全文获取类型
收费全文 | 171429篇 |
免费 | 21408篇 |
国内免费 | 5649篇 |
专业分类
耳鼻咽喉 | 3019篇 |
儿科学 | 3044篇 |
妇产科学 | 2782篇 |
基础医学 | 9163篇 |
口腔科学 | 5909篇 |
临床医学 | 34142篇 |
内科学 | 32580篇 |
皮肤病学 | 3740篇 |
神经病学 | 15288篇 |
特种医学 | 5960篇 |
外国民族医学 | 56篇 |
外科学 | 23671篇 |
综合类 | 11664篇 |
现状与发展 | 58篇 |
一般理论 | 5篇 |
预防医学 | 17228篇 |
眼科学 | 3621篇 |
药学 | 7868篇 |
93篇 | |
中国医学 | 4171篇 |
肿瘤学 | 14424篇 |
出版年
2024年 | 1956篇 |
2023年 | 6558篇 |
2022年 | 4055篇 |
2021年 | 6108篇 |
2020年 | 8056篇 |
2019年 | 4224篇 |
2018年 | 8994篇 |
2017年 | 9241篇 |
2016年 | 9713篇 |
2015年 | 10867篇 |
2014年 | 13729篇 |
2013年 | 14822篇 |
2012年 | 7781篇 |
2011年 | 7862篇 |
2010年 | 9596篇 |
2009年 | 11220篇 |
2008年 | 6165篇 |
2007年 | 5212篇 |
2006年 | 6427篇 |
2005年 | 4754篇 |
2004年 | 3466篇 |
2003年 | 3373篇 |
2002年 | 3047篇 |
2001年 | 3648篇 |
2000年 | 2723篇 |
1999年 | 3203篇 |
1998年 | 3110篇 |
1997年 | 2864篇 |
1996年 | 2654篇 |
1995年 | 2401篇 |
1994年 | 1687篇 |
1993年 | 1214篇 |
1992年 | 1145篇 |
1991年 | 966篇 |
1990年 | 771篇 |
1989年 | 774篇 |
1988年 | 685篇 |
1987年 | 523篇 |
1986年 | 478篇 |
1985年 | 380篇 |
1984年 | 287篇 |
1983年 | 328篇 |
1982年 | 244篇 |
1981年 | 217篇 |
1980年 | 135篇 |
1979年 | 72篇 |
1978年 | 121篇 |
1977年 | 115篇 |
1976年 | 84篇 |
1972年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
R. Gamzu L. Yogev PhD A. Botchan A. Amit J. B. Lessing D. Lichtenberg G. Paz and H. Yavetz 《Andrologia》1997,29(1):17-21
Summary. The study was conducted to evaluate the diverse effect and clinical significance of TEST yolk buffer treatment on sperm samples of 128 infertile men. Sperm samples were incubated with TEST yolk buffer and control medium (Ham's F-10) at room temperature for 2 h. The hemizona indices (mean ± SE) of the TEST yolk buffer and medium-treated sperm samples were 29 ± 2.3% and 22 ± 1.6%, respectively. Inspection of the individual response of each sperm sample to TEST yolk buffer revealed that 63 samples (49%) improved (double the interassay variation = 28%) their binding to zona pellucida, 36 (28%) remained unchanged, whereas the binding capacity of 29 samples (23%) decreased. Furthermore, TEST yolk buffer treatment of 24 samples (19%) resulted in an increased binding beyond the hemizona index threshold set up at 23%. This level was previously shown to be the cut-off point between fertile and infertile sperm samples. It was concluded that when applied to an unselected group of infertile men, TEST yolk buffer significantly increased sperm binding capacity to the zona pellucida. However, only 19% of the sperm samples showed improvement with clinical significance. The other sperm samples may have improved, remained unchanged or even deteriorated independently on basic sperm variables. Thus, the effect of TEST yolk buffer treatment on sperm binding should be tested prior to its clinical use to avoid possible damage to certain sperm samples. 相似文献
93.
Gregg H. Gilbert DDS Laurence G. Branch PhD Jeffrey Longmate PhD 《Journal of public health dentistry》1992,52(5):277-287
Veterans who were eligible for dental care in Department of Veterans Affairs (VA) facilities at no monetary cost responded to a mailed questionnaire. Seventy-one percent were aware that they were actually eligible for VA dental care. However, only 48 percent reported the VA as their only or primary source of dental care. Eligibility status, perceived quality of VA dental care, use of VA medical care, perception that one's income meets expenses, and perceived need for dental care were significant correlates of using the VA as one's current source of dental care. Level of formal education, perception that one's income meets expenses, transportation pattern, geographic distance from a VA facility, and eligibility status were significant correlates of using the VA as one's current medical care source. Research on VA utilization offers the opportunity to study issues of access to, and use of, a large public health care system whose patients largely receive care at no monetary cost. Veterans' use of VA dental and medical care is apparently influenced by a wide variety of factors, ranging from barriers to access to non-VA systems, to characteristics of the VA delivery system itself, to need for treatment. 相似文献
94.
利用仿生化学的原理,本文设计并合成了两个儿茶酚胺类和两个羟基吡啶酮类八配位的螯合剂,初步动物试验表明,具有较强的钚促排能力。 相似文献
95.
96.
97.
98.
Nigel Wynne RGN/Dip BSc Stuart Brand BSc PhD Roy Smith BA PhD 《Journal of advanced nursing》1997,26(3):470-474
There is an ongoing debate in nurse education concerning the role and delivery of the biological sciences in the nursing curriculum. One of the fundamental questions raised by this debate asks how best can teachers impart biological knowledge in a manner that can be readily applied by students and qualified nurses to inform their clinical practice. This paper will include a discussion of some of the features of pre-registration education that may have influenced the manner in which biological sciences are perceived, taught and used by nurses. It will be argued that nursing may have developed a form of incomplete holism and that this may be in part responsible for the challenges that remain to be met within this area of the nursing curriculum. As a response to incomplete holism an innovative approach within pre-registration education will be introduced. This development involves the use of linked teaching sessions which aim to develop the analytical skills necessary to apply physiological knowledge to nursing practice. 相似文献
99.
Correlation between sperm penetration into the human zona pellucida and in vitro fertilization rates
L. Yogev PhD R. Gamzu R. Hauser A. Botchan A. Amit J. B. Lessing G. Paz and H. Yavetz 《Andrologia》1997,29(2):71-75
Summary. Sperm penetration into the zona pellucida of unfertilized oocytes, and its correlation with in vitro fertilization rates of the sibling oocytes, were assessed. This was performed in order to evaluate the prediction rate of the sperm penetration test into the zona pellucida. Unfertilized oocytes ( n =1872) from 371 cycles were pipetted through a microcapillary, and the remaining sperm cells penetrating the zona pellucida were counted. The mean (±SD) number of spermatozoa that penetrated the zona pellucida of unfertilized oocytes was 12.9±16.37. A significant correlation was found between the fertilization rate and the mean number of spermatozoa that penetrated into the zona pellucida of the unfertilized sibling oocytes (r = 0.48; P < 0.001), or the percent of unpenetrated zonae pellucidae in a cohort (r= —0.43; P < 0.001). However, a distinct variation in the number of spermatozoa that penetrated into the zona pellucida was detected. A step-wise regression analysis proved the number of spermatozoa penetrating the zona pellucida to be more predictive for fertilization rates than the variable of percent of unpenetrated zonae pellucidae. The results imply that although there is interdependence between penetration into the zona pellucida and fertilization rate, the predictive value of sperm penetration test for prognosis and future management after the first in vitro fertilization attempt, is limited. 相似文献
100.
Jill Macleod Clark PhD BSc RGN Jill Maben MSc BA RGN Karen Jones BA RHV RGN 《Journal of advanced nursing》1997,26(1):161-168
This is the first of two papers which address aspects of the findings of a large scale study commissioned by the English National Board which set out to examine the impact of Project 2000 on perceptions of the philosophy and practice of nursing. The findings presented here suggest that there have been fundamental shifts in perceptions of the nature and discipline of nursing. Students and diplomates of the course perceive themselves as knowledgeable doers, with their practice well grounded in theory and research. They value the interpersonal skills teaching and place the patient firmly at the centre of care delivery, viewing the patient holistically and being prepared to be fierce patient advocates where necessary. It is difficult to determine the extent to which these shifts can be attributed to the Project 2000 course, although the Project 2000 approach to education appears to be an important factor. 相似文献