全文获取类型
收费全文 | 11334篇 |
免费 | 1075篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 112篇 |
儿科学 | 400篇 |
妇产科学 | 285篇 |
基础医学 | 1735篇 |
口腔科学 | 244篇 |
临床医学 | 1285篇 |
内科学 | 2197篇 |
皮肤病学 | 203篇 |
神经病学 | 716篇 |
特种医学 | 673篇 |
外科学 | 1367篇 |
综合类 | 224篇 |
一般理论 | 5篇 |
预防医学 | 1043篇 |
眼科学 | 159篇 |
药学 | 877篇 |
中国医学 | 9篇 |
肿瘤学 | 907篇 |
出版年
2021年 | 146篇 |
2020年 | 100篇 |
2019年 | 142篇 |
2018年 | 176篇 |
2017年 | 125篇 |
2016年 | 156篇 |
2015年 | 155篇 |
2014年 | 228篇 |
2013年 | 344篇 |
2012年 | 480篇 |
2011年 | 497篇 |
2010年 | 295篇 |
2009年 | 269篇 |
2008年 | 414篇 |
2007年 | 468篇 |
2006年 | 490篇 |
2005年 | 464篇 |
2004年 | 478篇 |
2003年 | 438篇 |
2002年 | 421篇 |
2001年 | 391篇 |
2000年 | 442篇 |
1999年 | 372篇 |
1998年 | 215篇 |
1997年 | 201篇 |
1996年 | 202篇 |
1995年 | 152篇 |
1994年 | 138篇 |
1993年 | 158篇 |
1992年 | 293篇 |
1991年 | 278篇 |
1990年 | 229篇 |
1989年 | 254篇 |
1988年 | 247篇 |
1987年 | 240篇 |
1986年 | 202篇 |
1985年 | 193篇 |
1984年 | 153篇 |
1983年 | 146篇 |
1982年 | 111篇 |
1981年 | 111篇 |
1980年 | 101篇 |
1979年 | 143篇 |
1978年 | 101篇 |
1977年 | 103篇 |
1976年 | 103篇 |
1975年 | 81篇 |
1974年 | 100篇 |
1973年 | 81篇 |
1969年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
As EC validity criteria for the production of Daphnia magna neonates in standard toxicity tests set fecundity minima which must be attained, it is important that culture conditions provide an adequate ration of high quality food. Maintaining a steady supply of fresh algae can be problematical so the possibility of using frozen food was investigated. The performance of three generations of D. magna fed on diets of fresh or frozen Chlorella was compared. There were no significant effects on fecundity due to food type or generation. Cumulative fecundity (over 21 days) on fresh or frozen food exceeded 120 neonates per female and satisfied that EC validity criterion (60 neonates per female). In addition criteria relating to survival and variability were met. We conclude that frozen Chlorella are an acceptable substitute for fresh algae. 相似文献
13.
14.
The decreasing incidence of direct causes of maternal death over the past half century has led to a heightened awareness of nonobstetric factors responsible for maternal mortality. For example, cerebrovascular accidents are an important nonobstetric cause of maternal morbidity and mortality. During the 6.5-year period from 1984 to mid-1990, we encountered 15 women in whom pregnancy or the puerperium was complicated by an acute cerebrovascular accident. Six of these women had hemorrhagic strokes and nine had ischemic strokes. During this same time, approximately 90,000 women were delivered at Parkland Memorial Hospital, and thus the incidence of stroke was about one in 6000 pregnancies. Chronic hypertension or preeclampsia was causative in three cases of hemorrhagic stroke. It is important that 20% of the women died as a result of stroke, and of the 12 survivors, 40% have residual neurologic deficits. An aggressive work-up to define the etiology of stroke is necessary in order to implement cause-specific management, with subsequent reduction in morbidity and mortality. 相似文献
15.
Parasellar syndrome caused by plasma cell leukemia 总被引:1,自引:0,他引:1
L D Bellan T A Cox R D Gascoyne 《Canadian journal of ophthalmology. Journal canadien d'ophtalmologie》1989,24(7):331-334
A 71-year-old man had incomplete third cranial nerve palsy caused by plasma cell leukemia and a parasellar plasmacytoma. This is the first reported case of plasma cell leukemia in which a central nervous system sign was the initial manifestation. Only one previous case of intracranial plasmacytoma associated with plasma cell leukemia has been reported. The characteristics of intracranial plasmacytomas and of plasma cell leukemia are discussed. 相似文献
16.
J D Cox 《International journal of radiation oncology, biology, physics》1987,13(9):1271-1281
17.
18.
J L Cox 《Canadian Medical Association journal》1987,136(6):577-579
19.
M.M. Bialoskurski MA RN RM C.L. Cox MSc PhD RN & R.D. Wiggins PhD 《Journal of advanced nursing》2002,37(1):62-69
AIM: The aim of this study was to investigate the nature and organization of maternal needs and priorities in a neonatal unit. BACKGROUND: The relationship between maternal needs and priorities appears to be an under studied area in neonatal nursing. METHODS: A quantitative survey was carried out based on 209 mothers with premature infants. Two self-assessment schedules were used: critical care maternal needs inventory (J. Leske, Heart and Lung 15, 27-42) and a ranking scale. The data were analysed with multivariate analysis. FINDINGS: Data analysis revealed clear priorities in maternal needs. In particular the need for accurate infant related information was a priority for 93% of the mothers. Good communication practices with professionals were also valued. The mothers displayed altruistic behaviour, and self-related needs took second place. It is proposed that maternal needs demonstrate a hierarchical organization. CONCLUSION: It is important for nurses to consider the individual needs of the mothers, simply because the satisfaction of these needs is essential for maternal well-being. 相似文献
20.
Development of a high performance zinc-62/copper-62 radionuclide generator for positron emission tomography. 总被引:2,自引:0,他引:2
J Zweit R Goodall M Cox J W Babich G A Potter H L Sharma R J Ott 《European journal of nuclear medicine》1992,19(6):418-425
Clinical utilisation of positron emission tomography could be enhanced by the availability of short-lived radionuclides derived from generator systems. The zinc-62/copper-62 combination is one such system which could be used as a source for a number of copper-62 radiopharmaceuticals. We have developed and optimised a high activity (5.6 GBq, 150 mCi) zinc-62/copper-62 generator to provide 62Cu in a form that is suitable for direct labelling of pyruvaldehyde-bis-(N4-methylthiosemicarbazone)-copper(II), Cu(PTSM). The distribution coefficients of Zn(II) and Cu(II) between anion-exchange resin and various hydrochloric acid/organic solvent mixtures were measured. Based on these measurements a generator eluent of 0.3 M HCl/40% ethanol provided 62Cu in greater than 90% yield in a 3-ml volume. A very low 62Zn breakthrough of less than 3 x 10(-7)% was achieved. Copper-PTSM was successfully labelled with the no-carrier-added 62Cu eluent directly from the generator with 94% radiochemical yield. 相似文献