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   8015篇
  免费   526篇
  国内免费   47篇
耳鼻咽喉   96篇
儿科学   195篇
妇产科学   168篇
基础医学   1129篇
口腔科学   617篇
临床医学   532篇
内科学   2056篇
皮肤病学   240篇
神经病学   580篇
特种医学   207篇
外科学   946篇
综合类   23篇
一般理论   4篇
预防医学   733篇
眼科学   92篇
药学   575篇
中国医学   67篇
肿瘤学   328篇
  2023年   104篇
  2022年   162篇
  2021年   344篇
  2020年   204篇
  2019年   286篇
  2018年   365篇
  2017年   230篇
  2016年   258篇
  2015年   290篇
  2014年   347篇
  2013年   422篇
  2012年   611篇
  2011年   680篇
  2010年   329篇
  2009年   253篇
  2008年   431篇
  2007年   451篇
  2006年   308篇
  2005年   367篇
  2004年   260篇
  2003年   249篇
  2002年   254篇
  2001年   195篇
  2000年   171篇
  1999年   135篇
  1998年   49篇
  1997年   31篇
  1996年   39篇
  1995年   32篇
  1994年   28篇
  1993年   24篇
  1992年   75篇
  1991年   63篇
  1990年   61篇
  1989年   60篇
  1988年   40篇
  1987年   53篇
  1986年   40篇
  1985年   34篇
  1984年   29篇
  1983年   25篇
  1982年   11篇
  1981年   13篇
  1979年   18篇
  1976年   11篇
  1975年   13篇
  1974年   16篇
  1973年   10篇
  1970年   17篇
  1967年   9篇
排序方式: 共有8588条查询结果,搜索用时 15 毫秒
61.
Environmental control in managing patients with immunodeficiency ranges from the exceedingly complex to the relatively simple. At one end of the spectrum is the total isolation technology applied to David, the "Bubble Boy" who lived his entire life behind sterile plastic barriers. At the other end of the spectrum is the simpler technology applied to patients receiving bone marrow transplants who are maintained in ordinary private hospital rooms and attended by personnel who merely observe handwashing precautions. Most properly performed and controlled studies of the use of special isolation procedures to reduce infections derive from patients receiving bone marrow transplants for conditions of aplastic anemia and leukemia or patients receiving chemotherapy for malignancy. The design of isolation procedures for immunodeficient patients borrows from these studies because of the relatively small number of immunodeficient patients. These studies have shown that laminar airflow rooms produce a significantly lower incidence of infections but may not change the mortality of all patients. Also, protective isolation has clearly reduced the incidence and severity of graft-versus-host disease in transplanted patients with aplastic anemia. Recently there has been a trend away from strict isolation procedures because careful studies have indicated that host rather than acquired pathogens are responsible for at least 85% of infections in these special patients. Also, the human stress of prolonged isolation is becoming increasingly recognized. The complex and expensive isolation techniques that were used in David's case are no longer being utilized in immunodeficient subjects, partly because new transplantation technology has made it possible to cross histocompatibility barriers, obviating the need for permanent isolation.  相似文献   
62.
Ten male patients with chronic cocaine abuse received a single dose of the dopamine agonist apomorphine. Self-ratings of cocaine craving, depression, and anxiety decreased in response to apomorphine. Neuroendocrine response was consistent with central dopaminergic stimulation. Patients in the "craving" phase of the cocaine abuse cycle differed in behavioral but not neuroendocrine response to apomorphine from patients in the "crash" phase. Decrease in cocaine craving correlated with decrease in plasma homovanillic acid (pHVA). Total cocaine consumption correlated negatively with baseline prolactin and pHVA levels and inversely with peak change in prolactin following apomorphine. Patients had blunted neuroendocrine response to apomorphine in comparison to historical normal controls. Implications for the "dopamine" hypothesis of cocaine abuse are discussed.  相似文献   
63.
Two thousand consecutive children have been evaluated for suspected heart disease in a 27-month period. The main reasons for referral were: murmur (70%), precordial pain (9.5%), suspicion of arrhythmia (8.5%) and breathless (5%). Five hundred and six (25%) cases did not complete the investigation and the results were not computed. A final diagnosis was obtained based on the reason for referral and the main conclusions were: 1) a high incidence of normality was found: murmur (83%), pain (98%), arrhythmia (97%) and breathless (94%); 2) heart disease is unlikely when other referral reasons were analyzed; 3) 14% of the children were considered abnormal and the necessity of therapeutic procedures was 0.8%. A pediatric cardiology outpatient clinic in a public setting seems to be justifiable in the region, due to the high current demand.  相似文献   
64.
OBJECTIVE: A measles outbreak occurred in S. Paulo state, during 1996 and 1997, resulting in 20,921 cases. Forty seven percent of the cases occurred in people between 20 and 29 years of age, and one of the control strategies of the Department of Health was the vaccination of health care workers. The prevalence of antibodies against measles among the hospital pediatricians was investigated. METHODS: One hundred and fifty samples were taken from volunteer pediatricians to test for measles antibodies using ELISA. A questionnaire about their having had measles and the vaccine was filled out. RESULTS: Of the 150 doctors, 122 (81.4%) were female and 28 (18.6%) male, of between 23 and 46 years of age (mean and median 27 years). The majority (98%-147/150) had protective levels of antibodies against measles (>100 UI/ml); 118 (80.3%-118/147) without and 29 (19.7%-29/147) with a history of measles. Only 3 pediatricians (2%-3/150), had negative serology, 2 without and 1 with a history of measles. Out of the 118 without history of measles, 79 (67%-39/118) in spite of the protective level of antibodies against measles, did not know if they, had been vaccinated. Out of the 79 vaccinated pediatricians, 64 (81%-64/79), had been vaccinated 25 years before, and still maintained protective levels of antibodies. Of the 3 doctors with negative serologies only one declared that he had been vaccinated. CONCLUSIONS: Measles seroprevalence among pediatricians of this hospital is high, especially due to preceding vaccination. On the other hand, the 2% of pediatricians with negative serology, in an epidemic situation could constitute a significant population for the acquisition and dissemination of the disease.  相似文献   
65.
Lapachol is a naphtoquinone with therapeutic potential against Chagas disease and is also used as an antimalarial agent. To study the reproductive toxicity potential of Lapachol, pregnant Wistar rats were treated with 0.5 mL of distilled water (control group), 0.5 mL of hydroalcoholic solution (vehicle group), or 20 mg of Lapachol in 0.5 mL of hydroalcoholic solution (treated group) by oral gavage from the 8th to the 12th day of pregnancy. The following variables were observed: maternal body weight on days 1, 6, 15, and 21; food intake on days 2, 6, 15, and 21 of pregnancy. The number of live and dead fetuses and the sites of resorptions were counted. The ovaries were weighed and the corpora lutea were counted. Data were analyzed by ANOVA one-way Dunnett test and chi 2 test. Results showed that mothers were uneffected but there was 100% fetal/embryo mortality, indicative of a strong interceptive effect of Lapachol in rats.  相似文献   
66.
The authors report on a 45-day-old boy with a congenital intramedullary tumor with clinical manifestations since birth. Neurologic examination disclosed severe bilateral lower-limb hypotonia and diplegia, with exacerbated deep tendon reflexes and clonus associated with severe pain at manipulation. Further evaluation of this patient included screening for infections, computed tomographic scan, myelography, and somatosensory evoked potentials. The definite diagnosis was a solid holocord astrocytoma. This report discusses a rare disorder in the neonatal period and makes other medical practitioners aware of this diagnosis. Previously published literature is also reviewed.  相似文献   
67.
68.
This paper reports the results of a series of 5 patients who underwent closure of persistent bronchopleural fistula using extrathoracic muscle flaps over a 6-year period. All patients had failed more conservative treatment. The surgeries were one- or two-stage procedures performed with the collaboration of cardiovascular and reconstructive surgical staffs. There were no associated mortalities. The muscle flaps utilized were the latissimus dorsi, serratus anterior, pectoralis major, pectoralis minor, and trapezius. The results have been encouraging and allowed the complete closure of the bronchopleural fistula in the majority of patients. The authors present the best management of this serious disease, as well as its pathophysiology and clinical aspects.  相似文献   
69.
Meta-analysis has been little explored to make an overall assessment of linkage from different studies. In practice, it is likely that published linkage studies will only report p-values. We compared the performance of the widely used Fisher method for combining p-values with that of pooling raw data. More loci were consistently found by pooling raw data. In the absence of further information, combining p-values can provide an overall, but limited, assessment of different linkage studies. However, meta-analysis would be better viewed as a preliminary step toward the goal of analyzing the pooled raw data.  相似文献   
70.
Research evidence suggests that actigraphy is a very important instrument in documenting sleep/wake patterns of people with a variety of sleep disorders or motor dysfunctions. The present actigraphic investigation examined physical activity and sleep profiles as a function of gender in volunteers monitored in their natural environment. Irrespective of age, women exhibited better sleep quality than did men. This was demonstrated by higher sleep efficiency index and lower frequency of transitions between sleep and wakefulness. Additionally, women slept more than men and had shorter sleep onset latency. However, no significant gender effect on daytime activity level and circadian activity amplitude was observed.  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