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   67173篇
  免费   3937篇
  国内免费   154篇
耳鼻咽喉   867篇
儿科学   1500篇
妇产科学   1352篇
基础医学   8941篇
口腔科学   2603篇
临床医学   5162篇
内科学   16854篇
皮肤病学   1660篇
神经病学   5936篇
特种医学   1591篇
外科学   9105篇
综合类   291篇
一般理论   26篇
预防医学   5789篇
眼科学   1261篇
药学   4436篇
中国医学   251篇
肿瘤学   3639篇
  2024年   47篇
  2023年   450篇
  2022年   206篇
  2021年   1113篇
  2020年   656篇
  2019年   1181篇
  2018年   2078篇
  2017年   1247篇
  2016年   1323篇
  2015年   2033篇
  2014年   2065篇
  2013年   3002篇
  2012年   5887篇
  2011年   5743篇
  2010年   2629篇
  2009年   1951篇
  2008年   4880篇
  2007年   5063篇
  2006年   5257篇
  2005年   4953篇
  2004年   4454篇
  2003年   4008篇
  2002年   3883篇
  2001年   1566篇
  2000年   2077篇
  1999年   1000篇
  1998年   225篇
  1997年   162篇
  1996年   164篇
  1995年   148篇
  1994年   118篇
  1993年   114篇
  1992年   122篇
  1991年   111篇
  1990年   75篇
  1989年   78篇
  1988年   60篇
  1987年   55篇
  1986年   71篇
  1985年   78篇
  1984年   93篇
  1983年   60篇
  1982年   77篇
  1981年   70篇
  1980年   80篇
  1979年   43篇
  1978年   39篇
  1977年   38篇
  1976年   35篇
  1974年   33篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
21.
We report on a 3‐year‐old girl with a microvesicular generalized rash in whom primary infection by parvovirus B19 was demonstrated by seroconversion. To our knowledge, this is the first instance of an eruption arising from parvovirus B19 with this peculiar clinical pattern.  相似文献   
22.
23.
24.

Aim

The purpose of this study is to find out whether telephone referral from Primary Health Care to Internal Medicine Consult manages to reduce waiting days as compared to traditional referral. This study also aims to know how acceptable is the telephone referral to general practitioners and their patients.

Design

No blind randomized controlled clinical trial.

Setting

Northern Huelva Health District.

Participants

154 patients.

Interventions

Patients referrals from intervention clinicians were sent via telephone consultation, whereas patients referrals from control clinicians were sent by traditional via.

Measurements

Number of days from referral request to Internal Medicine Consult. Number of telephone and traditional referrals. Number of doctors and patients denied. Denial reasons.

Results

A statistically significant difference was found between groups, with an average of 27 (21-34) days. Among General Practitioners, 8 of the first 58 total doctors after randomization and, subsequently, 6 of the 20 doctors of the test group refused to engage in the trial because they considered “excessive time and effort consuming”. 50% of patients referred by the 14 General Practitioners finally randomized to the intervention group were denied referral by telephone due to patient's complexity.

Conclusions

Telephone referral significantly reduces waiting days for Internal Medicine consult. This type of referral did not mean an “excessive time and effort consuming” to General Practitioners and was not all that beneficial to complex patients  相似文献   
25.
26.
Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods.  相似文献   
27.
The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c2 = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.  相似文献   
28.
We investigated the effects of the noble gas argon on the expression of locomotor sensitization to amphetamine and amphetamine-induced changes in dopamine release and mu-opioid neurotransmission in the nucleus accumbens. We found (1) argon blocked the increase in carrier-mediated dopamine release induced by amphetamine in brain slices, but, in contrast, potentiated the decrease in KCl-evoked dopamine release induced by amphetamine, thereby suggesting that argon inhibited the vesicular monoamine transporter-2; (2) argon blocked the expression of locomotor and mu-opioid neurotransmission sensitization induced by repeated amphetamine administration in a short-term model of sensitization in rats; (3) argon decreased the maximal number of binding sites and increased the dissociation constant of mu-receptors in membrane preparations, thereby indicating that argon is a mu-receptor antagonist; (4) argon blocked the expression of locomotor sensitization and context-dependent locomotor activity induced by repeated administration of amphetamine in a long-term model of sensitization. Taken together, these data indicate that argon could be of potential interest for treating drug addiction and dependence.  相似文献   
29.
30.
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