全文获取类型
收费全文 | 10242篇 |
免费 | 750篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 91篇 |
儿科学 | 327篇 |
妇产科学 | 247篇 |
基础医学 | 1297篇 |
口腔科学 | 737篇 |
临床医学 | 715篇 |
内科学 | 2192篇 |
皮肤病学 | 221篇 |
神经病学 | 1112篇 |
特种医学 | 201篇 |
外科学 | 1171篇 |
综合类 | 68篇 |
一般理论 | 9篇 |
预防医学 | 1056篇 |
眼科学 | 112篇 |
药学 | 716篇 |
中国医学 | 66篇 |
肿瘤学 | 685篇 |
出版年
2023年 | 133篇 |
2022年 | 261篇 |
2021年 | 457篇 |
2020年 | 317篇 |
2019年 | 428篇 |
2018年 | 449篇 |
2017年 | 321篇 |
2016年 | 315篇 |
2015年 | 376篇 |
2014年 | 480篇 |
2013年 | 585篇 |
2012年 | 817篇 |
2011年 | 808篇 |
2010年 | 457篇 |
2009年 | 415篇 |
2008年 | 630篇 |
2007年 | 598篇 |
2006年 | 502篇 |
2005年 | 485篇 |
2004年 | 406篇 |
2003年 | 359篇 |
2002年 | 352篇 |
2001年 | 162篇 |
2000年 | 124篇 |
1999年 | 110篇 |
1998年 | 70篇 |
1997年 | 32篇 |
1996年 | 32篇 |
1995年 | 22篇 |
1994年 | 28篇 |
1993年 | 15篇 |
1992年 | 56篇 |
1991年 | 44篇 |
1990年 | 49篇 |
1989年 | 30篇 |
1988年 | 27篇 |
1987年 | 31篇 |
1986年 | 22篇 |
1985年 | 18篇 |
1984年 | 16篇 |
1983年 | 17篇 |
1978年 | 11篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 11篇 |
1972年 | 12篇 |
1969年 | 9篇 |
1968年 | 10篇 |
1967年 | 9篇 |
1966年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
S. I. Aguiar I. Serrano F. R. Pinto J. Melo-Cristino M. Ramirez 《Clinical microbiology and infection》2008,14(9):835-843
The pneumococcal seven-valent conjugate vaccine (PCV7) has been administered in Portugal since late 2001 through the private sector. To evaluate the impact of PCV7 use, the serotypes and antimicrobial susceptibility of pneumococci causing invasive disease in Portugal during 2003–2005 were determined and compared with available data for the period 1999–2002. Changes in serotype distribution compatible with the introduction of PCV7 were shown for children ≤5 years of age from 2003 onwards and for adults from 2004 onwards. PCV7 use with coverage of 43% of children with four doses in the 2004 birth cohort, although substantially below universal coverage, seems to have contributed to greatly reducing the proportion of invasive infections due to vaccine serotypes 4, 6B, 14 and 23F. Similarly, significant indirect effects on the serotype distribution of pneumococci causing infections in adults were noted, with reductions in the proportion of invasive infections caused by serotypes 4, 5 and 14. These changes were accompanied by an increase in the proportion of two non-vaccine serotypes: 19A isolates in all age groups and 7F isolates in adults. Whereas serotypes 6B, 14 and 19A were associated with multidrug resistance, isolates expressing serotypes 4 and 7F were fully susceptible for the most part. There were no changes in the proportion of resistant isolates within each serotype and, in spite of the changes in serotype prevalence, there was not an overall reduction in the proportion of infections caused by resistant pneumococci. 相似文献
72.
Gislaine Garcia Pelosi Vera Lúcia Peres-PolonFernando Morgan Aguiar Corrêa 《Neuroscience letters》2006
Injection of noradrenaline (NA) into the lateral cerebral ventricle (i.c.v.) was reported to cause blood pressure increase in unanesthetized rats, blocked by i.v. injection of vasopressin antagonists. We report similar responses to NA injection into the III or IV ventricles, suggesting multiple sites of action for i.c.v. NA. These responses were blocked by i.v. pretreatment with vasopressin antagonist, suggesting a common mediation by vasopressin release into circulation. Selected ventricular spaces were occluded with Nivea® cream plugs to identify ventricular areas responding to i.c.v. NA. III ventricle or aqueduct occlusions markedly reduced pressor responses to i.c.v. NA. Microinjection of NA into the periaqueductal gray matter (PAG) caused pressor responses that were similar to those of i.c.v. NA, reinforcing the idea of a site of action in the aqueduct. IV ventricle occlusion only partially blocked the response to i.c.v. NA. The results suggest at least two sites of action for i.c.v. NA in unanesthetized rats. A primary site located in the PAG and another on the IV ventricle wall. 相似文献
73.
Baldomero Lara Luis Gandía Rafael Martínez-Sierra Andrés Torres A. G. García 《Pflügers Archiv : European journal of physiology》1998,435(4):472-478
This study uses a new strategy to investigate the hypothesis that, of the various Ca2+ channels expressed by a neurosecretory cell, a given channel subtype is coupled more tightly to the exocytotic apparatus
than others. The approach is based on the prediction that the degree of inhibition of the secretory response by various Ca2+ channel blockers will differ at low (0.5 mM) and high (5 mM) extracellular Ca2+ concentrations ([Ca2+]o). So, at low [Ca2+]o the K+-evoked catecholamine release from superfused bovine chromaffin cells was depressed 60–70% by 2 μM ω-agatoxin IVA (P/Q-type
Ca2+ channel blockade), by 3 μM ω-conotoxin MVIIC (N/P/Q-type Ca2+ channel blockade), or by 3 μM lubeluzole (N/P/Q-type Ca2+ channel blockade); in high [Ca2+]o these blockers inhibited the responses by only 20–35%. At 1–3 μM ω-conotoxin GVIA (N-type Ca2+ channel blockade) or 3 μM furnidipine (L-type Ca2+ channel blockade), secretion was inhibited by 30 and 50%, respectively; such inhibitory effects were similar in low or high
[Ca2+]o. Combined furnidipine plus ω-conotoxin MVIIC, ω-agatoxin IVA or ω-conotoxin GVIA exhibited additive blocking effects at
both Ca2+ concentrations. The results suggest that Q-type Ca2+ channels are coupled more tightly to exocytotic active sites, as compared to L-type channels. This hypothesis if founded
in the fact that external Ca2+ that enters the cell through a Ca2+ channel located near to chromaffin vesicles will saturate the K+ secretory response at both [Ca2+]o, i.e. 0.5 mM and 5 mM. In contrast, Ca2+ ions entering through more distant channels will be sequestered by intracellular buffers and, thus, will not saturate the
secretory machinery at lower [Ca2+]o.
Received: 23 September 1997 / Received after revision: 29 October 1997 / Accepted: 30 October 1997 相似文献
74.
Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy is a rare recessive autoimmune disorder caused by a defect in a single gene called AIRE (autoimmune regulator). Characteristics of this disease include a variable combination of autoimmune endocrine tissue destruction, mucocutaneous candidiasis and ectodermal dystrophies. The development of Aire-knockout mice has provided an invaluable model for the study of this disease. The aim of this review is to briefly highlight the strides made in APECED research using these transgenic murine models, with a focus on known roles of Aire in autoimmunity. The findings thus far are compelling and prompt additional areas of study which are discussed. 相似文献
75.
Droste MS Biel SS Terstegen L Wittern KP Wenck H Wepf R 《Journal of biomedical optics》2005,10(6):064017
To maintain the intracellular concentration of ions and small molecules on osmotic challenges, nature has developed highly sophisticated transport systems for regulating water and ion content. An ideal measurement technique for volume changes of cells during osmotic challenges has to fulfil two requirements: it has to be osmotically inert, and it should allow online monitoring of cell volume changes. Here, a simple fluorescence microscopy-based approach is presented. Using fluorescein as a negative stain, it is possible to monitor cell volume changes without affecting the functionality of cell membranes and cell osmolarity. Measurement of Madine-Darby canine kidney (MDCK) cells after hypo- and hyperosmotic challenges reveals the main advantages of this approach: besides providing precise and reproducible quantitative data on reversible cell volume changes, the viability of the cells can be assessed directly by the appearance of stain in the cytoplasm. This becomes evident especially after hypo-osmotic challenge of glutaraldehyde-treated cells, which become leaky after fixation, followed by a massive volume change. This new approach represents a very sensitive measurement technique for cell volume changes resulting from water or ion flux, and thus seems to be an ideal tool for studying cell volume regulatory processes. 相似文献
76.
A dense osmiophilic structure was found associated to the basal lamina of the outer limiting glial membrane of the carp olfactory bulb. In certain sections this material appears as "beads" composed of small strand-like structures, and in others it seems to form a palisade-like structure. The possible origin and function of this structure is discussed. 相似文献
77.
Dbora Godoy-Izquierdo Adelaida Ogallar Raquel Lara Alejandra Rodríguez-Tadeo Flix Arbinaga 《Nutrients》2021,13(4)
Recent evidence suggests that among behavioral-lifestyle factors, adherence to a healthy dietary pattern such as the Mediterranean Diet (MedDiet) is linked not only to better psychological health and mental positive status but also to increased subjective well-being (SWB). Nevertheless, this association has been unexplored among individuals with excessive weight. This study explored whether adherence to the MedDiet and the intake of healthy foods such as fruits and vegetables (FV) are associated with increased happiness and life satisfaction among Spanish adults with overweight or obesity when weight, body image, and body satisfaction are also considered. A convenience sample of adult individuals with excessive weight completed self-reports on the study variables, and weight and BMI were measured by bioimpedance. No evidence of a relationship with SWB indicators was obtained for MedDiet global indicators, probably due to the low adherence to a healthy diet by these individuals. In contrast, FV intake, as a powerful indicator of healthy eating, was associated with life satisfaction when BMI and body image dimensions were considered, among which body satisfaction had a key role. Moreover, life satisfaction fully mediated the relationship between FV consumption and happiness. Our findings are expected to make a relevant contribution to knowledge on the positive correlates or protective factors for overall well-being in obesity, including dietary habits and body appreciation. Our results may inform obesity management actions focused on inclusive, positive aesthetic models and promoting a healthy lifestyle for happiness in obesity. 相似文献
78.
Radhouene Doggui Hanin Al-Jawaldeh Jalila El Ati Rawhieh Barham Lara Nasreddine Nawal Alqaoud Hassan Aguenaou Laila El Ammari Jana Jabbour Ayoub Al-Jawaldeh 《Nutrients》2021,13(5)
The Eastern Mediterranean Region (EMR) is experiencing a nutrition transition, characterized by the emergence of overnutrition and micro-nutrient deficiencies. No previous study has comparatively examined nutrient intake in adults across countries in the EMR. This review examined the adequacy of nutrients in adults living in the EMR. Moreover, it analyzed the food balance sheets (FBS) for 1961–2018 to identify the trajectory of energy supply from macro-nutrients in the EMR. A systematic search was conducted from January 2012 to September 2020. Only observational studies were retained with a random sampling design. An assessment of the methodological quality was conducted. Levels of nutrient daily intake and their adequacy compared to the daily reference intake of the Institute of Medicine were reported across the region. No studies were identified for half of the region’s countries. Although nutrient energy intake was satisfactory overall, fat and carbohydrate intake were high. Intake of vitamin D, calcium, potassium, zinc, and magnesium were below that recommended. The analysis of the FBS data allowed for the identification of four linear patterns of trajectories, with countries in the EMR best fitting the ‘high-energy-supply from carbohydrate’ group. This systematic review warrants multi-sectorial commitment to optimize nutrient intake. 相似文献
79.
Rueda Jon García-Barranquero Pablo Lara Francisco 《Medicine, health care, and philosophy》2021,24(3):409-419
Medicine, Health Care and Philosophy - Biomedical innovations are making possible the enhancement of human capabilities. There are two philosophical stances on the role that medicine should play in... 相似文献
80.
Lara J. Akinbami Philip A. Chan Nga Vuong Samira Sami Dawn Lewis Philip E. Sheridan Susan L. Lukacs Lisa Mackey Lisa A. Grohskopf Anita Patel Lyle R. Petersen 《Emerging infectious diseases》2021,27(3):823
Healthcare personnel are recognized to be at higher risk for infection with severe acute respiratory syndrome coronavirus 2. We conducted a serologic survey in 15 hospitals and 56 nursing homes across Rhode Island, USA, during July 17–August 28, 2020. Overall seropositivity among 9,863 healthcare personnel was 4.6% (95% CI 4.2%–5.0%) but varied 4-fold between hospital personnel (3.1%, 95% CI 2.7%–3.5%) and nursing home personnel (13.1%, 95% CI 11.5%–14.9%). Within nursing homes, prevalence was highest among personnel working in coronavirus disease units (24.1%; 95% CI 20.6%–27.8%). Adjusted analysis showed that in hospitals, nurses and receptionists/medical assistants had a higher likelihood of seropositivity than physicians. In nursing homes, nursing assistants and social workers/case managers had higher likelihoods of seropositivity than occupational/physical/speech therapists. Nursing home personnel in all occupations had elevated seropositivity compared with hospital counterparts. Additional mitigation strategies are needed to protect nursing home personnel from infection, regardless of occupation. 相似文献