全文获取类型
收费全文 | 9186篇 |
免费 | 744篇 |
国内免费 | 2篇 |
专业分类
9932篇 |
出版年
2023年 | 62篇 |
2022年 | 45篇 |
2021年 | 109篇 |
2020年 | 90篇 |
2019年 | 112篇 |
2018年 | 296篇 |
2017年 | 263篇 |
2016年 | 325篇 |
2015年 | 466篇 |
2014年 | 451篇 |
2013年 | 600篇 |
2012年 | 765篇 |
2011年 | 696篇 |
2010年 | 437篇 |
2009年 | 324篇 |
2008年 | 498篇 |
2007年 | 506篇 |
2006年 | 409篇 |
2005年 | 385篇 |
2004年 | 381篇 |
2003年 | 350篇 |
2002年 | 353篇 |
2001年 | 251篇 |
2000年 | 291篇 |
1999年 | 209篇 |
1998年 | 78篇 |
1997年 | 49篇 |
1996年 | 64篇 |
1995年 | 46篇 |
1994年 | 28篇 |
1993年 | 33篇 |
1992年 | 108篇 |
1991年 | 88篇 |
1990年 | 84篇 |
1989年 | 70篇 |
1988年 | 68篇 |
1987年 | 57篇 |
1986年 | 77篇 |
1985年 | 53篇 |
1984年 | 49篇 |
1983年 | 44篇 |
1982年 | 42篇 |
1981年 | 19篇 |
1980年 | 20篇 |
1979年 | 20篇 |
1978年 | 19篇 |
1975年 | 13篇 |
1974年 | 18篇 |
1973年 | 21篇 |
1972年 | 11篇 |
排序方式: 共有9932条查询结果,搜索用时 10 毫秒
91.
Alda M Luciano JV Andrés E Serrano-Blanco A Rodero B del Hoyo YL Roca M Moreno S Magallón R García-Campayo J 《Arthritis research & therapy》2011,13(5):R173
Introduction
No randomised, controlled trials have been conducted to date on the efficacy of psychological and pharmacological treatments of pain catastrophising (PC) in patients with fibromyalgia. Our aim in this study was to assess the effectiveness of cognitive-behaviour therapy (CBT) and the recommended pharmacological treatment (RPT) compared with treatment as usual (TAU) at the primary care level for the treatment of PC in fibromyalgia patients. 相似文献92.
Yurixhi Maldonado–López Edelmira Linares–Mazari Robert Bye Guillermo Delgado Francisco J. Espinosa–García 《Economic botany》2008,62(2):161-170
Mexican Arnica Anti–Inflammatory Action: Plant Age Is Correlated with the Concentration of Anti–inflammatory Sesquiterpenes
in the Medicinal Plant
Heterotheca inuloides
Cass. (Asteraceae). Mexican árnica (Heterotheca inuloides Cass.) is a widely used anti–inflammatory medicinal plant in Mexican folk medicine. Although it has been suggested that plant
age, fertilization, and harvesting regime influence the concentration of secondary compounds affecting the therapeutic activity
of the plant, the effect of these variables on the concentration of the Mexican árnica anti–inflammatory compounds was not
known. We quantified anti–inflammatory sesquiterpenes (caryolan–1, 9β–diol, cadalen–15–oic acid, 7–hydroxycadalene, 4–hydroxy–2–isopropyl–4,
7–dimethyl–1[4H] naftalinone, 7–hydroxy–4αH–3, 4–dihydrocadalene, β–caryophyllene, and β–caryophyllene epoxide) in Mexican
árnica plants subjected to fertilization and successive harvests of flowering stems, conditions that mimic the cultivation
and harvesting for árnica in México. Fertilization and successive harvesting and their interaction had no significant effect
on the concentration of anti–inflammatory compounds. However, the concentrations of these compounds were 60% higher in flowering
stems from 15–month–old plants than in those from 4– or 8–month–old plants and was independent of the number of harvests and
fertilization regime applied. 相似文献
93.
Ramos R García E 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2007,144(4):348-355
Components of the cytochrome P(450) monooxygenase system (MFO) and antioxidant enzymes were investigated in the coral Montastraea faveolata exposed to the organic contaminant benzo(a)pyrene (B(a)P). For bioassays the corals were exposed to increasing concentrations of B(a)P (0.01 and 0.1 ppm) for 24 and 72 h, with water renewal every 24 h. Enzymatic activity of catalase (CAT), superoxide dismutase (SOD) and glutathione S-transferase (GST) were measured in host (polyp) and hosted (zooxanthellae) cells. NADPH cytochrome c reductase activity and contents of cytochrome P(450) and P(420) were only measured in the polyp. Antioxidant enzymes CAT and SOD in polyps and zooxanthellae and GST in polyps increased significantly at the highest concentration and maximum time of exposure. Cytochrome P(420) was found in all colonies, and the cytochrome P(450) content was greatest in the colonies from the highest concentrations of contaminant. NADPH cytochrome c reductase activity and the concentration of pigments did not vary between treatments. This is the first report of the induction of both detoxifying mechanisms, the MFO system and antioxidant enzymes on acute exposure to an organic contaminant in the reef-constructing coral species M. faveolata. 相似文献
94.
95.
Jenish R Patel Ankur Jain Yi‐ying Chou Alina Baum Taekjip Ha Adolfo García‐Sastre 《EMBO reports》2013,14(9):780-787
The cytosolic pathogen sensor RIG‐I is activated by RNAs with exposed 5′‐triphosphate (5′‐ppp) and terminal double‐stranded structures, such as those that are generated during viral infection. RIG‐I has been shown to translocate on dsRNA in an ATP‐dependent manner. However, the precise role of the ATPase activity in RIG‐I activation remains unclear. Using in vitro‐transcribed Sendai virus defective interfering RNA as a model ligand, we show that RIG‐I oligomerizes on 5′‐ppp dsRNA in an ATP hydrolysis‐dependent and dsRNA length‐dependent manner, which correlates with the strength of type‐I interferon (IFN‐I) activation. These results establish a clear role for the ligand‐induced ATPase activity of RIG‐I in the stimulation of the IFN response. 相似文献
96.
Iker Falces-Romero María Pilar Romero-Gómez Julio García-Rodríguez Emilio Cendejas-Bueno 《Revista iberoamericana de micología》2019,36(3):142-146
BackgroundIn Spain, data of candidemia are limited to surveys conducted in specific areas or tertiary care centers. Also, in recent years, attention has shifted toward episodes of candidemia in non-ICU wards.AimsWe reviewed the cases of Candida isolates recovered from the blood of patients admitted to the Emergency Room (ER) in our tertiary care hospital.MethodsThe patients selected for this study had an isolation of Candida in the blood culture. All data were collected retrospectively from the clinical records of a 11-year period.ResultsCandida albicans and other species of the genus were present in 10 and 18 patients, respectively. The patients did not present different clinical features in comparison with other reports of hospitalized patients. All patients had several risk factors for candidemia. Only two patients had received previous antifungal therapy before admission. All the isolates of C. albicans, Candida glabrata and the only isolate of Candida tropicalis were susceptible to all the antifungal agents tested. Only one isolate of Candida parapsilosis was susceptible dose-dependent to fluconazole, and the only isolate of Candida metapsilosis was resistant to fluconazole.ConclusionsIt is essential to evaluate the risk factors, underlying conditions and clinical features in non-hospitalized patients in order to determine whether an empirical treatment for candidemia is appropriate. 相似文献
97.
98.
Fabián Casas Ana Benítez‐López Jesús T. García Carlos A. Martín Javier Viñuela Francois Mougeot 《Ibis》2015,157(1):115-124
Capturing and marking free‐living birds permits the study of important aspects of their biology but may have undesirable effects. Bird welfare should be a primary concern, so it is necessary to evaluate and minimize any adverse effects of procedures used. We assess short‐term effects associated with the capture, handling and tagging with backpack‐mounted transmitters of Pin‐tailed Pterocles alchata and Black‐bellied Pterocles orientalis Sandgrouse, steppe birds of conservation concern. There was a significantly higher mortality (15%) during the first week after capture than during the following weeks (< 2.5%) in Pin‐tailed Sandgrouse, but no significant temporal mortality pattern in Black‐bellied Sandgrouse. In Pin‐tailed Sandgrouse, mortality rate during the first week increased with increasing relative transmitter and harness weight regardless of season, and with increasing handling time during the breeding season. There were no significant differences in mortality rate between study areas, type of tag, sex or age or an effect of restraint time. These results suggest the use of lighter transmitters (< 3% of the bird's weight) and a reduction of handling time (< 20 min), particularly during the breeding season, as essential improvements in procedure to reduce the mortality risk associated with the capture, handling and tagging of these vulnerable species. 相似文献
99.
100.