全文获取类型
收费全文 | 12781篇 |
免费 | 31篇 |
国内免费 | 2篇 |
专业分类
教育 | 9781篇 |
科学研究 | 1303篇 |
各国文化 | 20篇 |
体育 | 488篇 |
综合类 | 6篇 |
文化理论 | 392篇 |
信息传播 | 824篇 |
出版年
2023年 | 18篇 |
2022年 | 24篇 |
2021年 | 25篇 |
2020年 | 49篇 |
2019年 | 73篇 |
2018年 | 2241篇 |
2017年 | 2133篇 |
2016年 | 1618篇 |
2015年 | 156篇 |
2014年 | 169篇 |
2013年 | 308篇 |
2012年 | 251篇 |
2011年 | 745篇 |
2010年 | 861篇 |
2009年 | 451篇 |
2008年 | 659篇 |
2007年 | 1171篇 |
2006年 | 94篇 |
2005年 | 428篇 |
2004年 | 521篇 |
2003年 | 381篇 |
2002年 | 172篇 |
2001年 | 34篇 |
2000年 | 39篇 |
1999年 | 6篇 |
1998年 | 10篇 |
1997年 | 22篇 |
1996年 | 5篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 21篇 |
1990年 | 11篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1981年 | 5篇 |
1979年 | 3篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1969年 | 3篇 |
1966年 | 2篇 |
1921年 | 2篇 |
1868年 | 2篇 |
1860年 | 3篇 |
1859年 | 4篇 |
1826年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
991.
Rats confronted with the onset of a light gradient display a transient increase in locomotion called theactivity response (AR) and a dark preference (Godsil & Fanselow, 2004). These experiments demonstrate that the magnitude of the AR can be blunted
with Pavlovian fear-conditioning procedures via associative and nonassociative fear. Although manifested in decreased locomotion,
the blunted AR effect was not due to increased freezing or immobility behaviors. Instead, rats displayed reduced rearing and
an increase in a class of behaviors calledstationary activity. These results suggest that the lighting differential supplied by the cue influences the topography of defensive behavior
and reduces the expression of freezing. This procedure provides a means by which to examine learned and unlearned defensive
responses to the same stimulus. 相似文献
992.
Shaykh Muhammad al‐casnazāni al‐Husseini Jamāl N. Hussein Shetha al‐Dargazelli Hamid M. An‐Ni'aymi Louay J. Fatoohi 《Al-Masaq: Islam & the Medieval Mediterranean》1994,7(1):227-266
This pilot study presents a lunar and Gregorian chronology of the Sira, that is the biography of the prophet Muhammad. The paper discusses the problems surrounding the chronology of very early Islamic history, namely, the pre‐Hijra era. This history is not covered by the Hijra calendar, and therefore, historians dated its events using other primitive dating systems, resulting in considerable difficulties and inaccuracies when comparing Gregorian dates of this early Islamic history. In order to overcome this problem and establish an accurate chronology of the early Islamic history, the introduction of a new lunar calendar (the Muhammadi calendar) which starts with the birth month and year of the prophet Muhammad, and covers all Islamic history including the pre‐Hijra era, is suggested. The Muhammadi calendar was used to study the earliest three versions of the Sira. All dated events of the Sira were compiled from these sources and presented, for the first time, according to their historical order. The Muhammadi dates of these events were then calculated. For the first time, a computer program was designed to convert the Muliammadi dates to their Christian equivalent. The program was then used to compute the Gregorian dates of the events of the Sira. 相似文献
993.
Benjamin D. Duman Seung Youn Chyung Steven W. Villachica Donald Winiecki 《Performance Improvement》2011,50(1):17-24
A comprehensive needs assessment was conducted at ATA hospital to determine the root causes of a high number of errant radiology orders from requesting physicians. The Human Performance Technology Model, Gilbert's Behavior Engineering Model, and Rummler and Brache's Nine Performance Variables Model guided the needs assessment process. Three solutions were proposed. The development of the long‐term solution, a software utility, has been initiated. The Behavior Engineering Model was used to identify possible solutions to post‐training performance gaps identified during the evaluation. 相似文献
994.
995.
Kavita Shalia Sudha Savant Vijaya A. Haldankar Tulip Nandu Poonam Pawar Siddhi Divekar V. K. Shah Purvi Bhatt 《Indian journal of clinical biochemistry : IJCB》2012,27(1):74-82
To analyse the association of high sensitivity C-reactive (hsCRP) protein levels and −717A/G single nucleotide polymorphism
of CRP with acute myocardial infarction (AMI) in the Indian population. Study population included 100 MI cases wherein 32
patients had experienced previous MI (MI-Group-1), 68 MI cases were recruited at presentation (MI-Group-2) and equal number
of age and gender matched healthy individuals. hsCRP levels were determined by ELISA and genotyping of −717A/G was carried
out by polymerase chain reaction-based restriction digestion method. The −717A/G genotypes did not influence hsCRP level and
their distribution did not differ between groups. However, in the present study hsCRP demonstrated significant correlation
with BMI in controls of both the genders and with triglycerides in females of AMI at presentation who otherwise are with low
risk profile. Identifying traditional risk factors associated with inflammation may help in controlling the acute event. 相似文献
996.
Meera S. Ghadge Purva P. Naik Bijaynath P. Tiwari Ruprekha M. Hegde Tanaji J. Matale 《Indian journal of clinical biochemistry : IJCB》2012,27(1):97-99
Breast cancer is one of the most frequent malignancies in the world. Available staging procedures to detect breast cancer
are bone scan, chest X-ray, liver ultrasonography, computerized tomography, estimation of tumor markers like carbohydrate
antigen (CA15-3) and carcino embryonic antigen. These procedures are expensive and may not be required in all cases. Out of
70 patients studied, 55 had normal CA15-3 and 15 had elevated levels of Ca15-3. Eight (14.5%) of the 55 patients with normal
CA15-3 had abnormal bone scan. Fifteen patients had CA15-3 levels above the normal range and among these 9 (60%) had abnormal
bone scan. While prime facie it would appear that a high level of CA15-3 correlate with abnormal bone scan, it is also true
that the numbers are small at present and conclusions about the validity of CA15-3 as marker of bone metastasis may be premature. 相似文献
997.
Yong Huo 《Journal of Zhejiang University. Science. B》2010,11(8):631-633
##正##Dr.Gruntzig et al.(1979) successfully completed the world's first percutaneous coronary intervention (PCI),a percutaneous transluminal coronary 相似文献
998.
Ling Xia Ying-lan Gong Xiu-wei Zhu Yu Zhang Qi Sun Heng-gui Zhang 《Journal of Zhejiang University. Science. B》2010,11(6):402-416
The aim of this study is to build two mathematical models of canine ionic currents specific to right atria and left atria.The canine left atria mathematical model was firstly modified from the Ramirez-Nattel-Courtemanche(RNC) model using the recently available experimental data of ionic currents and was further developed based on our own experimental data.A model of right atria was then built by considering the differences between right atria and left atria.The two developed models well reproduced the exper... 相似文献
999.
Qing-jun Liu Wei-wei Ye Hui Yu Ning Hu Li-ping Du Ping Wang 《Journal of Zhejiang University. Science. B》2010,11(5):323-331
Neurochip based on light-addressable potentiometric sensor(LAPS),whose sensing elements are excitable cells,can monitor electrophysiological properties of cultured neuron networks with cellular signals well analyzed.Here we report a kind of neurochip with rat pheochromocytoma(PC12) cells hybrid with LAPS and a method of de-noising signals based on wavelet transform.Cells were cultured on LAPS for several days to form networks,and we then used LAPS system to detect the extracellular potentials with signals d... 相似文献
1000.
Su Ye Sohn Gi Young Jang Byung Min Choi 《Journal of Zhejiang University. Science. B》2010,11(7):539-541
Congenital atresia of the left main coronary artery is a rare occurrence, and surgical revascularizationbypass graft is required.
We here report a rare case of congenital coronary anomaly in an infant. A 10-month-old male infant was admitted to the hospital
with heart failure symptoms. Echocardiographic examinations revealed mitral valve regurgitation and ischemic changes of the
anterolateral papillary muscle and chordae. Coronary angiography showed atresia of the left main coronary artery with a severe
hypoplastic left anterior descending artery and a circumflex coronary artery. Unfortunately, sudden cardiac arrest occurred
after catheterization and the infant did not recover despite of immediate cardiopulmonary resuscitation. Further studies are
needed to find a newer diagnostic method to detect coronary anomaly in an infant, and coronary angiography, if necessary,
has to be performed very carefully. 相似文献