全文获取类型
收费全文 | 474293篇 |
免费 | 63540篇 |
国内免费 | 27341篇 |
专业分类
耳鼻咽喉 | 5245篇 |
儿科学 | 7464篇 |
妇产科学 | 6457篇 |
基础医学 | 43911篇 |
口腔科学 | 11255篇 |
临床医学 | 78843篇 |
内科学 | 75160篇 |
皮肤病学 | 7403篇 |
神经病学 | 30023篇 |
特种医学 | 17435篇 |
外国民族医学 | 224篇 |
外科学 | 50775篇 |
综合类 | 70992篇 |
现状与发展 | 125篇 |
一般理论 | 35篇 |
预防医学 | 41069篇 |
眼科学 | 12870篇 |
药学 | 42506篇 |
443篇 | |
中国医学 | 24844篇 |
肿瘤学 | 38095篇 |
出版年
2024年 | 1988篇 |
2023年 | 10271篇 |
2022年 | 15692篇 |
2021年 | 21250篇 |
2020年 | 19734篇 |
2019年 | 13905篇 |
2018年 | 18966篇 |
2017年 | 18946篇 |
2016年 | 18564篇 |
2015年 | 24769篇 |
2014年 | 31317篇 |
2013年 | 31170篇 |
2012年 | 32361篇 |
2011年 | 35580篇 |
2010年 | 28390篇 |
2009年 | 26583篇 |
2008年 | 24949篇 |
2007年 | 23639篇 |
2006年 | 23772篇 |
2005年 | 21391篇 |
2004年 | 14254篇 |
2003年 | 13493篇 |
2002年 | 11132篇 |
2001年 | 10473篇 |
2000年 | 9593篇 |
1999年 | 10141篇 |
1998年 | 7392篇 |
1997年 | 7011篇 |
1996年 | 5917篇 |
1995年 | 5415篇 |
1994年 | 4230篇 |
1993年 | 2943篇 |
1992年 | 3199篇 |
1991年 | 2808篇 |
1990年 | 2331篇 |
1989年 | 2096篇 |
1988年 | 1809篇 |
1987年 | 1583篇 |
1986年 | 1317篇 |
1985年 | 977篇 |
1984年 | 633篇 |
1983年 | 578篇 |
1982年 | 372篇 |
1981年 | 368篇 |
1980年 | 247篇 |
1979年 | 233篇 |
1978年 | 205篇 |
1977年 | 174篇 |
1976年 | 125篇 |
1974年 | 125篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Psychological Consequences of Food Restriction 总被引:1,自引:0,他引:1
JANET POLIVY PhD 《Journal of the American Dietetic Association》1996,96(6):589-592
A review of the literature and research on food restriction indicates that inhibiting food intake has consequences that may not have been anticipated by those attempting such restriction. Starvation and self-imposed dieting appear to result in eating binges once food is available and in psychological manifestations such as preoccupation with food and eating, increased emotional responsiveness and dysphoria, and distractibility. Caution is thus advisable in counseling clients to restrict their eating and diet to lose weight, as the negative sequelae may outweigh the benefits of restraining one's eating. Instead, healthful, balanced eating without specific food restrictions should be recommended as a long-term strategy to avoid the perils of restrictive dieting. J Am Diet Assoc. 1996; 96:589-592. 相似文献
32.
Peter Stone MD FRNZCOG FRCOG David Cook FRNZCOG MRCOG John Hutton PhD FRNZCOG FRCOG Gordon Purdie BSc Henry Murray MD FRNZCOG MRCOG Lauren Harcourt MPP BA 《The Australian & New Zealand journal of obstetrics & gynaecology》1995,35(1):32-37
Summary: This is the first report of the largest study of blood pressure measurement in pregnancy in a New Zealand population using standardized definitions and methodology. Over 3,800 women who delivered in an 8-month period in the Wellington region were included in the study. Blood pressure measurement and the presence of oedema and proteinuria were recorded from booking until delivery and in the puerperium. Only 2.7% of women were unable to be contacted after delivery for details on outcomes. The results established normal ranges for blood pressure throughout pregnancy. The data show that Mood pressure greater than 140/90 until 35 weeks' gestation is outside 2 standard deviations at all gestations and justifies using these measurements as the definition of hypertension in pregnancy. The fall in blood pressure in the 2nd trimester was less than 1 mm Ffg per week in both the systolic and diastolic pressures. This fall was smaller than previously recorded in other studies. Gestational hypertension was the commonest blood pressure abnormality occurring in 15.2% of the population. This represented 69% of the pregnant women with a hypertensive disorder. The overall incidence of both gestational hypertension and preeclampsia was 18.5% which is higher than reported in other parts of the world. In this study obesity was significantly associated with hypertensive disorders in pregnancy. An arm circumference of >33 cm, one of the measurements of obesity, was found in 6.8% of the study population. Even after the effect of arm circumference was taken into account, hypertensive disorders were also more common in Pacific Island women. Ankle oedema was significantly associated with the development of both gestational hypertension and preeclampsia but the incidence of oedema was noted in only 11.9% of the subjects. 相似文献
33.
缺氧缺血性脑病新生鼠补钙前后脑细胞,红细胞内外钙的变化 总被引:31,自引:0,他引:31
为了观察一般剂量补钙对缺氧缺血性脑病(HIE)脑细胞和红细胞内外钙变化的影响,以探讨HIE时补钙是否增加脑细胞钙超载,用HIE新生动物模型进行了实验研究,结果表明:(1)缺氧缺血时红细胞、脑细胞及脑组织出现钙积聚;(2)补钙后,血浆总钙浓度明显升高,而脑细胞、脑组织及红细胞钙积聚并未加重;(3)血浆总钙浓度与脑细胞或红细胞胞浆游离钙离子浓度无相关关系。提示:(1)HIE时钙内流可能是全身性的;(2)对HIE并低钙血症患儿吸氧后一般剂量补钙可能是安全的。 相似文献
34.
Nursing in the health care system of the postmodern world: crossroads, paradoxes and complexity 总被引:1,自引:0,他引:1
Ada Spitzer RN PhD 《Journal of advanced nursing》1998,28(1):164-171
Entering the postmodern world in which society is confronting crossroads, paradoxes, and complexity, the health care system is encountering a transformation more comprehensive and revolutionary than has ever been seen before. Analysis of the state of nursing vis a vis these transformations indicates that the current paradigm does not ensure the existence of the profession in the postmodern health care system. That is because of increased difficulties in consolidating the economic and quality issues into the core of nursing, and in understanding the complexity inherent in health related situations. 相似文献
35.
Cheryl Wallerstedt RNC MS Patricia Higgins RN PhD 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1996,25(5):389-400
Society often expects mothers and fathers to share equally in the perinatal grief process because the child was a common bond between them. Unfortunately, in perinatal grief, this is not always the case. The mother and the father can experience incongruent grieving and use discordant coping mechanisms. It is important to evaluate these differences to facilitate communication between the distraught parents. Improved communication can in turn facilitate the grieving process. 相似文献
36.
37.
38.
Comparison of PET, MRI, and CT with pathology in a proven case of Alzheimer's disease 总被引:1,自引:0,他引:1
Positron emission tomography (PET) with fluorodeoxyglucose (FDG), magnetic resonance imaging (MRI), and CT were carried out in a patient with Alzheimer's disease 16 months before he died. At autopsy, the gross appearance of the brain correlated with MRI and CT, which showed some regional atrophy. These were much less revealing than PET, which correlated with microscopic findings of neuronal loss and proliferation of glia. In areas of moderately impaired local cerebral metabolic rate of glucose, as revealed by reduced FDG uptake, there was some gliosis, primarily around the numerous senile plaques. In areas of severe metabolic impairment, there was a profound loss of neurons, extensive gliosis, and a diminished appearance of plaques. PET-FDG is a better measure of the severity of Alzheimer's disease than MRI or CT, because it reflects the degree of neuronal pathology. 相似文献
39.
Serum aminogram changes were prospectively studied in 95 patients with enteric fistula and intraabdominal infection who was under total parenteral nutrition (TPN) therapy with Anfuming 14s. In patients with sepsis and starvation, the aminogram showed remarkably low total free amino acids before TPN therapy. In 81 survivors, free amino acids increased gradually to normal in 2 weeks after use of TPN and in 14 dead cases increased rapidly to a significantly higher peak at terminal stage. Both in survivors and nonsurvivors, phenylalanine level remained high during the study. In response to infection, proline was also elevated but to a lesser degree; the ratio of branched chain amino acid (BCAA) to aromatic amino acid (AAA) was lower than normal and the decrease of arginine was parallel to the severity of infection. We conclude that the ideal amino acids preparation for the starvated and septic patients should be high in BCAA and arginine but low in phenylalanine, administration of inappropriate exogenous amino acids in decompensated metabolic septic patients may bring about more harm than benefit, and in septic patients that the levels of serum phenylalanine and proline are elevated persistently along with the decrease of arginine level is a useful prognostic indication. 相似文献
40.
The neuroprotective effects of dizocilipine maleate (MK-801), a noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) receptor/channel, were tested in the 4-vessel occlusion rat model of forebrain ischemia. Adult Wistar rats, treated intraperitoneally with MK-801 or saline using several different treatment paradigms were subjected to 5 (n = 208) or 15 (n = 62) min of severe, transient forebrain ischemia. In saline-treated animals, 15 min of ischemia (n = 13) produced extensive and consistent loss of pyramidal neurons in the CA1 zone of hippocampus. The degree and distribution of cell loss were not reduced by single dose preischemic administration of MK-801 at 1 (n = 7), 2.5 (n = 4), or 5 mg/kg (n = 8). In other animals subjected to 15 min of forebrain ischemia, multiple doses of MK-801 (5, 2.5, and 2.5 mg/kg) given immediately and at approximately 8 and 20 hr after cerebral reperfusion (n = 5) did not alter CA1 injury compared to saline-treated controls (n = 5). Five minutes of forebrain ischemia in saline-treated animals, (n = 82) resulted in significantly fewer (p less than 0.001) dead CA1 pyramidal cells and a greater variance compared to animals subjected to 15 min of ischemia. Power analysis of the preliminary saline-treated animals subjected to 5 min of ischemia (n = 22) indicated that 60 animals per group were necessary to detect a 15% difference between MK-801 and vehicle-treated groups. Multidose treatment with MK-801 (1 mg/kg) given 1 hr prior to 5 min of ischemia (n = 60) and again at approximately 8 and 16 hr after recirculation failed to attenuate hippocampal injury.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献