全文获取类型
收费全文 | 223999篇 |
免费 | 14992篇 |
国内免费 | 45篇 |
出版年
2021年 | 1775篇 |
2018年 | 3125篇 |
2017年 | 3024篇 |
2016年 | 3671篇 |
2015年 | 3207篇 |
2014年 | 4439篇 |
2013年 | 6329篇 |
2012年 | 7546篇 |
2011年 | 8067篇 |
2010年 | 5726篇 |
2009年 | 4884篇 |
2008年 | 7202篇 |
2007年 | 7484篇 |
2006年 | 7183篇 |
2005年 | 6708篇 |
2004年 | 6849篇 |
2003年 | 6574篇 |
2002年 | 6528篇 |
2001年 | 9278篇 |
2000年 | 8962篇 |
1999年 | 6990篇 |
1998年 | 2125篇 |
1997年 | 1956篇 |
1996年 | 1820篇 |
1992年 | 5470篇 |
1991年 | 5680篇 |
1990年 | 5653篇 |
1989年 | 5623篇 |
1988年 | 5212篇 |
1987年 | 4863篇 |
1986年 | 4444篇 |
1985年 | 4679篇 |
1984年 | 3698篇 |
1983年 | 3026篇 |
1982年 | 2013篇 |
1981年 | 1722篇 |
1980年 | 1725篇 |
1979年 | 3340篇 |
1978年 | 2576篇 |
1977年 | 2376篇 |
1976年 | 2330篇 |
1975年 | 2826篇 |
1974年 | 3117篇 |
1973年 | 3084篇 |
1972年 | 2746篇 |
1971年 | 2605篇 |
1970年 | 2213篇 |
1969年 | 2160篇 |
1968年 | 2032篇 |
1967年 | 1798篇 |
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
211.
Naumova E. V. Vladimirov Yu. A. Beloussov L. V. Tuchin V. V. Volodyaev I. V. 《Biophysics》2021,66(5):764-778
Biophysics - This review is devoted to the methods for studying the ultraweak luminescence of biological objects; in addition to modern methods aimed at studies in the visible, near-infrared, and... 相似文献
212.
Glushakova A. M. Lysak L. V. Kachalkin A. V. Ivanova A. E. Umarova A. B. Abramyan I. A. Ezhelev Z. S. Maksimova I. A. 《Microbiology》2021,90(2):176-186
Microbiology - In a model experiment, the transformation of microbial complexes of cultivated saprotrophic bacteria and yeasts during freezing-thawing was studied in various natural substrates that... 相似文献
213.
Kaminsky V. V. Emelyanenko A. M. Aleshkin A. V. Emelyanenko K. A. Boinovich L. B. 《Microbiology》2021,90(5):643-646
Microbiology - The surface of the MA8 magnesium alloy, modified by laser treatment, was found to acquire superhydrophilic properties and high bactericidal activity against Escherichia coli K12... 相似文献
214.
Journal of Evolutionary Biochemistry and Physiology - A study of the effect of a seasonal decrease in ambient temperature on the composition of free amino acids and ninhydrin-positive secondary... 相似文献
215.
Baikenova M. B. Chereshnev V. A. Sokolova K. V. Gette I. F. Emelyanov V. V. Danilova I. G. 《Journal of Evolutionary Biochemistry and Physiology》2021,57(4):772-781
Journal of Evolutionary Biochemistry and Physiology - Due to a high occurrence of diabetes mellitus (DM) and its complications, insulin-positive cells detected in different organs are of great... 相似文献
216.
Kolomeyets N. L. Syslonova O. V. Smirnova S. L. Peshkin E. A. Roshchevskaya I. M. 《Journal of Evolutionary Biochemistry and Physiology》2021,57(6):1351-1362
Journal of Evolutionary Biochemistry and Physiology - Changes in bioelectrical impedance of the myocardium and liver were revealed in male Wistar rats chronically exposed to doxorubicin.... 相似文献
217.
N P Veselkin I V Batueva 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》1999,85(6):743-750
Glycine and GABA play the role of inhibitory transmitters in the lamprey spinal cord. The mechanisms of action of both amino acids to the membrane receptors producing the postsynaptic inhibition as well as role and mechanism of GABA action producing the presynaptic inhibition are considered in this paper. The data concerned with morphological substrates of both type inhibitions are discussed. 相似文献
218.
The management of chronic viral hepatitis C is evolving rapidly. Monotherapy with interferon, the accepted standard of treatment until recently, achieves only a modest sustained virological response rate of 15%. Combination treatment with alpha-2b interferon and ribavirin has been shown to increase sustained response rates to 40% in patients who have never been treated with interferon and to 50% in those who have relapsed following monotherapy with interferon. However, side effects, which have led to the discontinuation of combination treatment in a significant proportion of patients, must be carefully monitored. Treatment with interferon alpha-2b and ribavirin has now been approved in Canada, but the selection and monitoring of patients suitable for combination treatment requires special expertise. Although improvements in current therapeutic options may be possible with more frequent, higher doses or long-acting forms of interferon together with ribavirin, low sustained response rates (i.e., below 30%) for patients with hepatitis C virus genotype 1 emphasize the need for novel antiviral medications that will target the functional sites of the HCV genome. 相似文献
219.
Bacopa monniera Wettst. (BM, syn. Herpestis monniera L; Scrophulariaceae), is an Ayurvedic drug used as a rasayana. Its fresh juice was earlier reported to have significant antiulcerogenic activity. In continuation, methanolic extract of BM (BME) standardized to bacoside-A content (percentage-38.0 ± 0.9), when given in the dose of 10–50 mg/kg, twice daily for 5 days, showed dose-dependent anti-ulcerogenic on various gastric ulcer models induced by ethanol, aspirin, 2 h cold restraint stress and 4 h pylorus ligation. BME in the dose of 20 mg/kg, given for 10 days, twice daily showed healing effects against 50% acetic acid-induced gastric ulcers. Further work was done to investigate the possible mechanisms of its action by studying its effect on various mucosal offensive acid-pepsin secretion and defensive factors like mucin secretion, mucosal cell shedding, cell proliferation and antioxidant activity in rats. BME 20 mg/kg showed no effect on acid-pepsin secretion, increased mucin secretion, while it decreased cell shedding with no effect on cell proliferation. BME showed significant antioxidant effect per se and in stressed animals. Thus, the gastric prophylactic and curative effects of BME may be due to its predominant effect on mucosal defensive factors. 相似文献
220.
P Kischel L Stevens V Montel F Picquet Y Mounier 《Journal of applied physiology》2001,90(5):1825-1832
We examined the changes in functional properties of triceps brachii skinned fibers from monkeys flown aboard the BION 11 satellite for 14 days and after ground-based arm immobilization. The composition of myosin heavy chain (MHC) isoforms allowed the identification of pure fibers containing type I (slow) or type IIa (fast) MHC isoforms or hybrid fibers coexpressing predominantly slow (hybrid slow; HS) or fast (hybrid fast) MHC isoforms. The ratio of HS fibers to the whole slow population was higher after flight (28%) than in the control population (7%), and the number of fast fibers was increased (up to 86% in flight vs. 12% in control). Diameters and maximal tensions of slow fibers were decreased after flight. The tension-pCa curves of slow and fast fibers were modified, with a decrease in pCa threshold and an increase in steepness. The proper effect of microgravity was distinguishable from that of immobilization, which induced less marked slow-to-fast transitions (only 59% of fast fibers) and changed the tension-pCa relationships. 相似文献