全文获取类型
收费全文 | 1643篇 |
免费 | 116篇 |
国内免费 | 5篇 |
专业分类
1764篇 |
出版年
2023年 | 24篇 |
2022年 | 41篇 |
2021年 | 73篇 |
2020年 | 37篇 |
2019年 | 38篇 |
2018年 | 51篇 |
2017年 | 34篇 |
2016年 | 54篇 |
2015年 | 80篇 |
2014年 | 87篇 |
2013年 | 109篇 |
2012年 | 121篇 |
2011年 | 131篇 |
2010年 | 77篇 |
2009年 | 68篇 |
2008年 | 91篇 |
2007年 | 72篇 |
2006年 | 46篇 |
2005年 | 56篇 |
2004年 | 58篇 |
2003年 | 41篇 |
2002年 | 48篇 |
2001年 | 21篇 |
2000年 | 24篇 |
1999年 | 26篇 |
1998年 | 16篇 |
1997年 | 11篇 |
1996年 | 8篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1992年 | 12篇 |
1991年 | 11篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 18篇 |
1986年 | 14篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1976年 | 8篇 |
1975年 | 7篇 |
1973年 | 6篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1968年 | 7篇 |
排序方式: 共有1764条查询结果,搜索用时 15 毫秒
991.
Gemma Pearce Hilary Pinnock Eleni Epiphaniou Hannah L. Parke Emily Heavey Christopher J. Griffiths Trish Greenhalgh Aziz Sheikh Stephanie J. C. Taylor 《PloS one》2015,10(12)
Background
Supporting self-management in stroke patients improves psychological and functional outcomes but evidence on how to achieve this is sparse. We aimed to synthesise evidence from systematic reviews of qualitative studies in an overarching meta-review to inform the delivery and development of self-management support interventions.Methods
We systematically searched eight electronic databases including MEDLINE, EMBASE and CINAHL for qualitative systematic reviews (published January 1993 to June 2012). We included studies exploring patients’, carers’ or health care professionals’ experiences relevant to self-management support following a stroke, including studies describing the lived experience of surviving a stroke. We meta-synthesised the included review findings using a meta-ethnographic framework.Results
Seven reviews, reporting 130 unique studies, were included. Themes emerging from the reviews were pertinent, consistent and showed data saturation; though explicit mention of self-management support was rare. Our meta-review highlighted the devastating impact of stroke on patients’ self-image; the varying needs for self-management support across the trajectory of recovery; the need for psychological and emotional support throughout recovery particularly when physical recovery plateaus; the considerable information needs of patients and carers which also vary across the trajectory of recovery; the importance of good patient-professional communication; the potential benefits of goal-setting and action-planning; and the need for social support which might be met by groups for stroke survivors.Conclusions
The observed data saturation suggests that, currently, no further qualitative research simply describing the lived experience of stroke is needed; we propose that it would be more useful to focus on qualitative research informing self-management support interventions and their implementation. Our findings demonstrate both the on-going importance of self-management support and the evolving priorities throughout the stages of recovery following a stroke. The challenge now is to ensure these findings inform routine practice and the development of interventions to support self-management amongst stroke survivors. 相似文献992.
993.
Shabhat Rasool Ishfaq Ahmed Rubiya Dar Sheikh Gazalla Ayub Sabia Rashid Tariq Jan Tahir Ahmed Niyaz A. Naikoo Khurshid I. Andrabi 《Biochemical genetics》2013,51(3-4):323-333
This study looks at novel variants of the TGFβ1 gene and their potential association with high myopia in an ethnic population from Kashmir, India. Allele frequencies of 247 Kashmiri subjects (from India) with high myopia and 176 ethnically matched healthy controls were tested for Hardy–Weinberg disequilibrium. The genotype and allele frequencies were evaluated using chi-square or Fisher’s exact tests. One of the three SNPs in codon 10 showed a significant difference between patients and control subjects (rs1982073: p genotype = 0.003, p allele = 0.001). There were no statistically significant differences between patients and control subjects for the other two SNPs, rs1800471 at codon 25 and a novel variant at codon 52. SNP rs1982073, substituting proline with leucine, appeared to be significantly associated with high myopia (p < 0.05). In silico predictions show that substitutions are likely to have an impact on the structure and functional properties of the protein, making it imperative to understand their functional consequences in relation to high myopia. 相似文献
994.
The effect of Ca2+, Cd2+, Ba2+, Mg2+ and pH on the renal epithelial Na(+)-channel was investigated by measuring the amiloride-sensitive 22Na+ fluxes into luminal membrane vesicles from pars recta of rabbit proximal tubule. It was found that intravesicular Ca2+ as well as extravesicular Ca2+ substantially lowered the channel-mediated flux. Amiloride sensitive Na+ uptake was nearly completely blocked by 10 microM Ca2+ at pH 7.4. The inhibitory effect of Ca2+ was dependent on pH. Thus, 10 microM Ca2+ produced 90% inhibition of 22Na+ uptake at pH 7.4, and only 40% inhibition at pH 7.0. The tracer fluxes measured in the absence of Ca2+ were pH independent over the range from 7.0 to 7.4. All the cations Ca2+, Cd2+, Ba2+ except Mg2+ inhibited the 22Na+ influx drastically when added extravesicularly in millimolar concentrations. The cations Cd2+, Ba2+ and Mg2+ in the same concentrations intravesicularly inhibited the 22Na+ influx only slightly. A millimolar concentration of Ca2+ intravesicularly blocked the amiloride-sensitive 22Na+ flux completely. The data indicate that Ca2+ inhibits Na+ influx specifically by binding to sites composed of one or several deprotonated groups on the channel proteins. 相似文献
995.
996.
Cannabinoid system plays an important role in controlling neuronal excitability and brain function. On the other hand, modulation
of gamma-aminobutyric acid (GABA) transmission is one of the initial strategies for the treatment of seizure. The aim of the
present study was to evaluate possible interaction between cannabinoidergic and GABAergic systems in pentylenetetrazole (PTZ)-induced
acute seizure in rat. Drugs were administered by intracerebroventricular (i.c.v.) administration 20 min before a single intraperitoneal
(i.p.) injection of PTZ and the latency to the first generalized tonic-clonic seizure was measured. Both the cannabinoid receptor
agonist WIN55212-2 (10, 30, 50 and 100 μg/rat) and the GABA-A receptor agonist isoguvacine (IGN; 10, 30 and 50 μg/rat) significantly
increased the latency of seizure occurrence. Moreover, the fatty acid amide hydrolase inhibitor URB597 showed no anticonvulsive
effect while the monoacyl glycerol lipase (MAGL) inhibitor URB602 (10, 50 and 100 μg/rat) protected rats against PTZ-induced
seizure. Moreover, co-administration of IGN and cannabinoid compounds attenuated the anticonvulsant action of both WIN55212-2
and IGN in this model of seizure. Our data suggests that exogenous cannabinoid WIN55212-2 and MAGL inhibitor URB602 imply
their antiseizure action in part through common brain receptorial system. Moreover, the antagonistic interaction of cannabinoids
and IGN in protection against PTZ-induced seizure could suggest the involvement of GABAergic system in their anticonvulsant
action. 相似文献
997.
Waqas Hameed Syed Khurram Azmat Moazzam Ali Muhammad Ishaque Sheikh Ghazunfer Abbas Marleen Temmerman Bilal Iqbal Avan 《PloS one》2014,9(8)
Introduction
There is little available evidence of associations between the various dimensions of women''s empowerment and contraceptive use having been examined - and of how these associations are mediated by women''s socio-economic and demographic statuses. We assessed these phenomena in Pakistan using a structured-framework approach.Methods
We analyzed data on 2,133 women who were either using any form of contraceptive or living with unmet need for contraception. The survey was conducted during May - June 2012, with married women of reproductive age (15–49 years) in three districts of Punjab. The dimensions of empowerment were categorized broadly into: economic decision-making, household decision-making, and women''s mobility. Two measures were created for each dimension, and for the overall empowerment: women''s independent decisions, and those taken jointly by couples. Contraceptive use was categorized as either female-only or couple methods on the basis of whether a method requires the awareness of, or some support and cooperation from, the husband. Multinomial regression was used, by means of Odds Ratios (OR), to assess associations between empowerment dimensions and female-only and couple contraceptive methods.Results
Overall, women tend to get higher decision-making power with increased age, higher literacy, a greater number of children, or being in a household that has superior socio-economic status. The measures for couples'' decision-making for overall empowerment and for each dimension of it showed positive associations with couple methods as well as with female-only methods. The only exception was the measure of economic empowerment, which was associated only with the couple method.Conclusion
Couples'' joint decision-making is a stronger determinant of the use of contraceptive methods than women-only decision-making. This is the case over and above the contribution of women''s socio-demographic and economic statuses. Effort needs to be made to educate women and their husbands equally, with particular focus on highly effective contraceptive methods. 相似文献998.
Eric R. Morgan Nor-Azlina A. Aziz Alexandra Blanchard Johannes Charlier Claude Charvet Edwin Claerebout Peter Geldhof Andrew W. Greer Hubertus Hertzberg Jane Hodgkinson Johan Höglund Hervé Hoste Ray M. Kaplan María Martínez-Valladares Siân Mitchell Harm W. Ploeger Laura Rinaldi Georg von Samson-Himmelstjerna Jozef Vercruysse 《Trends in parasitology》2019,35(1):52-71
999.
Mohamed Abdel Aziz Balah 《农业工程》2019,39(1):14-20
Oases are a specific ecosystems which date palm Phoenix dactylifera are the mainly crop growing for its fruits and others tree parts. Palm orchards are infested by many pests, including weeds species and exposed within time to the challenging invasive weeds to control. The heavy incidence of weeds negatively affects palm productivity, especially in small plantation and divergent distances, while the established orchards, palm trees shading cause deprives from the process of weeds photosynthesis to be lower competitive. The survey was conducted in El-Bahariya and El-Frafra than Siwa oases of which 375 plots were taken. Vegetative analysis in oases altogether demonstrate 91 weed specimens were encountered of which 18 perennial, 42 were broad leaved, and 30 narrow leaved as well as one parasitic weed species belonging to 22 families, whereas Poaceae is the most plentiful family displayed by 38.5% from all families, occurred in date palm orchards during the study. The geographical differentiation affected coefficient of similarity whereas, it in oases recorded the highest between El-Bahariya and El-Frafra than Siwa and El-Bahariya, while El-Frafra Oasis was the most diverse and richness than the others which have the middle soil properties, fertility, and structure. The correlation analysis of weed flora between both El-Bahariya and El-Frafra was higher and more than El-Bahariya and Siwa oases. Under the unique closed agroenvironment of oases, weeds population dynamics are a stable approximately. Regardless of the diversity of annual weed species, perennials species represent the highest dominant number and the pattern of grown weeds was more dominant than wild desert and some invasive weed species. The control action should be taken of perennial weeds and proactive as well as long term prevention for invasive species. 相似文献
1000.