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   31995篇
  免费   2338篇
  国内免费   94篇
耳鼻咽喉   365篇
儿科学   796篇
妇产科学   411篇
基础医学   4178篇
口腔科学   630篇
临床医学   2884篇
内科学   6755篇
皮肤病学   460篇
神经病学   3669篇
特种医学   1316篇
外国民族医学   3篇
外科学   4709篇
综合类   668篇
一般理论   66篇
预防医学   2782篇
眼科学   620篇
药学   1963篇
中国医学   20篇
肿瘤学   2132篇
  2023年   112篇
  2022年   189篇
  2021年   449篇
  2020年   258篇
  2019年   446篇
  2018年   574篇
  2017年   420篇
  2016年   486篇
  2015年   552篇
  2014年   847篇
  2013年   1332篇
  2012年   2039篇
  2011年   2173篇
  2010年   1160篇
  2009年   1106篇
  2008年   2066篇
  2007年   2194篇
  2006年   2170篇
  2005年   2364篇
  2004年   2093篇
  2003年   1927篇
  2002年   1946篇
  2001年   351篇
  2000年   280篇
  1999年   351篇
  1998年   425篇
  1997年   401篇
  1996年   371篇
  1995年   361篇
  1994年   292篇
  1993年   278篇
  1992年   247篇
  1991年   263篇
  1990年   246篇
  1989年   216篇
  1988年   195篇
  1987年   218篇
  1986年   190篇
  1985年   204篇
  1984年   242篇
  1983年   227篇
  1982年   279篇
  1981年   276篇
  1980年   228篇
  1979年   138篇
  1978年   151篇
  1977年   99篇
  1976年   120篇
  1975年   87篇
  1974年   109篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
An outbreak of Salmonella dublin infection occurred in England and Wales in October to December 1989. Forty-two people were affected, mainly adults, and most lived in south-east England. Microbiological and epidemiological investigations implicated an imported Irish soft unpasteurized cows' milk cheese as the vehicle of infection. A case-control study showed a statistically significant association between infection and consumption of the suspect cheese (p = 0.001). Salmonella dublin was subsequently isolated from cheeses obtained from the manufacturer's premises. Initial control measures included the withdrawal of the cheese from retail sale and a Food Hazard Warning to Environmental Health Departments, as well as a press release, from the Department of Health. Subsequently, a decision was taken by the manufacturer to pasteurize milk used in the production of cheese for the UK market and importation of the cheese resumed in June 1990.  相似文献   
34.
Summary: We report a series of 8 patients with ictal déjà vu. Subdural strip electrocorticographic (ECoG) monitoring localized the ictal epileptogenic focus as follows: right (n = 6) and left (n = 2) mesiotemporal lobe. In all 8 patients, the left hemisphere was dominant for language function based on intracarotid amytal testing. In 6 right-handed patients, ictal déjà vu was associated with a right temporal lobe focus. However, in the 2 left-handed patients, the ictal focus was left temporal lobe. Although ictal déjà vu localizes the epileptic focus to temporal lobe, this experiential phenomenon appears to lateralize to the hemisphere nondominant for handedness.  相似文献   
35.
36.
In 6 patients with Parkinson's disease (PD) and 6 age-matched controls, transcranial magnetic stimulation was applied at 56 regions over the motor cortex and premotor cortex of each hemisphere, with the first dorsal interosseous (FDI) muscle of both hands activated at 15% maximum voluntary contraction during stimulation. For each site, motor evoked potential (MEP) landmarks were recovered, including MEP amplitude, MEP onset latency, and silent period duration. Scaled MEP amplitudes were used to construct individual cortical maps of the FDI muscles. The maps revealed an anterior displacement of the muscle representation in PD patients. This anterior shift over motor cortical areas may reflect increased contributions of corticocortical connections between motor cortex and premotor cortical areas, possibly enhanced by the visual feedback aspect of the task. These alterations may reflect adaptations to the impairments in striatocortical circuits in PD.  相似文献   
37.
38.
39.
Throughout history, societies have developed their own codes of ethics, including those pertaining to the practice of medicine. In the United States, physicians have adopted a set of ethics based on religious values and historical teachings. We, as physicians, have been presented several codes of ethics, including the American Medical Association Code of Ethics and the American College of Radiology Code of Ethics. Over time, we have learned to appropriately apply these codes to our daily practice. With the advent of new technologies in imaging, we may lose sight as to the transfer of these principles to reflect current conditions. Recent history has shown a trend of new technology leading to potential misuse of this technology and further leading to stricter governmental regulations. It is the purpose of this review to give guidelines for dealing with new technologies, such as PET imaging, and we describe a radiologist's ethical responsibility in a doctor-patient relationship. A historical review of medical ethics will lead to discussions about various issues affecting radiologists and nuclear physicians. To be sure, not all ethical situations are black and white, and therefore there are many gray areas. The opinions expressed in this article are those of the authors and are based on extension of already established rules of ethical conduct.  相似文献   
40.
States of phosphorylation of neurofilament proteins were examined in the perikarya of rat sensory and motor neurons between 3 and 28 d following either a distal transection [6-7 cm from the L4-L5 dorsal root ganglia (DRG)] or a proximal transection (1-2 cm from the L4-L5 DRG) of the sciatic nerve. Paraffin sections of the right (experimental) and left (control) L4 and L5 DRG from animals with unilateral transection of the right distal sciatic nerve were stained immunocytochemically with monoclonal antibodies to phosphorylation-dependent (NF-P), dephosphorylation-dependent (NF-dP), or phosphorylation-independent (NF-ind) epitopes on the largest (NF200), mid-sized (NF150), or smallest (NF68) neurofilament protein subunits. Increased immunoreactivity to NF-P on NF200 and NF150 was detected in experimental DRC at 10 d, peaking by 20 d, and declining to near control levels by 28 d. Conversely, immunoreactivity to NF-dP declined in experimental DRG beginning at 6 d, reaching a maximum decline at 10-16 d, and returning to near control levels by 28 d. Immunocytochemical changes were confirmed with biochemical studies on tissue homogenates that demonstrated an increase of immunoreactivity to NF-P and a decrease of reactivity to NF-dP in the experimental DRG. Changes in immunoreactivities to NF-P and NF-dP were observed only in the perikarya of large neurons and were closely associated with chromatolytic changes in these neurons. Marked enhancement of chromatolysis, as well as the immunoreactivities to NF-P and NF-dP, occurred following a proximal (left side) versus distal (right side) transection in the same animal.(ABSTRACT TRUNCATED AT 250 WORDS)  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