全文获取类型
收费全文 | 4025篇 |
免费 | 257篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 60篇 |
儿科学 | 104篇 |
妇产科学 | 121篇 |
基础医学 | 487篇 |
口腔科学 | 13篇 |
临床医学 | 454篇 |
内科学 | 956篇 |
皮肤病学 | 43篇 |
神经病学 | 420篇 |
特种医学 | 62篇 |
外科学 | 464篇 |
综合类 | 26篇 |
一般理论 | 6篇 |
预防医学 | 596篇 |
眼科学 | 62篇 |
药学 | 226篇 |
中国医学 | 2篇 |
肿瘤学 | 204篇 |
出版年
2023年 | 28篇 |
2022年 | 25篇 |
2021年 | 90篇 |
2020年 | 56篇 |
2019年 | 90篇 |
2018年 | 136篇 |
2017年 | 77篇 |
2016年 | 67篇 |
2015年 | 66篇 |
2014年 | 135篇 |
2013年 | 213篇 |
2012年 | 252篇 |
2011年 | 242篇 |
2010年 | 138篇 |
2009年 | 128篇 |
2008年 | 239篇 |
2007年 | 270篇 |
2006年 | 252篇 |
2005年 | 267篇 |
2004年 | 214篇 |
2003年 | 224篇 |
2002年 | 194篇 |
2001年 | 58篇 |
2000年 | 47篇 |
1999年 | 63篇 |
1998年 | 34篇 |
1997年 | 35篇 |
1996年 | 36篇 |
1995年 | 35篇 |
1994年 | 38篇 |
1993年 | 36篇 |
1992年 | 35篇 |
1991年 | 33篇 |
1990年 | 28篇 |
1989年 | 30篇 |
1988年 | 27篇 |
1987年 | 23篇 |
1986年 | 22篇 |
1985年 | 25篇 |
1984年 | 20篇 |
1983年 | 22篇 |
1982年 | 18篇 |
1981年 | 15篇 |
1980年 | 16篇 |
1979年 | 21篇 |
1978年 | 20篇 |
1975年 | 15篇 |
1974年 | 20篇 |
1973年 | 15篇 |
1971年 | 15篇 |
排序方式: 共有4306条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
Hilary Eadon Marlene Rose Richard O'Neill Neil Leaver Magdi Yacoub 《Transplant international》1995,8(1):35-40
Pharmacokinetic profiles were obtained for 16 heart or lung recipients following the administration of identical doses of cyclosporin as oral solution and capsules on consecutive days. A comparison of pharmacokinetic parameters (AUC, Cmax, Cmin and tmax) showed that there were no significant differences between the two formulations except for the tmax, which was significantly longer for the capsules. The mean variation in day-to-day trough levels produced by the two different forms was 25.6%. A retrospective study was carried out of consecutive cyclosporin levels in patients at steady state on oral solution. The mean variation in day-to-day trough levels was 32.3%. This was not significantly different from the variation in consecutive trough levels seen in the oral solution/capsule comparison. This study shows that cyclosporin capsules can be substituted for oral solution without causing acute changes in cyclosporin blood levels, and that the pharmacokinetics of the two formulations are similar.This work was carried out in partial fulfillment of the requirements for the Master of Science Degree in Clinical Pharmacy, University of London 相似文献
5.
M Najimi D Jordan F Chigr J Champier N Kopp A Slama J Bertherat C Videau J Epelbaum 《Neuroscience》1991,40(2):321-335
Using in vitro quantitative autoradiography and [125I]Tyr0-D-Trp8SRIF 14 as radioligand, we characterized the detailed distribution of somatostatin binding sites in human hypothalamus of both infants and adults. Guanosine triphosphate pretreatment, before incubation, allowed us to detect higher [125I]Tyr0-D-Trp8SRIF 14 binding site densities in hypothalamic structures such as preoptic and anterior hypothalamic areas and ventromedial and dorsomedial nuclei. In contrast, guanosine triphosphate was without effect in the other hypothalamic regions. The regional effects of guanosine triphosphate pretreatment were not different in infant and adult hypothalamus. Scatchard analysis showed that in a guanosine triphosphate-sensitive region (preoptic area) and a guanosine triphosphate-insensitive area (infundibular nucleus), [125I]Tyr0-D-Trp8SRIF 14 bound to a single class of binding sites. Affinities were similar in both regions, not modified by guanosine triphosphate pretreatment and not different in the adult (1.5 +/- 1.2 nM vs 3.2 +/- 2.1 nM for preoptic area and infundibular nucleus, respectively) and infant (0.9 +/- 0.5 nM vs 2.4 +/- 1.7 nM for preoptic area and infundibular nucleus). [125I]Tyr0-D-Trp8SRIF 14 binding sites were widely distributed in the anterior, mediobasal and posterior hypothalamus. Somatostatin 28 was twice as potent as somatostatin 14 to displace [125I]Tyr0-D-Trp8SRIF 14 binding in the preoptic area and infundibular nucleus. However, IC50s were 30 times lower in the preoptic area as compared with the infundibular nucleus. In adult as well as in infant, high densities were found mainly in the diagonal band of Broca, preoptic area and infundibular nucleus. Intermediate densities were localized in the anterior hypothalamic area, ventromedial, dorsomedial and lateral mammillary nuclei. The dorsal hypothalamic area, the paraventricular and medial mammillary nuclei displayed low but measurable densities. The only marked difference in the distribution of [125I]Tyr0-D-Trp8SRIF 14 binding sites in adult vs infant was observed in the medial and tuberal nuclei where the concentrations were seven-fold higher in adult hypothalamus. 相似文献
6.
A Bodegas A Leenhardt B Cauchemez P Meslindrey P Menasche J F Leclercq P Coumel A Piwnica R Slama 《Revista espa?ola de cardiología》1991,44(6):400-407
Eighty two patients diagnosed of the Wolff-Parkinson-White syndrome (WPW) underwent operation for the surgical section of the Kent-His bundle. In these cases, posteroseptal localization (PS) occurred in 32, left lateral (LL) in 25, right lateral (RL) in six, anteroseptal (AS) in one, posteroseptal and left lateral in 14, right and left posteroseptal in two, anteroseptal and left lateral in one, and left lateral and right and left posteroseptal in one. All of the patients presented an invalidating clinical of palpitations and/or loss of consciousness, and episodes of atrial fibrillation and/or reciprocal rhythm were registered in all cases. The mean anterograde refractory period in the accessory pathways was 244 +/- 60 msec, and the shortest RR in atrial fibrillation was 190 +/- 36 msec. A mitral commissurotomy was carried out in 3 patients during surgery, mitral prostheses were implanted in two, a double aorto-coronary bypass was made in three and an interventricular communication was closed in one. After a follow-up of 36 +/- 18 months, the surgical section of the Kent bundle was found to be effective in 77 out 82 patients (94%). (In 70 out of 77 cases, both anterograde and retrograde conduction were totally abolished and in seven out of 77 obtunded. All patients were asymptomatic during the follow-up period). In 5 out of 82 patients, surgical treatment was ineffective all five showed a PS Kent-His and two presented a second Kent-His fascicle (LL).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
7.
8.
In vivo transfer and expression of a human epidermal growth factor gene accelerates wound repair. 总被引:18,自引:0,他引:18 下载免费PDF全文
C Andree W F Swain C P Page M D Macklin J Slama D Hatzis E Eriksson 《Proceedings of the National Academy of Sciences of the United States of America》1994,91(25):12188-12192
This report details the transfer of a human epidermal growth factor (hEGF) expression plasmid to porcine partial-thickness wound keratinocytes by particle-mediated DNA transfer (Accell). After gene transfer an external sealed fluid-filled wound chamber was used to protect the wound, provide containment of the exogenous DNA and expressed peptide, and permit sampling of the wound fluid. Analysis of wound fluid for hEGF and total protein, an indicator of reformation of the epithelial barrier, showed that wounds bombarded with the hEGF plasmid exhibited a 190-fold increase in EGF concentration and healed 20% (2.1 days) earlier than the controls. EGF concentrations in wound fluid persisted over the entire 10-day monitored period, decreasing from 200 pg/ml to 25 pg/ml over the first 5 days. Polymerase chain reaction results showed that plasmid DNA was present in the wound for at least 30 days. These findings demonstrate the possible utility of in vivo gene transfer to enhance epidermal repair. 相似文献
9.
This article analyzes hidden status among crack, powder cocaine, and heroin users and setters, in contrast to more accessible users/sellers. Several sampling strategies acquired 657 users (N=559) and sellers (N=98). Indicators of hidden status were those who (1) paid rent in full in the last 30 days, (2) used nonstreet drug procurement. (3) had legal jobs, and (4) earned $1,000 or more in legal income in the last 30 days. Nearly half had at least one indicator: approximately 16% of users/sellers had two to four indicators. In logistic regression analyses, those who had not panhandled in the last 30 days, those who had used powder cocaine in the last 30 days, and those never arrested were the most likely to have hidden status, whether the analysis predicted those having any indicators or those having two to four indicators. The four indicators begin to operationally define hidden status among users of cocaine and heroin. 相似文献
10.
A framework for evaluating image segmentation algorithms. 总被引:4,自引:0,他引:4
Jayaram K Udupa Vicki R Leblanc Ying Zhuge Celina Imielinska Hilary Schmidt Leanne M Currie Bruce E Hirsch James Woodburn 《Computerized medical imaging and graphics》2006,30(2):75-87
The purpose of this paper is to describe a framework for evaluating image segmentation algorithms. Image segmentation consists of object recognition and delineation. For evaluating segmentation methods, three factors-precision (reliability), accuracy (validity), and efficiency (viability)-need to be considered for both recognition and delineation. To assess precision, we need to choose a figure of merit, repeat segmentation considering all sources of variation, and determine variations in figure of merit via statistical analysis. It is impossible usually to establish true segmentation. Hence, to assess accuracy, we need to choose a surrogate of true segmentation and proceed as for precision. In determining accuracy, it may be important to consider different 'landmark' areas of the structure to be segmented depending on the application. To assess efficiency, both the computational and the user time required for algorithm training and for algorithm execution should be measured and analyzed. Precision, accuracy, and efficiency factors have an influence on one another. It is difficult to improve one factor without affecting others. Segmentation methods must be compared based on all three factors, as illustrated in an example wherein two methods are compared in a particular application domain. The weight given to each factor depends on application. 相似文献