalities, three of five aortic coarctations and four of five ascending aortic dilatations were solely MRI detected and not evident at echocardiographic examination. MRI is thus seen as a valuable adjunct to echocardiography in the cardiovascular evaluation of Turner syndrome patients. The usefulness of MRI primarily relates to its ability to provide excellent visualisation of the entire thoracic aorta where a large proportion of clinically significant anomalies occur in Turner syndrome. 相似文献
110.
A case of intentional overdose with 18 'Ecstasy' tablets is described. 'Ecstasy' is a semi-synthetic hallucinogenic amphetamine and acute adverse reactions follow from the effects of sympathetic stimulation. To our knowledge this is the first reported case of massive intentional overdose reported in the literature. 相似文献