全文获取类型
收费全文 | 12032篇 |
免费 | 670篇 |
国内免费 | 304篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 298篇 |
妇产科学 | 126篇 |
基础医学 | 1686篇 |
口腔科学 | 110篇 |
临床医学 | 1554篇 |
内科学 | 1876篇 |
皮肤病学 | 88篇 |
神经病学 | 579篇 |
特种医学 | 467篇 |
外科学 | 998篇 |
综合类 | 1495篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 770篇 |
眼科学 | 90篇 |
药学 | 2215篇 |
3篇 | |
中国医学 | 255篇 |
肿瘤学 | 317篇 |
出版年
2023年 | 123篇 |
2022年 | 213篇 |
2021年 | 364篇 |
2020年 | 331篇 |
2019年 | 294篇 |
2018年 | 295篇 |
2017年 | 302篇 |
2016年 | 312篇 |
2015年 | 375篇 |
2014年 | 656篇 |
2013年 | 708篇 |
2012年 | 599篇 |
2011年 | 669篇 |
2010年 | 498篇 |
2009年 | 545篇 |
2008年 | 578篇 |
2007年 | 525篇 |
2006年 | 442篇 |
2005年 | 435篇 |
2004年 | 356篇 |
2003年 | 324篇 |
2002年 | 257篇 |
2001年 | 242篇 |
2000年 | 213篇 |
1999年 | 209篇 |
1998年 | 189篇 |
1997年 | 193篇 |
1996年 | 181篇 |
1995年 | 177篇 |
1994年 | 157篇 |
1993年 | 132篇 |
1992年 | 165篇 |
1991年 | 118篇 |
1990年 | 127篇 |
1989年 | 148篇 |
1988年 | 132篇 |
1987年 | 126篇 |
1986年 | 104篇 |
1985年 | 158篇 |
1984年 | 157篇 |
1983年 | 89篇 |
1982年 | 153篇 |
1981年 | 114篇 |
1980年 | 80篇 |
1979年 | 68篇 |
1978年 | 51篇 |
1977年 | 53篇 |
1976年 | 61篇 |
1975年 | 41篇 |
1973年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
《Journal of labelled compounds & radiopharmaceuticals》2003,46(6):531-537
Exposure of captodative enone systems to deuterium in the presence of Crabtree's catalyst ( 1 ) results in deuteration at the vinylic site β‐ to the ketone carbonyl, as well as at any accessible ortho‐position. β‐exchange is also observed during the reduction of ethyl cinnamate ( 3 ) catalyzed by 1 . Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
12.
In today''s environment, providers are extremely time-constrained. Assembling relevant contextual data to make decisions on laboratory results can take a significant amount of time from the day. The Regenstrief Institute has created a system which leverages data within Indiana Health Information Exchange''s (IHIE''s) repository, the Indiana Network for Patient Care (INPC), to provide well-organized and contextual information on returning laboratory results to outpatient providers. The system described here uses data extracted from INPC to add historical test results, medication-dispensing events, visit information, and clinical reminders to traditional laboratory result reports. These “Enhanced Laboratory Reports” (ELRs) are seamlessly delivered to outpatient practices connected through IHIE via the DOCS4DOCS clinical messaging service. All practices, including those without electronic medical record systems, can receive ELRs. In this paper, the design and implementation issues in creating this system are discussed, and generally favorable preliminary results of attitudes by providers towards ELRs are reported. 相似文献
13.
In this study, the effect of regular khat (Catha edulis Forsk) chewing (200 and 400 g) in humans on plasma leptin, nonesterified fatty acid, triacyglycerol, and total cholesterol levels was investigated. The results presented show that khat chewing increases plasma leptin concentration particularly in individuals who chew 400 g of khat leaves. The significance of increased plasma leptin is in explaining the underlying mechanism of the observed effects associated with khat chewing such as loss of appetite, decreased body weight, and hyperthermia. The decreased body weight was evident from the significantly lower body mass index of the khat leaves chewers group as compared to the non–khat leaves chewers group (control). Moreover, like leptin, the plasma levels of nonesterified fatty acids were significantly higher in those chewing 400 g of khat leaves. On the other hand, the plasma levels of triacylglycerol were significantly lower in the 2 khat-chewers groups (200 and 400 g of khat leaves), whereas plasma cholesterol levels were not affected by the 2 levels of khat leaves used in this study. The significance of these results may suggest that khat leaves may contain a component(s) that has the ability to reduce body weight via decreasing appetite. 相似文献
14.
薄层扫描法测定血浆中盐酸氟桂利嗪浓度及药物动力学 总被引:2,自引:0,他引:2
血浆中盐酸氟桂利嗪经硼酸缓冲液酸化后,正戊烷-异丙醇(98:2)提取其原型,加酸使成盐溶于无机相中,再加碱后用二氯甲烷提取,样品点于硅胶GF254薄层板上,以环己烷-丙酮-氯仿(9:3:5)为展开剂。氟桂利嗪在254nm紫外灯下呈紫色斑点,Rf=0.54,于CS-930薄层扫描仪上测定,λs=215nm、λg=310nm,线性范围0.3 ̄8μg,平均回收率90.02%。用此法测定了氟桂利嗪血药浓度 相似文献
15.
熵代表无序的水平,作者使用通气的熵变(ECV)指示肺通气的不均匀性,ECV定义为当前泡潮气量趋近于零时每摩尔被吸入气体从不均匀通气到均匀通气的熵变的极限。本文从熵的基本公式民地出ECV的计算方程。用几个数学模型肺将ECV同其他7个洗出指标进行了比较。8个指标中,只有ECV仅取决于通气分布,其他7个指标不仅取决于通气分布,还同潮气量和死腔的大小有关。这影响了它们评价肺通气不均匀性的效果,ECV的另一 相似文献
16.
成人原发性肾病综合征血容量与肾素,醛固酮,心钠素的关系 总被引:2,自引:0,他引:2
探讨成人原发性肾病综合征(NS)血容量与肾素、醛固酮及心钠素的关系。方法 应用~(113)mInCl标记转铁蛋白稀释法测定血容量,放免法测定血浆激素水平。对水肿期NS28例、正常26例及其中NS缓解期随访18例进行检测。结果 (1)水肿期NS血容量与正常组无差别,血浆肾素活性(PRA)、血管紧张素Ⅱ(ATⅡ)、醛固酮(Ald)、心钠素(ANP)水平均较正常组高,白蛋白、各激素水平与血容量无显著相关;(2)缓解期与水肿期比较,总的血容量无差异,Ald、ANP显著降低,PRA、ATⅡ则无明显差异;(3)Ald与24小时尿排钠(UNaV)显著负相关。结论 Ald和ANP是NS钠排泄的主要调节因子。 相似文献
17.
M. A. El-Kalay M. H. Abdel-Kader† R. Y. Hamzah† S. A. Al-Shirbini† 《Artificial organs》1990,14(3):200-207
Using a plasma separator, it is possible to wash large volumes of whole blood free of plasma proteins in short periods. The novelty, however, is that the same apparatus can be used to reversibly hemolyze and reseal the red blood cells (RBCs) using hypotonic and hypertonic dialysates, respectively. This technique was assessed using the fluorescent exogenous agent uranin (fluorescein sodium). Results indicate that the encapsulation of the RBCs can be completed in under 2 h. The encapsulation efficiency of the RBCs was approximately 80% with a RBC recovery rate of 75%. 相似文献
18.
福建产舟山眼镜蛇毒细胞毒素的快速分离纯化及鉴定 总被引:8,自引:4,他引:4
目的 从舟山眼镜蛇毒中分离纯化细胞毒素(CTX),并鉴定其理化性质。方法 采用SP—Sephadex C-25阳离子交换色谱及Sephasil Peptide C18反相高效液相色谱法从舟山眼镜蛇毒中分离纯化CTX,SDS—PAGE(Tris—Tricine系统)鉴定纯度,Edman降解法测定N端氨基酸序列。结果 粗毒经阳离子交换色谱,得到14个蛋白峰,其中第X~XⅢ峰具CTX活性;再分别经反相色谱纯化,得到4个CTX.总得率为32.48%;SDS—PAGE显示为均一蛋白,分子量依次为:7.28,7.33,7.24和7.38kD;测定它们N端20个氨基酸序列。结论 采用阳离子交换和反相高效液相色谱可快速、高效地从眼镜蛇毒中获得4个CTX纯品。 相似文献
19.
LOWER POSTPRANDIAL PLASMA GLUCOSE AND INSULIN AFTER ADDITION OF ACACIA CORIACEA FLOUR TO WHEAT BREAD
Many Australian Aboriginal bushfoods contain slowly digested carbohydrate which elicit low postprandial blood glucose and insulin responses compared to Western foods, such as wheat bread. This study has shown that incorporation of flour made from a slowly digested seed, Acacia coriacea , into wheat bread (18 g/82 g wheat flour) significantly reduces the initial rise in plasma glucose levels ( p < 0.05) and the area under the plasma glucose curve ( p < 0.005) in six healthy subjects. Insulin values were also lowered at 60 minutes ( p < 0.025) and 90 minutes ( p < 0.05). Our findings suggest that Acacia flour, when used to dilute wheat flour in the manufacture of breads, produces a very palatable food which could be useful in the diets of diabetic individuals. 相似文献
20.
Elizabeth R. Woods M.D. M.P.H. Jonathan D. Klein M.D. M.P.H. Gina M. Wingood Sc.D. M.P.H. Eve S. Rose M.S.P.H. David Wypij Ph.D. Sion Kim Harris Ph.D. Ralph J. Diclemente Ph.D. 《The Journal of adolescent health》2006,38(6):753.e1-753.e7
PurposeAlthough an adult model of patient-provider mutual exchange of information has been proposed, there is no guiding model for adolescents or measurement methodology. Our purpose was to develop a new scale of patient-provider interaction for adolescents accessing reproductive health care and at risk for sexually transmitted diseases (STDs) and human immunodeficiency virus (HIV), and assess the reliability and validity of the scale.MethodsThe Adolescent Patient-Provider Interaction Scale (APPIS) was developed from the Roter and Hall theory of doctor-patient relationships, previously validated adolescent satisfaction and communication scales, and focus group and individual elicitation interviews. To assess construct validity, the new nine-item APPIS was compared with the satisfaction scale used by the Young Adult Health Care Survey (YAHCS), and Kahn’s Provider Communication Scale. Pearson correlation coefficients were used to examine convergence across scales, and factor analysis of the APPIS was performed.ResultsThe study recruited 192 African American girls aged 17.9 ± 1.7 years (range 15–21 years) from three sites: a county STD clinic (n = 51), urban adolescent clinic (n = 99), and a family planning clinic (n = 42). Most participants (85%) rated their overall health care highly (≥ 7 on a 10-point scale); 49% felt that both the provider and patient were “in charge” of the visit, and 88% “strongly agreed” or “agreed” that there was an equal “exchange of information” during the visit. The APPIS showed good internal consistency (Cronbach alpha = .75), and moderate convergence with the six-item YAHCS scale (r = .57, p < .001) and seven-item Kahn scale (r = .48, p < .001). Three factors emerged from exploratory factor analyses, supporting our conceptualization of patient-provider interaction as being multi-dimensional.ConclusionsA new theory-based scale of adolescent patient-provider interaction compares favorably with previous scales of health care satisfaction and communication. The new APPIS may be useful for evaluating approaches to improve health care outcomes for adolescents at-risk for STDs and HIV. 相似文献