全文获取类型
收费全文 | 984篇 |
免费 | 68篇 |
国内免费 | 1篇 |
出版年
2023年 | 4篇 |
2022年 | 16篇 |
2021年 | 16篇 |
2020年 | 19篇 |
2019年 | 19篇 |
2018年 | 25篇 |
2017年 | 19篇 |
2016年 | 31篇 |
2015年 | 39篇 |
2014年 | 62篇 |
2013年 | 73篇 |
2012年 | 76篇 |
2011年 | 71篇 |
2010年 | 43篇 |
2009年 | 34篇 |
2008年 | 44篇 |
2007年 | 57篇 |
2006年 | 55篇 |
2005年 | 47篇 |
2004年 | 44篇 |
2003年 | 44篇 |
2002年 | 31篇 |
2001年 | 9篇 |
2000年 | 12篇 |
1999年 | 20篇 |
1998年 | 10篇 |
1997年 | 12篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 11篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 7篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 9篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 7篇 |
1978年 | 2篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1969年 | 2篇 |
1962年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有1053条查询结果,搜索用时 15 毫秒
81.
Pasquale Florio Alberto Imperatore Mario Franchini Stefano Angioni Luca Bruni 《Steroids》2010,75(12):912-917
The presence of a thin endometrium has an important role in allowing the best conditions for hysteroscopic surgery. Here, we explored the efficacy of a 14-day administration of nomegestrol acetate, a progestogen with high progestogen potency effects, in rapid endometrial preparation to operative hysteroscopy.A total of 86 fertile women selected for operative hysteroscopy received for 14 days either 5 mg day−1 of nomegestrol acetate (n = 43; group A) or 4 mg day−1 of folic acid (n = 43; group B), starting on day 1 of the subsequent menstrual cycle. Before treatments on days 12-14 of the menstrual cycle, all patients underwent endometrial thickness measurement; ultrasonography of the ovaries to measure the appearance of a dominant follicle; diagnostic hysteroscopy with endometrial biopsy; plasma estradiol (E2), progesterone (P), luteinising hormone (LH) and follicle-stimulating hormone (FSH) levels measurements. On the day of surgery, patients repeated endometrial and ovarian ultrasonography and, E2, P, LH and FSH measurement.At enrolment, endometrial thickness, mean follicular diameter and E2, P, LH and FSH concentrations did not differ between groups. At the time of operative hysteroscopy (i.e., after 14 days’ treatment) group A, but not group B, showed significant (all P < 0.001) reduction of endometrial thickness, mean diameter of dominant follicle, E2, P and LH concentrations. Endometrial preparation was judged more effective in group A than B, since the endometrial mucosa in all of the women of group A appeared to be very thin, hypotrophic, regular and pale. In conclusion, administration of nomegestrol acetate was effective in reducing endometrial thickness, also acting on the hypothalamus-pituitary-ovarian axis, thus allowing highly favourable operative hysteroscopic conditions. 相似文献
82.
The Sapio Award was established in 1999 by the Sapio Group along with several Italian universities and research centers to recognize Italian scientists who have made a major contribution to the discovery or development of novel technologies in the fields of biotechnology, social and health services, nonotechnology and biosecurity in agricultural production and scientific distribution. The 2006 edition of the award meeting centered around the issues of tissue banks and biorepositories and translational medicine. The organizing committee divided this edition into a pre-meeting held in Milan on October 18, 2006 and a master meeting on October 19, 2006, held at the ISS in Rome. A summary of these meetings is given. 相似文献
83.
The acid base behavior of phytate has been studied (at t=25 degrees C by potentiometry, ISE-H+ glass electrode) in NaNO3aq at different ionic strengths (0.1 < or = I/mol L(-1) < or = 1.0). The interactions with copper(II) were investigated in the same experimental conditions in different metal to ligand (Phy) ratios (1:1 < or = Cu2+ :Phy < or = 4:1), by using both ISE-H+ and ISE-Cu2+ electrodes. Phytate acid base behavior in sodium nitrate is very similar to that in sodium chloride, previously investigated. In the experimental conditions adopted, the formation of three CuiHjPhy(12-2i-j)- species is observed: the mononuclear CuH4Phy6- and CuH5Phy5-, and the dinuclear Cu2H5Phy3-. Analysis of complex formation constants at different ionic strengths reveals that both ISE-H+ and ISE-Cu2+ electrodes gave, within the experimental error, analogous values. Dependence of complex formation constants on ionic strength was modeled by EDH (Extended Debye-Hückel) and SIT (Specific ion Interaction Theory) equations. The sequestering ability of phytate toward copper(II) has been evaluated by the calculation of pL50 (the total ligand concentration, as -log CL, able to bind 50% of metal cation), an empirical parameter already proposed for an objective "quantification" of this ability. A thorough analysis of literature data on phytate-copper(II) complexes has been performed. 相似文献
84.
Chun-yu YIN Hong-zhou LU Wei-ming JIANG Maria Pia De Pasquale Yue-kai HU Xiao-zhang PAN Xin-hua WENG Richard T. D'Aquila Yi-Wei TANG 《Virologica Sinica》2007,22(3):212-217
Illegally paid blood donation was a risk factor for HIV acquisition exclusively in Henan and Hubei Provinces of China,and not in Shanghai.Nucleotide sequences in the gag and env genes of HIV-1 were compared between isolates from Henan and Shanghai regions of China to test whether an expected higher degree of a common source of infections from this unique blood donation transmission risk would be evident as decreased variation among Henan isolates in an exploratory cross-sectional analysis.Among 38 isolates studied,23 of 23(100%)from Henan and 8 of 15(54%)from Shanghai were subtype B.In addition,fewer sequence differences were found in gp41 of subtype B isolates from Henan than from Shanghai isolates.Further studies with additional controls are therefore warranted to confirm the role of the degree of a common source of infections in differences in HIV variation across populations. 相似文献
85.
Slc7a7 disruption causes fetal growth retardation by downregulating Igf1 in the mouse model of lysinuric protein intolerance 总被引:4,自引:0,他引:4
86.
Patrussi L Mariggio' S Paccani SR Capitani N Zizza P Corda D Baldari CT 《Cellular signalling》2007,19(11):2351-2360
Glycerophosphoinositols (GPIs) are water-soluble phosphoinosite metabolites produced by all cell types, whose levels increase in response to a variety of extracellular stimuli, and are particularly high in Ras-transformed cells. GPIs are released to the extracellular space, wherefrom they can be taken up by other cells through a specific transporter. Exogenous GPIs affect a plethora of cellular functions. Among these compounds the most active is GroPIns4P, which affects cAMP levels and PKA-dependent functions through the inhibition of heterotrimeric Gs proteins. GroPIns4P has also recently been found to promote actin cytoskeleton reorganization by inducing Rho and Rac activation through an as yet unidentified mechanism. Here we have assessed the potential effects of GroPIns4P on T-cells. We found that GroPIns4P enhances CXCR4-dependent chemotaxis. This activity results from the capacity of GroPIns4P to activate the Rho GTPase exchange factor, Vav, through an Lck-dependent pathway which also results in activation of the stress kinases JNK and p38. GroPIns4P was also found to activate with a delayed kinetics the Lck-dependent activation of ZAP-70, Shc and Erk1/2. The activities of GroPIns4P were found to be dependent on its capacity to inhibit cAMP production and PKA activation. Collectively, the data provide the first evidence of a role of glycerophosphoinositols as modulators of T-cell signaling and establish a mechanistic basis for the effects of this phosphoinositide derivative on F-actin dynamics. 相似文献
87.
88.
Emanuela Dazzo Manuela Fanciulli Elena Serioli Giovanni Minervini Patrizia Pulitano Simona Binelli Carlo Di Bonaventura Concetta Luisi Elena Pasini Salvatore Striano Pasquale Striano Giangennaro Coppola Angela Chiavegato Slobodanka Radovic Alessandro Spadotto Sergio Uzzau Angela La Neve Anna Teresa Giallonardo Oriano Mecarelli Silvio C.E. Tosatto Ruth Ottman Roberto Michelucci Carlo Nobile 《American journal of human genetics》2015,96(6):992-1000
Autosomal-dominant lateral temporal epilepsy (ADLTE) is a genetic epilepsy syndrome clinically characterized by focal seizures with prominent auditory symptoms. ADLTE is genetically heterogeneous, and mutations in LGI1 account for fewer than 50% of affected families. Here, we report the identification of causal mutations in reelin (RELN) in seven ADLTE-affected families without LGI1 mutations. We initially investigated 13 ADLTE-affected families by performing SNP-array linkage analysis and whole-exome sequencing and identified three heterozygous missense mutations co-segregating with the syndrome. Subsequent analysis of 15 small ADLTE-affected families revealed four additional missense mutations. 3D modeling predicted that all mutations have structural effects on protein-domain folding. Overall, RELN mutations occurred in 7/40 (17.5%) ADLTE-affected families. RELN encodes a secreted protein, Reelin, which has important functions in both the developing and adult brain and is also found in the blood serum. We show that ADLTE-related mutations significantly decrease serum levels of Reelin, suggesting an inhibitory effect of mutations on protein secretion. We also show that Reelin and LGI1 co-localize in a subset of rat brain neurons, supporting an involvement of both proteins in a common molecular pathway underlying ADLTE. Homozygous RELN mutations are known to cause lissencephaly with cerebellar hypoplasia. Our findings extend the spectrum of neurological disorders associated with RELN mutations and establish a link between RELN and LGI1, which play key regulatory roles in both the developing and adult brain. 相似文献
89.
Pasquale Bianco Zsolt Mártonfalvi Katalin Naftz Dorina K?szegi Miklós Kellermayer 《Biophysical journal》2015,109(2):340-345
Titin is a giant filamentous protein of the muscle sarcomere in which stretch induces the unfolding of its globular domains. However, the mechanisms of how domains are progressively selected for unfolding and which domains eventually unfold have for long been elusive. Based on force-clamp optical tweezers experiments we report here that, in a paradoxical violation of mechanically driven activation kinetics, neither the global domain unfolding rate, nor the folded-state lifetime distributions of full-length titin are sensitive to force. This paradox is reconciled by a gradient of mechanical stability so that domains are gradually selected for unfolding as the magnitude of the force field increases. Atomic force microscopic screening of extended titin molecules revealed that the unfolded domains are distributed homogenously along the entire length of titin, and this homogeneity is maintained with increasing overstretch. Although the unfolding of domains with progressively increasing mechanical stability makes titin a variable viscosity damper, the spatially randomized variation of domain stability ensures that the induced structural changes are not localized but are distributed along the molecule''s length. Titin may thereby provide complex safety mechanims for protecting the sarcomere against structural disintegration under excessive mechanical conditions. 相似文献
90.