全文获取类型
收费全文 | 12352篇 |
免费 | 539篇 |
国内免费 | 3篇 |
出版年
2023年 | 71篇 |
2022年 | 72篇 |
2021年 | 136篇 |
2020年 | 105篇 |
2019年 | 121篇 |
2018年 | 327篇 |
2017年 | 282篇 |
2016年 | 349篇 |
2015年 | 328篇 |
2014年 | 458篇 |
2013年 | 711篇 |
2012年 | 920篇 |
2011年 | 1122篇 |
2010年 | 649篇 |
2009年 | 318篇 |
2008年 | 648篇 |
2007年 | 613篇 |
2006年 | 544篇 |
2005年 | 446篇 |
2004年 | 369篇 |
2003年 | 349篇 |
2002年 | 280篇 |
2001年 | 172篇 |
2000年 | 285篇 |
1999年 | 216篇 |
1998年 | 129篇 |
1997年 | 73篇 |
1996年 | 75篇 |
1995年 | 85篇 |
1994年 | 67篇 |
1992年 | 108篇 |
1991年 | 126篇 |
1990年 | 73篇 |
1989年 | 90篇 |
1988年 | 89篇 |
1987年 | 89篇 |
1985年 | 115篇 |
1984年 | 97篇 |
1983年 | 92篇 |
1982年 | 92篇 |
1981年 | 79篇 |
1980年 | 80篇 |
1979年 | 90篇 |
1978年 | 71篇 |
1977年 | 77篇 |
1976年 | 78篇 |
1975年 | 81篇 |
1974年 | 75篇 |
1972年 | 69篇 |
1969年 | 64篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
91.
92.
Summary Complex carbohydrates in secretory granules and at the apical cell surface of mouse gastric mucoid cells were studied during embryogenesis and in the early postnatal period by various cytochemical methods; the periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) and tannic acid-uranyl acetate (TA-UA) procedures made neutral mucosubstances (NMS) visible, whereas the hexose residues of glycoconjugates were identified using WGA-, RCA II- and ConA-ferritin. The glycocalyx was stained with ruthenium red (RR). During differentiation of the embryonic mucoid cells the number of secretory granules increased in parallel to the increase in their carbohydrate component. NMS-stainable parts in secretory granules also had binding sites for the conjugates RCA II- and WGA-ferritin, but the binding of ConA could not be identified. The increasing quantity of NMS in secretory granules was correlated with the increased amount of PA-TCH-SP and TA-UA positive substances in the apical glycocalyx only in 14- and 18-day-old embryos. The observed uniform affinity for RR and lectin conjugates in all analysed developmental stages remains to be explained. 相似文献
93.
Dr. Radivoj Krstić 《Cell and tissue research》1985,241(3):677-681
Summary Autophagosome formation in rat and gerbil pinealocytes is described. It starts with the setting up of a tubular acid phosphatase-rich cisterna which gradually wraps around cytoplasmic areas to be catabolized. In light of obtained findings, it seems that the autophagosome formation in pinealocytes is a type of lysosome wrapping mechanism. 相似文献
94.
Histochemical demonstration of calcium ions in the respiratory part of the rabbit lungs has revealed that the greatest amount of the reaction granules is localized in type II alveolocytes. "Calcium packs" have been discovered, on the basis of which osmiophilic laminar bodies are formed. Cooling of the body entails an increase in the number of osmiophilic laminar bodies with calcium oxalate granules in type II alveolocytes. 相似文献
95.
Formation of protoplasts and their reversion were followed in 7 strains of brevibacteria. The formation of protoplasts and
their reversion differed both between various species of brevibacteria and between various mutant strains of the same species. 相似文献
96.
Reversibility of the respiration-deficient locuspet23 and auxotrophic locuslys2 was followed in the standard (RAD1) and UV sensitive (rad1–2) strains ofSaccharomyces cerevisiae, both after identical doses of UV radiation and at identical survival. When comparing the reversibility after the treatment
with identical doses of UV radiation a much higher reversibility of both loci in strainrad1–2 could be detected. When comparing the reversibility of the loci in question at identical survival of both strains it could
be found that the reversibility of thepet23 locus is again much higher in strainrad1–2, whereas the reversibility of thelys2 locus is roughly identical in the two strains. Thus, the function of geneRAD1 in repair processes is apparently associated with the “error-free” repair, both at low and high doses of ultraviolet radiation. 相似文献
97.
Glucose inhibits the inducible synthesis of β-D-glucosidase inStreptomyces granaticolor. Neither cAMP nor cGMP influence the inhibitory effect of glucose. Glucose also inhibits the inducible synthesis of the cellobiose
uptake system but has no effect on its activity. This may be the mechanism underlying glucose inhibition of induction of β-D-glucosidase inS.granaticolor. 相似文献
98.
99.
M. Kučera 《Journal of invertebrate pathology》1984,43(2):190-196
Gel permeation, preparative isoelectric focusing, and affinity chromatography were used to purify three inhibitors of proteolytic activity from perchloric acid extracts of last instar Galleria mellonella larvae. Electrofocusing experiments revealed three isoinhibitors with different isoelectric points: inhibitor I-1 with p1 of pH 5.6, inhibitor I-2, pH 7.7, and inhibitor I-3 (of small inhibitory activity), pH 8.6. By affinity chromatography on trypsin-Sepharose 4B the I-1 was purified 9.7 ×, but 71.1% of inhibitory activity was lost. Molecular mass of the inhibitory complex was 12,600 Da. I-1 and I-2 are relatively stable to heat at several pHs with minor stability at pH 10. I-1 and I-2 inhibit serine proteases about 2.5 times as much as sulfhydryl proteases. In the same ratio protease P-1 and protease P-2 from Metarhizium anisopliae are inhibited. 相似文献
100.
I D Volotovski? L A Baranova L M She?ko A V Levko S V Konev 《Molekuliarnaia biologiia》1984,18(4):1053-1059
The binding of cGMP by structural components of bovine rod outer segments was studied. The discs and plasma membranes were shown to contain two types of the specific binding sites for cGMP which are distinct from cyclic GMP phosphodiesterase. The sites have a "high" and "low" (Kd = 0.1 divided by 0.35 and 1.5 divided by 2.0 X 10(-6) M respectively) affinity for cGMP. They belong to membraneous integral proteins presumably associated with phospholipids. Their affinity for cGMP is controlled by GTP and calmodulin. 相似文献