全文获取类型
收费全文 | 7588篇 |
免费 | 540篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 159篇 |
儿科学 | 179篇 |
妇产科学 | 170篇 |
基础医学 | 1085篇 |
口腔科学 | 232篇 |
临床医学 | 661篇 |
内科学 | 1621篇 |
皮肤病学 | 101篇 |
神经病学 | 454篇 |
特种医学 | 193篇 |
外国民族医学 | 3篇 |
外科学 | 1174篇 |
综合类 | 170篇 |
一般理论 | 5篇 |
预防医学 | 554篇 |
眼科学 | 207篇 |
药学 | 646篇 |
中国医学 | 106篇 |
肿瘤学 | 474篇 |
出版年
2024年 | 7篇 |
2023年 | 95篇 |
2022年 | 251篇 |
2021年 | 391篇 |
2020年 | 252篇 |
2019年 | 331篇 |
2018年 | 378篇 |
2017年 | 264篇 |
2016年 | 291篇 |
2015年 | 313篇 |
2014年 | 422篇 |
2013年 | 484篇 |
2012年 | 804篇 |
2011年 | 699篇 |
2010年 | 379篇 |
2009年 | 305篇 |
2008年 | 395篇 |
2007年 | 398篇 |
2006年 | 351篇 |
2005年 | 260篇 |
2004年 | 215篇 |
2003年 | 210篇 |
2002年 | 180篇 |
2001年 | 50篇 |
2000年 | 53篇 |
1999年 | 45篇 |
1998年 | 40篇 |
1997年 | 26篇 |
1996年 | 25篇 |
1995年 | 12篇 |
1994年 | 20篇 |
1993年 | 16篇 |
1992年 | 25篇 |
1991年 | 23篇 |
1990年 | 14篇 |
1989年 | 15篇 |
1988年 | 22篇 |
1987年 | 22篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1974年 | 8篇 |
1973年 | 10篇 |
1972年 | 3篇 |
1971年 | 6篇 |
排序方式: 共有8194条查询结果,搜索用时 15 毫秒
71.
Erin D. Wright Pota Christodoulopoulos Peter Small Saul Frenkiel Qutayba Hamid 《The Laryngoscope》1998,108(10):1528-1533
Objectives: Th-2 type cytokine production (inter-leukin-4 [IL-4] and interleukin-5 [IL-5]) has been demonstrated to play a significant role in the pathophysiology of allergic rhinitis (AR), and the treatment of AR with topical corticosteroids has been shown to reduce the expression of Th-2 type cytokines in vivo. However, the contribution and expression of Th-2 type cytokine receptors in AR and their response to corticosteroid treatment remain to be clarified. Objectives of the current study are 1. To examine the expression of the cytokine IL-4 and IL-5 receptors (IL-4R and IL-5R) in a nasal allergen challenge model and to contrast this with the expression of the receptor for the Th-1 type cytokine, interferon-gamma receptor (IFN-γR), and 2. to examine the effects of pretreatment with topical corticosteroid before allergen challenge on the expression of these same receptors. Study Design: Randomized prospective study involving 14 ragweed-allergic subjects evenly divided between placebo and corticosteroid pretreatment. Methods: Immunocytochemistry (alkaline phosphatase-antial-kaline phosphatase labeling [APAAP] technique) was used to stain nasal biopsy specimens before and after allergen challenge. Antibodies used included anti-CD3, CD4, CD8, MBP, IL-4R, IL-5R, and IFN-γR. Results: Following allergen challenge, we observed a significant increase in the Th-2 type cytokine receptors (IL-4R and IL-5R; P < .05), as well as a significant decrease in the expression of the Th-1 type cytokine receptor (IFN-γR; P < .05). Pretreatment with topical corticosteroids before nasal allergen challenge resulted in decreased expression of IL-4R (P < .05) and IL-5R (P < .05) and increased expression of IFN-γR (P < .05). Further, IL-4R and IL-5R expression correlated with eosinophil infiltration in the tissues. Conclusions: We have demonstrated that in AR, cytokine receptors for IL-4, IL-5, and IFN-γ follow a similar pattern to their ligands. In addition, pretreatment with topical corticosteroids was shown to alter the cytokine receptor expression pattern from a Th-2 profile more toward a Th-1 profile. Laryngoscope, 108:1528–1533,1998 相似文献
72.
Reqia Sagou Rachid Amanhir Hamid Taleb Paulo Vale Mohamed Blaghen Mohamed Loutfi 《Toxicon》2005,46(6):612-618
At the western Mediterranean coast of Morocco, the cockle (Acanthocardia tuberculatum) contained persistent high levels of paralytic shellfish toxins for several years, while other bivalve molluscs such as sweet clam (Callista chione) from the same vicinity were contaminated seasonally to a much lesser extent. In order to understand the causes of this prolonged contamination, a comparative study on PSP decontamination between sweet clam and cockle was conducted from November 2001 until June 2002. PSP toxicity was analysed by automated pre-column oxidation (Prechromatographic oxidation and LC-FD) in several organs of both species, namely digestive gland, foot, gill, mantle, muscle and siphon for sweet clams. The results showed that cockle sequester PSP toxins preferably in non-visceral organs (Foot, gill and mantle) contrary to sweet clam that sequester them in visceral tissues (digestive gland). The toxin profile of cockle organs indicated dominance of dcSTX, whereas sweet clam tissues contained especially C-toxins. Substantial differences in toxin profile between cockle and sweet clam, from the same area as well as from the composition of PSP toxin producer, Gymnodinium catenatum, confirm the bioconversion of PSP toxins in cockle. 相似文献
73.
Seyed Ali Tabatabaei Mohammad Soleimani Bahram Bohrani Ali Banafsheafshan Shahin Faghihi Houshang Faghihi 《国际眼科》2019,12(3):523-525
Letter to the Editor 相似文献
74.
75.
76.
77.
Koushan Sineh Sepehr Mohsen Saeidi Majid Mossahebi-Mohammadi Meghdad Abdollahpour-Alitappeh Seyed Mahmoud Hashemi 《Journal of immunoassay & immunochemistry》2018,39(2):207-217
Background: Mesenchymal stem cells (MSCs) were isolated from various sources, including various types of tumors. However choosing an appropriate isolation method is an important step in obtaining cells with optimal quality and yield in companion with economical considerations. The purpose of this study was to isolate more pure MSCs from human breast tumor tissue by a modified explant culture method.Methods and Materials: The tumor tissues (n = 8) were cut into 1 to 3-mm cube-like pieces (explant). Each explant was placed in a well of 24-well format plates, cultured in Dulbecco’s Modified Eagle’s medium (DMEM), and maintained at 37°C with 5% humidified incubator. Morphological phenotypes of the cells were surveyed by an inverted microscope and wells with rather homogenous fibroblast-like morphology cell were considered as positive and selected for more expansion and characterization.Results: A total of 185 wells, 63.7% of wells were positive that were chosen for expansion. Flowcytometry analysis demonstrated that isolated cells were positive for CD73, CD44, CD29, CD105, and CD90 but negative for CD11b, CD45, CD34, and HLA?DR. In addition, cells possessed the capability of multipotential differentiation into osteoblasts and adipocytes. 相似文献
78.
Behrooz Nikahval Seifollah Dehghani Nazhvani Mohammad Hadi Bagheri Nader Tanideh Mehrangiz Keramati Hamid Reza Gheisari 《Comparative clinical pathology》2012,21(6):1451-1456
The objectives of the present study were to describe radiographic and magnetic resonance imaging (MRI) findings of early osteoarthritis and their relationships at the same time. A total number of ten rabbits were used and randomly divided into two equal groups. In one group, cranial cruciate ligament (CCL) of the left knee was transected to produce experimental osteoarthritis and in the other group, only the articular capsule was entered as sham operation (arthrotomy group). All of the left knees were examined by MRI and radiography before operation to exclude preexisting abnormalities and serve as control. One month postoperation, two conventional radiographic views and MR imaging were performed under general anesthesia. Statistical analysis of the MRI results revealed that there was a significant difference between the CCL-transected group with arthrotomy and control groups. There was no significant difference in the radiographic findings between the operated, arthrotomy and control groups. It was concluded that osteoarthritic changes of the joints can be detectable 1?month postinjury by MRI. Meniscal degeneration and subchondral bone irregularity are detectable diagnostic signs. 相似文献
79.
80.
Seyed Mohammad Mousavi Elham Majdi Nasab Vahid Yavari Ebrahim Rajabzadeh Ghatrami Mohammad Razi Jalali 《Comparative clinical pathology》2012,21(5):859-863
For choosing an anaesthetic agent for a particular purpose, the different properties has been notified such as the convenience for use, safety for the fish, humans and the environment, effectiveness, physiological disturbances and its cost. Invariably, in any study with clove oil, it has been regarded as an effective and acceptable alternative to other anaesthetics. The aim of the present study was to investigate effects of two anaesthetic regimes, MS-222 and eugenol, on plasma biochemical parameters in Barbus sharpeyi. B. sharpeyi fingerlings (mean weight, 5?g?±?1; mean length, 6?cm?±?1) were exposed to MS-222 (100?ppm) and eugenol (40?ppm) for induction of anaesthesia. Blood samples were taken to verify the effects of these anaesthetics on plasma biochemical parameters may use as an indicator of stress at time 0 (designated for each tank at the time of exposure to anaesthetic agent), 0.5, 1, 2 and 24?h after exposure by caudal severance. Plasma biochemical parameters concentrations were not significantly affected in B. sharpeyi (p?<?0.05). These results were expected because the trials were conducted in short-term exposures. Ion balance appears to be altered only in long-term stressing condition. Based on the results of this study, eugenol appears to be a safe anesthetic for use in B. sharpeyi. 相似文献