全文获取类型
收费全文 | 1416篇 |
免费 | 58篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 20篇 |
妇产科学 | 26篇 |
基础医学 | 125篇 |
口腔科学 | 47篇 |
临床医学 | 114篇 |
内科学 | 335篇 |
皮肤病学 | 25篇 |
神经病学 | 126篇 |
特种医学 | 43篇 |
外科学 | 372篇 |
综合类 | 1篇 |
预防医学 | 35篇 |
眼科学 | 23篇 |
药学 | 41篇 |
中国医学 | 2篇 |
肿瘤学 | 143篇 |
出版年
2022年 | 14篇 |
2021年 | 32篇 |
2020年 | 17篇 |
2019年 | 28篇 |
2018年 | 38篇 |
2017年 | 20篇 |
2016年 | 28篇 |
2015年 | 47篇 |
2014年 | 39篇 |
2013年 | 55篇 |
2012年 | 92篇 |
2011年 | 81篇 |
2010年 | 51篇 |
2009年 | 44篇 |
2008年 | 73篇 |
2007年 | 79篇 |
2006年 | 73篇 |
2005年 | 54篇 |
2004年 | 69篇 |
2003年 | 52篇 |
2002年 | 40篇 |
2001年 | 53篇 |
2000年 | 35篇 |
1999年 | 40篇 |
1998年 | 8篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 11篇 |
1993年 | 5篇 |
1992年 | 22篇 |
1991年 | 32篇 |
1990年 | 26篇 |
1989年 | 22篇 |
1988年 | 20篇 |
1987年 | 16篇 |
1986年 | 18篇 |
1985年 | 16篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1973年 | 6篇 |
1972年 | 9篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1967年 | 5篇 |
排序方式: 共有1484条查询结果,搜索用时 15 毫秒
71.
72.
73.
Guzzetta A Haataja L Cowan F Bassi L Ricci D Cioni G Dubowitz L Mercuri E 《Biology of the neonate》2005,87(3):187-196
OBJECTIVES: The neurodevelopmental progress of newborn term infants is checked routinely at around 6 weeks of postnatal age. The maturation of neurological signs in this age range however has not been systematically studied and normative data are not available. The aim of this study was to document any changes in posture, tone, reflexes, behaviour and movements in low-risk full-term infants between 3 and 10 weeks of postnatal age. STUDY DESIGN: We performed a structured neurological examination previously standardised in full-term newborns in the first 48 h after birth. In the current study, a total of 76 examinations were performed between 3 and 10 weeks of age in low-risk full-term infants. RESULTS: The results of the examinations were divided according to postnatal age. In most items, the scores changed with time, with a definite shift in their distribution occurring around 6 weeks. At this age, a reduction in flexor tone of the limbs was observed, together with an increase in active neck tone. Visual orientation in contrast had already improved by 3 weeks when all infants were able to follow a target in a full circle compared to newborns that are often only able to follow a target in an arc. CONCLUSIONS: Our results suggest that 6 weeks post-term birth is an important milestone for changes in neurological signs, particularly those related to muscle tone and posture, probably reflecting maturation of the nervous system. These findings provide important guidelines for the interpretation of the neurological examination performed at this age. 相似文献
74.
Khatib AM Bassi D Siegfried G Klein-Szanto AJ Ouafik L 《Journal of molecular medicine (Berlin, Germany)》2005,83(11):856-864
Biological control of individual cells, organs, and organisms is achieved through interplay of a host of specific interactions that involve various peptidic molecules as modulators or effectors. In tumor cells, these processes may result in uncontrolled growth as a consequence of autocrine and/or paracrine actions. In recent years, growing evidence has accumulated for the important role of proprotein convertases (PCs) and peptide -amidation enzymes in these processes. The widespread belief that these enzymes are involved in the major features of tumor progression, namely, invasiveness and metastasis, has taken place because of their capacity to process and activate many protein precursors involved in the neoplastic progression and metastasis. This includes degrading extracellular matrix proteases, growth promoting factors, and adhesion molecules. Usually, when the processing of these precursor proteins is achieved by one or more of the known PC family members within the general motif (K/R)-(X)n-(K/R), where n=0, 2, 4, or 6, and X, any amino acid except Cys, the accomplishment of the maturation of these molecules is attained by various posttranslational modifications, including the carboxy-terminal -amidation. This review article summarizes recent findings on the role of these enzymatic systems in multiple cellular functions that impact on the invasive/metastatic potential of cancer cells and highlight the potential use of their inhibitors in the treatment of multiple cancers. 相似文献
75.
76.
PURPOSE: Measurements concerning the usability or safety of optical equipment are based on assumptions regarding luminous efficiency. The current luminous efficiency functions are derived from human sensitivity experiments taken at low light levels compared with the outdoor daytime environment. The amount of error induced by extrapolating from low light level data to high light level applications is not known. We sought to determine whether standard luminous efficiency curves CIE V(lambda) and CIE Heterochromatic Brightness Matching are appropriate for measuring day-use optical equipment such as display phosphors, lasers, LEDs, and laser eye protection, which are becoming more common in aviation. METHODS: Flicker photometry and successive heterochromatic brightness matching were used to measure changes in luminance efficiency functions with increasing levels (1, 10, 100, and 1000 fL) of light adaptation. RESULTS: Luminous efficiency was found to depend on both the method and the reference intensity with which the measurements were taken. For heterochromatic brightness matching, luminous efficiency increased for longer wavelengths as reference intensity increased. Peak luminous efficiency shifted from approximately 540 nm to greater than 600 nm with increasing intensity. Peak luminous efficiency was constant for flicker photometry across all intensities, but the function narrowed slightly at 100 fL. CONCLUSION: Luminous efficiency curves measured at high reference intensities are substantially different from the standard luminous efficiency functions. Caution should be used when measuring spectrally narrow and bright sources such as lasers and LEDs with a V(lambda) corrected photometer because the measured luminance may correlate poorly with perceived brightness. 相似文献
77.
78.
Bassi C Butturini G Molinari E Mascetta G Salvia R Falconi M Gumbs A Pederzoli P 《Digestive surgery》2004,21(1):54-59
BACKGROUND: Pancreatic fistula (PF) is still regarded as a serious complication both in terms of frequency and sequelae. The incidence varies greatly in different reports because of the different definitions used. The aim of this study was to compare several definitions of PF encountered in the current literature and to demonstrate that the PF rate in the same group of patients treated in a high volume center is dependent upon the definition applied. METHODS: A Medline search of the last 10 years was performed as regards the definition of PF. A score was assigned to the reproducible definitions based upon two basic parameters: daily output (cm3) and duration of the fistula represented by the number of days between the postoperative day of onset and the duration of the complication. Four definitions were formulated and were then applied to a group of 242 patients that underwent pancreatic head or intermediate resections with pancreatico-jejunal anastomosis in our Pancreatic Unit between November 1996 and December 2000. Statistical analysis was carried out using the Yates correct chi2 test with statistical significance set at p < 0.05. RESULTS: Among 26 different definitions identified, 14 were found suitable for the applied score. We formulated four final definitions summarizing the current concepts of PF. The incidence of PF ranged between 9.9 and 28.5% according to the different definitions applied with highly statistical differences between them. CONCLUSIONS: The PF rate after pancreatic resections is strictly dependent upon the definition used. An overall general agreement for an internationally accepted definition is urgently needed to correctly compare different experiences. 相似文献
79.
OBJECTIVE: Pathologists play a pivotal role in the diagnosis and in the report of the pathological features related to prognosis. METHODS: To meet these endpoints, the following issues must be accomplished: adequate information about the patient history, proper handling of the specimens, identification of the reliable histopathological techniques necessary to reach the more detailed diagnostic information and evaluate the prognostic variables, and a standardized pathological report. RESULTS: Recent efforts to standardize the histopathological evaluation have generated significant confusion among the urological and pathological communities as well. No consensus has been achieved about the optimal pathological grading of urothelial tumors, to date. CONCLUSION: A proposal for standardization of sampling and reporting of the urothelial tissues achieved within Uropathology follows. The urologists have a great role in assisting pathologists in the proper examination by providing them with clinical information. 相似文献
80.
A patient treated with prophylactic infradiaphragmatic radiation therapy for clinical stage I left testicular pure seminoma developed a large mass of the chest wall 12 years after primary treatment. An incisional biopsy confirmed pure seminoma. After chemotherapy, surgical removal of the residual mass and second-line chemoradiation therapy for persistent seminoma, the patient had a vertebral relapse. He died of progression 24 months after the first relapse despite further therapy. 相似文献