全文获取类型
收费全文 | 8013篇 |
免费 | 502篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 36篇 |
儿科学 | 167篇 |
妇产科学 | 79篇 |
基础医学 | 867篇 |
口腔科学 | 110篇 |
临床医学 | 873篇 |
内科学 | 1950篇 |
皮肤病学 | 143篇 |
神经病学 | 431篇 |
特种医学 | 194篇 |
外国民族医学 | 1篇 |
外科学 | 1518篇 |
综合类 | 209篇 |
现状与发展 | 1篇 |
一般理论 | 5篇 |
预防医学 | 498篇 |
眼科学 | 149篇 |
药学 | 779篇 |
中国医学 | 155篇 |
肿瘤学 | 416篇 |
出版年
2024年 | 13篇 |
2023年 | 137篇 |
2022年 | 419篇 |
2021年 | 646篇 |
2020年 | 386篇 |
2019年 | 469篇 |
2018年 | 461篇 |
2017年 | 280篇 |
2016年 | 305篇 |
2015年 | 334篇 |
2014年 | 396篇 |
2013年 | 468篇 |
2012年 | 727篇 |
2011年 | 658篇 |
2010年 | 311篇 |
2009年 | 291篇 |
2008年 | 425篇 |
2007年 | 398篇 |
2006年 | 339篇 |
2005年 | 312篇 |
2004年 | 241篇 |
2003年 | 229篇 |
2002年 | 104篇 |
2001年 | 41篇 |
2000年 | 27篇 |
1999年 | 19篇 |
1998年 | 19篇 |
1997年 | 7篇 |
1996年 | 11篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 9篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 12篇 |
1980年 | 3篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1972年 | 3篇 |
1969年 | 2篇 |
排序方式: 共有8581条查询结果,搜索用时 234 毫秒
91.
92.
Muhammad Waseem Tahir Ahrar Khan Muhammad Yousaf Salman Latif Butt Wattasit Siriwong 《Toxin reviews》2017,36(3):187-193
The present study was designed to investigate the toxico-pathological effect of cadmium (Cd) and its amelioration with silymarin (SL) and milk thistle (MT) in male Japanese quail (Coturnix japonica). A total of 144 male quail were divided into nine equal groups (A–I). Experimental feeds were offered to these groups containing different combinations of Cd chloride (Cd1: 150 and Cd2: 300?mg/kg feed), SL (250?mg/kg of feed), and MT (10?g/kg of feed). The duration of the experiment was 60 days. The physical parameters studied included feed intake and body weight. Hematobiochemical parameters included total protein, albumin, ALT, AST, creatinine, urea, hemoglobin, and hematocrit. The data were analyzed by analysis of variance (ANOVA) technique, and group means were compared by Duncan’s multiple range test. The body weight decreased significantly in Cd-treated groups while SL and MT ameliorated the toxic effects of Cd as compared to control group. The hemoglobin (Hb) concentration and hematocrit (Hct) values were decreased significantly in Cd2-treated group, while Hb and Hct decreased nonsignificantly in Cd1-treated group compared with control. Similar hematological findings were observed, when Cd was used in combinations with SL and MT. Urea, creatinine, and AST increased significantly, while ALT increased nonsignificantly in Cd-treated groups as compared to control group, while total protein, albumin, and globulin decreased significantly in Cd-treated groups as compared to control group. The SL and MT completely ameliorated these toxic effects at low dose of Cd; however, amelioration was partial at higher doses of Cd. These compounds (SL &; MT) might be used to ameliorate toxic effects of Cd in Japanese quail. 相似文献
93.
El-Khalik Sarah Ragab Abd Ibrahim Rowida Raafat Ghafar Muhammad Tarek Abdel Shatat Doaa El-Deeb Omnia Safwat 《Journal of assisted reproduction and genetics》2022,39(5):1115-1124
Journal of Assisted Reproduction and Genetics - Ferroptosis is associated with oxidative stress (OS) and is caused by iron-dependent lipid-peroxidative damage, but its role in PE is unclear. The... 相似文献
94.
95.
β-Thalassemia (β-thal) is a monogenic disease characterized by mutations on the HBB gene, affecting the production of globin that results in hypochromic and microcytic anemia. The aim of this study was to determine the prevalence of six common β-thal mutations, and their frequency and inheritance pattern in affected populations of North Waziristan Agency, Pakistan. In this study, 130 blood samples from 37 unrelated β-thalassemic families having a minimum of one transfusion-dependent child with β-thal major (β-TM), were retrieved either from the Thalassaemia Centre for Women and Children Hospital Bannu or their home towns situated in Noth Waziristan Agency. All samples were analyzed by the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) using six allele-specific primers for the presence of the six β-thal mutations common in the Pakistani population. Of the six common mutations, our study demonstrated five HBB mutations comprising HBB: c.27_28insG, HBB: c.92+5G>C, HBB: c.126_129delCTTT, HBB: c.92+1G>T and HBB: c.17_18delCT from the families studied, while mutation HBB: c.47G>A [codon 15 (G>A)] was not detected in any of the studied families. Furthermore, the HBB: c.27_28insG and HBB: c.92+5G>C were noted to be the most common with frequencies of 42.85 and 31.42%, respectively. The findings of the present study may be useful in launching carrier screening and prenatal diagnosis (PND) programs by screening analyzed and other unanalyzed affected families for the possible presence of common mutations through the ARMS-PCR technique that will help to control the disease. 相似文献
96.
97.
Musarrat Riaz Abdul Basit Muhammad Zafar Iqbal Hydrie Fariha Shaheen Akhtar Hussain Rubina Hakeem Abdus Samad Shera 《Primary Care Diabetes》2012,6(4):297-302
ObjectiveTo develop and evaluate a risk score to predict people at high risk of developing type 2 diabetes in Pakistan.MethodologyCross sectional data regarding primary prevention of diabetes in Pakistan. Diabetes risk score was developed by using simple parameters namely age, waist circumference, and family history of diabetes. Odds ratios of the model were used to assign a score value for each variable and the diabetes risk score was calculated as the sum of those scores.ResultsWe externally validated the score using two data from 1264 subjects and 856 subjects aged 25 years and above from two separate studies respectively. Validating this score using the first data from the second screening study gave an area under the receive operator characteristics curve [AROC] of 0.758. A cut point of 4 had a sensitivity of 47.0% and specificity of 88% and in the second data AROC is 0.7 with 44% sensitivity and 89% specificity.ConclusionsA simple diabetes risk score, based on a set of variables can be used for the identification of high risk individuals for early intervention to delay or prevent type 2 diabetes in Pakistani population. 相似文献
98.
John T. Heap Jan Theys Muhammad Ehsaan Aleksandra M Kubiak Ludwig Dubois Kim Paesmans Lieve Van Mellaert Richard Knox Sarah A. Kuehne Phillipe Lambin Nigel P. Minton 《Oncotarget》2014,5(7):1761-1769
Spores of some species of the strictly anaerobic bacteria Clostridium naturally target and partially lyse the hypoxic cores of tumors, which tend to be refractory to conventional therapies. The anti-tumor effect can be augmented by engineering strains to convert a non-toxic prodrug into a cytotoxic drug specifically at the tumor site by expressing a prodrug-converting enzyme (PCE). Safe doses of the favored prodrug CB1954 lead to peak concentrations of 6.3 μM in patient sera, but at these concentration(s) known nitroreductase (NTR) PCEs for this prodrug show low activity. Furthermore, efficacious and safe Clostridium strains that stably express a PCE have not been reported. Here we identify a novel nitroreductase from Neisseria meningitidis, NmeNTR, which is able to activate CB1954 at clinically-achievable serum concentrations. An NmeNTR expression cassette, which does not contain an antibiotic resistance marker, was stably localized to the chromosome of Clostridium sporogenes using a new integration method, and the strain was disabled for safety and containment by making it a uracil auxotroph. The efficacy of Clostridium-Directed Enzyme Prodrug Therapy (CDEPT) using this system was demonstrated in a mouse xenograft model of human colon carcinoma. Substantial tumor suppression was achieved, and several animals were cured. These encouraging data suggest that the novel enzyme and strain engineering approach represent a promising platform for the clinical development of CDEPT. 相似文献
99.
100.
Muhammad Arif 《Journal of medical systems》2012,36(3):1173-1181
In pattern classification problems, feature extraction is an important step. Quality of features in discriminating different
classes plays an important role in pattern classification problems. In real life, pattern classification may require high
dimensional feature space and it is impossible to visualize the feature space if the dimension of feature space is greater
than four. In this paper, we have proposed a Similarity-Dissimilarity plot which can project high dimensional space to a two
dimensional space while retaining important characteristics required to assess the discrimination quality of the features.
Similarity-dissimilarity plot can reveal information about the amount of overlap of features of different classes. Separable
data points of different classes will also be visible on the plot which can be classified correctly using appropriate classifier.
Hence, approximate classification accuracy can be predicted. Moreover, it is possible to know about whom class the misclassified
data points will be confused by the classifier. Outlier data points can also be located on the similarity-dissimilarity plot.
Various examples of synthetic data are used to highlight important characteristics of the proposed plot. Some real life examples
from biomedical data are also used for the analysis. The proposed plot is independent of number of dimensions of the feature
space. 相似文献