全文获取类型
收费全文 | 175950篇 |
免费 | 33096篇 |
国内免费 | 2461篇 |
专业分类
耳鼻咽喉 | 5344篇 |
儿科学 | 5982篇 |
妇产科学 | 2955篇 |
基础医学 | 6873篇 |
口腔科学 | 1814篇 |
临床医学 | 29166篇 |
内科学 | 52064篇 |
皮肤病学 | 7715篇 |
神经病学 | 17210篇 |
特种医学 | 6893篇 |
外国民族医学 | 3篇 |
外科学 | 44275篇 |
综合类 | 763篇 |
现状与发展 | 72篇 |
一般理论 | 42篇 |
预防医学 | 9371篇 |
眼科学 | 4172篇 |
药学 | 3132篇 |
中国医学 | 43篇 |
肿瘤学 | 13618篇 |
出版年
2024年 | 697篇 |
2023年 | 4932篇 |
2022年 | 1424篇 |
2021年 | 3620篇 |
2020年 | 6348篇 |
2019年 | 2721篇 |
2018年 | 7916篇 |
2017年 | 7746篇 |
2016年 | 8904篇 |
2015年 | 8986篇 |
2014年 | 16295篇 |
2013年 | 16844篇 |
2012年 | 7256篇 |
2011年 | 7377篇 |
2010年 | 11382篇 |
2009年 | 15126篇 |
2008年 | 7356篇 |
2007年 | 5715篇 |
2006年 | 8239篇 |
2005年 | 5526篇 |
2004年 | 4759篇 |
2003年 | 3501篇 |
2002年 | 3484篇 |
2001年 | 3996篇 |
2000年 | 3177篇 |
1999年 | 3443篇 |
1998年 | 3958篇 |
1997年 | 3725篇 |
1996年 | 3602篇 |
1995年 | 3441篇 |
1994年 | 2123篇 |
1993年 | 1763篇 |
1992年 | 1518篇 |
1991年 | 1523篇 |
1990年 | 1150篇 |
1989年 | 1262篇 |
1988年 | 1115篇 |
1987年 | 939篇 |
1986年 | 961篇 |
1985年 | 800篇 |
1984年 | 640篇 |
1983年 | 615篇 |
1982年 | 641篇 |
1981年 | 521篇 |
1980年 | 452篇 |
1979年 | 356篇 |
1978年 | 385篇 |
1977年 | 457篇 |
1975年 | 323篇 |
1972年 | 341篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
22.
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
23.
Although extracellular matrix (ECM) glycoproteins play important roles in neural development, their levels are generally believed to decrease in the adult brain. Immunohistochemical analysis indicates that the anti-adhesive ECM glycoprotein SPARC/osteonectin, which contains a follistatin ‘module’, is expressed in the adult rabbit nervous system. In the cerebellum, SPARC is present in Bergmann glia, with a strong signal along their radial fibres. SPARC, while enriched in membrane fractions, is not a transmembrane protein. In the hippocampus, colocalization of SPARC is observed in cells which express the astrocytic marker GFAP. The expression of SPARC by a subset of astrocytes, particularly in synaptic enriched areas, suggests a continuing role for the ECM in the adult brain. 相似文献
24.
Alexandros Karabetsos MD Dr ; George Karachalios MD Dr ; Paraskevoula Bourlinou RN Nurse ; Asimina Reppa RN Nurse ; Rozeta Koutri MD Dr ; Androniki Fotiadou MD Dr 《Headache》1997,37(1):12-14
The efficacy and safety of ketoprofen and paracetamol were compared for the treatment of acute migraine in a randomized, double-blind study of 64 patients. Thirty-four patients received ketoprofen 100 mg intramuscularly, and 30 patients received paracetamol 500 mg intramuscularly. Partial or complete relief of pain and other symptoms was achieved 15 to 20 minutes after administration in the ketoprofen group and within 35 minutes in the paracetamol group. Complete relief of pain was achieved within 30 to 40 minutes after ketoprofen in 28 patients (82.5%) compared to 5 patients (17.5%) in the paracetamol group. Six of the patients treated with ketoprofen needed a second dose for complete relief of pain during the 4-hour follow-up period. Side effects were rare and minimal. Our findings suggest that ketoprofen produced statistically significant benefit in the treatment of acute migraine. 相似文献
25.
26.
27.
28.
29.
Human balancing of an inverted pendulum: position control by small, ballistic-like, throw and catch movements 总被引:12,自引:4,他引:8
In standing, there are small sways of the body. Our interest is to use an artificial task to illuminate the mechanisms underlying the sways and to account for changes in their size. Using the ankle musculature, subjects balanced a large inverted pendulum. The equilibrium of the pendulum is unstable and quasi-regular sway was observed like that in quiet standing. By giving full attention to minimising sway subjects could systematically reduce pendulum movement. The pendulum position, the torque generated at each ankle and the soleus and tibialis anterior EMGs were recorded. Explanations about how the human inverted pendulum is balanced usually ignore the fact that balance is maintained over a range of angles and not just at one angle. Any resting equilibrium position of the pendulum is unstable and in practice temporary; movement to a different resting equilibrium position can only be accomplished by a biphasic 'throw and catch' pattern of torque and not by an elastic mechanism. Results showed that balance was achieved by the constant repetition of a neurally generated ballistic-like biphasic pattern of torque which can control both position and sway size. A decomposition technique revealed that there was a substantial contribution to changes in torque from intrinsic mechanical ankle stiffness; however, by itself this was insufficient to maintain balance or to control position. Minimisation of sway size was caused by improvement in the accuracy of the anticipatory torque impulses. We hypothesise that examination of centre of mass and centre of pressure data for quiet standing will duplicate these results. 相似文献
30.