全文获取类型
收费全文 | 862016篇 |
免费 | 70557篇 |
国内免费 | 1839篇 |
学科分类
医药卫生 | 934412篇 |
出版年
2018年 | 7331篇 |
2015年 | 7722篇 |
2014年 | 11106篇 |
2013年 | 16776篇 |
2012年 | 22707篇 |
2011年 | 23823篇 |
2010年 | 13860篇 |
2009年 | 13061篇 |
2008年 | 22566篇 |
2007年 | 24616篇 |
2006年 | 24488篇 |
2005年 | 24135篇 |
2004年 | 23703篇 |
2003年 | 22834篇 |
2002年 | 21932篇 |
2001年 | 35822篇 |
2000年 | 36464篇 |
1999年 | 30895篇 |
1998年 | 9220篇 |
1997年 | 8545篇 |
1996年 | 8476篇 |
1995年 | 8006篇 |
1994年 | 7723篇 |
1992年 | 26658篇 |
1991年 | 26098篇 |
1990年 | 25617篇 |
1989年 | 24677篇 |
1988年 | 23219篇 |
1987年 | 22883篇 |
1986年 | 21740篇 |
1985年 | 21097篇 |
1984年 | 16385篇 |
1983年 | 13996篇 |
1982年 | 8854篇 |
1981年 | 8201篇 |
1980年 | 7671篇 |
1979年 | 16736篇 |
1978年 | 12114篇 |
1977年 | 10181篇 |
1976年 | 9328篇 |
1975年 | 10147篇 |
1974年 | 12641篇 |
1973年 | 12136篇 |
1972年 | 11538篇 |
1971年 | 10685篇 |
1970年 | 10218篇 |
1969年 | 9909篇 |
1968年 | 8900篇 |
1967年 | 8230篇 |
1966年 | 7653篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
1.
2.
3.
4.
5.
6.
O. Ieromina C. J. M. Musters P. M. Bodegom W. J. G. M. Peijnenburg M. G. Vijver 《Ecotoxicology (London, England)》2016,25(6):1170-1180
Analyzing functional species’ characteristics (species traits) that represent physiological, life history and morphological characteristics of species help understanding the impacts of various stressors on aquatic communities at field conditions. This research aimed to study the combined effects of pesticides and other environmental factors (temperature, dissolved oxygen, dissolved organic carbon, floating macrophytes cover, phosphate, nitrite, and nitrate) on the trait modality distribution of aquatic macrofauna communities. To this purpose, a field inventory was performed in a flower bulb growing area of the Netherlands with significant variation in pesticides pressures. Macrofauna community composition, water chemistry parameters and pesticide concentrations in ditches next to flower bulb fields were determined. Trait modalities of nine traits (feeding mode, respiration mode, locomotion type, resistance form, reproduction mode, life stage, voltinism, saprobity, maximum body size) likely to indicate pesticides impacts were analyzed. According to a redundancy analysis, phosphate -and not pesticides- constituted the main factor structuring the trait modality distribution of aquatic macrofauna. The functional composition could be ascribed for 2–4 % to pesticides, and for 3–11 % to phosphate. The lack of trait responses to pesticides may indicate that species may have used alternative strategies to adapt to ambient pesticides stress. Biomass of animals exhibiting trait modalities related to feeding by predation and grazing, presence of diapause form or dormancy, reproduction by free clutches and ovoviviparity, life stage of larvae and pupa, was negatively correlated to the concentration of phosphate. Hence, despite the high pesticide pollution in the area, variation in nutrient-related stressors seems to be the dominant driver of the functional composition of aquatic macrofauna assembly in agricultural ditches. 相似文献
7.
8.
9.
10.
Simeprevir added to peginterferon and ribavirin lessens time with fatigue,depressive symptoms and functional limitations in patients with chronic hepatitis C compared with peginterferon and ribavirin: results from 1161 patients in the QUEST‐1, QUEST‐2 and PROMISE studies 下载免费PDF全文
J. Scott L. Gilles M. Fu E. Brohan C. Panter R. Arbuckle W. Jessner M. Beumont 《Journal of viral hepatitis》2015,22(8):639-650
The value of adding simeprevir (SMV) vs placebo (PBO) to peginterferon and ribavirin (PR) for treatment of chronic hepatitis C virus infection was examined using patient‐reported outcomes (PROs); further, concordance of PROs with virology endpoints and adverse events (AEs) was explored. Patients (n = 768 SMV/PR, n = 393 PBO/PR) rated fatigue (FSS), depressive symptoms (CES‐D) and functional impairment (WPAI: Hepatitis C Productivity, Daily Activity and Absenteeism) at baseline and throughout treatment in three randomised, double‐blind trials comparing the addition of SMV or PBO during initial 12 weeks of PR. PR was administered for 48 weeks (PBO group) and 24/48 weeks (SMV group) using a response‐guided therapy (RGT) approach. Mean PRO scores (except Absenteeism) worsened from baseline to Week 4 to the same extent in both groups but reverted after Week 24 for SMV/PR and only after Week 48 for PBO/PR. Accordingly, there was a significantly lower area under the curve (baseline–Week 60, AUC60) and fewer weeks with clinically important worsening of scores in the SMV/PR group at any time point. Incidences of patients with fatigue and anaemia AEs were similar in both groups, but FSS scores showed that clinically important increases in fatigue lasted a mean of 6.9 weeks longer with PBO/PR (P < 0.001). PRO score subgroup analysis indicated better outcomes for patients who met the criteria for RGT or achieved sustained virological response 12 weeks post‐treatment (SVR12); differences in mean PRO scores associated with fibrosis level were only observed with PBO/PR. Greater efficacy of SMV/PR enabled reduced treatment duration and reduced time with PR‐related AEs without adding to AE severity. 相似文献