全文获取类型
收费全文 | 3063篇 |
免费 | 271篇 |
出版年
2023年 | 23篇 |
2022年 | 50篇 |
2021年 | 73篇 |
2020年 | 58篇 |
2019年 | 72篇 |
2018年 | 109篇 |
2017年 | 96篇 |
2016年 | 123篇 |
2015年 | 140篇 |
2014年 | 172篇 |
2013年 | 185篇 |
2012年 | 208篇 |
2011年 | 250篇 |
2010年 | 163篇 |
2009年 | 141篇 |
2008年 | 149篇 |
2007年 | 138篇 |
2006年 | 153篇 |
2005年 | 110篇 |
2004年 | 112篇 |
2003年 | 101篇 |
2002年 | 85篇 |
2001年 | 70篇 |
2000年 | 78篇 |
1999年 | 59篇 |
1998年 | 29篇 |
1997年 | 29篇 |
1996年 | 35篇 |
1995年 | 23篇 |
1994年 | 14篇 |
1993年 | 12篇 |
1992年 | 31篇 |
1991年 | 23篇 |
1990年 | 30篇 |
1989年 | 13篇 |
1988年 | 14篇 |
1987年 | 19篇 |
1986年 | 10篇 |
1985年 | 13篇 |
1984年 | 6篇 |
1983年 | 14篇 |
1982年 | 14篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1972年 | 5篇 |
1971年 | 9篇 |
1970年 | 7篇 |
排序方式: 共有3334条查询结果,搜索用时 234 毫秒
1.
The relations between the saccus lacrimalis and different portions of the musculus orbicularis oculi were studied in orbital regions of human fetuses sectioned into numbered series. No insertions of the pars lacrimalis or Horner's muscle on the saccus were found. These muscular fibres pass along the dorsal wall of the saccus and are separated from it by the reflex tendon of the ligamentum palpebrale mediale. The only muscular fibres that insert on the saccus are those that approach the anterior face of the saccus and the fornix. The fibres that insert on the anterior face proceed from the deep bundles of the pars preseptalis of the lower eyelids, and those that insert on the fornix derive from the deep bundles of the pars preseptalis of the upper eyelid. 相似文献
2.
Carlos Rico José Luis Rico Noelia Muñoz Beatriz Gómez Iñaki Tejero 《Engineering in Life Science》2011,11(5):476-481
The effect of mixing on biogas production of a 1.5‐m3 pilot continuous stirred tank reactor (CSTR) processing screened dairy manure was evaluated. Mixing was carried out by recirculation of reactor content with a mono pump. The experiment was conducted at a controlled temperature of 37±1°C and hydraulic retention times (HRTs) of 20 and 10 days. The effect of continuous and intermittent operation of the recirculation pump on biogas production was studied. At 10 days of HRT, the results showed a minimal influence of recirculation rate on biogas production and that continuous recirculation did not improve reactor performance. At 20 days of HRT, the recirculation rate did not affect reactor performance. Combination of low solid content in feed animal slurry and long HRTs results in minimal mixing requirements for anaerobic digestion. 相似文献
3.
The peptidic sequence (Sarcosine-1-Isoleucine-8)-Angiotensin II has been demonstrated to be an in vitro specific and competitive antagonist of the Angiotensin II action. The present results show it to be a competitive antagonist also in vivo since pA2 values are similar, always reaches a 100% response on increasing the Angiotensin II dose, and when relating log (DR-1) and log dose of agonist, the slope is very near to one (0.925). 相似文献
4.
5.
Manjón A Iborra JL Gómez JL Gómez E Bastida J Bódalo A 《Biotechnology and bioengineering》1987,30(4):491-497
A design equation is presented for packed-bed reactors containing immobilized enzymes in spherical porous particles with internal diffusion effects and obeying reversible one-intermediate Michaelis-Menten kinetics. The equation is also able to explain irreversible and competitive product inhibition kinetics. It allows the axial substrate profiles to be calculated and the dependence of the effectiveness factor along the reactor length to be continuously evaluated. The design equation was applied to explain the behavior of naringinase immobilized in Glycophase-coated porous glass operating in a packed-bed reactor and hydrolyzing both p-nitrophenyl-alpha-L-rhamnoside and naringin. The theoretically predicted results were found to fit well with experimentally measured values. 相似文献
6.
Pablo Rodriguez-Palenzuela Joaquin Royo Luis Gómez Rosa Sánchez-Monge Gabriel Salcedo José Luis Molina-Cano Francisco Garcia-Olmedo Pilar Carbonero 《Molecular & general genetics : MGG》1989,219(3):474-479
Summary A cDNA encoding trypsin inhibitor CMe from barley endosperm has been cloned and characterized. The longest open reading frame of the cloned cDNA codes for a typical signal peptide of 24 residues followed by a sequence which is identical to the known amino acid sequence of the inhibitor, except for an Ile/Leu substitution at position 59. Southern blot analysis of wheat-barley addition lines has shown that chromosome 3H of barley carries the gene for CMe. This protein is present at less than 2%–3% of the wild-type amount in the mature endosperm of the mutant Risø 1508 with respect to Bomi barley, from which it has been derived, and the corresponding steady state levels of the CMe mRNA are about I%. One or two copies of the CMe gene (synonym Itc1) per haploid genome have been estimated both in the wild type and in the mutant, and DNA restriction patterns are identical in both stocks, so neither a change in copy number nor a major rearrangement of the structural gene account for the markedly decreased expression. The mutation at the lys 3a locus in Risø 1508 has been previously mapped in chromosome 7 (synonym 5H). A single dose of the wild-type allele at this locus (Lys 3a) restores the expression of gene CMe (allele CMe-1) in chromosome 3H to normal levels. 相似文献
7.
Summary The effect of glucose and ammonium sulfate concentration on the kinetics of lactic acid formation by a heterogeneous mixed culture was evaluated by the sole product formation using the Gompertz model, which can be used to define culture media composition taking into account product accumulation and acidification rate constant. A compromise between ionic inhibition and nitrogen limitation was found by using ammonium sulfate as nitrogen source. The sugar tolerance was similar to that in exenic cultures. 相似文献
8.
9.
Summary Various tissues of common winkles,Littorina littorea (L.), experimentally exposed to cadmium (Cd) chloride were examined using light and electron microscopy and their elemental
composition determined by X-ray microanalysis and histochemistry. Membrane granules in gill epithelial cells with paddle cilia
contain carbonates, phosphates and sulphides associated with different cations in different types of granules. Traces of Cd
have been found only in those granules containing sulphur and iron. Nephrocytes also contain small amounts of this metal in
the cytoplasm of excretory cells. X-ray microanalysis reveals that concretions of basophilic cells are minor sites for Cd
sequestration while BTAN-ASSG stain for unbound Cd indicates that most of the Cd is located within the lysosomes of digestive
cells in association with proteins. Low amounts of the metal have been evidenced in the granules of epithelial mantle cells
rich in sulphur. The results also indicate that hemocytes contain granules of calcium phosphate and iron sulphide. Cd is also
associated to sulphur rather than to phosphate. These hemocytes may act as Cd carrier from gills to kidney and digestive gland.
A hypothetical pathway for Cd accumulation and detoxification is suggested. 相似文献
10.