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   20961篇
  免费   1574篇
  国内免费   31篇
耳鼻咽喉   206篇
儿科学   788篇
妇产科学   616篇
基础医学   2537篇
口腔科学   176篇
临床医学   4030篇
内科学   3556篇
皮肤病学   355篇
神经病学   1801篇
特种医学   346篇
外科学   1824篇
综合类   404篇
一般理论   34篇
预防医学   2808篇
眼科学   201篇
药学   1362篇
  2篇
中国医学   7篇
肿瘤学   1513篇
  2023年   129篇
  2022年   154篇
  2021年   444篇
  2020年   294篇
  2019年   454篇
  2018年   536篇
  2017年   450篇
  2016年   469篇
  2015年   514篇
  2014年   693篇
  2013年   1022篇
  2012年   1536篇
  2011年   1544篇
  2010年   858篇
  2009年   773篇
  2008年   1408篇
  2007年   1523篇
  2006年   1503篇
  2005年   1401篇
  2004年   1365篇
  2003年   1254篇
  2002年   1170篇
  2001年   176篇
  2000年   114篇
  1999年   164篇
  1998年   239篇
  1997年   196篇
  1996年   205篇
  1995年   182篇
  1994年   183篇
  1993年   145篇
  1992年   118篇
  1991年   110篇
  1990年   120篇
  1989年   94篇
  1988年   102篇
  1987年   77篇
  1986年   71篇
  1985年   65篇
  1984年   67篇
  1983年   50篇
  1982年   68篇
  1981年   77篇
  1980年   77篇
  1979年   49篇
  1978年   53篇
  1977年   33篇
  1976年   24篇
  1974年   24篇
  1973年   22篇
排序方式: 共有10000条查询结果,搜索用时 588 毫秒
61.
Objective Detection of HPV DNA in oral and genital lesions of a heterosexual male. 4 months after oral and vaginal intercourse with a woman with vulvar warts. Passible modes of acquisition of oral HPV infection in the male sexual partner are discussed. Setting Genitourinary Medicine clinic. Methods Polymerase chain reaction amplification of genomic DNA from oral and genital lesions. HPV DNA typing by dot blot hybridization. Results HPV DNA types 6 and 11 were identified in a polypoid tongue lesion and in a penile wart from the male sexual partner. Conclusions The acquisition of oral HPV infection in the male sexual partner may have resulted from genital-oral HPV transfer, either by direct contact with vulvar warts or by digital self-inoculation.  相似文献   
62.
Little is known about oral health care behaviors of community-dwelling, cognitively impaired elderly (CIE) persons. Few studies have been conducted regarding the actual provision of oral care for CIE persons or the attitudes and concerns about oral health among their caregivers. The CIE person's ability to perform self-care decreases over time, and the role of the caregiver in daily oral care becomes increasingly important. The purpose of this pilot study was to explore the attitudes toward oral health and identify related concerns among caregivers who care for community-dwelling CIE persons. Caregivers were surveyed by means of a self-administered, mailed questionnaire. To maintain confidentiality, an intermediary was used for recruitment and data collection. Overall, 148 caregivers were invited by an intermediary to participate in the survey; only 21 (14%) consented to participate and returned the questionnaire. This paper discusses some of the numerous methodological challenges identified when an attempt was made to survey caregivers' attitudes toward and barriers to providing oral care for a dependent CIE.  相似文献   
63.
Background: Ketamine is a potent bronchodilator that, in clinically used concentrations, relaxes airway smooth muscle in part by a direct effect. This study explored the role of calcium concentration (Ca2+) in this relaxation.

Methods: Canine trachea smooth muscle strips were loaded with the fluorescent probe fura-2 and mounted in a spectrophotometric system to measure force and intracellular calcium concentration ([Ca2+]i) simultaneously. Calcium influx was estimated using a manganese quenching technique. Cyclic nucleotides in the airway smooth muscle strips were measured by radioimmunoassay.

Results: In smooth muscle strips stimulated with submaximal (0.1 micro Meter) and maximal (10 micro Meter) concentrations of acetylcholine, ketamine caused a concentration-dependent decrease in force and [Ca2+]i. The sensitivity of the force response to ketamine significantly decreased as the intensity of muscarinic receptor stimulation increased; the median effective concentration for relaxation induced by ketamine was 59 micro Meter and 850 micro Meter for tissue contracted by 0.1 micro Meter or 10 micro Meter acetylcholine, respectively (P < 0.05). In contrast, the sensitivity of the [Ca2+] sub i response did not depend on the intensity of muscarinic receptor stimulation. Ketamine at 1 mM significantly inhibited calcium influx. Ketamine did not significantly increase cyclic nucleotide concentrations.  相似文献   

64.
Book Reviews : RESPIRATORY DISORDERS Susan F. Wilson & June M. Thompson Book Reviews : PROCEEDINGS FROM THE FIRST COLLOQUIUM ON PREVENTING SECONDARY DISABILITIES AMONG PEOPLE WITH SPINAL CORD INJURY Philip L. Graitcer & Frederick M. Maynard (Eds.) Book Reviews : KRUSEN'S HANDBOOK OF PHYSICAL MEDICINE AND REHABILITATION (4th ed.) Frederick J. Kottke & Justus F. Lehmann (Eds.) Book Reviews : PSYCHOLOGICAL MANAGEMENT OF TRAUMATIC BRAIN INJURIES IN CHILDREN AND ADOLESCENTS Ellen Lehr Book Reviews : TRAUMA, TRANSFORMATION, AND HEALING John P. Wilson, Brunner/Mazel Book Reviews : REHABILITATION AND DISABILITY: PSYCHOSOCIAL CASE STUDIES E. Davis Martin, Jr., & Gerald L. Gandy, Charles C. Thomas  相似文献   
65.
Congenital hydrocephalus associated with aqueductal stenosis and/or agenesis of the corpus callosum has been described in newborn males with mutations in L1CAM, a gene that encodes a neural cell adhesion molecule. These males usually have severe mental retardation and may have spastic paraplegia and adducted thumbs. In contrast, Hirschsprung disease, or absence of ganglion cells in the distal gut, has rarely been described in such individuals. We report a male infant who had severe hydrocephalus identified in the prenatal period with evidence of aqueductal stenosis and adducted thumbs at birth. He developed chronic constipation, and rectal biopsy confirmed the diagnosis of Hirschsprung disease. Molecular testing of the L1CAM gene revealed a G2254A mutation, resulting in a V752M amino acid substitution. A common polymorphism in RET, but no mutation, was identified. Our patient represents the third example of coincident hydrocephalus and Hirschsprung disease in an individual with an identified L1CAM mutation. We hypothesize that L1CAM‐mediated cell adhesion may be important for the ability of ganglion cell precursors to populate the gut, and that L1CAM may modify the effects of a Hirschsprung disease–associated gene to cause intestinal aganglionosis. © 2002 Wiley‐Liss, Inc.  相似文献   
66.
‘Wandering’ is one of the most troublesome of behavioural problems in dementia. The term ‘wandering’ covers many different types of behaviour. We examined the hypothesis that the different types of wandering behaviour seen in dementia from a scale using data collected on 83 elderly subjects suffering from either Alzheimer's disease or multiinfarct dementia. We reject the scaling hypothesis. Our data suggest that there are three main categories of wandering behaviour, and that one of these categories is usefully divided into four subcategories.  相似文献   
67.
For 3 months in 1969 a family in the United States that included a pregnant mother consumed pork containing methylmercury. Children, aged 20, 13, and 8 years and a neonate, developed severe neurological signs. Twenty-two years later, the 2 oldest had cortical blindness or constricted visual fields, diminished hand proprioception, choreoathetosis, and atentional deficits. Magnetic resonance images showed tissue loss in the calcarine and parietal cortices and cerebellar folia. The youngest had quadriplegia, blindness, and severe mental retradation until their deaths. The brain of the 8-year-old who died at age 30 showed cortical atrophy, neuronal loss, and gliosis, most pronounced in the paracentral and parietooccipital regions. The total mercury level in formalin-fixed, left occipital cortex was 1,974 ng/gm as measured by atomic absorption. Regional brain mercury levels correlated with extent of brain damage. A control patient had 38.5 ng of mercury/gm in the occipital cortex. Systemic organs in the patient and a control subject had comparable mercury levels. In mercury-intoxicated rats, we found that only 5 to 10% of total brain mercury was lost by formalin fixation. Brain inorganic mercury in the patient ranged from 82 to 100%. Since inorganic mercury crosses the blood-brain barrier poorly, biotransformation of methyl to inorganic mercury may have occurred after methylmercury crossed the blood-brain barrier, accounting for its persistence in brain and causing part of the brain damage.  相似文献   
68.
On inpatient psychiatric units, nurses control the tone, pace, and activity level of the environment. But under the influence of factors such as high patient acuity and negative group contagion, a milieu can become unacceptably loud and chaotic. A volatile milieu is a potentially dangerous environment because patients' anxiety and agitation can quickly lead to acting out and aggression. This article focuses on how nurses can regain control of a milieu spiralling into chaos by tightening the structure of the routine, anticipating potential problems, and maintaining a confident calm manner. The charge nurse orchestrates the staff group's response to escalation through detailed planning, decisive interventions, and strategic use of every available resource.  相似文献   
69.
70.
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