全文获取类型
收费全文 | 1291篇 |
免费 | 185篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 23篇 |
妇产科学 | 60篇 |
基础医学 | 218篇 |
口腔科学 | 22篇 |
临床医学 | 354篇 |
内科学 | 278篇 |
皮肤病学 | 17篇 |
神经病学 | 48篇 |
特种医学 | 53篇 |
外科学 | 157篇 |
综合类 | 5篇 |
预防医学 | 95篇 |
眼科学 | 12篇 |
药学 | 42篇 |
中国医学 | 1篇 |
肿瘤学 | 86篇 |
出版年
2023年 | 27篇 |
2022年 | 20篇 |
2021年 | 36篇 |
2020年 | 29篇 |
2019年 | 14篇 |
2018年 | 49篇 |
2017年 | 52篇 |
2016年 | 52篇 |
2015年 | 50篇 |
2014年 | 58篇 |
2013年 | 43篇 |
2012年 | 52篇 |
2011年 | 41篇 |
2010年 | 40篇 |
2009年 | 55篇 |
2008年 | 35篇 |
2007年 | 46篇 |
2006年 | 53篇 |
2005年 | 29篇 |
2004年 | 44篇 |
2003年 | 38篇 |
2002年 | 34篇 |
2001年 | 27篇 |
2000年 | 26篇 |
1999年 | 21篇 |
1998年 | 21篇 |
1997年 | 21篇 |
1996年 | 19篇 |
1994年 | 9篇 |
1992年 | 22篇 |
1991年 | 26篇 |
1990年 | 28篇 |
1989年 | 29篇 |
1988年 | 25篇 |
1987年 | 46篇 |
1986年 | 32篇 |
1985年 | 27篇 |
1984年 | 18篇 |
1983年 | 9篇 |
1979年 | 17篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 12篇 |
1974年 | 9篇 |
1973年 | 12篇 |
1972年 | 12篇 |
1971年 | 11篇 |
1969年 | 8篇 |
1968年 | 10篇 |
排序方式: 共有1478条查询结果,搜索用时 26 毫秒
21.
The rapid determination of the hemagglutinating and the blood coagulating activity of staphylococci]
A solid-phase preparation, designated by the authors "plasma pencil", has been developed for rapid measurements of plasma-agglutinating and plasma-coagulating activities of microorganisms. Plasma pencil employed instead of liquid plasma is economic, ready-to-use, may be stored for a long time, makes the procedure more rapid and simple. Measurements of the aforesaid activities in 388 staphylococcal clinical strains, carried out with the use of this pencil, have demonstrated a high efficacy of the preparation; the results coincided with those obtained by the routine methods. 相似文献
22.
Early mutation of the neu (erbB-2) gene during ethylnitrosourea-induced oncogenesis in the rat Schwann cell lineage. 下载免费PDF全文
Nikitin AYu L A Ballering J Lyons M F Rajewsky 《Proceedings of the National Academy of Sciences of the United States of America》1991,88(22):9939-9943
The development of malignant tumors of the peripheral nervous system (schwannomas) within a defined intracranial section of the rat trigeminal nerve ("trigeminal box") was used as a model to identify genetic alterations typically associated with the process of cell-lineage-specific oncogenesis induced by exposure to N-ethyl-N-nitrosourea on postnatal day 1. All 47 trigeminal schwannomas (and 12 extracranial neurinomas) investigated carried a T.A----A.T transversion mutation at nucleotide 2012 of the neu (erbB-2) gene sequence encoding the transmembrane domain of pg185neu. This mutation was absent in all 18 tumors in the brain and spinal cord (central nervous system) isolated from the same animals. Identical observations were made in cell lines derived from N-ethyl-N-nitrosourea-induced rat schwannomas vs. brain tumors. By asymmetric PCR and mutant-specific Mnl I restriction fragment length analyses, cells carrying the mutant neu allele became detectable and could be localized within the trigeminal box as early as 7 days after the carcinogen pulse. The proliferation rate of the mutant cells strongly exceeded that of the wild-type cells up to the time of maturation of the trigeminal nerve around postnatal day 30 and thereafter to a lesser extent until the appearance of schwannomas. A specific mutation of the neu gene thus represents a very early, probably the first, step in the malignant conversion of immature rat Schwann cells exposed to N-ethyl-N-nitrosourea in vivo and is diagnostic for a subset of proliferative cells at high risk of progressing toward the expression of fully malignant phenotypes. Loss of heterozygosity for the mutant neu allele is a candidate event for a critical second step in the process. 相似文献
23.
24.
N. A. Dimitrova G. V. Dimitrov O. A. Nikitin 《Journal of medical engineering & technology》2013,37(1):34-40
We aimed to reveal reasons for longitudinal variations of characteristic frequencies of electromyographic signals detected by surface longitudinal multi-electrodes. Since the terminal phases were reduced in bipolar recordings, wetested whether the frequency variations reflected the effects of the excitation origin and extinction as in monopolar recordings. A precise and fast convolution method to calculate the signals detected by a multielectrode was suggested. The contribution of different electrode poles was introduced in the impulse response. When a longitudinal multi-electrode with an even number of poles was positioned above the end-plate of asymmetrical fibres, the signal mainly reflected the processes of the excitation extinction. This increased the signal mean and median frequencies. Although the effects of origin and extinction of the excitation were significantly reduced in the spatially filtered signals, the frequency variations along the fibre reflected these intrinsic features of any skeletal muscle fibre of finite length. 相似文献
25.
26.
Pulmonary hypertension: Barrier or just a bump in the road in transplanting adults with congenital heart disease 下载免费PDF全文
Jonathan N. Menachem MD Edo Y. Birati MD Payman Zamani MD Anjali T. Owens MD Pavan Atluri MD Christian A. Bermudez MD David Drajpuch NP Stephanie Fuller MD Yuli Y. Kim MD Christopher E. Mascio MD Vikram Palanivel MD J. Eduardo Rame MD Joyce Wald DO Michael A. Acker MD Jeremy A. Mazurek MD 《Congenital heart disease》2018,13(4):492-498
27.
Translation and validation of the Canadian diabetes risk assessment questionnaire in China 下载免费PDF全文
Jia Guo RN PhD Zhengkun Shi RN MSN Jyu‐Lin Chen PhD Jane K. Dixon PhD James Wiley PhD Monica Parry NP‐Adult PhD 《Public health nursing (Boston, Mass.)》2018,35(1):18-28
Objectives
To adapt the Canadian Diabetes Risk Assessment Questionnaire for the Chinese population and to evaluate its psychometric properties.Design and Sample
A cross‐sectional study was conducted with a convenience sample of 194 individuals aged 35–74 years from October 2014 to April 2015.Methods
The Canadian Diabetes Risk Assessment Questionnaire was adapted and translated for the Chinese population. Test–retest reliability was conducted to measure stability. Criterion and convergent validity of the adapted questionnaire were assessed using 2‐hr 75 g oral glucose tolerance tests and the Finnish Diabetes Risk Scores, respectively. Sensitivity and specificity were evaluated to establish its predictive validity.Results
The test–retest reliability was 0.988. Adequate validity of the adapted questionnaire was demonstrated by positive correlations found between the scores and 2‐hr 75 g oral glucose tolerance tests (r = .343, p < .001) and with the Finnish Diabetes Risk Scores (r = .738, p < .001). The area under receiver operating characteristic curve was 0.705 (95% CI .632, .778), demonstrating moderate diagnostic value at a cutoff score of 30. The sensitivity was 73%, with a positive predictive value of 57% and negative predictive value of 78%.Conclusions
Our results provided evidence supporting the translation consistency, content validity, convergent validity, criterion validity, sensitivity, and specificity of the translated Canadian Diabetes Risk Assessment Questionnaire with minor modifications. This paper provides clinical, practical, and methodological information on how to adapt a diabetes risk calculator between cultures for public health nurses. 相似文献28.
29.
30.