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   12361篇
  免费   1380篇
  国内免费   171篇
耳鼻咽喉   27篇
儿科学   514篇
妇产科学   214篇
基础医学   1476篇
口腔科学   123篇
临床医学   2864篇
内科学   1163篇
皮肤病学   101篇
神经病学   1312篇
特种医学   45篇
外国民族医学   2篇
外科学   501篇
综合类   894篇
现状与发展   1篇
一般理论   4篇
预防医学   3025篇
眼科学   46篇
药学   626篇
  13篇
中国医学   107篇
肿瘤学   854篇
  2024年   59篇
  2023年   261篇
  2022年   398篇
  2021年   526篇
  2020年   631篇
  2019年   605篇
  2018年   530篇
  2017年   548篇
  2016年   483篇
  2015年   554篇
  2014年   767篇
  2013年   1237篇
  2012年   621篇
  2011年   591篇
  2010年   489篇
  2009年   537篇
  2008年   539篇
  2007年   590篇
  2006年   479篇
  2005年   443篇
  2004年   383篇
  2003年   342篇
  2002年   319篇
  2001年   274篇
  2000年   214篇
  1999年   177篇
  1998年   165篇
  1997年   153篇
  1996年   122篇
  1995年   129篇
  1994年   113篇
  1993年   97篇
  1992年   87篇
  1991年   94篇
  1990年   67篇
  1989年   47篇
  1988年   57篇
  1987年   40篇
  1986年   28篇
  1985年   17篇
  1984年   15篇
  1983年   14篇
  1982年   13篇
  1981年   11篇
  1980年   11篇
  1979年   6篇
  1978年   9篇
  1975年   7篇
  1974年   4篇
  1968年   3篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
252例儿童哮喘的门诊治疗和管理   总被引:15,自引:0,他引:15  
目的为探讨儿童哮喘得到长期缓解有效方法。方法我们开展前瞻性的对252例哮喘儿童进行了门诊治疗与管理和家庭治疗与自我管理相结合地研究,强调长期规范治疗,并对部分患儿进行了缓解期肺功能的测定,以此评价疗效。结果经半年~1年随访,系统管理治疗规范组哮喘缓解率明显高于间歇规范组及不规范组(P<0001)。缓解期肺功能测定也表明规范组肺功能基本正常率明显高于其他两组(P<005)。结论儿童哮喘要得到长期缓解及根本控制,必须要有系统的门诊治疗管理和家庭治疗与自我管理相结合。  相似文献   
102.
Summary TheerbB-2 receptor plays an important role in the prognosis of breast cancer and is expressed at high levels in nearly 30% of tumors in breast cancer patients. While evidence accumulates to support the relationship betweenerbB-2 overexpression and poor overall survival in human breast cancer, understanding of the biological consequence(s) oferbB-2 overexpression remains elusive. The discovery ofheregulin has allowed us to identify a number of related but distinct biological endpoints which appear responsive to signal transduction through theerbB-2/4 receptor. These endpoints of growth, invasiveness, and differentiation have clear implications for the emergence, maintenance, and/or control of malignancy, and represent established endpoints in the assessment of malignant progression in human breast cancer. Preliminary studiesin vitro have shown thatheregulin induces a biphasic growth effect on cells witherbB-2 overexpression. Interestingly, we observed that expression ofheregulin correlates with a more aggressive/invasive, vimentin-positive phenotype in breast cancer cells lines. Therefore, we have postulated thatheregulin is involved in breast cancer tumor progression. We have shown thatheregulin inducesin vitro chemoinvasion and chemotaxis of breast cancer cells as well as growth in an anchorage dependent and independent manner. Interestingly, aheregulin neutralizing antibody inhibits chemotaxis and results in cell growth inhibition and blockade of the invasive phenotype. Strikingly, genetically engineered cells which constitutively expressheregulin demonstrate critical phenotypic changes that are associated with a more aggressive phenotype. Specifically, these cells are no longer dependent on estrogen for growth and are resistant to tamoxifenin vitro andin vivo, and moreover these cells metastasize to lymph nodes in athymic nude mice. These tumors appear to have lostbcl-2 expression as compared with the control tumors. In addition, presumably by activation/regulation of topoisomerase II, theheregulin-transfected cells become exquisitely sensitive to doxorubicin and VP-16. Clearly, mechanistic aspects of theerbB-2/4 andheregulin interaction need to be understood from a therapeutic standpoint which could provide additional insights into synergistic treatments for certain patients, or improve treatment regimens for a large number of women. The study ofheregulin and its co-expression witherbB-2/4 receptor and the assessment of its involvement in the progression from the in situ stage of breast tumors to the invasive one will additionally increase the relevance ofheregulin as a prognostic/diagnostic factor. We believe that our studies provide new insights into breast cancer diagnosis, prognosis, and treatment.Presented at the symposium "New Approaches in the Therapy of Breast Cancer", Georgetown University Medical Center, Washington DC, October 1994, generously supported by an education grant from Bristol-Myers Squibb.  相似文献   
103.
1991年我国8省已婚妇女婚姻状况分析   总被引:2,自引:0,他引:2  
利用1991年我国与美国北卡罗莱纳大学人口中心合作项目"中国经济、人口和营养健康状况调查"的调查资料,对中国辽宁、江苏、山东、河南、湖北、湖南、广西、贵州共8个省的4288名50岁以下的已婚妇女的婚姻状况进行了统计分析。结果表明:1991年8省城、乡妇女在婚比为87.71%,离婚和分居比为0.44%,丧偶比为10.30%。妇女已婚比20岁以下为0.90%,20~30岁为66.92%,30岁以上为97.77%。1991年8省妇女平均初婚年龄为23.70岁,普通生育率达1.903%,生育1胎的比例为46.92%,生育2胎或2胎以上者占32.63%和20.44%,男女性别比1.11:1。从计划生育指标来看,城、乡妇女晚婚率为46.66%,总节育率为63.41%,绝育率达24.97%,避孕率为31.89%。城、乡主要使用的节育措施为绝育术和避孕环,各占49.71%和44.49%,而使用避孕套节育的只占1.00%,药物避孕占3.36%。总的看来,8省妇女的婚姻较稳定,平均初婚年龄逐年推迟,普通生育率水平较低。计划生育工作成效显著,但某些地区仍存在早婚早育和多胎生育的现象。  相似文献   
104.
Patterns of family response to drinking and smoking were studied in a sample of 1034 adults in Ontario in 1993. Concerning tobacco smoking, 69% of respondents reported having said something to a relative and 82% to a friend; concerning drinking, 46% had said something to a relative and 65% to a friend. Having said something did not vary much with the respondent's age, educational level and smoking or drinking status, except that current smokers were less likely than others to have said something to a friend or acquaintance, while heavier drinkers were more likely to have said something to a friend or acquaintance, and ex-drinkers were more likely to have said something to a relative. About half of all who had ever smoked reported a family member (57%) or a friend (47%) had said something to them about their smoking, compared with much smaller proportions of ever-drinkers who reported that a family member (14%) or a friend (8%) had ever said anything about their drinking. Both drinking and smoking are recognized by many respondents as imposing burdens on the family. Family members often comment on drinking and smoking, and make suggestions about cutting down or quitting.  相似文献   
105.
Nine members, MEL2–MEL10, of the MEL gene family coding for -galactosidase were physically mapped to the ends of the chromosomes by chromosome fragmentation. Genetic mapping of the genes supported the location of all the MEL genes in the left arm of their resident chromosomes.  相似文献   
106.
Northern blot analysis was used to demonstrate high levels of hippocampus-derived neurotrophic factor/neurotrophin-3 (HDNF/NT-3) mRNA in the embryonic day (E) 13 - 14 and 15 - 16 spinal cord. The level decreased at E18 - 19 and remained the same until postnatal day (P) 1, after which it decreased further to a level below the detection limit in the adult. In situ hybridization revealed that the NT-3 mRNA detected in the developing spinal cord was derived from motoneurons and the decrease seen at E18 - 19 was caused by a reduction in the number of motoneurons expressing NT-3 mRNA. The distribution of NT-3 mRNA-expressing cells in the E15 spinal cord was very similar to the distribution of cells expressing choline acetyltransferase or nerve growth factor receptor (NGFR) mRNA. Moreover, a striking similarity between the developmentally regulated expression of NT-3 and NGFR mRNA was noted in spinal cord motoneurons. A subpopulation of all neurons in the dorsal root ganglia expressed brain-derived neurotrophic factor (BDNF) mRNA from E13, the earliest time examined, to adulthood. These results are consistent with a trophic role of NT-3 for proprioceptive sensory neurons innervating the ventral horn, and imply a local action of BDNF for developing sensory neurons within the dorsal root ganglia.  相似文献   
107.
This paper reviews the empirical literature on the clinically significant problems found within families containing a member with post-traumatic stress disorder. Recommendations are made regarding specific instruments that can be useful for evaluating marital and familial adjustment. Assessment issues concerning the need to weigh historical relationship factors vis-á-vis the influences of a traumatized family member are discussed. A multiple-gating model is presented for assessing different aspects of family dysfunction, and suggestions for future research and clinical directions are offered.  相似文献   
108.
昆山郑氏妇科二十九代世医考   总被引:5,自引:1,他引:4  
江苏昆山郑氏妇科世医、代代相传二十九世,历经宋,元、明、清、民国、迄今已有近800年历史,堪与江南何氏二十九代世医媲美,成为中外医学史上罕见的奇迹。整理其家谱、墓志,方志,文稿,医著等传世文献资料,地郑氏二十九代妇科的世系,医家传略,医术,著述等进行了较详细的考证和整理,并编绘了世系图。  相似文献   
109.
Effects of Pediatric Chronic Physical Disorders on Child and Family Adjustment   总被引:26,自引:0,他引:26  
Research conducted primarily over the past 5–8 years on the psychosocial effects of pediatric chronic physical disorders on children and their families is reviewed. A large body of studies show that both children and their mothers, as groups, are at increased risk for psychosocial adjustment problems compared to peers, but that there is considerable individual variation in outcome. Since the last review on this topic (Eiser, 1990a), many studies have been conducted to identify risk and resistance factors associated with differences in adjustment among these children and their mothers. Improvements are noted in the theoretical basis for this work, programmatic nature of some of the research, and efforts at producing clinically relevant information. Evaluations of interventions, however, are lagging. Critical issues and future directions regarding developmental approaches, theory, method, measurement and intervention are discussed.  相似文献   
110.
Objectives: A case-control-family study of breast cancer in women under the age of 40 was carried out in Melbourne and Sydney, Australia, from 1992 to 1995 to determine the risk factors for these women. Subjects included 467 incident cases identified by state cancer registries and 408 population-based controls. Methods: All participants completed a structured risk-factor questionnaire and family pedigree during an in-person interview. Where possible, cancers in first- and second-degree relatives were verified. Results: Multiple logistic regression analysis showed that the strongest risk factor for breast cancer was a family history of the disease - having at least one affected first-degree relative trebled the risk (relative risk [RR] = 3.3, 95 percent confidence interval [CI] = 1.9-5.8). Risk increased with height by three percent (standard error [SE] of one percent) per cm, and after adjusting for height, there was evidence for a decreased risk in women weighing 73 kg or more. There was an increased risk of breast cancer after the first full-term birth (RR = 1.8, CI = 1.0-3.5) but this risk fell by 30 percent (SE = 11 percent) with each subsequent livebirth. Conclusions: The effects of other reproductive factors and oral contraceptive use, although not nominally significant, were in accord with published findings from similar studies in young women. This study of Australian women has indicated that some risk factors for breast cancer in women under age 40 differ from those reported for older women either in direction (e.g., weight) or relative importance (e.g., family history).  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