全文获取类型
收费全文 | 302篇 |
免费 | 61篇 |
出版年
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2016年 | 4篇 |
2015年 | 10篇 |
2014年 | 9篇 |
2013年 | 10篇 |
2012年 | 13篇 |
2011年 | 12篇 |
2010年 | 10篇 |
2009年 | 4篇 |
2008年 | 8篇 |
2007年 | 10篇 |
2006年 | 13篇 |
2005年 | 11篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 10篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 12篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 10篇 |
1986年 | 10篇 |
1985年 | 8篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 18篇 |
1974年 | 17篇 |
1973年 | 11篇 |
1972年 | 9篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 5篇 |
1966年 | 2篇 |
排序方式: 共有363条查询结果,搜索用时 15 毫秒
121.
122.
Development and characterization of highly polymorphic long TC repeat microsatellite markers for genetic analysis of peanut 总被引:4,自引:0,他引:4
Selma E Macedo Márcio C Moretzsohn Soraya C M Leal-Bertioli Dione MT Alves Ediene G Gouvea Vania CR Azevedo David J Bertioli 《BMC research notes》2012,5(1):1-10
Background
The immune system has paradoxical roles during cancer development and the prognostic significance of immune modulating factors is controversial. The aim of this study was to determine the expression of cyclooxygenase 2 (COX-2), transforming growth factor-beta (TGF- beta), interleukin-10 (IL-10) and their prognostic significance in breast cancers. Ki67 was included as a measure of growth fraction of tumor cells.Methods
On immunohistochemical stained slides from 38 breast cancer patients, we performed digital video analysis of tumor cell areas and adjacent tumor stromal areas from the primary tumors and their corresponding lymph node metastases. COX-2 was recorded as graded staining intensity.Results
The expression of TGF-beta, IL-10 and Ki67 were recorded in tumor cell areas and adjacent tumor stromal areas. In both primary tumors and metastases, the expression of COX-2 was higher in the tumor stromal areas than in the tumor cell areas (both P < 0.001). High stromal staining intensity in the primary tumors was associated with a 3.9 (95% CI 1.1-14.2) times higher risk of death compared to the low staining group (P = 0.036). The expression of TGF-beta was highest in the tumor cell areas of both primary tumors and metastases (both P < 0.001). High stromal expression of TGF-beta was associated with increased mortality. For IL-10, the stromal expression was highest in the primary tumors (P < 0.001), whereas in the metastases the expression was highest in tumor cell areas (P < 0.001). High IL-10 expression in tumor- and stromal cell areas of primary tumors predicted mortality. Ki67 was higher expressed in tumor stromal areas of the metastases, and in tumor cell areas of the primary tumors (P < 0.001). Ki67 expression in tumor cell areas and stromal areas of the metastases was independently associated with breast cancer mortality.Conclusions
Stromal expression of COX-2, TGF-beta and Ki67 may facilitate tumor progression in breast cancer. 相似文献123.
Debra S Harris Thomas Everhart Peyton Jacob III Emil Lin John E Mendelson Reese T Jones 《BMC clinical pharmacology》2009,9(1):13-18
Background
The selective MAO-B inhibitor selegiline has been evaluated in clinical trials as a potential medication for the treatment of cocaine dependence. This study evaluated the safety of and pharmacologic interactions between 7 days of transdermal selegiline dosed with patches (Selegiline Transdermal System, STS) that deliver 6 mg/24 hours and 2.5 mg/kg of cocaine administered over 4 hours. 相似文献124.
Background
There is a frequent need to obtain sets of functionally equivalent homologous proteins (FEPs) from different species. While it is usually the case that orthology implies functional equivalence, this is not always true; therefore datasets of orthologous proteins are not appropriate. The information relevant to extracting FEPs is contained in databanks such as UniProtKB/Swiss-Prot and a manual analysis of these data allow FEPs to be extracted on a one-off basis. However there has been no resource allowing the easy, automatic extraction of groups of FEPs – for example, all instances of protein C. 相似文献125.
126.
Bacillus subtilis 5:7, a derivative of macrofiber-producing strain FJ7, carries the lacZ reporter gene within Tn917 at an unknown location in the host genome. Expression of the host gene carrying lacZ within colonies of 5:7 was observed by examining growth under different conditions in the presence of 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal). At a high plating density small colonies arose that expressed the host gene early and throughout the colony, whereas at a low density large colonies were produced that expressed the host gene late in development and only in cells forming a ring pattern close to the colony periphery. A highly regulated spatial and temporal gene expression pattern was observed in growth from cross-streaks, suggesting that gene expression is responsive to concentration gradient fields established by neighboring growth. Colonies cultured on agar blocks revealed that expression was governed by depletion of a medium component and also by the geometry of the substrate upon which the colonies grew. At least three factors influenced the control of expression: (i) the concentration of a diffusible component of the medium exhausted by cell growth, (ii) a spatial-temporal factor related to growth within the colony, and (iii) the geometry of the growth substrate. 相似文献
127.
P Skolnick M M Schweri S M Paul J V Martin R L Wagner W B Mendelson 《Life sciences》1983,32(21):2439-2445
Intravenous administration of 3-carboethoxy-beta-carboline (beta-CCE, 10 mg/kg) to rats resulted in multiple bursts of rhythmic waves (2-4 second duration, 5-7 Hz) with amplitudes of 100-250 microV. Pretreatment of animals with the benzodiazepine receptor antagonists CGS 8216 prevented the electroencephalographic seizures elicited by beta-CCE. This dose of CGS 8216 did not produce any electroencephalographic abnormalities when administered alone. These observations suggest that the electroencephalographic seizures elicited by beta-CCE are mediated via an interaction with benzodiazepine receptors. An in vitro study of the rate of degradation of beta-CCE and 3-carbomethoxy-beta-carboline (beta-CCM) in rat plasma demonstrated that the rate of degradation of the former compound was three times more rapid than the latter. These observations, taken together with previous studies demonstrating that parenteral administration of beta-CCM elicits tonic and clonic seizures, suggests that pharmacokinetic factors may be involved in defining the pharmacologic profile of beta-carboline-3-carboxylic acid esters. 相似文献
128.
Morphological and genetic characterization of a bacteriophage-resistant Bacillus subtilis macrofiber-producing strain. 总被引:2,自引:1,他引:1
下载免费PDF全文
![点击此处可从《Journal of bacteriology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bacillus subtilis C6 phi R4 is an SPO1-resistant derivative of strain C6D, a left-hand macrofiber-producing strain described previously (N. H. Mendelson, Proc. Natl. Acad. Sci. U.S.A. 75:2478-2482, 1978). In addition to the phage resistance property, strain C6 phi R4 differs from its parent in macrofiber organization and formation of aggregates in liquid shake cultures. The phage resistance mutation was located in the gtaC gene. The macrofiber organization and aggregation phenotypes also appear to be controlled by the gtaC locus. Strains constructed by introduction of the gtaC mutation into C6D appear to be identical to the original C6 phi R4 strain in all phenotypic properties. In contrast, other constructs carrying either gtaA or gtaB that are resistant to SPO1 do not display the characteristic C6 phi R4 morphological phenotypes. 相似文献
129.
Cross-helix separation of tropomyosin molecules in acto-tropomyosin as determined by neutron scattering.
下载免费PDF全文
![点击此处可从《Biophysical journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The cross-helix separation of Tm molecules in acto-tropomyosin has been determined using neutron scattering. Deuterated Dictyostelium discoideum actin was density matched in a 93% D2O buffer so that effectively only the protonated tropomyosin was "visible" to neutrons. Analysis of the solution scattering pattern in the region of the first oscillation yielded a value for the cross-helix separation of 7.9 +/- 0.3 nm. The implications of this value for the mechanism of the regulation of muscle contraction are discussed in light of recent results by others. 相似文献
130.