全文获取类型
收费全文 | 8936篇 |
免费 | 473篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 106篇 |
儿科学 | 196篇 |
妇产科学 | 147篇 |
基础医学 | 1135篇 |
口腔科学 | 654篇 |
临床医学 | 1076篇 |
内科学 | 1630篇 |
皮肤病学 | 311篇 |
神经病学 | 809篇 |
特种医学 | 158篇 |
外科学 | 882篇 |
综合类 | 73篇 |
一般理论 | 4篇 |
预防医学 | 1121篇 |
眼科学 | 106篇 |
药学 | 443篇 |
中国医学 | 45篇 |
肿瘤学 | 544篇 |
出版年
2023年 | 58篇 |
2022年 | 126篇 |
2021年 | 222篇 |
2020年 | 158篇 |
2019年 | 202篇 |
2018年 | 292篇 |
2017年 | 190篇 |
2016年 | 221篇 |
2015年 | 241篇 |
2014年 | 364篇 |
2013年 | 478篇 |
2012年 | 688篇 |
2011年 | 791篇 |
2010年 | 405篇 |
2009年 | 327篇 |
2008年 | 576篇 |
2007年 | 616篇 |
2006年 | 596篇 |
2005年 | 505篇 |
2004年 | 519篇 |
2003年 | 389篇 |
2002年 | 366篇 |
2001年 | 99篇 |
2000年 | 90篇 |
1999年 | 90篇 |
1998年 | 80篇 |
1997年 | 60篇 |
1996年 | 45篇 |
1995年 | 39篇 |
1994年 | 35篇 |
1993年 | 41篇 |
1992年 | 50篇 |
1991年 | 43篇 |
1990年 | 38篇 |
1989年 | 37篇 |
1988年 | 31篇 |
1987年 | 20篇 |
1986年 | 22篇 |
1985年 | 23篇 |
1984年 | 24篇 |
1983年 | 31篇 |
1982年 | 31篇 |
1981年 | 28篇 |
1980年 | 14篇 |
1978年 | 14篇 |
1977年 | 13篇 |
1976年 | 10篇 |
1975年 | 10篇 |
1973年 | 10篇 |
1970年 | 10篇 |
排序方式: 共有9440条查询结果,搜索用时 0 毫秒
1.
Milena Soares Santos Guilherme de Sousa Ribeiro Tainara Queiroz Oliveira Renan Cardoso Nery Santos Edilane Gouveia Kátia Salgado Daniele Takahashi Cleuber Fontes Leila Carvalho Campos Mitermayer Galvão Reis Albert Icksang Ko Joice Neves Reis 《International journal of infectious diseases》2009,13(4):456-461
2.
Benjamin Clapp Melba Jarmillo Valeria Vigil Luis Macias Marcia Bouton Cuatemoc Gallardo Andrew Kassir 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2007,11(2):242-245
BACKGROUND AND OBJECTIVES: The purpose of this study was to determine patient recall and comprehension after laparoscopic appendectomy in an underserved population. Laparoscopic surgery can lead to diagnostic uncertainty secondary to poor recall and variable port placement. METHODS: After institutional review board approval, we identified a cohort of patients who underwent laparoscopic appendectomy from 2000 to 2004 at a single institution. We then attempted to contact the patients to conduct a 10-question telephone survey, which determined whether the patient spoke English or Spanish as a primary language, ethnicity, educational level, and questions about recall of perioperative events and diagnoses. If we could not reach the patient, we tried to call back on 2 different occasions. RESULTS: Between 2000 and 2004, 186 patients underwent laparoscopic appendectomy. Of these, 65% were Hispanic. We found that only 17% of these patients returned for a postoperative visit. Only 19.3% could be contacted by phone. Forty-seven percent of the patients contacted by phone spoke Spanish exclusively. Overall 92% of patients contacted knew what operation they had, and gave their correct diagnosis. CONCLUSIONS: The low percentage of patients available to follow-up makes this study statistically insignificant. However, we believe that fact in itself is important. In Southwestern states, we see a large migrant population. This highlights the need to communicate effectively with the patients at the time of surgery, which we speculate we did based on the percentage of patients that knew their diagnosis. 相似文献
3.
Marcia C Willing James C Torner Trudy L Burns Kathleen F Janz Teresa A Marshall Julie Gilmore John J Warren Steven M Levy 《Journal of clinical densitometry》2005,8(1):39-47
Four hundred twenty-eight white children (200 boys and 228 girls) ages 4.5-6.5 yr had spine, hip, and whole-body bone mineral density (BMD) and bone mineral content (BMC) measured by dual-energy X-ray absorptiometry(DXA) as part of the Iowa Bone Development Study. Anthropometric measurements, including height, weight, and body mass index (BMI) were determined for each child at the time the bone measurements were made. The age- and gender-specific height percentile based on the 2000 CDC Growth Charts (www.cdc.gov/growthcharts/) was determined for each child. These percentiles were used to classify children into four groups as defined by the 25th, 50th,and 75th percentile cutpoints. Percentile distributions were determined within each height quartile group to delineate percentiles (5th, 25th, 50th, 75th, 95th) for BMD and BMC. Gender differences in BMD and BMC were investigated before and after stratification into height groups. Boys had higher age-height-weight-adjusted means for most BMD and BMC measures except spine BMD. Bone measurements increased with height quartile, indicating that taller children have greater BMD and BMC compared to shorter children of the same age and gender. Within any given quartile,mean BMD and BMC measurements were similar for boys and girls, with the exception of hip BMD, for which values were consistently higher for boys (p < 0.05). In addition, whole-body BMC values were higher for boys in quartiles 1 and 3 (p < 0.05). These bone measures provide norms for young white children and serve as a reference for comparison with other racial and ethnic groups, as well as with childhood populations that are at risk for osteopenia because of chronic disease. Gender, age, and height are useful clinical predictors of BMD and BMC in young children. 相似文献
4.
Marcia Finlayson 《The American journal of occupational therapy》2004,58(1):54-63
Multiple sclerosis (MS) is a chronic, progressive neurological disease that causes demyelination of the central nervous system. Typically diagnosed in adulthood, it does not significantly reduce life expectancy. The goal of this exploratory study was to describe the health-related concerns and service needs of 27 older adults with MS, ages 55 to 81 years. Through in-depth interviews using a phenomenological approach, fear of the future was found to be a predominant concern among the participants. Within this fear, participants expressed particular concerns about experiencing further losses of mobility and independence, becoming a burden on caregivers, and having to move to a nursing home. The findings raise three major challenges for occupational therapists that include: (1) developing or modifying interventions that can enable older adults with MS to gain a sense of control over their future, (2) working with families affected by MS together with other disciplines such as psychology and social work, and (3) advocating for more and better community support options for persons with MS. 相似文献
5.
The number of left ventricular assist device (LVAD) implantations is growing as a result of increased waiting periods for cardiac transplantation and the decreased availability of organ donors. Furthermore, the Food and Drug Administration (FDA) has approved permanent LVAD support. After an acute hospitalization, patients with LVADs may need prolonged convalescence in a healthcare facility because they have complex medical needs and are physically disabled. Admission criteria need to be developed as essential patient and nursing competencies need to be defined as a part of a successful LVAD program in an acute rehabilitation center. Acute rehabilitation centers can help patients with LVADs transition to a home setting. 相似文献
6.
Ira R Katz Marcia Rupnow Chris Kozma Lon Schneider 《The American journal of geriatric psychiatry》2004,12(5):499-508
OBJECTIVE: Authors evaluated the association between use/dosage of risperidone (RIS) and falls in a residential-care dementia population. METHODS: Authors performed secondary analysis of data from ambulatory patients in a randomized, double-blind, placebo-controlled, 12-week trial of three RIS dosages (0.5 mg/day, 1 mg/day, 2 mg/day). Outcomes included number of fallers, rate of falls, and time until the first fall after randomization. Additional analyses evaluated wandering as a potential moderating or mediating variable. RESULTS: The ambulatory sample included 537 subjects. Of those, 22.3% on placebo, 18.0% on RIS 0.5 mg/day, 12.7% on 1 mg/day, and 27.3% on 2 mg/day, respectively, fell during the trial. The difference between the RIS 1 mg/day group and placebo was significant, with a significantly lower hazard ratio in the RIS 1-mg/day group than placebo. Wandering was associated with an increased risk of falls. Among 205 patients with the highest levels of wandering at baseline, RIS 1 mg/day was associated with approximately a 70% reduction in risk for falls versus placebo condition. However, in those with the lowest levels of wandering at baseline, RIS 2 mg/day may have increased the risk of falls. CONCLUSIONS: Evaluating the benefits versus risks of risperidone in patients with dementia is complex and must consider multiple outcomes as a function of dose. At 1 mg/day, RIS was associated with decreased falls, especially in patients who exhibit wandering. However, at 2 mg/day, it may increase the risk of falls in ambulatory individuals with low levels of wandering. 相似文献
7.
A peer tutorial programme which is available to all first- and second-year medical students has been in operation at Case Western Reserve University School of Medicine since 1972. A retrospective study of the classes of 1982, 1983 and 1984 was undertaken to assess the participation levels in the tutorial programme and to compare the participation level to available performance parameters. The analysis revealed that 54% of the first-year classes and 22% of the second-year classes participated in the peer tutorial programme. X2 analysis of the data demonstrated that the relationship between participation in the tutorial programme and performance on examinations reached statistical significance. The results suggested that an open peer tutorial programme responded to the needs, both cognitive and affective, of medical students. 相似文献
8.
Marcia W. Swanson P.T. Forrest C. Bennett M.D. Kirkwood K. Shy M.D. Michael F. Whitfield M.D. 《Developmental medicine and child neurology》1992,34(4):321-337
The predictive validity of infant neuromotor evaluation by the Movement Assessment of Infants (MAI) was investigated in low-birthweight infants. Motor performance at four and eight months was examined in relation to neurodevelopmental outcome at 18 months of age. Correlations were equally strong between total MAI risk scores at four and eight months and performance on the Bayley Scales. Muscle tone observations were more discriminating at four months, and automatic reactions and volitional movement were most predictive at eight months. The MAI was highly sensitive to neurodevelopmental abnormality at four and eight months and more sensitive than the Bayley Motor Scale; both assessment tools had lower specificity at eight months. The high false-positive rate is attributed to transient neuromotor abnormalities and immaturity of motor function in low-birthweight infants with normal outcome. 相似文献
9.
Nuno Fonseca Filomena Caetano José Santos Filipe Seixo Leonel Bernardino Isabel Silvestre Paula Cardoso Filomena Segurado Lopes Inês 《Revista portuguesa de cardiologia》2004,23(3):365-375
INTRODUCTION: In patients (pts) with atrial fibrillation (AF) of more than 48 hours' duration, electrical cardioversion (ECV) should only be performed after 3 weeks of effective anticoagulation. Transesophageal echocardiography (TEE) allows earlier ECV; however, despite exclusion of thrombi in the atrium and left atrial appendage (LAA), cases of thromboembolism related to ECV have been documented in AF. To define a low-risk group for cardioversion without previous anticoagulation, pts were selected for immediate ECV if no thrombi or dynamic spontaneous echo contrast (auto-contrast) were found after TEE and if LAA velocity was more than 0.25 m/sec. METHODS AND RESULTS: We performed TEE in 31 consecutive pts referred for ECV for AF of more than 48 hours' duration and without previous anticoagulation. After TEE the pts eligible for immediate ECV began anticoagulation with low molecular weight heparin (enoxaparin), subcutaneously in therapeutic doses, together with warfarin immediately before cardioversion. Enoxaparin was continued until an INR of over 2 was reached. Based on the TEE findings, the pts were divided in 2 groups: immediate ECV, group A, 20 pts with a mean age of 62 +/- 13 years, 6 female; and conventional therapy with warfarin before ECV, group B, 11 pts, mean age of 67 +/- 10 years (p < 0.05), 2 female. None of the pts in either group had mitral stenosis or previous episodes of thromboembolism. The mean transverse diameter of the left atrium in the 31 pts was 47 +/- 4.5 mm, without statistically significant differences between the 2 groups. Of the 11 pts in group B, 3 had a thrombus in the LAA, 6 dynamic spontaneous echo contrast and the remainder LAA velocities of less than 0.25 m/sec. ECV was achieved in all the pts, with no complications. Oral anticoagulation was maintained for at least a month. At one month, sinus rhythm was maintained in 75% of group A and 45% of group B (p < 0.01). CONCLUSION: In pts with AF of more than 48 hours' duration and no previous history of thromboembolism, the use of our exclusion criteria during TEE enabled stratification of a low-risk population for immediate ECV, which was accomplished effectively and safely in 2/3 of the pts. This strategy is associated with early symptomatic improvement, and may contribute to maintenance of sinus rhythm after one month, which was significantly better than in the pts who had prolonged therapy with warfarin before ECV, despite the differences found in age and left ventricular function. 相似文献
10.
We report a case of mammaplasty followed by a marked convergence of the nipple-areolar complex and describe the surgical repair by means of an inferior dermal-fat curved flap. The curve of the inferior pedicle permits one to raise the nipple to its normal position with ease and exceptional viability, even if a breast reduction procedure is associated. 相似文献