全文获取类型
收费全文 | 24731篇 |
免费 | 1867篇 |
国内免费 | 69篇 |
专业分类
耳鼻咽喉 | 237篇 |
儿科学 | 971篇 |
妇产科学 | 826篇 |
基础医学 | 3228篇 |
口腔科学 | 336篇 |
临床医学 | 3148篇 |
内科学 | 4408篇 |
皮肤病学 | 539篇 |
神经病学 | 2374篇 |
特种医学 | 543篇 |
外科学 | 2636篇 |
综合类 | 251篇 |
一般理论 | 36篇 |
预防医学 | 3364篇 |
眼科学 | 311篇 |
药学 | 1578篇 |
中国医学 | 22篇 |
肿瘤学 | 1859篇 |
出版年
2024年 | 29篇 |
2023年 | 265篇 |
2022年 | 308篇 |
2021年 | 807篇 |
2020年 | 510篇 |
2019年 | 844篇 |
2018年 | 857篇 |
2017年 | 646篇 |
2016年 | 668篇 |
2015年 | 717篇 |
2014年 | 980篇 |
2013年 | 1418篇 |
2012年 | 2127篇 |
2011年 | 2278篇 |
2010年 | 1180篇 |
2009年 | 1059篇 |
2008年 | 1688篇 |
2007年 | 1797篇 |
2006年 | 1589篇 |
2005年 | 1404篇 |
2004年 | 1244篇 |
2003年 | 1107篇 |
2002年 | 1011篇 |
2001年 | 197篇 |
2000年 | 142篇 |
1999年 | 146篇 |
1998年 | 176篇 |
1997年 | 105篇 |
1996年 | 86篇 |
1995年 | 91篇 |
1994年 | 67篇 |
1993年 | 48篇 |
1992年 | 76篇 |
1991年 | 61篇 |
1990年 | 68篇 |
1989年 | 51篇 |
1988年 | 67篇 |
1987年 | 66篇 |
1986年 | 55篇 |
1985年 | 61篇 |
1984年 | 41篇 |
1983年 | 35篇 |
1982年 | 31篇 |
1981年 | 27篇 |
1979年 | 40篇 |
1975年 | 31篇 |
1974年 | 38篇 |
1973年 | 42篇 |
1972年 | 29篇 |
1971年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Janine Barden-O'Fallon Chirayath Suchindran Amy O Tsui 《American journal of human biology》2006,18(2):214-218
This study uses data from a population-based survey to examine the fertility schedules of 704 women in a rural district of Malawi. The main objective is to assess self-reported fecundity status as a measure of fertility impairment. Life tables are used to examine the timing and tempo of births for women reporting difficulty getting pregnant as compared to women with no reported fecundity difficulties. Results of the analysis indicate that women with self-reported fecundity difficulties are older at each birth and have longer median birth intervals than do women with no reported difficulties. Cox proportional hazards models show that the report of a difficulty getting pregnant is significantly associated with at least a 30% lower likelihood of a first, second, or third birth. The relationships are not modified when accounting for demographic characteristics, previous sexual behaviors, or STI status. 相似文献
62.
Amy K. McNulty PhD ; Marisa Schmidt BS ; Teri Feeley BS ; Kris Kieswetter PhD 《Wound repair and regeneration》2007,15(6):838-846
Vacuum Assisted Closure brand Negative Pressure Wound Therapy (V.A.C. NPWT) has been shown to be an effective therapeutic option for the treatment of recalcitrant wounds; however, the mechanism of action at the cellular level remains to be elucidated. Here, we examined the effects of negative pressure wound therapy, manifolded with two different dressings, on fibroblast viability, chemotactic signaling, and proliferation in a fibrin clot matrix. Fibroblasts were grown in a three-dimensional fibrin matrix and were treated for 48 hours with either V.A.C. NPWT and GranuFoam Dressing, or with gauze under suction, or as static controls without negative pressure or dressings. Cells treated by gauze under suction showed significantly greater cell death and stimulated less migration and proliferation than static and V.A.C. NPWT-treated cells (p<0.05). Apoptosis was also significantly higher in gauze under suction than in static treatments. These results indicate that the dressing material has a significant effect on cell response following negative pressure wound therapy. The ability to support cell growth, stimulate chemotaxis, and proliferation without increasing apoptosis may provide an insight into the mechanisms of action of V.A.C. NPWT. 相似文献
63.
Plasma pharmacokinetics of high-dose oral busulfan in children and adults undergoing bone marrow transplantation 总被引:2,自引:0,他引:2
Bruce Bostrom Karen Enockson Amy Johnson Alyssa Bruns Bruce Blazar 《Pediatric transplantation》2003,7(S3):12-18
Abstract: We have analyzed the plasma pharmacokinetics of busulfan in 272 patients receiving high-dose oral busulfan and intravenous cyclophosphamide in conjunction with allogeneic or autologous bone marrow transplantation. The patients ranged in age from 2 months to 59 yr (mean 10, median 12 yr) and had the following diagnoses: thalassemia or sickle cell anemia (n = 74); leukemia or myelodysplasia (n = 112); inborn errors of metabolism (n = 41) or immunodeficiency (n = 45). Plasma specimens were collected following the first dose for each patient which ranged from 1 to 4 mg/kg (mean ± SD, 1.21 ± 0.41, median 1.15). Busulfan was quantitated using ultraviolet absorbance detection after derivatization and HPLC separation. Pharmacokinetic parameters were derived by modeling the raw data to fit first-order single compartment kinetics. The kinetic parameters showed wide interpatient variability independent of age and diagnosis. There was a statistically significant correlation of age with the following parameters: area under the curve (AUC); maximal concentration; minimum concentration; clearance; volume of distribution and absorption half-time. The coefficients of determination (i.e. correlation coefficient squared) were low ranging from 0.04 to 0.12 implying only a small part (i.e. 4–12%) of the variance was explained by age. Although busulfan pharmacokinetics are age-related most of the variability is not explained by age or diagnosis. 相似文献
64.
Background. Redundant facial and neck skin is a major feature of aging and historically has been corrected surgically. Recently, monopolar radiofrequency application has been introduced for nonablative tissue tightening of skin by volumetric heating of the deep dermis. It has been able to improve neck and cheek laxity and periorbital rhytides and to elevate eyebrows. However, questions remain as to the ideal parameters needed to optimize the use of radiofrequency.
Objective. To determine the safety and report on the efficacy of a radiofrequency application that involves a multipass vector (mpave) technique to target facial and neck skin laxity.
Methods. Twenty-five patients (skin types I to V) with mild to severe facial and neck laxity received one treatment session with monopolar radiofrequency. Treatment parameters, adverse events, and digital photographs were recorded. All patients were treated with a multipass vector technique consisting of four to five passes targeted over areas of skin that would most improve facial laxity. The multipass vector (mpave) treatment approach is described. Energy levels ranged from 62 to 91 J/cm2 per pulse.
Results. All patients experienced some immediate erythema and edema, which had completely resolved in most patients within 48 hours. No scarring or dyspigmentation was noted on follow-up at 6 and 12 weeks. Photographic analysis of pre- and post-treatment digital images revealed cosmetic improvement in facial and neck laxity in 96% of patients. The majority of patients demonstrated a moderate or better improvement. Stacked pulses in the submental region were shown to reduce fat.
Conclusions. The direct application of monopolar radiofrequency to facial and neck skin using a multipass vector (mpave) treatment approach was safely tolerated in patients of all skin types. Patient satisfaction correlated well with photographic analysis, and the technique was shown to be efficacious for most patients. 相似文献
Objective. To determine the safety and report on the efficacy of a radiofrequency application that involves a multipass vector (mpave) technique to target facial and neck skin laxity.
Methods. Twenty-five patients (skin types I to V) with mild to severe facial and neck laxity received one treatment session with monopolar radiofrequency. Treatment parameters, adverse events, and digital photographs were recorded. All patients were treated with a multipass vector technique consisting of four to five passes targeted over areas of skin that would most improve facial laxity. The multipass vector (mpave) treatment approach is described. Energy levels ranged from 62 to 91 J/cm2 per pulse.
Results. All patients experienced some immediate erythema and edema, which had completely resolved in most patients within 48 hours. No scarring or dyspigmentation was noted on follow-up at 6 and 12 weeks. Photographic analysis of pre- and post-treatment digital images revealed cosmetic improvement in facial and neck laxity in 96% of patients. The majority of patients demonstrated a moderate or better improvement. Stacked pulses in the submental region were shown to reduce fat.
Conclusions. The direct application of monopolar radiofrequency to facial and neck skin using a multipass vector (mpave) treatment approach was safely tolerated in patients of all skin types. Patient satisfaction correlated well with photographic analysis, and the technique was shown to be efficacious for most patients. 相似文献
65.
Bernadette Lalonde Jacqueline E Wolvaardt Elize M Webb Amy Tournas‐Hardt 《Journal of the International AIDS Society》2007,9(1):6-6
The objective of the study was to conduct a process and outcomes evaluation of the International AIDS Conference (IAC). Reaction evaluation data are presented from a delegate survey distributed at the 2004 IAC held in Thailand. Input and output data from the Thailand IAC are compared to data from previous IACs to ascertain attendance and reaction trends, which delegates benefit most, and host country effects. Outcomes effectiveness data were collected via a survey and intercept interviews. Data suggest that the host country may significantly affect the number and quality of basic science IAC presentations, who attends, and who benefits most. Intended and executed HIV work‐related behavior change was assessed under 9 classifications. Delegates who attended 1 previous IAC were more likely to report behavior changes than attendees who attended more than 1 previous IAC. The conference needs to be continually evaluated to elicit the required data to plan effective future IACs. 相似文献
66.
Amy Farabaugh David Mischoulon Maurizio Fava Wendy Guyker Jonathan Alpert 《Annals of clinical psychiatry》2004,16(4):217-224
BACKGROUND: Research studies have focused attention on the importance of the comorbidity of personality disorders and depression. METHODS: The present review examines seven potential explanations for the overlap to clarify the nature of the relationship, if any, between depression and personality disorder diagnoses. RESULTS: There may be many explanations for the potential overlap of personality disorders (PD) and major depressive disorder (MDD). For example, the distinction between states and traits may not be as clear and definitive as suggested in the DSM-IV. In some cases, depression may influence personality pathology, and may even lead to personality disorders. In other cases, personality disorders may lead to MDD. CONCLUSION: Further research may clarify the nature of the relationship, if any, between depression and personality disorder diagnoses, as well as the relationship between comorbidity and treatment response. 相似文献
67.
68.
Zvi Metzger Hadar Better Itzhak Abramovitz 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(3):425-433
OBJECTIVE: The study was designed to test application of ultraviolet light to root canal walls, as a mean of complementary immediate disinfection after the use of sodium hypochlorite. STUDY DESIGN: Root canals were infected ex vivo with Enterococcus faecalis for 48 hours. Non-attached bacteria were washed away, and the remaining attached bacteria were subjected to disinfection, with 5% sodium hypochlorite alone or followed by exposure to ultraviolet light (254 nm, 300 mJ/cm(2)). Root canals were then tested for remaining viable bacteria. Canals were obturated and tested again after 14 days. RESULTS: Sodium hypochlorite alone achieved negative cultures in only 47% of the cases, but 96% was achieved with sodium hypochlorite followed by ultraviolet light (P < .001). This status was also maintained after 14 days. CONCLUSIONS: Illumination of root canals with ultraviolet light may be an effective supplementary means to achieve immediate disinfection of infected root canals. 相似文献
69.
The lymph flow of the thoracic duct, the protein content of the lymph, bile flow and bile composition are studied during the first three hours of the recirculation phase in experimental liver transplantation. It is established that the lymph flow and the protein content of the thoracic duct decrease as a result of the interruption of hepatic lymph flow of a high protein concentration. The change in bile composition and flow is due to the reduced bile acid excretion of the transplanted hepatic tissue. 相似文献
70.
W. Bruce Vogel PhD Jeffrey W. Dwyer PhD Amy J. Barton PhD 《The Journal of rural health》1994,10(4):258-265
When rural/urban differences are found in health status or health care use, it is often desirable to identify those factors (such as age, social structure, income, etc.) that influence such differences. To this end, researchers often test rural/urban differences in age, social structure, income, etc., for statistical significance. Also, researchers commonly perform multivariate analyses (such as multiple regressions) to examine rural-urban differences in the influence of various independent variables on the dependent variable of interest. Frequently, researchers discover: (1) statistically significant rural/urban differences in the independent variables (such as age, social structure, income, etc.) and (2) statistically significant rural/urban differences in the effects of these independent variables (i.e., statistically significant rural/urban differences in regression coefficients). The analysis typically stops here, without addressing the relative contributions of (1) and (2) to the rural/urban differences in the dependent variable. This paper argues that the relative contributions of (1) and (2) have important implications for the way policy-makers address rural health problems. This paper presents a method for assessing the relative contributions of differences in the independent variables and differences in regression coefficients to observed differences in the dependent variable, and illustrates the application of the method by analyzing rural/urban differences in the risk of institutionalization. 相似文献