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   22876篇
  免费   2084篇
  国内免费   30篇
耳鼻咽喉   292篇
儿科学   622篇
妇产科学   443篇
基础医学   2867篇
口腔科学   534篇
临床医学   2852篇
内科学   4216篇
皮肤病学   254篇
神经病学   2104篇
特种医学   853篇
外国民族医学   3篇
外科学   2968篇
综合类   528篇
一般理论   42篇
预防医学   2442篇
眼科学   695篇
药学   2039篇
中国医学   24篇
肿瘤学   1212篇
  2022年   167篇
  2021年   439篇
  2020年   289篇
  2019年   403篇
  2018年   443篇
  2017年   277篇
  2016年   406篇
  2015年   438篇
  2014年   571篇
  2013年   816篇
  2012年   1168篇
  2011年   1206篇
  2010年   678篇
  2009年   573篇
  2008年   1032篇
  2007年   1135篇
  2006年   1157篇
  2005年   1055篇
  2004年   1047篇
  2003年   941篇
  2002年   900篇
  2001年   620篇
  2000年   625篇
  1999年   571篇
  1998年   286篇
  1997年   236篇
  1996年   232篇
  1995年   226篇
  1994年   204篇
  1993年   185篇
  1992年   443篇
  1991年   438篇
  1990年   404篇
  1989年   419篇
  1988年   363篇
  1987年   356篇
  1986年   349篇
  1985年   334篇
  1984年   282篇
  1983年   236篇
  1982年   171篇
  1981年   145篇
  1979年   206篇
  1978年   180篇
  1977年   152篇
  1976年   138篇
  1974年   167篇
  1973年   151篇
  1972年   137篇
  1971年   122篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
81.
OBJECTIVE: The purpose of this paper is the assessment of the healer's listening as an aspect of the history of caring and curing, with particular attention to its place in psychological healing. METHOD: An extensive range of philosophical, religious, and medical sources from antiquity to the present were studied. RESULTS: Over the centuries, listening has been a crucial aspect of the various endeavors undertaken by healers in the interest of acquiring information from, achieving understanding of, and bringing about healing effects for sufferers. Yet it has been vision rather than hearing that has been emphasized in knowing and understanding, and looking rather than listening that has been emphasized in healing endeavors. Only around the turn of the twentieth century did there emerge the focused study of care in listening, of listening beyond the words themselves, and of the significance of the interested listener as a soothing, empathic force. CONCLUSIONS: The place of listening in depth and with empathy is a crucial element in healing. While the emphasis on looking remains significant in the gathering and appraisal of data, at times it threatens to overwhelm the need for an attentive and concerned listener. There appears to be a natural tension between the two modes that has, in modern times, been translated into a tension between the two modes that has, in modern times, been translated into a tension between a scientific mode of gaining information and a humanistic mode of knowing sufferers. A healer neglects either one at his or her peril--and at the peril of his or her patients.  相似文献   
82.
We examined the effects of chronic exercise on fitness and immune status in Caucasian males (34.9 +/- 5.6 yr) diagnosed by Western blot as seropositive for the HIV-1 virus. The exercise regimen involved 12 wk of 1 h sessions 3 d.wk: 20 min of cycle exercise at 60-80% HRreserve was followed by 35 min of strength and flexibility training. After matching subjects on health status (modified Walter Reed criteria), subjects (N = 37) were randomly assigned to exercise or a counseling control condition. Changes in strength, responses to the YMCA cycle test, and serum lymphocytes were tested by MANOVA in a condition (exercise or counseling)-by-time (pretest, posttest) design with repeated measures on time. Results indicated significant (P less than 0.001) group-by-time interactions for strength (N.m) (chest press and leg extension) and for HR (beats.min-1) and total time (TT) on the cycle test at 150 W. Strength and TT increased and HR decreased in the exercise condition, while control subjects did not change. Total leukocyte, lymphocyte, CD4+, and CD8+ cell counts, and the CD4+/CD8+ ratio were statistically unchanged for each condition. We conclude that HIV-1+ men, including those symptomatic for AIDS-related complex, can experience significant increases in neuromuscular strength and cardiorespiratory fitness without changes in lymphocyte phenotypes or clinical diagnosis when the exercise regimen is prescribed and monitored in accordance with ACSM guidelines for healthy adults.  相似文献   
83.
Serotonin receptor ligands, with differential affinity for subtypes of serotonin (5-HT) receptors, were administered intravenously or iontophoretically to urethane-anesthetized rats and the effects of these compounds on glutamate-evoked firing of spinal motoneurons were tested. The excitability of spinal motoneurons was markedly enhanced after intravenous administration of the selective 5-HT1A ligand 8-hydroxy-2-(di-n-propylamino) tetralin (DPAT) in rats with acute spinal transections at C1. However, local application of DPAT, directly into the ventral horn by microiontophoresis, inhibited the glutamate-evoked firing of motoneurons in direct contrast to the facilitatory effects of iontophoretically applied 5-HT. The DPAT-induced inhibition may have been nonspecific, since it was not antagonized by methysergide. Other 5-HT agonists, with relatively selective affinity for 5-HT1B, 5-HT1C and 5-HT2 receptors, increased the excitability of spinal motoneurons when applied iontophoretically or intravenously. The excitatory effect of iontophoretically applied 5-HT was antagonized by the nonselective 5-HT antagonist, methysergide and by ketanserin and ritanserin, which have relatively selective affinity for 5-HT1C and 5-HT2 receptors. These results indicate that 5-HT1A receptors do not mediate facilitation of excitability of motoneurons produced by local application of 5-HT directly into the vicinity of the motoneurons. However, the marked increase in firing of motoneurons that was caused by intravenous administration of DPAT in spinal transected rats, suggests that 5-HT1A receptors in the spinal cord may participate in 5-HT-induced enhancement of somatomotor outflow, at sites presynaptic to the motoneurons. The iontophoretic results suggest that 5-HT1B, 5-HT1C and 5-HT2 receptors may all play a role in facilitation of the excitability of spinal motoneurons by locally applied 5-HT. Differentiation between these subtypes of receptor awaits the development of more completely selective agonists and antagonists.  相似文献   
84.
Administration of antiserum to thyrotropin-releasing hormone (TRH) into the lateral cerebral ventricle of mice significantly attenuated recovery from hyperglycemia induced by treatment with 2-deoxyglucose but had no effect on the plasma glucose of saline-treated mice. TRH, injected centrally together with the anti-TRH antibody, reversed the effect of the antiserum and blocked the development of hyperglycemia. These findings suggest that activation of TRH neurons in the central nervous system may be a physiological event influencing recovery from hyperglycemia.  相似文献   
85.
86.
OBJECTIVE: Screening for diabetes is recommended for individuals > or =45 years of age, or earlier if they manifest > or = one specific risk factors. This study examined the sensitivity and positive predictive value (PPV) of risk factor total for identifying individuals with diabetes and prediabetes. DESIGN: Subjects were interviewed to assess the presence of risk factors. Fasting plasma glucose levels were obtained. SETTING: The study occurred at a health fair in Greensburg, PA. PATIENTS: Six hundred sixty-one Caucasians between the ages of 19 and 100. RESULTS: Using the criterion of screening individuals with > or = one risk factors detected 100% of both diabetics and prediabetics. This dropped to 91.2% when screening individuals with > or = two factors. The PPV of the risk factor total was poor (80% of individuals with a total of four factors were not diabetic). The ability of the risk factor total to predict individuals with impaired glucose metabolism (prediabetics + diabetics) was considerably better, and increased almost linearly with the risk factor total. Of the subjects with normal glucose values, the mean glucose increased as the risk factor total increased. CONCLUSION: While the sensitivity of using > one risk factor as an algorithm to screen is 100% for identifying diabetics, the PPV of risk factor analysis for identifying diabetics is poor. The same algorithm works well to identify at-risk individuals, presumably allowing early intervention and education.  相似文献   
87.
当病人出现咳血、胸膜痛等症状,一般都会诊断为肺栓塞。现在有一种趋势就是为了不耽误病人的治疗,在诊断阶段还没有彻底的检查就开始治疗。通常早期使用肝素来减少可疑为肺栓塞病人的死亡率和发病率。然而,如道其它一些并不常见的咳血的原因也非常重要。  相似文献   
88.
89.
This study used magnetic resonance imaging to examine pituitary gland volume (PGV) in teenage patients with a first presentation of borderline personality disorder (BPD). No difference in PGV was observed between healthy controls (n = 20) and the total BPD cohort (n = 20). However, within the BPD cohort, those exposed to childhood trauma (n = 9) tended to have smaller pituitaries (− 18%) than those with no history of childhood trauma (n = 10). These preliminary findings suggest that exposure to childhood trauma, rather than BPD, per se, might be associated with reduced PGV, possibly reflecting hypothalamic–pituitary–adrenal axis dysfunction.  相似文献   
90.
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