全文获取类型
收费全文 | 5132篇 |
免费 | 398篇 |
国内免费 | 491篇 |
专业分类
6021篇 |
出版年
2024年 | 19篇 |
2023年 | 76篇 |
2022年 | 170篇 |
2021年 | 242篇 |
2020年 | 170篇 |
2019年 | 205篇 |
2018年 | 184篇 |
2017年 | 152篇 |
2016年 | 186篇 |
2015年 | 298篇 |
2014年 | 376篇 |
2013年 | 377篇 |
2012年 | 480篇 |
2011年 | 446篇 |
2010年 | 288篇 |
2009年 | 244篇 |
2008年 | 300篇 |
2007年 | 256篇 |
2006年 | 224篇 |
2005年 | 198篇 |
2004年 | 163篇 |
2003年 | 165篇 |
2002年 | 149篇 |
2001年 | 61篇 |
2000年 | 73篇 |
1999年 | 67篇 |
1998年 | 61篇 |
1997年 | 50篇 |
1996年 | 39篇 |
1995年 | 46篇 |
1994年 | 45篇 |
1993年 | 25篇 |
1992年 | 28篇 |
1991年 | 19篇 |
1990年 | 23篇 |
1989年 | 25篇 |
1988年 | 12篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1976年 | 3篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1968年 | 3篇 |
排序方式: 共有6021条查询结果,搜索用时 0 毫秒
61.
Cell communication affects all aspects of cell structure and behavior, such as cell proliferation, differentiation, division, and coordination of various physiological functions. The moving RNA in plants and mammalian cells indicates that nucleic acid could be one of the various types of messengers for cell communication. The microvesicle is a critical pathway that mediates RNA moving and keeps moving RNA stable in body fluids. When moving miRNA enters the target cell, it functions by altering the gene expression profile and significantly inhibiting mRNA translation in recipient cells. Thus, moving RNA may act as a long-range modulator during development, organogenesis, and tumor metastasis. 相似文献
62.
Background
Diabetes Mellitus is a multifaceted chronic illness and its life-long treatment process requires patients to continuously engage with the healthcare system. The understanding of how patients manoeuvre through the healthcare system for treatment is crucial in assisting them to optimise their disease management. This study aims to explore issues determining patients’ treatment strategies and the process of patients manoeuvring through the current healthcare system in selecting their choice of treatment for T2DM.Methods
The Grounded Theory methodology was used. Twelve patients with Type 2 Diabetes Mellitus, nine family members and five healthcare providers from the primary care clinics were interviewed using a semi-structured interview guide. Three focus group discussions were conducted among thirteen healthcare providers from public primary care clinics. Both purposive and theoretical samplings were used for data collection. The interviews were audio-taped and transcribed verbatim, followed by line-by-line coding and constant comparison to identify the categories and core category.Results
The concept of “experimentation” was observed in patients’ help-seeking behaviour. The “experimentation” process required triggers, followed by information seeking related to treatment characteristics from trusted family members, friends and healthcare providers to enable decisions to be made on the choice of treatment modalities. The whole process was dynamic and iterative through interaction with the healthcare system. The decision-making process in choosing the types of treatment was complex with an element of trial-and-error. The anchor of this process was the desire to fulfil the patient’s expected outcome.Conclusion
Patients with Type 2 Diabetes Mellitus continuously used “experimentation” in their treatment strategies and help-seeking process. The “experimentation” process was experiential, with continuous evaluation, information seeking and decision-making tinged with the element of trial-and-error. The theoretical model generated from this study is abstract, is believed to have a broad applicability to other diseases, may be applied at varying stages of disease development and is non-context specific. 相似文献63.
64.
Phuong H. Nguyen Sunny S. Kim Tuan T. Nguyen Lan M. Tran Nemat Hajeebhoy Edward A. Frongillo Marie T. Ruel Rahul Rawat Purnima Menon 《PloS one》2016,11(3)
Adequate utilization of services is critical to maximize the impact of counselling on infant and young child feeding (IYCF), but little is known about factors affecting utilization. Our study examined supply- and demand-side factors associated with the utilization of IYCF counselling services in Viet Nam. We used survey data from mothers with children <2y (n = 1,008) and health staff (n = 60) from the evaluation of a program that embedded IYCF counseling into the existing government health system. The frequency of never users, one-time users, repeat users, and achievers of the recommended minimum number of visits at health facilities were 45.1%, 13.0%, 28.4% and 13.5%, respectively. Poisson regression showed that demand-generation strategies, especially invitation cards, were the key factors determining one-time use (Prevalence ratio, PR 3.0, 95% CI: 2.2–4.2), repeated use (PR 3.2, 95% CI: 2.4–4.2), and achievement of minimum visits (PR 5.5, 95% CI: 3.6–8.4). Higher maternal education was associated with higher utilization both for one-time and repeated use. Being a farmer, belonging to an ethnic minority, and having a wasted child were associated with greater likelihood of achieving the minimum recommended number of visits, whereas child stunting or illness were not. Distance to health center was a barrier to repeated visits. Among supply-side factors, good counselling skills (PR: 1.3–1.8) was the most important factor associated with any service use, whereas longer employment duration and greater work pressure of health center staff were associated with lower utilization. Population attributable risk estimations showed that an additional 25% of the population would have achieved the minimum number of visits if exposed to three demand-generation strategies, and further increased to 49% if the health staff had good counseling skills and low work pressure. Our study provides evidence that demand-generation strategies are essential to increase utilization of facility-based IYCF counselling services in Viet Nam, and may be relevant for increasing and sustaining use of nutrition services in similar contexts. 相似文献
65.
66.
Fish samples for the study were collected from the Yangtze River in China. Length–weight relationships were determined for two endemic fish species (Leiocassis longirostris Günther, 1864 and Schistura fasciolata Nichols & Pope, 1927) for the first time. 相似文献
67.
Chemotherapy via oral route of anticancer drugs offers much convenience and compliance to patients. However, oral chemotherapy has been challenged by limited absorption due to poor drug solubility and intestinal efflux. In this study, we aimed to develop a nanosuspension formulation of oridonin (Odn) using its cyclodextrin inclusion complexes to enhance oral bioavailability. Nanosuspensions containing Odn/2 hydroxypropyl-β-cyclodextrin inclusion complexes (Odn-CICs) were prepared by a solvent evaporation followed by wet media milling technique. The nanosuspensions were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and dissolution. The resulting nanosuspensions were approximately 313.8 nm in particle size and presented a microcrystal morphology. Nanosuspensions loading Odn-CICs dramatically enhanced the dissolution of Odn. Further, the intestinal effective permeability of Odn was markedly enhanced in the presence of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and poloxamer. Bioavailability studies showed that nanosuspensions with Odn-CICs can significantly promote the oral absorption of Odn with a relative bioavailability of 213.99% (Odn suspensions as reference). Odn itself possesses a moderate permeability and marginal intestinal metabolism. Thus, the enhanced bioavailability for Odn-CIC nanosuspensions can be attributed to improved dissolution and permeability by interaction with absorptive epithelia and anti-drug efflux. Nanosuspensions prepared from inclusion complexes may be a promising approach for the oral delivery of anticancer agents. 相似文献
68.
69.
70.