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   479篇
  免费   21篇
  国内免费   29篇
耳鼻咽喉   2篇
儿科学   29篇
妇产科学   62篇
基础医学   39篇
口腔科学   14篇
临床医学   38篇
内科学   81篇
皮肤病学   16篇
神经病学   12篇
特种医学   54篇
外科学   44篇
综合类   60篇
预防医学   28篇
眼科学   2篇
药学   31篇
肿瘤学   17篇
  2022年   2篇
  2021年   4篇
  2020年   1篇
  2019年   2篇
  2016年   4篇
  2015年   6篇
  2014年   11篇
  2013年   11篇
  2012年   9篇
  2011年   10篇
  2010年   19篇
  2009年   19篇
  2008年   23篇
  2007年   26篇
  2006年   36篇
  2005年   18篇
  2004年   16篇
  2003年   11篇
  2002年   11篇
  2001年   15篇
  2000年   10篇
  1999年   11篇
  1998年   32篇
  1997年   36篇
  1996年   32篇
  1995年   19篇
  1994年   13篇
  1993年   19篇
  1992年   14篇
  1991年   2篇
  1990年   6篇
  1989年   11篇
  1988年   6篇
  1987年   7篇
  1986年   4篇
  1985年   14篇
  1984年   4篇
  1983年   5篇
  1982年   6篇
  1981年   6篇
  1980年   1篇
  1978年   4篇
  1977年   2篇
  1976年   1篇
  1975年   3篇
  1973年   1篇
  1970年   2篇
  1969年   2篇
  1967年   1篇
  1966年   1篇
排序方式: 共有529条查询结果,搜索用时 171 毫秒
11.
The secret is comprised in three words – work, finish, publish.’Michael FaradayThere are many reasons doctors want to publish their work. For most at an early stage in their career, this may be to add a line to their curriculum vitae and advance their careers but for academics, publishing is an expectation. Many will believe they have something important to say, and wish to provoke debate and discussion; others wish to share knowledge and experiences, which in medicine can lead to a satisfying change in clinical practice. All serve to register one’s idea and educate others. However, for some, the reason is as basic as money. As we celebrate the 350th anniversary of the first academic publication, perhaps we have come full circle when it comes to why people publish?Publishing is a flourishing business. There were approximately 28,100 active scholarly peer-reviewed journals in mid-2012, collectively publishing about 1.8–1.9 million articles per year. The number of articles published each year and the number of journals have both grown steadily for more than two centuries, by about 3% and 3.5% per year respectively.1 Journals have a responsibility to refine and define information and act as a scientific filter. Many of us will receive daily invitations in our email inbox from eclectic and new journals that are likely to take anything – is the filter now too porous? But this industry is like any other commercial activity and the supply still far outstrips the demand. Perhaps the internet revolution has merely fuelled our hunger to publish more?The launch of this exciting and innovative series about publishing coincides with the 350th celebration of the publication of the first academic journal. In the age of social media, the first question is ‘What are journals for?’, which Simon Rallison sets out to answer. Simon is Director of Publications at the Physiological Society, and was previously a journal publisher with Earthscan, Springer and Blackwell.Writing is hard work and, through this series, I hope the reader will get some useful insight into this service industry for academia.Jyoti ShahCommissioning EditorIn an age of the internet and social media, why are we still using (admittedly with refinements and improvements) a form of publication dating from 1665? What exactly is a journal in the 21st century and what role does it have to perform? Surprisingly, the academic journal has not evolved since it was invented 350 years ago.1 The first issue of the Philosophical Transactions of the Royal Society was published in 1665, the brainchild of Henry Oldenburg and Robert Hooke. Since then, journals have digitised and now offer greater opportunity for research communication – but are authors taking advantage of what journals can offer? The academic and research community is generally very conservative about what it reads and how it views journals. There are, however, also frequent misunderstandings about the operation of journals.  相似文献   
12.
Masouredis  SP; Branks  MJ; Victoria  EJ 《Blood》1987,70(3):710-715
IgG autoantibodies eluted from RBCs of antiglobulin positive normal blood donors contained at least two antibody populations, an IgG autoantibody (Ab 1), and an IgG population (Ab 2) that agglutinated RBCs coated with some Rh(D) alloantibodies. Eight of 24 autoantibody eluates tested agglutinated 3 of 10 anti-Rh(D) sensitized RBCs. The agglutinating activity was inhibited specifically by preincubation of the autoantibody eluate with the reactive anti-D. The reaction did not require the Fc domain of the anti-Rh(D), since autoantibody eluates agglutinated RBCs coated with F(ab')2 prepared from the reactive anti-D sera. These findings indicate that the RBCs of some antiglobulin- positive blood donors contain an immunoglobulin auto-antiidiotype (Ab 2) against the RBC autoantibody (Ab 1) which is demonstrable through its cross-reactivity with selected Rh(D) alloantibodies. Identification of auto-antiidiotypes in RBC autoimmunity lends support to the idiotype- antiidiotype network hypothesis of immune regulation and is consistent with the bizarre and complex serology of autoimmune hemolytic anemia. The absence of clinical hemolysis in antiglobulin-positive normal blood donors suggests that immunoglobulin idiotype-antiidiotype interactions may play a role in modulating the effects of RBC autoimmunity.  相似文献   
13.
Fetal persistent middle cerebral artery reversed end diastolic flow is a rare and ominous finding. Previous cases have been associated with intracranial hemorrhage, growth restriction, anaemia, and hepatic anomaly. Intrauterine demise or early neonatal death is a common outcome. We report the case of persistent middle cerebral artery reversed end diastolic flow in a well-grown fetus at 32 weeks’ gestation resulting from acute, severe anaemia due to a large feto-maternal hemorrhage. An emergency cesarean section was performed and the neonate required advanced resuscitation and immediate blood transfusion. Postnatal magnetic resonance imaging confirmed a hemorrhagic parietal infarct and bilateral ischaemic changes in the basal ganglia. This provides further evidence that persistent middle cerebral artery reversed end diastolic flow in any fetus is an ominous finding warranting urgent diagnostic evaluation and/or delivery.  相似文献   
14.
Cai  SP; Chang  CA; Zhang  JZ; Saiki  RK; Erlich  HA; Kan  YW 《Blood》1989,73(2):372-374
We used in vitro DNA amplification by the polymerase chain reaction and nonradioactive probes for prenatal diagnosis of beta thalassemia in Chinese from the Guangdong province. Exact molecular diagnoses were made in all 20 fetuses studied over a 6-month period. We conclude that this method of prenatal diagnosis for beta thalassemia is a viable approach in many parts of the world where this disease is common.  相似文献   
15.
16.
17.
While most women with epilepsy can expect a normal pregnancy outcome, epilepsy remains a significant contributor to both maternal and perinatal morbidity. Pre-pregnancy planning must address reliable contraception and optimisation of antiepileptic drug (AED) regimens to minimise teratogenic risk while maintaining seizure control. The most recent data from the AED registries regarding malformations is presented in this review, as is the limited data on the newer AEDs and studies linking neurocognitive outcomes to AED exposure. During pregnancy, important considerations include; therapeutic drug monitoring, surveillance for obstetric complications and vigilance for seizures during the intrapartum and postpartum period.  相似文献   
18.
Background Perceived age is important to women and is a primary driver for topical product use and facial cosmetic surgery. Changes in facial features and biophysical skin parameters with chronological age and their associations with perceived age have not been described in Asian populations. Objective To investigate the relationship between biophysical properties of the skin, visual features of skin ageing and perceived facial age in Chinese women. Methods Facial photographs were collected of 250 Chinese women, aged 25–70 years in Shanghai, China. The perceived facial age was determined and related to the chronological age for each participant and to a range of visual assessments of skin appearance and objective biophysical measurements of the skin. The profile of changes in these parameters with age was investigated together with the differences in those parameters for women judged to look younger than their chronological age and those judged to look older than their chronological age. Results Large discrepancies in perceived age (up to 29 years) were found in women of the same chronological age. Each objective skin measure and visual assessment parameter had a stronger correlation with perceived age than with chronological age. The strongest relationships to perceived age were for wrinkles and hyperpigmentation. Skin colour, hydration and trans‐epidermal water loss (TEWL) had weaker associations with perceived age. Women judged to look older than their chronological age had significantly higher scores than those judged to look younger for coarse wrinkles and hyperpigmentation across all age groups. The appearance differences between these groups were evident in composite facial images of the same average chronological age. Conclusions We have identified the skin attributes which differ with perceived age in Chinese women. Perceived age is a better measure of the biological age of facial skin than is chronological age in this population.  相似文献   
19.
20.
Maternal serum alpha 2-macroglobulin levels were measured twice, at approximately 18 and 30 weeks' gestation, in 289 pregnant women who later delivered at or after 37 weeks. Levels were elevated as early as 18 weeks' gestation in women destined to have a growth-retarded infant, and this elevation persisted through 30 weeks' gestational age. Furthermore, levels were higher in white women than black, in smokers than in non-smokers, and in thin than in heavier women. When the effect of alpha 2-macroglobulin on birth weight was evaluated in a multiple regression analysis adjusting for gestational age, race, body size, smoking, fetal sex, and a history of a low birth weight infant, high alpha 2-macroglobulin levels were associated with a statistically significant decrease in birth weight. The effect was greater in women who smoked. This relationship did not appear to be associated with differences in serum zinc or hematocrit levels.  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