首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   45715篇
  免费   4122篇
  国内免费   938篇
耳鼻咽喉   673篇
儿科学   840篇
妇产科学   1431篇
基础医学   4096篇
口腔科学   554篇
临床医学   5595篇
内科学   5907篇
皮肤病学   696篇
神经病学   3199篇
特种医学   690篇
外国民族医学   6篇
外科学   2950篇
综合类   6509篇
现状与发展   7篇
一般理论   4篇
预防医学   8421篇
眼科学   415篇
药学   3675篇
  53篇
中国医学   3528篇
肿瘤学   1526篇
  2024年   135篇
  2023年   943篇
  2022年   1377篇
  2021年   2323篇
  2020年   2273篇
  2019年   2018篇
  2018年   1984篇
  2017年   1888篇
  2016年   1982篇
  2015年   1597篇
  2014年   3205篇
  2013年   4093篇
  2012年   2871篇
  2011年   2888篇
  2010年   2307篇
  2009年   2003篇
  2008年   1963篇
  2007年   1976篇
  2006年   1674篇
  2005年   1392篇
  2004年   1252篇
  2003年   1192篇
  2002年   841篇
  2001年   842篇
  2000年   669篇
  1999年   579篇
  1998年   460篇
  1997年   439篇
  1996年   382篇
  1995年   340篇
  1994年   300篇
  1993年   237篇
  1992年   207篇
  1991年   200篇
  1990年   176篇
  1989年   148篇
  1988年   125篇
  1987年   146篇
  1986年   114篇
  1985年   176篇
  1984年   177篇
  1983年   114篇
  1982年   127篇
  1981年   118篇
  1980年   131篇
  1979年   75篇
  1978年   81篇
  1977年   65篇
  1976年   61篇
  1975年   32篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
目的了解旬阳县蜀河镇已婚育龄妇女避孕节育知识知晓程度和接受避孕节育服务情况,村级药具发放点现状及存在问题。方法采用随机数字表法,抽取了285名旬阳县蜀河镇内的22个行政村和一个居委会的已婚育龄妇女为调查对象进行问卷调查;查看了22个村级、1个居委会药具发放点的发放和库存情况。结果有效问卷342份。调查对象使用药具基本情况院接受避孕节育知识教育比例99%,口服避孕药30.53%,外用避孕药及避孕套68.77%,皮埋0.7%。实施避孕措施失败率3.5%。村级发放点人员文化程度院初中65%,高中及中专30%,其它5%。接受药具知识培训100%,存档备案但均未办理上岗证,无职称。报酬落实100%。发放点品种在5种以上90%,3个品种10%,发现存在过期、失效、霉变等1.6%,原因为过期、失效。发放点保证发放周期每月1次占97%。结论村级避孕节育知识的宣传普及、咨询和随访服务以及提高卫生资源的利用方面,应进一步改善服务,提高服务质量。村级发放点人员整体文化水平不高,专业知识解答能力不足,但通过经常性开展工作,基本满足了农村育龄群众对避孕药具的服务需求。  相似文献   
982.
HPLC法同时测定多维元素片中维生素A和维生素E的含量   总被引:1,自引:0,他引:1  
目的建立高效液相色谱(HPLC)法同时测定多维元素片中维生素A和维生素E的含量。方法采用C18色谱柱(250mm×4.6mm,5μm);流动相为甲醇-水(98∶2);流速为1.0mL·min-1;检测波长为265nm;柱温为25℃。结果维生素A和维生素E的线性关系良好,相关系数(r)均大于0.999 9;专属性强,维生素A、维生素E与药品中其他成分之间均有良好的分离度;稳定性和精密度良好,相对标准偏差(RSD值)均小于1.0%;回收率良好,回收率在91.07%~92.85%之间;稳定性能满足实验要求。结论该法可同时定性和定量分析多维元素片中的维生素A和维生素E,其方法的精密度、回收率和检出限能满足实际检测要求,可用于该制剂中维生素A和维生素E的监测。  相似文献   
983.
目的探讨定坤丹联合炔诺酮治疗月经不调的临床疗效。方法选取2017年3月—2019年3月在开封市人民医院治疗的月经不调患者92例,根据用药的差别分为对照组(46例)和治疗组(46例)。对照组口服炔诺酮片,2.5mg/次,4次/d;治疗组在对照组基础上口服定坤丹,7 g/次,2次/d。两组患者均经过3个月经周期治疗。观察两组患者临床疗效,同时比较治疗前后两组患者临床症候积分、性激素水平、月经失血图(PBAC)、中华生存质量量表(Ch QOL)、高温相评分(HPS)、匹茨堡睡眠质量指数量表(PSQI)评分以及血清细胞因子水平。结果治疗后,对照组临床有效率为82.61%,显著低于治疗组的97.83%,两组比较差异具有统计学意义(P0.05)。治疗后,两组患者症候积分明显下降(P0.05),且治疗组临床症候积分明显低于对照组(P0.05)。治疗后,两组血清孕酮(P)、雌二醇(E2)水平显著升高(P0.05),黄体生成激素(LH)、促卵泡成熟激素(FSH)水平显著下降(P0.05),且治疗组E2、P、LH和FSH水平明显好于对照组(P0.05)。治疗后,两组PBAC和PSQI评分显著下降(P0.05),Ch QOL和HPS评分显著升高(P0.05),且治疗组PBAC、PSQI、Ch QOL和HPS评分明显好于对照组(P0.05)。治疗后,两组患者血清表皮生长因子(EGF)、血管内皮生长因子(VEGF)水平均明显升高(P0.05),且治疗组EGF和VEGF水平明显高于对照组(P0.05)。结论定坤丹联合炔诺酮片治疗月经不调可有效改善患者临床症状,改善机体性激素水平,提高患者睡眠和生活质量。  相似文献   
984.
Adolescents in HIV endemic settings are a priority demographic with respect to HIV prevention. Some studies have shown that behaviours associated with HIV transmission, may be mediated by mental health factors such as depression. We undertook this study to explore the prevalence and associations of depression symptomology among adolescents living in the HIV endemic community of Soweto, South Africa through the Botsha Bophelo Adolescent Health Study (BBAHS). We estimated the prevalence of depression using the Centre for Epidemiological Studies of Depression Scale, using a score of ≥24 to indicate ‘probable depression’. Among the 789 adolescents (14–19 years) with depression scores, 262 (33%) met the criteria for probable depression (99 [38%] men and 163 [62%] women; p = 0.061). In multivariable logistic regression, factors independently associated with depression included being female (AOR = 2.44, 95% CI: 1.45–4.00), marijuana use (AOR = 2.67, 95% CI: 1.21–5.93), physical violence (AOR = 1.63, 95% CI: 1.01–2.62), pregnancy (AOR = 2.00, 95% CI: 1.03–3.88) and incarceration (AOR = 2.09, 95% CI: 0.99–4.42). These data indicate that a concerning proportion of adolescents in Soweto may be suffering from depression and those screened as potentially depressed, were more likely to be female and have cofactors relating to increased risk for HIV. As part of a comprehensive HIV prevention strategy, we recommend that depression screening for adolescents be integrated into public and school health programs that triage those suffering into treatment programs.  相似文献   
985.
986.
987.
The present study aims is to investigate the metabolic mechanism of Xue-Fu-Zhu-Yu decoction (XFZYD) in the treatment of blood-stasis syndrome in Coronary Heart Disease (CHD). To that end, 30 CHD patients with Blood-Stasis Syndrome (BSS) and 20 healthy subjects were enrolled. LC-Q-TOF/MS analysis determined that in comparison between CHD with BSS patients (Group A) and healthy subjects (Group C), 59 significantly differential metabolites in the positive mode and 18 significantly differential metabolites in the negative mode. The metabolite constituents in the plasma of 30 CHD with BSS patients before (group A) and after 30 days of treatment (Group B), and 20 healthy subjects (Group C) were analyzed using LC-Q-TOF/MS and GC-MS. Based on multivariate statistical analysis (PCA, PLS-DA and OPLS-DA), we determined 69 differential metabolites. The levels of hemorheology indexes were significantly down-regulated after treatment. Metabolic pathway attribution analysis showed that lipid metabolism, amino acid metabolism and bile acid metabolism pathways are involved. Our study identifies the metabolic networks of CHD and demonstrates the efficacy of this metabolomics approach to systematically study the therapeutic effect of XFZYC on CHD.  相似文献   
988.
989.
990.
The trabecular bone score (TBS, Med-Imaps, Pessac, France) is an index of bone microarchitecture texture extracted from anteroposterior dual-energy X-ray absorptiometry images of the spine. Previous studies have documented the ability of TBS of the spine to differentiate between women with and without fractures among age- and areal bone mineral density (aBMD)-matched controls, as well as to predict future fractures. In this cross-sectional analysis of data collected from 3 geographically dispersed facilities in the United States, we investigated age-related changes in the microarchitecture of lumbar vertebrae as assessed by TBS in a cohort of non-Hispanic US white American women. All subjects were 30 yr of age and older and had an L1–L4aBMDZ-score within ±2 SD of the population mean. Individuals were excluded if they had fractures, were on any osteoporosis treatment, or had any illness that would be expected to impact bone metabolism. All data were extracted from Prodigy dual-energy X-ray absorptiometry devices (GE-Lunar, Madison, WI). Cross-calibrations between the 3 participating centers were performed for TBS and aBMD. aBMD and TBS were evaluated for spine L1–L4 but also for all other possible vertebral combinations. To validate the cohort, a comparison between the aBMD normative data of our cohort and US non-Hispanic white Lunar data provided by the manufacturer was performed. A database of 619 non-Hispanic US white women, ages 30–90 yr, was created. aBMD normative data obtained from this cohort were not statistically different from the non-Hispanic US white Lunar normative data provided by the manufacturer (p = 0.30). This outcome thereby indirectly validates our cohort. TBS values at L1–L4 were weakly inversely correlated with body mass index (r = −0.17) and weight (r = −0.16) and not correlated with height. TBS values for all lumbar vertebral combinations decreased significantly with age. There was a linear decrease of 16.0% (−2.47 T-score) in TBS at L1–L4 between 45 and 90 yr of age (vs. −2.34 for aBMD). Microarchitectural loss rate increased after age 65 by 50% (−0.004 to −0.006). Similar results were obtained for other combinations of lumbar vertebra. TBS, an index of bone microarchitectural texture, decreases with advancing age in non-Hispanic US white women. Little change in TBS is observed between ages 30 and 45. Thereafter, a progressive decrease is observed with advancing age. The changes we observed in these American women are similar to that previously reported for a French population of white women (r2 > 0.99). This reference database will facilitate the use of TBS to assess bone microarchitectural deterioration in clinical practice.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号