全文获取类型
收费全文 | 3860篇 |
免费 | 265篇 |
国内免费 | 1篇 |
出版年
2022年 | 14篇 |
2021年 | 47篇 |
2020年 | 35篇 |
2019年 | 47篇 |
2018年 | 68篇 |
2017年 | 66篇 |
2016年 | 109篇 |
2015年 | 176篇 |
2014年 | 176篇 |
2013年 | 277篇 |
2012年 | 305篇 |
2011年 | 265篇 |
2010年 | 205篇 |
2009年 | 159篇 |
2008年 | 244篇 |
2007年 | 217篇 |
2006年 | 210篇 |
2005年 | 174篇 |
2004年 | 182篇 |
2003年 | 180篇 |
2002年 | 165篇 |
2001年 | 41篇 |
2000年 | 48篇 |
1999年 | 38篇 |
1998年 | 52篇 |
1997年 | 38篇 |
1996年 | 27篇 |
1995年 | 44篇 |
1994年 | 35篇 |
1993年 | 33篇 |
1992年 | 30篇 |
1991年 | 29篇 |
1990年 | 37篇 |
1989年 | 31篇 |
1988年 | 20篇 |
1987年 | 17篇 |
1986年 | 10篇 |
1985年 | 26篇 |
1984年 | 31篇 |
1983年 | 29篇 |
1982年 | 20篇 |
1981年 | 27篇 |
1980年 | 11篇 |
1979年 | 12篇 |
1978年 | 13篇 |
1977年 | 12篇 |
1976年 | 9篇 |
1975年 | 17篇 |
1974年 | 8篇 |
1971年 | 8篇 |
排序方式: 共有4126条查询结果,搜索用时 15 毫秒
991.
992.
993.
Proinflammatory role of glucocorticoid-induced TNF receptor-related gene in acute lung inflammation 总被引:3,自引:0,他引:3
Cuzzocrea S Nocentini G Di Paola R Agostini M Mazzon E Ronchetti S Crisafulli C Esposito E Caputi AP Riccardi C 《Journal of immunology (Baltimore, Md. : 1950)》2006,177(1):631-641
Glucocorticoid-induced TNFR-related gene (GITR) participates in the immune/inflammatory response. Because GITR expression has been described in cells other than T lymphocytes, we investigated whether it also modulates acute inflammatory response. Using GITR-deficient (GITR(-/-)) mice, we analyzed the role of GITR in the development of carrageenan-induced lung inflammation (pleurisy) by studying several proinflammatory markers 2-8 h after carrageenan injection. When compared with GITR(+/+), GITR(-/-) mice exhibited decreased production of turbid exudate containing a lower number of leukocytes. This was correlated with the reduction of inflammatory markers (including TNF-alpha, IL-1beta, myeloperoxidase, inducible NO synthase, and cyclooxygenase 2) in the pleural exudate and/or in the lung. Moreover, endothelial cells expressed lower levels of adhesion molecules. In lungs of GITR(+/+) mice, GITR ligand expression was not modulated during pleurisy, while that of GITR increased, as a consequence of increased infiltration by GITR-expressing cells and of GITR up-regulation in macrophages and endothelial cells. Finally, cotreatment of GITR(+/+) mice with carrageenan and Fc-GITR fusion protein decreased the number of inflammatory cells (pleural macrophages and lung neutrophils) as compared with carrageenan treatment alone, confirming that GITR plays a role in the modulation of pleurisy. 相似文献
994.
Pannellini T Spadaro M Di Carlo E Ambrosino E Iezzi M Amici A Lollini PL Forni G Cavallo F Musiani P 《Journal of immunology (Baltimore, Md. : 1950)》2006,176(12):7695-7703
Double transgenic mice overexpressing the transforming rat HER-2/neu oncogene and the mutated p53, with both dominant-negative and a gain-of-function properties, display early aggressive and metastasizing parotid tumors. Multiple acinar and ductal hyperplasia foci overexpressing the HER-2/neu gene product are evident at wk 5 and progress to poorly differentiated carcinoma by wk 7. Mice die before wk 18 with invasive carcinomas and multiple metastases that no longer express HER-2/neu. A combination of repeated electroporations of plasmids coding for the extracellular and transmembrane domains of the rat HER-2/neu receptor with systemic IL-12 administrations started when the parotids that present diffuse hyperplasia protected all female and 50% of the male mice until the close of the experiment at wk 40. This combined treatment began when multifocal in situ carcinomas that were already present cured 33% of the females and 25% of the males. The most prominent immunologic features associated with the antitumor protection were the production of high titers of anti-HER-2/neu Abs and the nonappearance of cell-mediated cytotoxic reactivity. In conclusion, anti-HER-2/neu vaccination combined with systemic IL-12 control parotid carcinomas as far as p53 mutation makes their growth independent of HER-2/neu expression. 相似文献
995.
996.
Lador F Azabji Kenfack M Moia C Cautero M Morel DR Capelli C Ferretti G 《American journal of physiology. Regulatory, integrative and comparative physiology》2006,290(4):R1071-R1079
We tested whether the kinetics of systemic O(2) delivery (QaO(2)) at exercise start was faster than that of lung O(2) uptake (Vo(2)), being dictated by that of cardiac output (Q), and whether changes in Q would explain the postulated rapid phase of the Vo(2) increase. Simultaneous determinations of beat-by-beat (BBB) Q and QaO(2), and breath-by-breath Vo(2) at the onset of constant load exercises at 50 and 100 W were obtained on six men (age 24.2 +/- 3.2 years, maximal aerobic power 333 +/- 61 W). Vo(2) was determined using Gr?nlund's algorithm. Q was computed from BBB stroke volume (Q(st), from arterial pulse pressure profiles) and heart rate (f(h), electrocardiograpy) and calibrated against a steady-state method. This, along with the time course of hemoglobin concentration and arterial O(2) saturation (infrared oximetry) allowed computation of BBB QaO(2). The Q, QaO(2) and Vo(2) kinetics were analyzed with single and double exponential models. f(h), Q(st), Q, and Vo(2) increased upon exercise onset to reach a new steady state. The kinetics of QaO(2) had the same time constants as that of Q. The latter was twofold faster than that of Vo(2). The Vo(2) kinetics were faster than previously reported for muscle phosphocreatine decrease. Within a two-phase model, because of the Fick equation, the amplitude of phase I Q changes fully explained the phase I of Vo(2) increase. We suggest that in unsteady states, lung Vo(2) is dissociated from muscle O(2) consumption. The two components of Q and QaO(2) kinetics may reflect vagal withdrawal and sympathetic activation. 相似文献
997.
Multiphasic Approach To Study the Bacterial Ecology of Fermented Sausages Inoculated with a Commercial Starter Culture 下载免费PDF全文
Luca Cocolin Rosalinda Urso Kalliopi Rantsiou Carlo Cantoni Giuseppe Comi 《Applied microbiology》2006,72(1):942-945
In this paper, the ability of a commercial starter culture to perform a sausage fermentation is evaluated. Molecular analysis revealed the presence of several strains of the same species contained in the starter culture with different behavior during the fermentation, and the contribution of Lactobacillus curvatus, which was only marginally isolated during the transformation. 相似文献
998.
Barbero G Carta F Giribaldi G Mandili G Crobu S Ceruti C Fontana D Destefanis P Turrini F 《Analytical biochemistry》2006,349(1):62-71
A small amount of bioptic tissue ( approximately 5-10mg of fresh tissue) usually does not contain enough material to extract protein and RNA separately, to obtain preparative two-dimensional polyacrylamide gel electrophoresis (2-DE), and to identify a large number of separated proteins by MS. We tested a method, on small renal cancer specimens, for the coextraction of protein and RNA coupled with 2-DE and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) or quadrupole time-of-flight (Q-TOF) analysis. We coextracted 0.28+/-0.05mg of proteins and 2.5+/-0.33microg of RNA for each 10mg of renal carcinoma tissue. Small and large 2-DE gels were compared: they showed a similar number of spots, and it was possible to match each other; using small format gels, one-fifth of the protein amount was required to identify, by Q-TOF analysis, the same number of proteins identifiable in large-format gel using MALDI-TOF analysis. Quality of RNA coextracted with the proteins was tested by real-time PCR on a set of housekeeping genes. They were quantified with high amplification efficiency and specificity. In conclusion, using 5 to 10mg of fresh tissue, it was possible to perform comprehensive parallel proteomic and genomic analysis by high-resolution, small-format 2-DE gels, allowing approximately 300 proteins identification and 1000 genes expression analysis. 相似文献
999.
Fabio Badalamenti Giuseppe Di Carlo Giovanni D’Anna Michele Gristina Marco Toccaceli 《Hydrobiologia》2006,555(1):253-261
Between 1981 and 1993 a methane pipeline was deployed between Sicily (Italy) and Tunisia. This involved the construction of
a pipeline trench, which damaged the Posidonia oceanica (L.) Delile meadow at Capo Feto (SW Sicily, Italy) and disturbed the surrounding meadow. Seagrass growth and population dynamics
were examined at different depth ranges and at increasing distances from the construction site outer limit (5, 15, 30, 50 m).
Results showed significant differences between the shallow (10±3.3 m) and the deep (20±4.6 m) meadow as well as differences
among distances. The age structure of P. oceanica varied along the distance gradient and with depth. The mortality rate decreased with distance from the trench at all depth
ranges, showing that the plants close to the excavation suffered a higher level of disturbance. Turnover and annual gross
shoot recruitment rate (Rgross) were higher in the shallow portion of the meadow than in the deep range. Forecast of future meadow development (Rnet) close to the trench indicates that, if present conditions are maintained, shoot density will be reduced by 50% over the
next 6 to 17 yrs. 相似文献
1000.
Speranza G Morelli CF Cairoli P Müller B Schink B 《Biochemical and biophysical research communications》2006,349(2):480-484
Triethanolamine (TEA) is converted into acetate and ammonia by a strictly anaerobic, gram-positive Acetobacterium strain LuTria3. Fermentation experiments with resting cell suspensions and specifically deuterated substrates indicate that in the acetate molecule the carboxylate and the methyl groups correspond to the alcoholic function and to its adjacent methylene group, respectively, of the 2-hydroxyethyl unit of TEA. A 1,2 shift of a hydrogen (deuterium) atom from -CH2-O- to =N-CH2- without exchange with the medium was observed. This fact gives evidence that a radical mechanism occurs involving the enzyme and/or coenzyme molecule as a hydrogen carrier. Such a biodegradation appears analogous to the conversion of 2-phenoxyethanol into acetate mediated by another strain of the anaerobic homoacetogenic bacterium Acetobacterium. 相似文献