全文获取类型
收费全文 | 53853篇 |
免费 | 3513篇 |
国内免费 | 244篇 |
专业分类
耳鼻咽喉 | 557篇 |
儿科学 | 1262篇 |
妇产科学 | 1125篇 |
基础医学 | 7321篇 |
口腔科学 | 995篇 |
临床医学 | 5117篇 |
内科学 | 10388篇 |
皮肤病学 | 1119篇 |
神经病学 | 5250篇 |
特种医学 | 1909篇 |
外科学 | 8553篇 |
综合类 | 523篇 |
现状与发展 | 1篇 |
一般理论 | 37篇 |
预防医学 | 3906篇 |
眼科学 | 1387篇 |
药学 | 3972篇 |
中国医学 | 301篇 |
肿瘤学 | 3887篇 |
出版年
2023年 | 324篇 |
2022年 | 717篇 |
2021年 | 1391篇 |
2020年 | 822篇 |
2019年 | 1154篇 |
2018年 | 1409篇 |
2017年 | 1061篇 |
2016年 | 1208篇 |
2015年 | 1500篇 |
2014年 | 2078篇 |
2013年 | 2540篇 |
2012年 | 4101篇 |
2011年 | 4097篇 |
2010年 | 2370篇 |
2009年 | 2109篇 |
2008年 | 3492篇 |
2007年 | 3704篇 |
2006年 | 3409篇 |
2005年 | 3285篇 |
2004年 | 3053篇 |
2003年 | 2808篇 |
2002年 | 2579篇 |
2001年 | 687篇 |
2000年 | 625篇 |
1999年 | 600篇 |
1998年 | 512篇 |
1997年 | 448篇 |
1996年 | 418篇 |
1995年 | 365篇 |
1994年 | 325篇 |
1993年 | 281篇 |
1992年 | 307篇 |
1991年 | 259篇 |
1990年 | 238篇 |
1989年 | 212篇 |
1988年 | 228篇 |
1987年 | 198篇 |
1986年 | 185篇 |
1985年 | 184篇 |
1984年 | 176篇 |
1983年 | 188篇 |
1982年 | 208篇 |
1981年 | 195篇 |
1980年 | 165篇 |
1979年 | 122篇 |
1978年 | 158篇 |
1977年 | 140篇 |
1976年 | 107篇 |
1975年 | 119篇 |
1974年 | 100篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Localised endosteal bone lysis in relation to the femoral components of cemented total hip arthroplasties 总被引:7,自引:0,他引:7
P P Anthony G A Gie C R Howie R S Ling 《The Journal of bone and joint surgery. British volume》1990,72(6):971-979
Four cases are described of localised endosteal bone lysis in the femur occurring in association with cemented femoral components that were not obviously 'loose' radiologically. In each, the area of lysis was shown at operation to be related directly to a region in which there was a local defect in the cement mantle surrounding the stem. Via the space between the stem and cement, such defects provide a route through which the contents of the joint cavity may reach the endosteal surface of the femur, subsequently leading to localised bone lysis, and later to frank loosening. 相似文献
62.
A prospective controlled trial of cold-storage versus machine-perfusion preservation in cadaveric renal transplantation 总被引:2,自引:0,他引:2
A prospective controlled study was carried out in 60 consecutive cadaver renal donors comparing cold storage to pulsatile machine-perfusion preservation. Each donor served as its own control, by allocating one of the kidneys to each of the two preservation methods. There were 51 evaluable pairs of kidneys. Recipient age, panel-reactive antibody level, history of prior renal transplant, and immunosuppressive regimen were similar in the two preservation groups. Almost all recipients were treated with cyclosporine, and over 50% received antilymphoblast globulin. Total cold ischemic time was 1262 +/- 387 min in the machine-perfused group and 1309 +/- 426 min in the cold-storage group (P = NS). Prolonged ischemia (greater than 24 hr) occurred in 31% of machine-perfused and 22% of cold-stored kidneys (P = NS). Post-operative serum creatinine levels at 1, 7, and 30 days posttransplant were similar in both groups. Dialysis requirements were also similar, with 21 recipients of machine-perfused kidneys (41%) requiring at least one dialysis treatment compared to 16 patients (31%) in the cold-stored group (P = NS); the mean number of dialysis treatments required was 3.14 +/- 1.46 and 3.06 +/- 1.29, respectively (P = NS). Long ischemic time (greater than 24 hr) was associated with a higher rate of dialysis requirement in both groups, but in neither case did this achieve statistical significance. The distribution of graft losses within the first 30 days was similar in both groups, and the incidence of preservation-related graft failure was not significantly different. These results demonstrate that, in the cyclosporine era, machine perfusion offers no significant advantages over cold storage for cadaver renal preservation. Because machine perfusion is considerably more expensive and cold storage is simpler and facilitates the logistics of organ sharing, we recommend simple hypothermic storage of renal allografts as the preservation method of choice. 相似文献
63.
Peter R. Ellis Victoria J. Burley Anthony R. Leeds David B. Peterson† 《Journal of human nutrition and dietetics》1988,1(2):77-84
We have developed a guar wholemeal bread and tested its physiological efficacy and sensory qualities. The objective of the study was to estimate the optimum concentration of guar in bread required to reduce postprandial glycaemia and insulinaemia without adversely affecting the quality of the bread. Following overnight fasts, 15 normal weight, non-diabetic subjects consumed meals of wholemeal bread alone (controls) and supplemented with guar at three different concentrations (5, 10 and 15% replacement of wheat flour). Blood samples for glucose and insulin analysis were taken preprandially, and at 30 and 60 min after the start of each meal. The acceptability of the wholemeal control and guar breads was assessed using a hedonic scaling method. A significantly lower blood glucose rise at 30 min was found after the 15% guar bread meal compared to the control. Plasma insulin responses at 30 and 60 min were significantly lower after the 10 and 15% guar bread meals compared to the controls. Hedonic scores indicated that the subjects found the 5 and 10% guar breads acceptable and in the case of the 5% variety the mean score was identical to the control. We suggest that a guar concentration of between 5 and 10% replacement of wheat flour (wholemeal or white) should be used for the baking of guar wholemeal bread but further work is needed to define the precise quantity of guar required. 相似文献
64.
Within a number of physiological preparations, the effects of alcohol and cocaine in combination are reported to be greater
than the effects of either drug given alone. Little has been reported, however, on the behavioral effects of the interaction.
The present study investigated this issue by assessing the effects of cocaine and alcohol (alone and in combination) on schedule-controlled
responding. Specifically, rats were trained to respond on an FR20 schedule for a water reinforcer. They were then administered
cumulative doses of cocaine or alcohol. Following this, subjects were administered ineffective doses of alcohol prior to further
dose-response assessments with cocaine and with ineffective doses of cocaine prior to further dose-response assessments with
alcohol. Cocaine and alcohol alone produced dose-related decreases in responding. Furthermore, the dose-response function
for cocaine was shifted to the left by alcohol and the dose-response function for alcohol was shifted to the left by cocaine.
An isobolographic analysis revealed that the interaction between cocaine and alcohol was additive in nature. The possible
bases for the interaction (e.g., changes in cocaine pharmacokinetics by alcohol and the formation of cocaethylene following
co-administration of cocaine and alcohol) were discussed.
Received: 22 February 1996 / Final version: 23 August 1996 相似文献
65.
Ann E. Klasner MD Sharon R. Smith MD Michael W. Thompson BS Pharm Anthony J. Scalzo MD 《Academic emergency medicine》1998,5(10):992-996
Abstract. Objectives:To describe the outcomes of a mass carbon monoxide (CO) intoxication, and to calculate the CO half-life in a pediatric school-aged population.
Methods:A retrospective chart review was performed based on Regional Poison Center database information, hospital laboratory data, and medical records of the pediatric patients who sought care at one of 3 St. Louis area hospitals, after exposure to high levels of CO. Exposures occurred on January 5, 1996, after evidence of a CO leak was discovered at an area elementary school. Charts were reviewed for major demographics, symptoms reported, carboxyhemoglobin (COHb) levels and times, and level of effect.
Results:Information about 177 (35%) of the 504 children in attendance at school that day was available. Mean age was 8.7 ± 1.8 years (range 4–12 years). Symptoms were present in 155 (88%) of the 177 children for whom data were available. Initial COHb levels were obtained for 147 (83.1%) of the 177 children. First mean COHb level was 7.0% (95% CI = 6.6–7.5%). Second COHb level was obtained for 26 children with a mean of 2.7% (95% CI = 2.2–3.2%). Calculated half-life of COHb, on 100% 02 at 1 atm, was 44.0 minutes (95% CI = 39.6–48.2 minutes).
Conclusion:Some children had symptoms at COHb levels that traditionally have been considered nontoxic. The elimination of COHb was found to be more rapid in this population of children than reported in other studies. 相似文献
Methods:A retrospective chart review was performed based on Regional Poison Center database information, hospital laboratory data, and medical records of the pediatric patients who sought care at one of 3 St. Louis area hospitals, after exposure to high levels of CO. Exposures occurred on January 5, 1996, after evidence of a CO leak was discovered at an area elementary school. Charts were reviewed for major demographics, symptoms reported, carboxyhemoglobin (COHb) levels and times, and level of effect.
Results:Information about 177 (35%) of the 504 children in attendance at school that day was available. Mean age was 8.7 ± 1.8 years (range 4–12 years). Symptoms were present in 155 (88%) of the 177 children for whom data were available. Initial COHb levels were obtained for 147 (83.1%) of the 177 children. First mean COHb level was 7.0% (95% CI = 6.6–7.5%). Second COHb level was obtained for 26 children with a mean of 2.7% (95% CI = 2.2–3.2%). Calculated half-life of COHb, on 100% 0
Conclusion:Some children had symptoms at COHb levels that traditionally have been considered nontoxic. The elimination of COHb was found to be more rapid in this population of children than reported in other studies. 相似文献
66.
Mark Beuger md Anthony Tommasello ms Robert Schwartz md Mary Clinton pharmd 《Journal of substance abuse treatment》1998,15(6):15-593
Forty-eight consecutive applicants and 30 known clonidine-abusing methadone patients at three methadone treatment programs were surveyed regarding their use of clonidine. Two distinct patterns of clonidine use emerged. Of 22 applicants who took clonidine illicitly, 15 used it primarily to decrease opioid withdrawal, as well as for its sedating effect. Applicants mostly obtained it from physicians, used an average dose of 0.37 mg at a time, and about one third believed clonidine to be addictive. In contrast, clonidine-using patients took clonidine primarily for its psychoactive effects, including the interaction with methadone, in addition to decreasing opioid withdrawal. Patients obtained clonidine frequently on the street and from family or friends, but less from physicians. The average reported dose for patients was 0.6 mg. The vast majority of these patients felt clonidine was addictive. Our findings, when coupled with the risk inherent in clonidine overdose, suggest that further research into the identification and treatment of clonidine abuse among methadone patients is warranted. 相似文献
67.
Robert C. Flanigan Joseph H. Saiers Michael Wolf Eric H. Kraut Anthony Y. Smith Brent Blumenstein E. David Crawford 《Investigational new drugs》1994,12(2):147-149
Summary The Southwest Oncology Group (SWOG) studied the response rate and toxicity of merbarone (1,000 mg/m2 IV continuous infusion days 1–5, q 21 days) in patients with advanced metastatic renal cell carcinoma. Among 36 eligible patients, there was one partial response for a response rate of 3% (95% C.I. 0.1–15%). There were no mixed responses. There were no treatment related deaths or adverse drug reactions. Significant anemia, diarrhea, and hypercalcemia were observed. Mild to moderate degrees of malaise/fatigue/lethargy, dizziness/vertigo, hyperglycemia, creatinine increase, nausea, vomiting, weight loss, pedal edema, dyspnea, and granulocytopenia were noted. Merbarone does not have significant activity as a single agent in advanced renal cell carcinoma. 相似文献
68.
69.
70.
Deborah Bray Preston Anthony R D'Augelli Cathy D Kassab Richard E Cain Frederick W Schulze Michael T Starks 《AIDS education and prevention》2004,16(4):291-303
Research investigating predictors of risky sexual behavior of rural MSM is sparse, even though the prevalence of HIV in rural areas has increased. This study explored two sets of predictors of 93 rural MSM's levels of risky sexual behavior: mental health variables and stigma emanating from men's family members, health care professionals, and people in the rural communities in which they live. Over 47% of the men were found to be at modified high to high risk. Logistic regression using a continuation logit model was used to test the relationship of the predictor variables and the four levels of risk. Findings indicate that self-esteem was predictive of the highest sexual risk behavior but not lower levels of risk. Stigma was predictive of modified high sexual risk when compared to low and no risk categories. No variables differentiated men at low risk from men at no risk. 相似文献