全文获取类型
收费全文 | 981篇 |
免费 | 52篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 5篇 |
妇产科学 | 5篇 |
基础医学 | 73篇 |
口腔科学 | 3篇 |
临床医学 | 42篇 |
内科学 | 24篇 |
皮肤病学 | 45篇 |
神经病学 | 18篇 |
特种医学 | 7篇 |
外科学 | 7篇 |
综合类 | 78篇 |
预防医学 | 419篇 |
眼科学 | 2篇 |
药学 | 227篇 |
中国医学 | 53篇 |
肿瘤学 | 45篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 6篇 |
2021年 | 13篇 |
2020年 | 17篇 |
2019年 | 13篇 |
2018年 | 25篇 |
2017年 | 28篇 |
2016年 | 39篇 |
2015年 | 19篇 |
2014年 | 39篇 |
2013年 | 119篇 |
2012年 | 49篇 |
2011年 | 55篇 |
2010年 | 67篇 |
2009年 | 56篇 |
2008年 | 79篇 |
2007年 | 53篇 |
2006年 | 41篇 |
2005年 | 37篇 |
2004年 | 23篇 |
2003年 | 26篇 |
2002年 | 22篇 |
2001年 | 20篇 |
2000年 | 23篇 |
1999年 | 14篇 |
1998年 | 19篇 |
1997年 | 21篇 |
1996年 | 12篇 |
1995年 | 18篇 |
1994年 | 15篇 |
1993年 | 13篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 14篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1984年 | 4篇 |
1983年 | 9篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有1055条查询结果,搜索用时 15 毫秒
31.
32.
Juthasiri Rohitrattana Tanasorn Tunsaringkarn Parinya Panuwet P. Barry Ryan Dana Boyd Barr 《Journal of agromedicine》2014,19(4):406-416
Organophosphate pesticides (OPs) are widely used in agricultural sectors in Thailand. Previous studies have documented that children residing in agricultural areas have higher exposure to OPs than children living in other residential areas. The objective of this study was to quantify urinary biomarkers of OP exposure and determine the environmental conditions and activities that predict their levels among children living in Central Thailand farming regions. In October 2011, 53 6–8-year-old participants were recruited from Pathum Thani Province, Thailand. Twenty-four lived in rice farming communities at Khlong Luang District where OPs are the pesticides used frequently. Twenty-nine participants, living in aquacultural farming communities at Lum Luk Ka District where OPs are not used, were recruited to serve as controls for pathways of exposure (e.g., residential, dietary) other than occupational/paraoccupational exposures encountered in rice farming. Household environments and participants’ activities were assessed using a parental structured interview. Urine samples (first morning voids) were collected from participants for OP urinary metabolite (i.e., dialkylphosphates [DAPs] and 3,5,6-trichloro-2-pyridinol [TCPy]) measurements. The levels of most urinary OP metabolites were significantly higher in participants who lived in a rice farming community than those who lived in an aquacultural farming community (P < .05). The results from linear regression analysis revealed that the frequency of OP application on rice farms (∑DAP: P = .001; TCPy: P = .001) and living in a rice farming community (∑DAP: P = .009; TCPy: P < .001) were significant predictors of urinary DAP metabolite levels in participants. Increasing TCPy levels were significantly related to proximity to rice farm (P = .03), being with parent while working on a farm (P = .02), playing on a farm (P = .03), and the presence of observable dirt accumulated on the child’s body (P = .02). In conclusion, OP metabolite levels among children who live in rice farming communities were strongly influenced by farming activity, household environments, and child behaviors, suggesting that these are the primary pathways in which children living in these agricultural communities in Thailand were exposed to OPs. 相似文献
33.
This study aims to review agricultural pesticide usage and trends and to identify hazardous pesticides for regulation, in terms of public health, in South Korea. The authors collected data on usage and trends of agricultural pesticides through agriculture-related databases. Criteria from the US Environmental Protection Agency classification for carcinogenicity, World Health Organization classification for acute toxicity, and European Union prioritization list for endocrine-disrupting chemicals were used for the hazard categorization of identified individual active ingredients. Pesticides to be prioritized among all pesticides used in South Korea between 2007 and 2011 were selected by taking into account the volume of usage, toxicity, and epidemiological evidence. Annual agricultural use of pesticides has increased rapidly from the 1970s to 1990s in South Korea, but has declined since 2001. The quantity of pesticides used in 2011 was reported as 19,131 tons, and was comprised of 34.7% insecticides, 28.0% fungicides, and 27.1% herbicides. The 50 pesticides with the greatest volume of usage accounted for 82.6% of the total volume of pesticides used between 2007 and 2011, with the most-used active ingredient being machine oil, followed by mancozeb and then paraquat. Organophosphates were the most used among the top 50 pesticides. A total of 24 pesticides were selected for recommendation of intensive regulation in South Korea. In conclusion, the authors described the usage and trends of overall agricultural pesticides, which would serve as a fundamental step forward in managing pesticide in terms of public health. Intensive efforts are required for the prevention of potential health effects from the 24 identified pesticides. 相似文献
34.
OBJECTIVE: This study investigates the effects of Organophosphate (OP) pesticides exposure on the cognitive and behavioral functioning of Hispanic children living in an agricultural community. METHODS: Forty-eight children were administered a battery of cognitive measures, and their parents and teachers completed behavior rating scales. Children provided a urine sample for analysis of OP pesticides metabolites. RESULTS: All children had a detectable level of at least one OP pesticide metabolite. Higher OP pesticide metabolite concentration levels were significantly correlated with poorer performance on some subtests of the Wisconsin Card Sorting Test. However, the significance of this association was dependent upon the inclusion of two samples with noticeable higher OP pesticide metabolite concentration levels. CONCLUSIONS: Short-term OP pesticide exposure seems to have deleterious effects on children's speed of attention, sequencing, mental flexibility, visual search, concept formation, and conceptual flexibility. This study is among a relatively small number of studies investigating an extremely complex problem. Limitations and suggestions for future studies are discussed. 相似文献
35.
Dietary intake of organophosphorus pesticide residues through vegetables from Kumasi, Ghana 总被引:1,自引:0,他引:1
Contamination and health risk hazards of organophosphorus pesticides residues in vegetables were studied. Ethyl-chlorpyrifos, observed at an average level of 0.211 ± 0.010 mg kg−1 in 42% of tomato, 0.096 ± 0.035 mg kg−1 in 10% of eggplant and 0.021 ± 0.013 mg kg−1 in 16% of pepper was below the 0.5 mg kg−1 MRL. Dichlorvos was the most frequently detected residue in all the samples analyzed. Levels of malathion in tomatoes (0.120 ± 0.101 mg kg−1) and pepper (0.143 ± 0.042 mg kg−1) exceeded the MRL of 0.1 mg kg−1. Health risks were found to be associated with methyl-chlorpyrifos, ethyl-chlorpyrifos, and omethioate in tomatoes and methyl-chlorpyrifos, ethyl-chlorpyrifos, dichlorvos, monocrotophos and omethioate in eggplant. Routine monitoring of these pollutants in food items is required to prevent, control and reduce the pollution and to minimize health risks. 相似文献
36.
Veruska Lima Moura Brasil Mariana Bitu Ramos Pinto Roberta Ferreti Bonan Luiz Paulo Kowalski Danyel Elias da Cruz Perez 《Journal of oral pathology & medicine》2018,47(7):641-651
Humans may be exposed to pesticides such as fungicides, herbicides, and insecticides, during occupational and non‐occupational activities. Pesticides could be related to cancer development mainly because of their effects on the endocrine and immune systems and their cumulative effect. The present review evaluated in current literature evidence of an association between exposure to pesticides and the occurrence of head and neck cancer (HNC). A literature search for cohort studies was conducted in the PubMed, Web of science, and Cochrane databases. Methodological quality of each study was rated with the Scottish Intercollegiate Guidelines Network (SIGN) checklist. One thousand one hundred and thirty‐two studies were identified. Thirty‐two were included. Most of the studies found addressed occupational exposure to pesticides and were conducted in Europe and North America. Eleven high‐quality studies were found. Most of them found no association between exposure to pesticides and increased risk of HNC. Two studies found some evidence of a positive association between pesticide (malathion and atrazine) exposure and thyroid cancer. The literature review does not support a clear evidence for association between pesticides exposure and HNC. Only limited evidence points to a positive association between exposure to some pesticides and thyroid cancer. Further standardized studies based on appropriate designs are required to clarify the effect of pesticides on the genesis of HNC, considering dose, length of exposure, and type of pesticide. 相似文献
37.
38.
Yue Liang Fang Tong Lin Zhang Wenhe Li Weisheng Huang 《Clinical toxicology (Philadelphia, Pa.)》2018,56(2):140-142
Context: Terbufos (TBF) is a class Ia (extremely hazardous) organophosphate pesticide (OP) and its distribution in industrialized countries has been severely restricted. Thus, acute occupational poisoning is rather uncommon. However, it still occurs in rural areas of some developing countries, where the sale of TBF is not controlled and its use is thus not properly regulated. We report a case of a 43-year-old female farmer who died after applying TBF granules.Case: The patient died within 3?h after applying 20 bags of 5% TBF granules (900?g per bag). Investigation showed that her personal protective equipment (PPE) did not provide effective protection against dermal and inhalational exposure. Postmortem analysis revealed extremely low red blood cell acetylcholinesterase activity. Toxicological analysis of TBF showed 1.45?×?10?2?μg/ml in the heart blood and 0.17?μg/g in the liver.Discussions: This patient died as a result of toxicity from dermal and inhalational exposure to TBF. Over-application, improper equipment, inadequate and defective PPE, and lack of hygienic precautions were all contributing factors.Conclusions: TBF is a highly toxic OP. Inadequate regulatory control, improper environmental application, and ineffective PPE resulted in a fatal human exposure. 相似文献
39.
气相色谱-质谱联用法测定金银花中192种农药多残留 总被引:2,自引:0,他引:2
目的 建立气相色谱-质谱联用法(GC-MS)测定金银花中192种农药多残留的分析方法,对样品进行普查,了解金银花中农药残留情况。 方法 用丙酮进行提取,采用凝胶渗透色谱(GPC)与固相萃取(SPE)结合净化的分析方法,采用气相色谱质谱联用法进行测定。结果 回收率总体处于70% ~110%之间,相对标准偏差≤15%,方法检出限总体处于0.01 mg·kg-1以下。结论 此方法灵敏度高,准确,可靠,可作为金银花中的农药多残留测定法。样品普查结果表明,金银花中农药残留污染情况较为严重。
相似文献
相似文献
40.