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   37680篇
  免费   4403篇
  国内免费   448篇
耳鼻咽喉   342篇
儿科学   668篇
妇产科学   735篇
基础医学   2312篇
口腔科学   848篇
临床医学   8370篇
内科学   5703篇
皮肤病学   288篇
神经病学   1833篇
特种医学   750篇
外国民族医学   4篇
外科学   4464篇
综合类   3653篇
现状与发展   2篇
一般理论   7篇
预防医学   6481篇
眼科学   178篇
药学   3707篇
  39篇
中国医学   525篇
肿瘤学   1622篇
  2024年   434篇
  2023年   1059篇
  2022年   1174篇
  2021年   1933篇
  2020年   2016篇
  2019年   1975篇
  2018年   1843篇
  2017年   1749篇
  2016年   1583篇
  2015年   1684篇
  2014年   2517篇
  2013年   2946篇
  2012年   2153篇
  2011年   2253篇
  2010年   1847篇
  2009年   1787篇
  2008年   1706篇
  2007年   1631篇
  2006年   1434篇
  2005年   1244篇
  2004年   1017篇
  2003年   922篇
  2002年   686篇
  2001年   607篇
  2000年   560篇
  1999年   493篇
  1998年   430篇
  1997年   348篇
  1996年   308篇
  1995年   349篇
  1994年   233篇
  1993年   207篇
  1992年   191篇
  1991年   180篇
  1990年   144篇
  1989年   104篇
  1988年   132篇
  1987年   99篇
  1986年   91篇
  1985年   94篇
  1984年   82篇
  1983年   49篇
  1982年   50篇
  1981年   31篇
  1980年   39篇
  1979年   28篇
  1978年   28篇
  1977年   18篇
  1975年   10篇
  1973年   13篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
To address knowledge gaps about Turner syndrome (TS) associated disease mechanisms, the Turner Syndrome Society of the United States created the Turner Syndrome Research Registry (TSRR), a patient‐powered registry for girls and women with TS. More than 600 participants, parents or guardians completed a 33‐item foundational survey that included questions about demographics, medical conditions, psychological conditions, sexuality, hormonal therapy, patient and provider knowledge about TS, and patient satisfaction. The TSRR platform is engineered to allow individuals living with rare conditions and investigators to work side‐by‐side. The purpose of this article is to introduce the concept, architecture, and currently available content of the TSRR, in anticipation of inviting proposals to utilize registry resources.  相似文献   
52.
53.
Summary The reliability of noninvasive, automatic blood pressure monitoring is not yet clearly established. A 24-h ambulatory blood pressure profile was obtained in 9 healthy, normotensive subjects with an automatic, noninvasive device. The blood pressure profile showed the typical circadian pattern with lower systolic and diastolic values during sleep, although pulse pressure was fairly constant (about 40 mm Hg). The systolic blood pressure rose steeply in the early morning hours — before waking up. The results were compared with simultaneous hourly readings using the auscultatory method. There were no statistically significant differences between the automatic and auscultatory readings, 13 of the 18 mean values at. different time points being within 2 mm Hg of each other. All the auscultatory means fell within the 95% confidence limits of those measured hourly by the automatic method. Although the automatic method seemed to be reliable compared with the auscultatory method, its sensitivity to motion artifacts is a disadvantage in a truly ambulatory setting.  相似文献   
54.
本文通过28例正常人及28例癌症病患者的头发的分析,得出癌症病患者的头发区别于正常人的头发的特征是:癌症病患者的头发中含有微量元素As、Ni、Mn。  相似文献   
55.
The paper considers the limiting factors in EEG enhancement in the presence of electrosurgery interference and presents a design for a useful fibre-optic EEG monitoring instrument which is free from such problems as electrical shock (micro and macroshock), patient burns and susceptibility to electrosurgery interference associated with conventional EEG monitors.  相似文献   
56.
Chromosome aberrations (CA), micronuclei (MN, cytokinesis-block [CB] method), and sister-chromatid exchanges (SCE) were analysed in blood lymphocytes of 17 workers and 17 control subjects. The mean urinary mandelic acid level (average 9.4 mmol/l) and styrene glycol in blood (average 2.5 mumol/l) implied exposure to about 300 mg/m3 of styrene in the plant. The number of CA was significantly higher in non-smoking workers compared with nonsmoking controls. A significant correlation was observed between duration of exposure and individual CA level of all workers. No significant effects were observed in MN or SCE. Single-strand breaks (SSB) in DNA of isolated lymphocytes were studied in nine of the workers and eight of the controls by the DNA-unwinding technique. The results showed an increase in SSB among the exposed workers. The present findings support earlier reports on the increase of structural CA in blood lymphocytes of workers in the reinforced plastic industry, and also show that SSBs are elevated in such workers.  相似文献   
57.
The direct measurement of blood pressure has found widespread use in intensive care units, operating rooms, and in emergency departments. Infection, air embolism and thrombosis are some of the risks to patients associated with both the cannulation procedure and with the apparatus used in the blood-pressure measuring process. Although there is constant revision in an attempt to reduce these risks, they cannot be completely eliminated. The need for direct blood-pressure measurements and the physiological effects of air embolism and thrombosis are reviewed. Infection and problems related to the techniques used to insert the catheters are not discussed.  相似文献   
58.
Fanconi-Bickel syndrome (FBS), or glycogen storage disease type XI, is a rare autosomal recessive disorder characterized by hepatorenal glycogen accumulation, Fanconi nephropathy, and impaired utilization of glucose and galactose. Recently, this disease was elucidated to link mutations in the glucose transporter 2 (GLUT2) gene. Only three mutations in three FBS families have been reported. Therefore, it is important to elucidate mutations in the GLUT2 gene in FBS by answering the question of whether the syndrome is a single gene disease. In this report, we describe two patients in two unrelated families clinically diagnosed with FBS. No mutation in the entire protein coding region of the GLUT2 gene was detected in patient 1, which suggested that no mutation existed in the GLUT 2 gene, or that some mutations had affected the expression of the GLUT 2 gene. In patient 2, a novel homozygous nonsense mutation (W420X, Trp at codon 420 to stop codon) was detected. These results support the correlation between GLTU2 gene mutation and FBS syndrome. However, many patients must be analyzed to determine whether other genes are involved in FBS. Received: July 16, 1999 / Accepted: September 3, 1999  相似文献   
59.
The development of a multichannel unconstrained memory system for monitoring physiological information is described. The system comprises a portable recorder, worn by the subject, to detect and store data in memory and a readout unit for transferring the data to a microcomputer. Using the microcomputer, the physiological data are displayed, retrieved and analysed. The portable recorder consists of a memory control unit, an instrumentation unit, an LCD timer and batteries. In the memory-control unit the data are transferred to EPROM (erasable programmable read-only memory), which is a nonvolatile memory. This memory, removed from the protable recorder, can be delivered to the laboratory and its contents analysed without interrupting the field experiment. In connection with the instrumentation unit, an 8-channel skin thermometer was designed and tested. It was accurate to within ±0.08°C compared with a standard thermometer.  相似文献   
60.
BACKGROUND: The aim of the study was to assess infertile couples' attitudes toward the procedures of embryo donation (ED) and to identify factors predicting interest in donation. METHODS: Fifty-one couples who had received IVF treatment and had subsequently had embryos cryopreserved for >3 years were located and sent written information about the procedures for ED and possible implications of donation. A total of 49 couples agreed to participate in the study with 36 women and 31 men subsequently returning questionnaires describing their reasons for not claiming unused embryos and attitudes towards ED. RESULTS: Patients were supportive of donor screening procedures, but less comfortable sharing non-identifying information. Comfort levels declined as information became increasingly personal. Support for unconditional (i.e. the donation of embryos without conditions attached) and conditional (i.e. where couples could limit the donation of their embryos to persons/couples according to their preferences) models of donation was highly polarized and a substantial minority expressed strong opposition to each model. Willingness to donate was associated with greater comfort about disclosing personal information, a desire to know the outcome of donation and willingness to have future contact with a child, but not with current family size. CONCLUSIONS: Comfort in sharing information with a recipient couple is more important than acceptance of screening procedures, or attainment of family size goals in predicting willingness to donate embryos. Offering the option of conditional donation could increase the acceptability of ED for some patients.  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