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11.
CM van der Loos 《Biotechnic & histochemistry》2013,88(3):141-154
Three fixation issues related to immunostaining are discussed here: 1) Generally, a tissue block is fixed, then embedded and sectioned (pre-fixation). The type of fixative applied, crosslinking or coagulating, has an impact on selecting an epitope retrieval method. Individual antigens have a fixation–retrieval characteristic. 2) A long fixation time, especially with crosslinking fixatives, may compromise the result of immunostaining. This negative effect varies among different antigens and can be partially restored by applying a more sensitive/efficient detection system such as tyramide amplification. 3) Sections cut from a fresh frozen tissue block usually are acetone fixed (post-fixation). This was accepted as the “gold standard” for a long time. Post-fixation, however, may have serious consequences for preservation of small peptides leaking from the cut open cells, whereas this is not the case with pre-fixed intact cells. Consequently, the concept of an acetone post-fixed cryostat tissue section as “gold standard” no longer exists and a more appropriate use of the terms immunohistochemistry and immunocytochemistry therefore seems justified. For many antibodies, it is not known whether a formalin fixed, paraffin embedded tissue specimen is appropriate. Suggestions are made for creating a positive control cell block for testing such antibodies. 相似文献
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Abstract Opportunistic sightings and strandings of Caperea marginata (n=196) from the vicinity of Australia and New Zealand (1884 to early 2007) were used to relate geographic and temporal patterns to oceanographic and broad-scale climatic variability. Records were not uniformly distributed along the coast and more (69%) were from Australia than New Zealand. Seven coastal whale ‘hotspots’ were identified which accounted for 61% of records with locality data. Half of the hotspot records were from southeast (37) and northwest (20) Tasmania—others each had 9–15 events. Upwelling and/or high zooplankton abundance has been documented near all whale hotspots. Records of C. marginata occurred in all months, with 75% in spring and summer. Inter-annual variability showed broad agreement between increased whale records (usually in spring/summer) and strongly positive ‘Niño 3.4’ during 1980–1995 but not thereafter. Coastal upwelling and productivity increase during climatic phenomena such as El Niño and are likely to be quickly beneficial to plankton-feeding whales such as C. marginata. 相似文献
13.
Matthew R. Scholfield Crystal M. Vander Zanden Megan Carter P. Shing Ho 《Protein science : a publication of the Protein Society》2013,22(2):139-152
The concept of the halogen bond (or X‐bond) has become recognized as contributing significantly to the specificity in recognition of a large class of halogenated compounds. The interaction is most easily understood as primarily an electrostatically driven molecular interaction, where an electropositive crown, or σ‐hole, serves as a Lewis acid to attract a variety of electron‐rich Lewis bases, in analogous fashion to a classic hydrogen bonding (H‐bond) interaction. We present here a broad overview of X‐bonds from the perspective of a biologist who may not be familiar with this recently rediscovered class of interactions and, consequently, may be interested in how they can be applied as a highly directional and specific component of the molecular toolbox. This overview includes a discussion for where X‐bonds are found in biomolecular structures, and how their structure–energy relationships are studied experimentally and modeled computationally. In total, our understanding of these basic concepts will allow X‐bonds to be incorporated into strategies for the rational design of new halogenated inhibitors against biomolecular targets or toward molecular engineering of new biological‐based materials. 相似文献
14.
Henderson Christopher J. Stevens Tim Lee Shing Y. Gilby Ben L. Schlacher Thomas A. Connolly Rod M. Warnken Jan Maxwell Paul S. Olds Andrew D. 《Ecosystems》2019,22(6):1368-1380
Ecosystems - Animals are central to numerous ecological processes that shape the structure and function of ecosystems. It follows that species that are strongly linked to specific functions can... 相似文献
15.
Lijuan Sun Sanjay Verma Navin Michael Siew Pang Chan Jianhua Yan Suresh Anand Sadananthan Stefan G. Camps Hui Jen Goh Priya Govindharajulu John Totman David Townsend Julian Pak‐Nam Goh Lei Sun Bernhard Otto Boehm Su Chi Lim Siew Kwan Sze Christiani Jeyakumar Henry Houchun Harry Hu S. Sendhil Velan Melvin Khee‐Shing Leow 《Obesity (Silver Spring, Md.)》2019,27(9):1434-1442
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Suresh Anand Sadananthan Mya Thway Tint Navin Michael Izzuddin M. Aris See Ling Loy Kuan Jin Lee Lynette Pei‐Chi Shek Fabian Kok Peng Yap Kok Hian Tan Keith M. Godfrey Melvin Khee‐Shing Leow Yung Seng Lee Michael S. Kramer Peter D. Gluckman Yap Seng Chong Neerja Karnani Christiani Jeyakumar Henry Marielle Valerie Fortier S. Sendhil Velan 《Obesity (Silver Spring, Md.)》2019,27(3):470-478
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Compared with other SARS-related coronaviruses (SARSr-CoVs), SARS-CoV-2 possesses a unique furin cleavage site (FCS) in its spike. This has stimulated discussion pertaining to the origin of SARS-CoV-2 because the FCS has been observed to be under strong selective pressure in humans and confers the enhanced ability to infect some cell types and induce cell–cell fusion. Furthermore, scientists have demonstrated interest in studying novel cleavage sites by introducing them into SARSr-CoVs. We review what is known about the SARS-CoV-2 FCS in the context of its pathogenesis, origin, and how future wildlife coronavirus sampling may alter the interpretation of existing data. 相似文献
19.
G A Gao D X Zhu X Tao J Zheng A Scharfman G Lamblin Y W Shing K K Han 《The International journal of biochemistry》1989,21(4):391-399
1. Colony-stimulating factor (CSF-1) was isolated from a large volume of fresh normal human urine by 5 steps of purification and enrichment. 2. The purification factor is 100,000 fold and the purified compound exhibits a 2.16 x 10(7) U/mg of protein sp. act. 3. The isolated CSF-1 is a sialoglycoprotein with 41.5% of carbohydrate. The almost complete removal of this carbohydrate moiety (up to 91%) was achieved by incubation with trifluoromethane sulfonic acid. 4. The deglycosylated CSF-1 (DG-CSF-1) possesses an apparent Mr 38,000 compared to native CSF-1 with an initial Mr 57,000 (Goa et al., 1988). 5. The features of the interaction of radio-iodinated [125I]CSF-1 with single cell suspensions from various human tissues (bone marrow, spleen, blood, peritoneal cavity, alveolar lavage, lymph node and thymus), were studied. 6. The binding activity of peritoneal macrophages was the highest among the cells examined and erythrocytes, thymus and blood granulocytes showed no CSF-1 binding. 7. On incubation with [125I]CSF-1 at 0 degrees C, cellular binding of [125I]CSF-1 reached a stable maximum within 16 hr. This is in contrast to the association behaviour at higher temperature. 8. At 37 degrees C, cellular associated [125I]CSF-1 levels reached, within 90 min, an unstable maximum which was up to 10 times less than that occurring under the same conditions at 0 degree C. From the Scatchard plot analysis, we obtained the affinity constant and the number of receptor(s). 9. The binding site is sensitive to trypsin. 10. The receptor alone, (labelled by cross-linking to [125I]CSF-1 with di-succinylimidyl-suberate), is a polypeptide with an approx. Mr 110,000. 11. Our results showed that the receptor of CSF-1 is a tyrosin-kinase. 相似文献
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