全文获取类型
收费全文 | 17403篇 |
免费 | 1305篇 |
国内免费 | 115篇 |
出版年
2023年 | 150篇 |
2022年 | 319篇 |
2021年 | 618篇 |
2020年 | 411篇 |
2019年 | 539篇 |
2018年 | 627篇 |
2017年 | 539篇 |
2016年 | 734篇 |
2015年 | 992篇 |
2014年 | 1087篇 |
2013年 | 1272篇 |
2012年 | 1417篇 |
2011年 | 1249篇 |
2010年 | 809篇 |
2009年 | 684篇 |
2008年 | 846篇 |
2007年 | 802篇 |
2006年 | 738篇 |
2005年 | 668篇 |
2004年 | 634篇 |
2003年 | 595篇 |
2002年 | 517篇 |
2001年 | 319篇 |
2000年 | 273篇 |
1999年 | 250篇 |
1998年 | 128篇 |
1997年 | 113篇 |
1996年 | 88篇 |
1995年 | 75篇 |
1994年 | 65篇 |
1993年 | 65篇 |
1992年 | 114篇 |
1991年 | 84篇 |
1990年 | 68篇 |
1989年 | 81篇 |
1988年 | 69篇 |
1987年 | 80篇 |
1986年 | 59篇 |
1985年 | 65篇 |
1984年 | 61篇 |
1983年 | 38篇 |
1982年 | 37篇 |
1981年 | 28篇 |
1980年 | 27篇 |
1979年 | 50篇 |
1978年 | 26篇 |
1976年 | 28篇 |
1975年 | 34篇 |
1974年 | 29篇 |
1973年 | 37篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Vigh B. Vigh-Teichmann I. Manzano e Silva M. J. van den Pol A. N. 《Cell and tissue research》1983,230(3):615-630
Cell and Tissue Research - Cerebrospinal fluid (CSF)-contacting neurons were studied by means of electron microscopy in the spinal cord and/or terminal ventricle of the ray, Raja clavata... 相似文献
92.
93.
H. Steffen M. Da Prada A. Pletscher 《Biochimica et Biophysica Acta (BBA)/General Subjects》1974,338(2):561-571
THe quantum yield, the life time and the degree of polarization of the fluorescence of intact chromaffin granules isolated from bovine adrenal medulla were compared to those of catecholamines solutions and catecholamine/ATP mixtures. Rising concentrations of catecholamines in aqueous solutions exhibited increasing quenching and decreasing life times indicating that the quenching was collision induced. Similar effects occurred in mixtures of catecholamines with ATP and Ca2+ showing that the nucleotide did not remarkedly hinder the mobility of the catechol group. In suspensions of whole granules stron quenching and shortening of life time was observed compared with solutions of disrupted granules. Fluorescence yield and life time were decreased by about the same factor suggesting that storage of the amines was not correlated with a major immobilization of the catechol group. The degree of polarization of intact granules was higher than that of solutions of catecholamines alone, but similar to catecholamine/ATP mixtures with concentrations corresponding to those found in the granules. This indicates an interaction of catecholamines with ATP in the granules. The results are in agreement with a storage model for catecholamines in the chromaffin granules of adrenal medulla in which catecholamines are bound to ATP, but in a non-rigid way. 相似文献
94.
Immunologic and clinical improvement of progressive coccidioidomycosis following administration of transfer factor 总被引:8,自引:0,他引:8
Three patients with progressive coccidioidomycosis were given preparations of transfer factor (TF). Adverse reactions to TF were minimal. Following TF administration two of these patients had prolonged clinical remissions in their coccidioidal disease. Cellular immune responses were sequentially evaluated by coccidioidininduced delayed-type skin tests, lymphocyte blast transformation and macrophage inhibition factor production (MIF). These three patients each exhibited different cellular immune patterns before and after TF administration. Two patients converted their coccidioidin skin tests, and one converted lymphocyte transformation response to coccidioidin. Also, TF apparently favorably affected the MIF response in all three patients. 相似文献
95.
96.
97.
Summary The fluorescent antibody technique was used to study antigenic relationships betweenParacoccidioides loboi and other pathogenic fungi. The findings suggest thatP. loboi is more closely related antigenically to certainP. brasiliensis strains than to others and that it has antigens in common with the yeast form ofHistoplasma capsulatum, H. duboisii, Blastomyces dermatitidis, Candida albicans and also the mycelial form ofCoccidioides immitis. Serum globulins from 3 cases of keloidal blastomycosis were labelled with fluorescein isothiocyanate. These conjugates showed slight or no reactivity withP. loboi, the yeast forms ofP. brasiliensis, H. capsulatum, H. duboisii andB. dermatitidis, However, they stained brightlyC. albicans, serotypes A and B, the tissue form ofC. immitis and the yeast form ofSporotrichum schenckii. Adsorption of these reagents withC. albicans eliminated all staining except that forS. schenckii. These patients had no history of clinical sporotrichosis.Deceased. Last address: Fundacão Gonçalo Moniz, Salvador, Bahia, Brazil. Requests for reprints should be sent to Dr.William Kaplan.Dr.Miranda is in private practice in Rio de Janeiro, Brazil. 相似文献
98.
99.
P. De Silva 《CMAJ》1966,94(9):449-450
100.
Of four species studied, tolerance of extreme temperatures in greatest in Spirorbis pagenstecheri (which extends highest on the shore) and least in S. corallinae (which always occurs immersed in water). The latter species breeds between May and August, the other three from May to October. S. borealis liberates its larvae mainly at the moon's quarters, but this fortnightly rhythm is less obvious in S. corallinae and not found in the other two species. S. corallinae differs from S. borealis in being slower to re-emerge after disturbance and in having a lesser breeding size, maximum size and life span. Growth in the laboratory is slower in S. tridentatus than in the other species. Growth of S. borealis under natural conditions is much faster in summer than in winter. 相似文献