全文获取类型
收费全文 | 936篇 |
免费 | 26篇 |
国内免费 | 12篇 |
出版年
2023年 | 5篇 |
2022年 | 17篇 |
2021年 | 18篇 |
2020年 | 15篇 |
2019年 | 16篇 |
2018年 | 23篇 |
2017年 | 11篇 |
2016年 | 17篇 |
2015年 | 15篇 |
2014年 | 28篇 |
2013年 | 54篇 |
2012年 | 22篇 |
2011年 | 33篇 |
2010年 | 34篇 |
2009年 | 43篇 |
2008年 | 47篇 |
2007年 | 35篇 |
2006年 | 53篇 |
2005年 | 41篇 |
2004年 | 27篇 |
2003年 | 32篇 |
2002年 | 33篇 |
2001年 | 21篇 |
2000年 | 13篇 |
1999年 | 20篇 |
1998年 | 17篇 |
1997年 | 17篇 |
1996年 | 24篇 |
1995年 | 17篇 |
1994年 | 13篇 |
1993年 | 17篇 |
1992年 | 20篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1988年 | 12篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 19篇 |
1984年 | 15篇 |
1982年 | 5篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 12篇 |
1976年 | 7篇 |
1974年 | 4篇 |
1973年 | 8篇 |
1972年 | 6篇 |
排序方式: 共有974条查询结果,搜索用时 187 毫秒
51.
52.
《Chronobiology international》2013,30(6):961-972
The efficacy of a light/darkness intervention designed to promote circadian adaptation to night shift work was tested in this combined field and laboratory study. Six full-time night shift workers (mean age ± SD:37.1 ± 8.1 yrs) were provided an intervention consisting of an intermittent exposure to full-spectrum bright white light (~2000 lux) in the first 6 h of their 8 h shift, shielding from morning light by tinted lenses (neutral gray density, 15% visual light transmission), and regular sleep/darkness episodes in darkened quarters beginning 2 h after the end of each shift. Five control group workers (41.1 ± 9.9 yrs) were observed in the presence of a regular sleep/darkness schedule only. Constant routines (CR) performed before and after a sequence of ~12 night shifts over 3 weeks revealed that treatment group workers displayed significant shifts in the time of peak cortisol expression and realignment of the rhythm with the night-oriented schedule. Smaller phase shifts, suggesting an incomplete adaptation to the shift work schedule, were observed in the control group. Our observations support the careful control of the pattern of light and darkness exposure for the adaptation of physiological rhythms to night shift work. 相似文献
53.
《Chronobiology international》2013,30(4):782-806
This study investigated the physiological function of suppressed melatonin through thermoregulation in a cold environment. Interactions between thermoregulation directly affected by exposure to a cold environment and indirectly affected by endogenous melatonin suppression by bright-light exposure were examined. Ten male subjects were exposed to two different illumination intensities (30 and 5000 lux) for 4.5?h, and two different ambient temperatures (15 and 27°C) for 2?h before sleep under dark and thermoneutral conditions. Salivary melatonin level was suppressed by bright light (p?<?0.001), although the ambient temperature condition had no significant effect on melatonin. During sleep, significant effects of pre-sleep exposure to a cold ambient temperature (p?<?0.001) and bright light (p?<?0.01) on rectal temperature (Tre) were observed. Pre-sleep, bright-light exposure led to an attenuated fall in Tre during sleep. Moreover, Tre dropped more precipitously after cold exposure than thermoneutral conditions (cold: ?0.54?±?0.07°C/h; thermoneutral: ?0.16?±?0.03°C/h; p?<?0.001). Pre-sleep, bright-light exposure delayed the nadir time of Tre under thermoneutral conditions (p?<?0.05), while cold exposure masked the circadian rhythm with a precipitous decrease in Tre. A significant correlation between the Tre nadir and melatonin level (r?=??0.774, p?<?0.05) indicated that inter-individual differences with higher melatonin levels lead to a reduction in Tre after cold exposure. These results suggest that suppressed endogenous melatonin inhibits the downregulation of the body temperature set-point during sleep. (Author correspondence: ishibasi@design. kyushu-u. ac. jp) 相似文献
54.
Takao Morita Akihiro NezuYosuke Tojyo Akihiko Tanimura 《Biochemical and biophysical research communications》2013
Adenoviruses have been used for gene transfer to salivary gland cells in vivo. Their use to study the function of salivary acinar cells was limited by a severe inflammatory response and by the destruction of fluid-secreting acinar cells. In the present study, low doses of adenovirus were administered to express Stim1-mKO1 by retrograde ductal injection to submandibular glands. The approach succeeded in increasing muscarinic stimulation-induced Ca2+ responses in acinar cells without inflammation or decreased salivary secretions. This increased Ca2+ response was notable upon weak muscarinic stimulation and was attributed to increased Ca2+ release from internal stores and increased Ca2+ entry. The basal Ca2+ level was higher in Stim1-mKO1-expressing cells than in mKO1-expressing and non-expressing cells. Exposure of permeabilized submandibular acinar cells, where Ca2+ concentration was fixed at 50 nM, to inositol 1,4,5-trisphosphate (IP3) produced similar effects on the release of Ca2+ from stores in Stim1-mKO1-expressing and non-expressing cells. The low toxicity and relative specificity to acinar cells of the mild gene transfer method described herein are particularly useful for studying the molecular functions of salivary acinar cells in vivo, and may be applied to increase salivary secretions in experimental animals and human in future. 相似文献
55.
Ž. P. Marinšek N. Nolde I. Kardum‐Skelin R. Nizzoli B. Önal T. Rezanko E. Tani K. T. Ostović P. Vielh F. Schmitt G. Kocjan 《Cytopathology》2013,24(1):7-20
?. P. Marin?ek, N. Nolde, I. Kardum‐Skelin, R. Nizzoli, B. Önal, T. Rezanko, E. Tani, K. T. Ostovi?, P. Vielh, F. Schmitt and G. Kocjan Multinational study of oestrogen and progesterone receptor immunocytochemistry on breast carcinoma fine needle aspirates Objectives: To collect data on the variability of immunocytochemical (ICC) procedures used to detect oestrogen/progesterone receptors (ER/PR) on cytological material; to test the reproducibility of results; and to identify the crucial points in the ICC procedures that affect the result. Methods: Ten laboratories from eight countries participated in a two‐part study. In the first part, one of the participants (the coordinator) prepared and distributed cytospins from a fine needle aspirate of a primary breast carcinoma. Laboratories performed ICC staining for ER/PR according to their own methods on the test slides and in‐house positive controls. Slides were returned to the coordinator together with information on the preparation of positive control slides and the ICC methodology used. In the second part, obligatory methods of fixation and antigen retrieval were specified. Evaluation of results included grading the number of positive cells, staining intensity, background staining, cytoplasmic staining, sample condition and cellularity. Participants evaluated their own results, which were subsequently evaluated by the coordinator. Results: There was great variability in the preparation of slides for in‐house controls and ICC methodology. The outcome of ICC staining of in‐house control slides was excellent in two laboratories, adequate in three, sub‐optimal in four and inadequate in one. Only six obtained a positive reaction on the test slides and not all were of a high quality. Results of the second run were greatly improved in terms of cellularity of in‐house positive control slides, and scores for the percentage of stained cells and staining intensity of control and test slides. Cytospins and monolayer (ThinPrep®) preparations were superior to direct smears; methods of fixation and antigen retrieval were the key points in the staining process. Conclusions: Our experience points to the need for guidelines for hormonal receptor determination and external quality control on cytological material, in order for cytological methods to be used in routine clinical practice with a suitable degree of confidence. 相似文献
56.
57.
Roberta De Grandi Pasquale Capaccio Alessandro Bidossi Marta Bottagisio Lorenzo Drago Sara Torretta Lorenzo Pignataro Elena De Vecchi 《Microbes and infection / Institut Pasteur》2019,21(2):109-112
Sialolithiasis represents the most common disorders of salivary glands in middle-aged patients. It has been hypothesized that the retrograde migration of bacteria from the oral cavity to gland ducts may facilitate the formation of stones. Thus, in the present study, a microbiome characterization of salivary calculi was performed to evaluate the abundance and the potential correlations between microorganisms constituting the salivary calculi microbiota. Our data supported the presence of a core microbiota of sialoliths constituted principally by Streptococcus spp., Fusobacterium spp. and Eikenella spp., along with the presence of important pathogens commonly involved in infective sialoadenitis. 相似文献
58.
The experimental and clinical data about antibodies against environmental chemical carcinogens and endogenous steroids are represented. The conception of immunomodulation of carcinogens- and steroids-dependent human diseases is proposed. It is postulated that antibodies to polycyclic aromatic hydrocarbons and heterocyclic amines in cooperation with antibodies to cholesterol, sex hormones, mineralo- and glucocorticoids stimulate or inhibit cancer, malformation, cardiovascular and autoimmune diseases depending on their personal combination. It is recommended to use immunoassay of these antibodies for the human diseases prediction. The alternative approaches for prevention using the probiotics transformed by anti-carcinogen antibodies are substantiated. 相似文献
59.
Mammary analogue secretory carcinoma of the salivary glands has morphological shares molecular similarities to secretory carcinoma of the breast. Here, we report a 46‐year‐old woman who presented with a right submandibular gland mass. Fine needle aspiration differential diagnosis included oncocytosis, oncocytoma, acinic cell carcinoma and mammary analogue secretory carcinoma. We also review the current literature regarding clinical presentation and diagnostic workup of this entity. 相似文献
60.
Laminin alpha5 is necessary for submandibular gland epithelial morphogenesis and influences FGFR expression through beta1 integrin signaling 总被引:3,自引:0,他引:3
Rebustini IT Patel VN Stewart JS Layvey A Georges-Labouesse E Miner JH Hoffman MP 《Developmental biology》2007,308(1):15-29
Laminin alpha chains have unique spatiotemporal expression patterns during development and defining their function is necessary to understand the regulation of epithelial morphogenesis. We investigated the function of laminin alpha5 in mouse submandibular glands (SMGs). Lama5(-/-) SMGs have a striking phenotype: epithelial clefting is delayed, although proliferation occurs; there is decreased FGFR1b and FGFR2b, but no difference in Lama1 expression; later in development, epithelial cell organization and lumen formation are disrupted. In wild-type SMGs alpha5 and alpha1 are present in epithelial clefts but as branching begins alpha5 expression increases while alpha1 decreases. Lama5 siRNA decreased branching, p42 MAPK phosphorylation, and FGFR expression, and branching was rescued by FGF10. FGFR siRNA decreased Lama5 suggesting that FGFR signaling provides positive feedback for Lama5 expression. Anti-beta1 integrin antibodies decreased FGFR and Lama5 expression, suggesting that beta1 integrin signaling provides positive feedback for Lama5 and FGFR expression. Interestingly, the Itga3(-/-):Itga6(-/-) SMGs have a similar phenotype to Lama5(-/-). Our findings suggest that laminin alpha5 controls SMG epithelial morphogenesis through beta1 integrin signaling by regulating FGFR expression, which also reciprocally regulates the expression of Lama5. These data link changes in basement membrane composition during branching morphogenesis with FGFR expression and signaling. 相似文献