全文获取类型
收费全文 | 879篇 |
免费 | 90篇 |
国内免费 | 108篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 102篇 |
妇产科学 | 8篇 |
基础医学 | 132篇 |
口腔科学 | 36篇 |
临床医学 | 170篇 |
内科学 | 158篇 |
皮肤病学 | 6篇 |
神经病学 | 40篇 |
特种医学 | 78篇 |
外科学 | 65篇 |
综合类 | 45篇 |
一般理论 | 1篇 |
预防医学 | 97篇 |
眼科学 | 15篇 |
药学 | 63篇 |
中国医学 | 1篇 |
肿瘤学 | 57篇 |
出版年
2023年 | 4篇 |
2021年 | 15篇 |
2020年 | 4篇 |
2019年 | 9篇 |
2018年 | 15篇 |
2017年 | 14篇 |
2016年 | 16篇 |
2015年 | 19篇 |
2014年 | 15篇 |
2013年 | 28篇 |
2012年 | 37篇 |
2011年 | 37篇 |
2010年 | 24篇 |
2009年 | 27篇 |
2008年 | 25篇 |
2007年 | 74篇 |
2006年 | 29篇 |
2005年 | 51篇 |
2004年 | 34篇 |
2003年 | 31篇 |
2002年 | 33篇 |
2001年 | 25篇 |
2000年 | 40篇 |
1999年 | 16篇 |
1998年 | 51篇 |
1997年 | 38篇 |
1996年 | 40篇 |
1995年 | 21篇 |
1994年 | 27篇 |
1993年 | 17篇 |
1992年 | 25篇 |
1991年 | 12篇 |
1990年 | 17篇 |
1989年 | 21篇 |
1988年 | 21篇 |
1987年 | 18篇 |
1986年 | 21篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 13篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1977年 | 8篇 |
1976年 | 12篇 |
1975年 | 4篇 |
1967年 | 4篇 |
1966年 | 6篇 |
1965年 | 4篇 |
排序方式: 共有1077条查询结果,搜索用时 15 毫秒
41.
Delta V as a predictor of significant injury for children involved in frontal motor vehicle crashes 下载免费PDF全文
OBJECTIVE: The objective of this study was to examine the association between delta V and risk of injury to children involved in frontal motor vehicle crashes. BACKGROUND: Previous studies, primarily focused on adult occupants, have demonstrated the relationship between crash severity, as measured by delta V and injury severity. As children have unique safety needs, these results cannot be directly applied to the pediatric population. METHODS: Case series crash investigation data and clinical injury information were reviewed from a child-focused crash surveillance system. Analyses were performed examining the relationship between the estimated delta V and any AIS > or = 2 or any AIS > or = 3 injury. RESULTS: Detailed crash investigation and clinical data were available on 407 children involved in 235 frontal crashes. The average delta V for all crashes was 29 +/- 16.9 kph [18 +/- 10.5 mph (range, 5-123 kph)]. Delta V was strongly and positively associated with the odds of both an AIS > or = 2 and AIS > or = 3 injury (P < 0.0001). The adjusted odds of at least one AIS > or = 2 injury increased on average by 56% (95% confidence interval [CI], 33%-85%) for each 10 kph increase in delta V. Similarly, the adjusted odds of at least one AIS > or = 3 injury increased on average by 67% (95% CI, 40%-102%) for each 10 kph increase in delta V. The delta V at which 50% of child occupants would be expected to sustain any AIS > or = 2 injury was 37 kph [23.0 mph (95% CI, 32-45 kph)], and any AIS > or = 3 injury was 63 kph [39.1 mph (95% CI, 51-infinity kph)]. CONCLUSION: Delta V is strongly predictive of injury risk for child occupants. As many newer generation cars are now fitted with event data recorders, this information is increasingly available and may become useful as a clinical predictor. 相似文献
42.
Jeffrey A. Cigrang G. Wayne Talcott JoLyn Tatum Monty Baker Daniel Cassidy Scott Sonnek Douglas K. Snyder Christina Balderrama‐Durbin Richard E. Heyman Amy M. Smith Slep 《Journal of traumatic stress》2014,27(1):58-65
Although previous research has indicated an elevated prevalence of posttraumatic stress disorder (PTSD) and other mental health problems among veterans of Operations Iraqi Freedom and Enduring Freedom following deployment, most of this research has been cross‐sectional and has focused on a limited range of military groups and outcome criteria. This investigation was a longitudinal study of U.S. Air Force security forces assigned to a year‐long high‐threat ground mission in Iraq to determine the degree to which airmen's emotional and behavioral health and committed relationships were adversely impacted by an extended deployment to a warzone. Participants were a cohort of 164 security forces airmen tasked to a 365‐day deployment to train Iraqi police. Airmen completed study measures both prior to and 6–9 months following deployment. Rates of deterioration in individual and interpersonal adjustment were both significant and medium to large in magnitude of effect, d = 0.43 to 0.90. Results suggest that the negative effects of deployment are related to levels of traumatic experiences and do not spontaneously remit within the first 6–9 months following return from deployment—particularly among those service members having relatively lower levels of social support. 相似文献
43.
Frederick H Koh Jason MW Chua Joselyn LJ Tan Fung-Joon Foo Winson J Tan Sharmini S Sivarajah Leonard Ming Li Ho Bin-Tean Teh Min-Hoe Chew 《World journal of gastrointestinal surgery》2021,13(8):734-755
A growing body of evidence has demonstrated the prognostic significance of sarcopenia in surgical patients as an independent predictor of postoperative complications and outcomes. These included an increased risk of total complications, major complications, re-admissions, infections, severe infections, 30 d mortality, longer hospital stay and increased hospitalization expenditures. A program to enhance recovery after surgery was meant to address these complications; however, compliance to the program since its introduction has been less than ideal. Over the last decade, the concept of prehabilitation, or “pre-surgery rehabilitation”, has been discussed. The presurgical period represents a window of opportunity to boost and optimize the health of an individual, providing a compensatory “buffer” for the imminent reduction in physiological reserve post-surgery. Initial results have been promising. We review the literature to critically review the utility of prehabilitation, not just in the clinical realm, but also in the scientific realm, with a resource management point-of-view. 相似文献
44.
45.
46.
R E Brolin MD JH Gorman MD RC Gorman MD AJ Petschenik M D LJ Bradley MS RD HA Kenler PhD RP Cody Pb D 《Journal of gastrointestinal surgery》1998,2(5):436-442
Although iron, vltamm B12, and folate deficiency have been well documented after gastric bypass operations performed for morbid obesity, there is surprisingly
little information on either the natural course or the treatment of these deficiencies in Roux-en-Y gastric bypass (RYGB)
patients Durmg a l0-year period, a complete blood count and serum levels of iron, total iron-binding capacity, vltamin B12, and folate were obtained in 348 patients preoperatively and postoperatively at 6-month intervals for the first 2 years,
then annually thereafter The principal objectives of this study were to determine how readily patients who developed metabolic
deficiencies after Roux-en-Y gastric bypass responded to postoperative supplements of the deficient micronutrient and to learn
whether the risk of developmg these deficiencies decreases over time Hemoglobin and hematocrit levels were slgnificantly decreased
at all postoperative intervals in comparison to preoperative values Moreover, at each successive interval through 5 years,
hemoglobin and hematocrit were decreased signifiantly compared to the preceding interval Folate levels were significantly
increased compared to preoperative levels at all time intervals Iron and vltamin B12 levels were lower than preoperative measurements and remained relatively stable postoperatively Half of the low hemoglobin
levels were not associated with iron deficiency Taking multivltamin supplements resulted in a lower incidence of folate deficiency
but did not prevent iron or vitamin B12 deficiency Oral supplementation of iron and vitamin B12 corrected defiaencies in 43% and 81% of cases, respectively Folate deficiency was almost always corrected with multivitamins
alone No patient had symptoms that could be attributed to either vitamin B12 or folate deficiency Conversely, many patients had symptoms of iron deficiency and anenua Lack of symptoms of vitamin B12 and folate deficiency suggests that these deficiencies are not clinically important after RYGB Conversely, iron deficiency
and anemia are potentially serious problems after RYGB, particularly in younger women Hence we recommend prophylactic oral
iron supplements to premenopausal women who undergo RYGB 相似文献
47.
A novel retinal biomarker for Parkinson's disease: Quantifying the foveal pit with optical coherence tomography 下载免费PDF全文
48.
Meniscal injuries: detection using MR imaging 总被引:15,自引:0,他引:15
Reicher MA; Hartzman S; Duckwiler GR; Bassett LW; Anderson LJ; Gold RH 《Radiology》1986,159(3):753-757
Both retrospective and blinded analyses of thin-section, high-resolution magnetic resonance (MR) images of the knee joint, produced using a solenoid surface coil, indicate that MR imaging is an effective technique for evaluating meniscal injuries. Images of 49 patients were evaluated, and the results were correlated with those of subsequent arthroscopy. A grading scale was developed to rate the index of suspicion of a meniscal tear based on the MR images. Overall, approximately 80% of menisci rated grade 4 (definite tear) or 3 (probable tear) were found to have corresponding tears at arthroscopy. In many other patients with a grade 4 or 3 meniscus in whom a corresponding tear was not found arthroscopically, meniscal tears at other sites or other abnormalities were correctly diagnosed using MR. A majority of the false-positive MR images involved the posterior horns of the menisci, the sites of most false-negative arthroscopic diagnoses. The predictive value of a negative MR image was almost 100%. Even in patients with moderate-to-large effusions, the menisci were accurately evaluated. The results imply that MR imaging is useful in the preoperative evaluation of suspected meniscal tears. 相似文献
49.
Auber ML; Horwitz LJ; Blaauw A; Khorana S; Tucker S; Woods T; Warmuth M; Dicke KA; McCredie KB; Spitzer G 《Blood》1988,71(1):166-172
Relatively nonmyelotoxic drugs and drug combinations were investigated for their ability to eliminate malignant cells from human bone marrow. In vitro 90% inhibitory concentration (IC90) doses were established on granulocyte macrophage colony-forming units (GM-CFU) in culture of bone marrow by using the GM-CFU assay for the following drugs: 4- hydroperoxycyclophosphamide (4-HC), Adriamycin, L-asparaginase, bleomycin, hydrocortisone, VP-16, spirogermanium, Taxol, and vincristine. The leukemic cell kill efficiency of these drugs at IC90 doses was compared with that of 4-HC on acute lymphoid leukemia (ALL) cell lines by using the limiting-dilution assay. Under these conditions, no single drug was superior to 4-HC. To increase the in vitro effect in leukemic cell kill, combinations of vincristine with hydrocortisone, Adriamycin, VP-16, and 4-HC were investigated. Vincristine at 1 to 5 micrograms/mL increased the marrow cytotoxicity of hydrocortisone, Adriamycin, and VP-16, but it was protective (subadditive) with 4-HC. Vincristine and 4-HC in combination was additive to supraadditive on ALL cell lines, increased the leukemic cell kill by one to two logs above 4-HC alone at IC90 doses (P less than .05), and was not affected by the addition of excess marrow cells. The recommended doses for chemopurging in clinical studies are vincristine, 1 to 5 micrograms/mL, plus 4-HC, 5 micrograms/mL. 相似文献
50.