全文获取类型
收费全文 | 3548篇 |
免费 | 220篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 141篇 |
妇产科学 | 132篇 |
基础医学 | 449篇 |
口腔科学 | 33篇 |
临床医学 | 642篇 |
内科学 | 552篇 |
皮肤病学 | 47篇 |
神经病学 | 367篇 |
特种医学 | 59篇 |
外科学 | 254篇 |
综合类 | 41篇 |
一般理论 | 2篇 |
预防医学 | 537篇 |
眼科学 | 25篇 |
药学 | 172篇 |
中国医学 | 10篇 |
肿瘤学 | 286篇 |
出版年
2023年 | 21篇 |
2022年 | 24篇 |
2021年 | 49篇 |
2020年 | 31篇 |
2019年 | 50篇 |
2018年 | 61篇 |
2017年 | 40篇 |
2016年 | 74篇 |
2015年 | 49篇 |
2014年 | 81篇 |
2013年 | 175篇 |
2012年 | 193篇 |
2011年 | 196篇 |
2010年 | 113篇 |
2009年 | 98篇 |
2008年 | 237篇 |
2007年 | 248篇 |
2006年 | 202篇 |
2005年 | 225篇 |
2004年 | 205篇 |
2003年 | 199篇 |
2002年 | 178篇 |
2001年 | 53篇 |
2000年 | 32篇 |
1999年 | 50篇 |
1998年 | 36篇 |
1997年 | 42篇 |
1996年 | 50篇 |
1995年 | 42篇 |
1994年 | 34篇 |
1993年 | 28篇 |
1992年 | 37篇 |
1991年 | 29篇 |
1990年 | 35篇 |
1989年 | 26篇 |
1988年 | 39篇 |
1987年 | 32篇 |
1986年 | 28篇 |
1985年 | 26篇 |
1984年 | 24篇 |
1983年 | 40篇 |
1982年 | 41篇 |
1981年 | 23篇 |
1980年 | 15篇 |
1978年 | 24篇 |
1977年 | 14篇 |
1976年 | 15篇 |
1975年 | 19篇 |
1973年 | 22篇 |
1968年 | 14篇 |
排序方式: 共有3780条查询结果,搜索用时 31 毫秒
1.
2.
3.
P Helwig G Faust U Hindenlang B Kr?plin C Eingartner 《Technology and health care》2006,14(4-5):411-419
Static analysis with finite element of a realistic femur nail bone-implant system in a typical proximal femoral fracture under physiological load bearing situations provides results for stress, displacement and strain. The question to be answered is, if simulation with the finite element analysis is able to explain biomechanically clinical observed patterns of failure. Surface-Reconstruction with CT database of a proximal femur and reconstruction with CT based density data was done. Next steps were to unite the bone structure with the Proximal Femoral Nail and to model two relevant fractures (31-A2.2 and A2.3 according AO). After modelling of geometry, isotropic material behaviour and load application numeric calculation of the femur-nail system with FE-software was performed. FE simulation mainly shows an axial dislocation of the femoral head screw with nearly no dislocation of the antirotation screw. This so-called z-effect therefore means: (1) Tilting of the proximal main fragment around the sagittal axis between the screws and (2) relative movement of both screws in the frontal plane. Relative movement of the two screws against each other could be the reason for implant failure, the so called cut out. Furthermore simulation shows different gliding of the screws explaining the so called z-telescoping. The analyzed stress patterns have to be relativized, because isotropic material behaviour of cancellous bone was assumed. Further examinations for this issue are necessary. 相似文献
4.
M A Keller J Faust L J Rolewic D D Stewart 《Journal of pediatric gastroenterology and nutrition》1986,5(3):439-443
Lymphocytes from 10 paired colostrum and peripheral blood specimens were examined to determine if the colostral T cell population differs from the peripheral blood T cell population in subset distribution. The percentages of lymphocytes staining with OKT3, OKT4, and OKT8 murine monoclonal antibody were determined. Lymphocytes from colostrum were 74.7 +/- 2.5% OKT3+, 50.6 +/- 2.3% OKT4+, 24.0 +/- 1.7% OKT8+, whereas peripheral blood lymphocytes were 78.7 +/- 1.9% OKT3+, 48.4 +/- 1.4% OKT4+, and 29.8 +/- 1.6% OKT8+. The percentage of colostrum lymphocytes positive for OKT3 was significantly although not strikingly lower than the OKT3 percentage for blood lymphocytes (p less than 0.05). This difference was due to the lower percentage of OKT8 positive lymphocytes in colostrum compared with blood (p less than 0.01). Although the T cell subset distribution of colostrum generally appears to be similar to that in the peripheral blood, there were small differences in OKT3 and OKT8 percentages that were statistically significant suggesting the possibility of some selectivity of the colostral T cell population. 相似文献
5.
Dorothy Doughty Janet Ramundo Phyllis Bonham Janice Beitz Paula Erwin-Toth Renee Anderson Bonnie Sue Rolstad 《Journal of wound, ostomy, and continence nursing》2006,33(2):125-30; quiz 131-2
Wound assessment is a key element of effective wound care, and assessment of pressure ulcers includes accurate determination of wound stage. Although the original staging system established by Shea was based on his understanding of the pathology involved in pressure ulcer development, subsequent staging systems (and the one currently in use) were intended simply to establish the level of tissue damage. Recently, clinicians have drawn attention to numerous limitations associated with the current staging system, including the inability to differentiate between an inflammatory response involving intact skin and a deep tissue injury (deep bruising) underneath intact skin. This is a clinically significant difference because clinicians have noted that most inflammatory responses resolve with intervention, whereas most areas of deep tissue injury progress to full-thickness ulcers even when appropriate intervention is provided. A second area of controversy involves partial-thickness (Stage 2) lesions; because many of these lesions are caused by maceration and/or friction (as opposed to pressure) clinicians are frequently unclear regarding which of these lesions should be staged. In response to these concerns, the National Pressure Ulcer Advisory Panel convened a consensus forum and published white papers to clearly outline the issues; they solicited clinician feedback on the white papers and the Wound, Ostomy, Continence Nurses Society provided a written response. This article summarizes the key points of the white papers, WOCN Society response, and consensus forum discussion. 相似文献
6.
It was hypothesized that members of an older cohort of seriously mentally ill community mental health clients would develop stronger alliances with intensive case managers. Eighty-six clients participating in a study of case management services completed a measure of working alliance and structured interviews. It was found that older cohort clients, those age 45 or older, showed much stronger alliances with their case managers than younger clients.This research is funded by NIMH/SAMHSA grant R18MH46082. 相似文献
7.
Differentiation of pancreatic epithelial progenitor cells into hepatocytes following transplantation into rat liver
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mariana D. Dabeva Seong-Gyu Hwang Srinivasa Rao G. Vasa Ethel Hurston Phyllis M. Novikoff Douglas C. Hixson Sanjeev Gupta David A. Shafritz 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(14):7356-7361
The ability to identify, isolate, and transplant progenitor cells from solid tissues would greatly facilitate the treatment of diseases currently requiring whole organ transplantation. In this study, cell fractions enriched in candidate epithelial progenitor cells from the rat pancreas were isolated and transplanted into the liver of an inbred strain of Fischer rats. Using a dipeptidyl dipeptidase IV genetic marker system to follow the fate of transplanted cells in conjunction with albumin gene expression, we provide conclusive evidence that, after transplantation to the liver, epithelial progenitor cells from the pancreas differentiate into hepatocytes, express liver-specific proteins, and become fully integrated into the liver parenchymal structure. These studies demonstrate the presence of multipotent progenitor cells in the adult pancreas and establish a role for the liver microenvironment in the terminal differentiation of epithelial cells of foregut origin. They further suggest that such progenitor cells might be useful in studies of organ repopulation following acute or chronic liver injury. 相似文献
8.
We examine major criticisms of studies comparing paraprofessionals' and professionals' therapeutic effectiveness. Such analysis does not support the contention that methodological weaknesses of the studies produced systematic biases against professional therapists. Thus, despite common beliefs to the contrary, the finding that formal training does not predict successful therapy appears sound. We discuss the implications of this finding for research, training, and clinical practice. 相似文献
9.
Algal toxicity of binary combinations of pesticides 总被引:5,自引:0,他引:5
10.
Phyllis W Sharps Ayman A E El-Mohandes M Nabil El-Khorazaty Michele Kiely Tessa Walker 《Journal of perinatology》2003,23(5):414-419
OBJECTIVE: To describe breastfeeding initiation among 210 urban African-American mothers with inadequate prenatal care. METHODS: This study is a case-control study of postpartum mothers recruited from four large urban hospitals. RESULTS: Mothers who chose to breastfeed were more educated, employed before birth, married, and using contraception postnatally. Regression model analysis controlling for demographic differences revealed that breastfeeding was significantly associated with a higher perception of severity of illness and higher confidence in the ability of health care to prevent illness. Breastfeeding mothers were less likely to reverse parent-child roles and had a lower perception of hassle from their infant's behavior. When comparing mothers who breastfed longer than 8 weeks to those who did not breastfeed, breastfeeding mothers had high scores related to empathy toward infants on the Adult-Adolescent Parenting Inventory as well as a low perception of hassle on the Parenting Daily Hassle. The perception of existing formal or informal social support did not influence breastfeeding behavior. CONCLUSION: Personal attributes of low-income urban mothers such as health beliefs and parental attitudes may play a role in the initiation and duration of breastfeeding. Low-income African-American mothers may be influenced in their choice to breastfeed by supportive messages from physicians and nurses delivering care to mothers and their newborns. Emphasis should be placed on the role breastfeeding can play in preventing childhood illnesses. 相似文献