全文获取类型
收费全文 | 1234篇 |
免费 | 122篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 56篇 |
妇产科学 | 50篇 |
基础医学 | 161篇 |
口腔科学 | 102篇 |
临床医学 | 136篇 |
内科学 | 230篇 |
皮肤病学 | 17篇 |
神经病学 | 112篇 |
特种医学 | 126篇 |
外科学 | 132篇 |
综合类 | 14篇 |
一般理论 | 1篇 |
预防医学 | 116篇 |
眼科学 | 13篇 |
药学 | 61篇 |
肿瘤学 | 33篇 |
出版年
2021年 | 11篇 |
2019年 | 19篇 |
2018年 | 22篇 |
2016年 | 13篇 |
2015年 | 16篇 |
2014年 | 20篇 |
2013年 | 34篇 |
2012年 | 58篇 |
2011年 | 70篇 |
2010年 | 39篇 |
2009年 | 38篇 |
2008年 | 46篇 |
2007年 | 70篇 |
2006年 | 58篇 |
2005年 | 43篇 |
2004年 | 56篇 |
2003年 | 51篇 |
2002年 | 40篇 |
2001年 | 43篇 |
2000年 | 29篇 |
1999年 | 30篇 |
1998年 | 30篇 |
1997年 | 15篇 |
1996年 | 25篇 |
1995年 | 30篇 |
1994年 | 21篇 |
1993年 | 12篇 |
1992年 | 29篇 |
1991年 | 18篇 |
1990年 | 19篇 |
1989年 | 25篇 |
1988年 | 23篇 |
1987年 | 34篇 |
1986年 | 23篇 |
1985年 | 23篇 |
1984年 | 12篇 |
1983年 | 12篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 15篇 |
1979年 | 11篇 |
1978年 | 10篇 |
1976年 | 10篇 |
1974年 | 10篇 |
1973年 | 8篇 |
1971年 | 9篇 |
1970年 | 9篇 |
1968年 | 10篇 |
1967年 | 11篇 |
1966年 | 8篇 |
排序方式: 共有1366条查询结果,搜索用时 15 毫秒
1.
Wynn L. Walker Elliot M. Landaw Richard E. Dickerson David S. Goodsell 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(11):5634-5639
Three- and four-ring polyamides containing N-methylimidazole and N-methylpyrrole, and their hairpin-linked derivatives, bind side-by-side in the minor groove of DNA in a sequence-specific manner. The sequences recognized by side-by-side molecules are dependent on the pairings of the polyamide rings to the bases. In this study we report a mathematical model for estimating the free energies of binding for γ-aminobutyric acid-linked polyamides to 5- and 6-bp DNA sequences. The model parameters are calibrated by a least-squares fit to 35 experimental binding constants. The model performs well in cross-validation experiments and the parameters are consistent with previously proposed empirical rules of polyamide–DNA binding. We apply the model to the design of targeted polyamides, evaluating the ability of the proposed polyamides to bind to a DNA sequence of interest while minimizing binding to the remaining DNA sequences. 相似文献
2.
3.
A review of 179 autopsies was undertaken over a 1-year period to determine if clinically useful information was obtainable from coroners post mortems performed on patients referred from the A&E department. Fifty-six patients had undergone unsuccessful resuscitation. The leading causes of death were heart disease and trauma. Discrepancies between the diagnosis made during resuscitation and the cause of death found at autopsy were revealed especially in those dying from noncardiac causes. Iatrogenic trauma from resuscitation attempts occurred in a significant number of cases. It is suggested that review of selected Coroners post mortems should be part of departmental audit, with a view to improving clinical skills. 相似文献
4.
In a prospective, randomized, double-blind study, 49 patients underwent lumbar myelography using iotrol (24 patients) or metrizamide (25 patients). The diagnostic imaging adequacy of iotrol was comparable with that of metrizamide. After iotrol myelography, adverse reactions were fewer, less severe, and of shorter duration than were those following metrizamide myelography. Thirteen of 24 patients (54%) receiving iotrol reported some adverse reactions compared with 24 of 25 patients (96%) receiving metrizamide. Five moderate and one severe adverse reaction occurred in the group receiving iotrol. Fourteen moderate and eight severe adverse reactions occurred in the group receiving metrizamide. Thirty-eight patients underwent electroencephalography both before and after myelography (19 iotrol and 19 metrizamide). None of the EEGs obtained after iotrol myelography changed from baseline, while seven of the EEGs obtained after metrizamide myelography showed changes from baseline. Iotrol was judged superior to metrizamide as a contrast medium in this patient population. 相似文献
5.
6.
7.
8.
Anderson RA; Evans LW; Irvine DS; McIntyre MA; Groome NP; Riley SC 《Human reproduction (Oxford, England)》1998,13(12):3319-3325
Follistatin is a binding protein for the activin and inhibin family of
hormones, regulating their biological activity. In the male reproductive
tract, the interaction of these factors is likely to be involved in the
regulation of the proliferation of several cell types. We have investigated
the presence of follistatin and activin A in seminal plasma using specific
immunoassays and have localized follistatin and activin/inhibin subunits in
the adult human testis, prostate and seminal vesicle to establish their
likely sources. High concentrations of immunoreactive follistatin were
present in seminal plasma in normal men (mean 97.9 ng/ml; 1.43 ng/ml in
peripheral plasma) and were similar in men with oligo/azoospermia and
following vasectomy. Follistatin immunoreactivity was localized to both
Leydig and Sertoli cells of the testis, and to epithelial cells of the
prostate gland and seminal vesicle, which are likely to be the predominant
sources of the hormone in seminal plasma. Activin A was also present in
seminal plasma in normal men but was undetectable following vasectomy, thus
deriving from the testis. Consistent with this finding, the betaA-subunit
was immunolocalized in Sertoli and Leydig cells but was not present in
seminal vesicle or prostate gland. The functional significance of the high
concentrations of follistatin secreted into seminal plasma by the prostate
gland and/or seminal vesicle is uncertain, but they may regulate the
biological activity of testis-derived activin A and inhibin B.
相似文献
9.
10.
We have presented the case of a 32-year-old man who sustained blunt trauma to the chest in a motor vehicle accident. Plain roentgenograms showed a widened mediastinum and pneumomediastinum, and an esophagogram with water-soluble contrast material showed an esophageal laceration at the T-4 level. 相似文献