全文获取类型
收费全文 | 566篇 |
免费 | 70篇 |
国内免费 | 2篇 |
出版年
2023年 | 8篇 |
2022年 | 12篇 |
2021年 | 23篇 |
2020年 | 12篇 |
2019年 | 17篇 |
2018年 | 28篇 |
2017年 | 27篇 |
2016年 | 29篇 |
2015年 | 22篇 |
2014年 | 38篇 |
2013年 | 40篇 |
2012年 | 26篇 |
2011年 | 61篇 |
2010年 | 33篇 |
2009年 | 19篇 |
2008年 | 28篇 |
2007年 | 24篇 |
2006年 | 30篇 |
2005年 | 16篇 |
2004年 | 14篇 |
2003年 | 9篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 9篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 6篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1974年 | 6篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 3篇 |
排序方式: 共有638条查询结果,搜索用时 0 毫秒
631.
632.
Somal Anjali Bhat Irfan A. Pandey Sriti Ansari Mohd Matin Indu B. Panda Bibhudatta S. K. Bharti Mukesh Kumar Chandra Vikash Saikumar G. Sharma G. Taru 《Molecular biology reports》2021,48(5):3913-3923
Molecular Biology Reports - The caprine mesenchymal stem cells (MSCs) derived from fetal adnexa are highly proliferative. These cells possess tri-lineage differentiation potential and express MSC... 相似文献
633.
O. Zethner Bashir M. Khan M. Ismail Chaudhry B. Bolet Sharfuddin Khan Habibullah Khan Hanif Gul L. Øgaard M. Zaman Gul Nawaz 《BioControl》1987,32(5):449-455
Agrotis segetum Schiff granulosis virus (AsGV) propagated in Denmark was supplied against naturally occurring cutworm populations (A. ipsilon and to a less extentA. segetum) in experimental field plots of tobacco, okra, potato and sugar beet in northern Pakistan. AsGV doses varied between 4 ×
107 and 4 × 1011 capsules per m2 plot, and no. of applications between 1 and 3.
One treatment with AsGV did not reduce cutworm damage significantly to tobacco seedlings and potato plants.
Two treatments with AsGV reduced cutworm damage significantly. In tobacco, reduction was 64–82%, in okra and potato 85% and
77% respectively. Damage in sugar beet was reduced 78%.
Three treatments with AsGV dis not reduce damage significantly better than two treatments.
AsGV and the chemical insecticides Tamaran and Dieldrin, andBacillus thuringiensis (Thuricide) were about equally effective, reducing damage by 85%, 79%, 87% and 69%, respectively. No difference was found
between the efficiency of highly purified AsGV to which activated charcoal was added and partially purified AsGV without charcoal.
相似文献
634.
A. S. M. Abdul Matin 《Entomologia Experimentalis et Applicata》1976,20(1):99-103
In an attempt to delay hatching without affecting their viability, the eggs ofLatheticus oryzae W. were subjected to cold treatment at 5° for varying periods and at different stages of their development. A small dose
of 0.5 krad of gamma radiation was also given at each of those temperature treatments. Most of the eggs hatched at 30° following
low-temperature exposures of 1 and 2 days. There was a significant decrease in hatch as the exposure period increased further
(P<0.05). An egg exposure to 5° also led to an increase in egg period and the increase was nearly equal to the period of cold
exposure. Radiation did not alter the situation. 相似文献
635.
Enes Elvin Gul Reda Abuelatta Sohaib Haseeb Mohammad Melhem Osama Al Amoudi 《Indian pacing and electrophysiology journal》2019,19(1):27-29
Venous revascularization is an approach used in patients with total venous occlusion requiring venous access for cardiac device lead placement. Several percutaneous approaches to venous revascularization have been proposed. For the first time, we describe the case of a 69-year-old male with total venous occlusion who was successfully revascularized using a ‘diathermy’ technique. 相似文献
636.
Miquel Nadal María J. Clemente-Moreno Alicia V. Perera-Castro Margalida Roig-Oliver Yusuke Onoda Javier Gulías Jaume Flexas 《Ecology letters》2023,26(4):549-562
In recent years, attempts have been made in linking pressure–volume parameters and the leaf economics spectrum to expand our knowledge of the interrelationships among leaf traits. We provide theoretical and empirical evidence for the coordination of the turgor loss point and associated traits with net CO2 assimilation (An) and leaf mass per area (LMA). We measured gas exchange, pressure–volume curves and leaf structure in 45 ferns and angiosperms, and explored the anatomical and chemical basis of the key traits. We propose that the coordination observed between mass-based An, capacitance and the turgor loss point (πtlp) emerges from their shared link with leaf density (one of the components of LMA) and, specially, leaf saturated water content (LSWC), which in turn relates to cell size and nitrogen and carbon content. Thus, considering the components of LMA and LSWC in ecophysiological studies can provide a broader perspective on leaf structure and function. 相似文献
637.
Ruchira Chatterjee Louise Lassalle Sheraz Gul Franklin D. Fuller Iris D. Young Mohamed Ibrahim Casper de Lichtenberg Mun Hon Cheah Athina Zouni Johannes Messinger Vittal K. Yachandra Jan Kern Junko Yano 《Physiologia plantarum》2019,166(1):60-72
In nature, an oxo‐bridged Mn4CaO5 cluster embedded in photosystem II (PSII), a membrane‐bound multi‐subunit pigment protein complex, catalyzes the water oxidation reaction that is driven by light‐induced charge separations in the reaction center of PSII. The Mn4CaO5 cluster accumulates four oxidizing equivalents to enable the four‐electron four‐proton catalysis of two water molecules to one dioxygen molecule and cycles through five intermediate S‐states, S0 – S4 in the Kok cycle. One important question related to the catalytic mechanism of the oxygen‐evolving complex (OEC) that remains is, whether structural isomers are present in some of the intermediate S‐states and if such equilibria are essential for the mechanism of the O‐O bond formation. Here we compare results from electron paramagnetic resonance (EPR) and X‐ray absorption spectroscopy (XAS) obtained at cryogenic temperatures for the S2 state of PSII with structural data collected of the S1, S2 and S3 states by serial crystallography at neutral pH (~6.5) using an X‐ray free electron laser at room temperature. While the cryogenic data show the presence of at least two structural forms of the S2 state, the room temperature crystallography data can be well‐described by just one S2 structure. We discuss the deviating results and outline experimental strategies for clarifying this mechanistically important question. 相似文献
638.