全文获取类型
收费全文 | 552篇 |
免费 | 41篇 |
专业分类
儿科学 | 20篇 |
妇产科学 | 12篇 |
基础医学 | 83篇 |
口腔科学 | 8篇 |
临床医学 | 40篇 |
内科学 | 60篇 |
皮肤病学 | 1篇 |
神经病学 | 71篇 |
特种医学 | 13篇 |
外科学 | 41篇 |
综合类 | 7篇 |
预防医学 | 106篇 |
眼科学 | 17篇 |
药学 | 17篇 |
肿瘤学 | 97篇 |
出版年
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2016年 | 3篇 |
2015年 | 10篇 |
2014年 | 10篇 |
2013年 | 15篇 |
2012年 | 22篇 |
2011年 | 44篇 |
2010年 | 15篇 |
2009年 | 18篇 |
2008年 | 42篇 |
2007年 | 31篇 |
2006年 | 26篇 |
2005年 | 19篇 |
2004年 | 26篇 |
2003年 | 27篇 |
2002年 | 21篇 |
2001年 | 29篇 |
2000年 | 16篇 |
1999年 | 22篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 8篇 |
1992年 | 22篇 |
1991年 | 13篇 |
1990年 | 6篇 |
1989年 | 14篇 |
1988年 | 12篇 |
1987年 | 12篇 |
1986年 | 6篇 |
1985年 | 11篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 2篇 |
1976年 | 4篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1972年 | 5篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1967年 | 1篇 |
1966年 | 2篇 |
排序方式: 共有593条查询结果,搜索用时 31 毫秒
1.
2.
Use of hair coloring products and the risk of lymphoma, multiple myeloma, and chronic lymphocytic leukemia.
下载免费PDF全文
![点击此处可从《American journal of public health》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S H Zahm D D Weisenburger P A Babbitt R C Saal J B Vaught A Blair 《American journal of public health》1992,82(7):990-997
OBJECTIVES. Hair coloring products are widely used and contain components that are mutagenic and carcinogenic. An association between occupational exposure to hair coloring products and hematopoietic cancers has been reported, but the risk for these cancers among users has not been carefully evaluated. METHODS. We conducted a population-based, case-control study with telephone interviews from 385 with telephone interviews from 385 non-Hodgkin's lymphoma cases, 70 Hodgkin's disease cases, 72 multiple myeloma cases, 56 chronic lymphocytic leukemia cases, and 1432 controls. RESULTS. Among women, use was associated with odds ratios of 1.5 for non-Hodgkin's lymphoma, 1.7 for Hodgkin's disease, 1.8 for multiple myeloma, and 1.0 for chronic lymphocytic leukemia. Risk was higher for permanent hair coloring products than for semi- or nonpermanent products, particularly for dark colors. Long duration and early age of first use tended to increase risk, but the patterns were inconsistent. Use was much less common in men and did not significantly increase risk. CONCLUSIONS. The use of hair coloring products appears to increase the risk of non-Hodgkin's lymphoma. Multiple myeloma and Hodgkin's disease were also associated, although based on far fewer subjects. If these results represent a causal association, use of hair coloring products would account for 35% of non-Hodgkin's lymphoma cases in exposed women and 20% in all women. 相似文献
3.
4.
5.
Ellen F. Heineman Shelia Hoar Zahm Joseph K. McLaughlin Jimmie B. Vaught Zdenek Hrubec 《Cancer causes & control : CCC》1992,3(1):31-36
The relationship between the use of cigarettes and other tobacco products and the risk of multiple myeloma was examined in a cohort of nearly 250,000 American veterans followed prospectively for 26 years. Compared with men who had never used tobacco, the risk of death from myeloma was not increased among current (relative risk [RR]=0.9, 95 percent confidence interval [CI]=0.8–1.2) or former (RR=1.0, CI=0.8–1.3) cigarette smokers, nor among users of chewing tobacco or snuff (RR=1.0, CI=0.4–2.3). Risk was only slightly and nonsignificantly increased among pipe or cigar smokers (RR=1.2, CI=0.9–1.5). There was no indication of increasing risk with amount of tobacco used or earlier age at first use. With over 90 percent power to detect a 30 percent increased risk of this tumor occuring among current cigarette smokers, this study provides the strongest evidence to date against an association of cigarette smoking with multiple myeloma.Epidemiology and Biometry Program, Division of Cancer Etiology, National Cancer Institute. Westat, Inc. Rockville, MD. National Cancer Institute, 6130 Executive Blvd, Room 418, Rockville, MD 20892, USA. 相似文献
6.
Development of a reconstructed human skin model for angiogenesis 总被引:4,自引:0,他引:4
Parbinder S. Sahota MB ChB MRCS ; J. Lance Burn PhD ; Martin Heaton FRCS MD ; Eric Freedlander FRCS MD ; Simon K. Suvarna FRCPath ; Nicola J. Brown PhD ; Shelia Mac Neil PhD 《Wound repair and regeneration》2003,11(4):275-284
We have previously shown that reconstructed human skin engineered from autologous keratinocytes, fibroblasts, and sterilized donor allodermis stimulates angiogenesis within 5-7 days when placed on well-vascularized wound beds in nude mice. When this reconstructed skin was used clinically in more demanding wound beds, some grafts were lost, possibly due to delayed vascularization. As this reconstructed skin lacks any endothelial cells, our aim in this study was to develop an angiogenic reconstructed skin model in which to explore strategies to improve angiogenesis both in vitro and in vivo. We report that culture of small-vessel human dermal microvascular endothelial cells (HuDMECs) was achieved using magnetic beads coated with an antibody to platelet cell adhesion molecule as a means of purifying the culture. Keratinocytes, fibroblasts, and HuDMECs could be cultured from the same skin biopsy. Initial studies culturing HuDMECs and other sources of endothelial cells with the tissue-engineered skin showed that these cells were capable of slowly entering the dermis under standard culture conditions in vitro. In conclusion, this provides us with a model in which to explore strategies for improving angiogenesis in vitro and also establishes the culture methodologies for the production of reconstructed skin containing autologous keratinocytes, fibroblasts, and endothelial cells. 相似文献
7.
Phyllis E. Hoar W. Glenn L. Kerrick 《Pflügers Archiv : European journal of physiology》1988,412(3):225-230
Two effects of Mn2+ on skinned fibers from chicken gizzard smooth muscle were observed, dependent on the presence of absence of dithiothreitol (DTT) reducing agent. One involves protein oxidation (in the absence of DTT) with production of a latch-like state, and the other involves direct Mn2+ activation of contractile proteins. Cells activated by Mn2+ in the presence of ATP and the absence of Ca2+, Mg2+ and DTT did not relax when transferred to normal relaxing solutions. In contrast, when 5 mM DTT was included in the Mn2+ contracting solution to prevent protein oxidation by Mn2+, the cells still contracted when exposed to Mn2+, but relaxed rapidly when the Mn2+ was removed. In the presence of DTT both the Mn2+ activation and the relaxation following removal of Mn2+ were more rapid than normal Ca2+-activated contractions and relaxations. The skinned fibers activated by Mn2+ in the absence of DTT showed little active shortening unless DTT was added. This rigor-like state is probably due to oxidation of contractile proteins since the cells relaxed when exposed to a relaxing solution containing DTT (50mM) and then contracted again in response to Ca2+ and relaxed normally. The Mn2+ activation was not associated with myosin light chain phosphorylation, in contrast to Ca2+-activated contractions.A preliminary report of this work was given at the Biophysical Society Meeting, February 1987: Hoar PE, Kerrick WGL (1987) Mn2+ activates skinned smooth muscle cells directly without myosin light chain phosphorylation and by reversible oxidation. Biophys J 51:332a 相似文献
8.
W. G. L. Kerrick D. A. Malencik P. E. Hoar J. D. Potter R. L. Coby S. Pocinwong E. H. Fischer 《Pflügers Archiv : European journal of physiology》1980,386(3):207-213
The mechanism of contraction in rabbit fast-twitch, and bovine and rabbit cardiac muscle was examined using functionally skinned fibers, ATPase activity of myofibrils, and cardiac or skeletal troponintropomyosin regulated actin heavy meromyosin. The Ca2+ and Sr2+ activation properties for the different measures of contraction were evaluated. (1) Tension in rabbit and bovine cardiac skinned fibers and rabbit cardiac myofibrillar ATPase were activated equally well by either Ca2+ or Sr2+. By contrast, rabbit adductor magnus (fast-twitch) skinned fibers required substantially higher [Sr2+] than [Ca2+] for activation, as did rabbit myofibrils from back muscle (fast-twitch). (2) Substantially more Sr2+ than Ca2+ was also required for activation of skeletal muscle actin heavy meromyosin ATPase, controlled by either the skeletal or cardiac troponin-tropomyosin complex, similar to the activation of fast-twitch muscle. (3) The absence of correlation between the divalent cation selectivity properties of actin heavy meromyosin ATPase controlled by cardiac troponin-tropomyosin and cardiac muscle tension or myofibrillar ATPase activation by Ca2+ and Sr2+ suggests that troponin, if primarily responsible for the activation of cardiac muscle, has very different in vivo and in vitro binding properties. (4) The close correlation between percentage of maximal Ca2+- and Sr2+-activated myofibrillar ATPase and tension in skinned fibers strongly justifies the use of myofibrillar ATPase, in contrast to a reconstituted troponin-tropomyosin actin heavy meromyosin ATPase system, as a biochemical measure of contraction. 相似文献
9.
The appropriate functioning of tissues and organ systems depends on intercellular communication such as gap junctions formed by connexin (Cx) protein channels between adjacent cells. We have previously shown that Swiss 3T3 cells aggregated on hydrophilic cellulose substratum Cuprophan (CU) establish short linear gap junctions composed of Cx 43 in cell surface plaques. This phenomenon seems to depend on the high intracellular cyclic AMP (cAMP) concentration triggered by attachment of the cells to CU. We have now used a cellulose-coated polystyrene inducing the same cell behaviour to analyse the gap junction communication between aggregated cells. The transfer of the dye Lucifer Yellow (LY) between cells showed that cells aggregated on cellulose substratum rapidly (within 90 min) establish functional gap junctions. Inhibitors of cAMP protein kinase (PKI) or protein kinase C (GF109203X) both inhibited the diffusion of LY between neighbouring cells. Western blot analysis showed that this change in permeability was correlated with a decrease in Cx 43 phosphorylation. Thus, cellulose substrata seem to induce cell-cell communication through Cx 43 phosphorylation modulated by PKA and PKC. To understand the mechanisms by which a substratum regulates gap junctional communication is critically important for the emerging fields of tissue engineering and biohybrid devices. 相似文献
10.
Linda Madisen David I. Hoar Catherine D. Holroyd Margaret Crisp M. E. Hodes James F. Reynolds 《American journal of medical genetics. Part A》1987,27(2):379-390
Long-term storage of DNA is required for a number of genetic studies; prior to extraction, blood samples may be subject to elevated temperatures for variable intervals. We have studied the effect of temperatures ranging from ?70°C to +65°C on human blood and on DNA extracted from it. DNA in solution stored at ambient temperatures up to 37°C for 6 months was digestible by three different restriction endonucleases, whereas storage at 45°C is deleterious after 6-7 weeks. DNA can be extracted from blood samples stored at ?70°C for at least 2 months or at 23°C for a week or more, but blood stored at these temperatures may yield less high-molecular-weight DNA. Cell pellets from which plasma has been removed also can serve as a source of DNA. Isolated DNA stored dry for years (up to 30) is difficult to dissolve and may appear degraded, but a sample stored dry for 13 years and then in solution at ?20°C for 7 years appeared to be intact. 相似文献