全文获取类型
收费全文 | 216篇 |
免费 | 10篇 |
专业分类
儿科学 | 2篇 |
妇产科学 | 8篇 |
基础医学 | 24篇 |
口腔科学 | 2篇 |
临床医学 | 26篇 |
内科学 | 53篇 |
皮肤病学 | 2篇 |
神经病学 | 37篇 |
特种医学 | 3篇 |
外科学 | 18篇 |
综合类 | 2篇 |
预防医学 | 20篇 |
眼科学 | 3篇 |
药学 | 10篇 |
肿瘤学 | 16篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 15篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 5篇 |
2013年 | 13篇 |
2012年 | 13篇 |
2011年 | 18篇 |
2010年 | 9篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 16篇 |
2006年 | 10篇 |
2005年 | 16篇 |
2004年 | 10篇 |
2003年 | 10篇 |
2002年 | 5篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 4篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有226条查询结果,搜索用时 15 毫秒
21.
Jesús Álvarez de Sotomayor Merino María Guichot Muñoz Ángeles Orta Cuevas Jorge Rodríguez Casares María Antonia Sánchez Oliver Dahlia Quijada To-Ong 《Progresos de Obstetricia y Ginecología》2007
We presenta an inusual case of passage of methylene blue to uterine vessels during chromopertubacion after laparoscopic extirpation ovarian endometrioma. We have revised the literature on the sugest secundary complication related to this diagnostic procedure. 相似文献
22.
23.
Thymus and spleen grafts from neonatal C57BL mice were implanted beneath the kidney capsule of (A x C57BL) F1 hybrids. At various intervals after implantation, the grafts were analyzed serologically. Cells of each graft were tested for the presence of cells of host origin, TL (thymus-leukemia) antigenicity, and sensitivity to the cytotoxic effect of guinea pig serum (GPS). Thymus grafts showed partial repopulation by host cells 11 days after grafting, and some grafts were completely repopulated by host cells 13 days after grafting. All thymus grafts were fully repopulated 18 days after grafting. With one exception, thymus grafts contained no significant number of TL-positive cells within 14 days after grafting. TL-positive cells appeared in thymus grafts examined 15 days after implantation, and their number increased up to the 18th day after implantation. Cells residing in thymus grafts remained sensitive to GPS throughout the period of observation. The acquisition of thymus-distinctive serological properties by host cells repopulating thymus grafts was similar in intact and in thymectomized recipients. Spleen grafts were completely repopulated by host cells as early as 8 days after grafting. The cells residing in spleen grafts remained TL-negative throughout the period of observation, and were refractory to the cytotoxic effect of GPS. It is thus apparent that, while both spleen and thymus grafts are invaded by TL-negative cells, only those entering the thymus acquire the antigen. The nature of the process by which the thymus endows thymus-distinctive properties on cells entering it is discussed. 相似文献
24.
Neurotrophins promote revascularization by local recruitment of TrkB+ endothelial cells and systemic mobilization of hematopoietic progenitors 总被引:1,自引:0,他引:1
Kermani P Rafii D Jin DK Whitlock P Schaffer W Chiang A Vincent L Friedrich M Shido K Hackett NR Crystal RG Rafii S Hempstead BL 《The Journal of clinical investigation》2005,115(3):653-663
The neurotrophin brain-derived neurotrophic factor (BDNF) is required for the maintenance of cardiac vessel wall stability during embryonic development through direct angiogenic actions on endothelial cells expressing the tropomysin receptor kinase B (TrkB). However, the role of BDNF and a related neurotrophin ligand, neurotrophin-4 (NT-4), in the regulation of revascularization of the adult tissues is unknown. To study the potential angiogenic capacity of BDNF in mediating the neovascularization of ischemic and non-ischemic adult mouse tissues, we utilized a hindlimb ischemia and a subcutaneous Matrigel model. Recruitment of endothelial cells and promotion of channel formation within the Matrigel plug by BDNF and NT-4 was comparable to that induced by VEGF-A. The introduction of BDNF into non-ischemic ears or ischemic limbs induced neoangiogenesis, with a 2-fold increase in the capillary density. Remarkably, treatment with BDNF progressively increased blood flow in the ischemic limb over 21 days, similar to treatment with VEGF-A. The mechanism by which BDNF enhances capillary formation is mediated in part through local activation of the TrkB receptor and also by recruitment of Sca-1+CD11b+ pro-angiogenic hematopoietic cells. BDNF induces a potent direct chemokinetic action on subsets of marrow-derived Sca-1+ hematopoietic cells co-expressing TrkB. These studies suggest that local regional delivery of BDNF may provide a novel mechanism for inducing neoangiogenesis through both direct actions on local TrkB-expressing endothelial cells in skeletal muscle and recruitment of specific subsets of TrkB+ bone marrow-derived hematopoietic cells to provide peri-endothelial support for the newly formed vessels. 相似文献
25.
Hepatitis B virus DNA prediction rules for hepatitis B e antigen-negative chronic hepatitis B 总被引:5,自引:0,他引:5
Feld JJ Ayers M El-Ashry D Mazzulli T Tellier R Heathcote EJ 《Hepatology (Baltimore, Md.)》2007,46(4):1057-1070
After hepatitis B e antigen (HBeAg) seroconversion, hepatitis B may become inactive or progress to HBeAg-negative hepatitis with persistent or intermittent alanine aminotransferase (ALT) elevation. The aim of this study was to prospectively identify factors predictive of the clinical course in HBeAg-negative chronic hepatitis B (CHB). Patients were stratified by ALT and HBeAg status and followed every 3 months for up to 5 years. Kaplan-Meier and Cox regression analysis using the change from normal ALT to elevated ALT as endpoints were performed to determine factors associated with ALT elevation/normalization. Seventy-four HBeAg-negative and 32 HBeAg-positive patients were prospectively evaluated. For HBeAg-negative patients, hepatitis B virus (HBV) DNA was predictive of future ALT. Only 1 patient with normal ALT and an HBV DNA value lower than 10,000 copies/mL developed an elevated ALT within the subsequent year, whereas 67% with an HBV DNA value greater than 100,000 copies/mL had a rise in ALT above normal within 1 year. Patients with a previous history of ALT elevation and longer follow-up at all levels of HBV DNA were more likely to experience ALT elevations. For HBeAg-negative patients with elevated ALT and all HBeAg-positive patients, HBV DNA did not predict future ALT. Other viral and host factors were not predictive of future ALT. CONCLUSION: HBeAg-negative CHB has a fluctuating course. HBV DNA values lower than 10,000 copies/mL predict persistently normal ALT for at least 1 year. Patients with HBV DNA values between 10,000 and 100,000 copies/mL can safely be followed at 6 monthly intervals, whereas HBV DNA values greater than 100,000 copies/mL are highly predictive of future ALT elevation and should prompt regular follow-up. 相似文献
26.
27.
Havlíková H Hill M Kancheva L Vrbíková J Pouzar V Cerny I Kancheva R Stárka L 《The Journal of clinical endocrinology and metabolism》2006,91(8):3092-3099
BACKGROUND: Pregnanolone isomers (PI) with a hydroxy group in the 3alpha-position are neuroinhibitors operating via positive modulation of GABA(A) receptors. The 3beta-PI and sulfates of PI and pregnenolone exert the opposite effect. In addition to the brain's in situ synthesis, some circulating steroids can penetrate the blood-brain barrier. METHODS: To assess the physiological impact of peripheral endogenous neuroactive pregnanolone isomers and their polar conjugates in women, serum allopregnanolone (P3alpha5alpha), isopregnanolone (P3beta5alpha), pregnanolone (P3alpha5beta), epipregnanolone (P3beta5beta), pregnenolone, estradiol (including their polar conjugates), and additional steroids were measured in 16 women in the follicular and luteal phases of the menstrual cycle using gas chromatography/mass spectrometry and RIA for the analysis. Linear models and Spearman's correlations were used for data evaluation. RESULTS AND DISCUSSION: The levels of conjugated PI were from one to almost three orders of magnitude higher in comparison with the free steroids. The results indicate that a substantial proportion of the progesterone is metabolized in the sequence progesterone-->5beta-dihydroprogesterone-->P3alpha5beta-->conjugated P3alpha5beta. The sulfation of PI and particularly of P3alpha5beta moderates the levels of free PI and restrains estradiol biosynthesis via progesterone degradation. PI including the conjugates reflected changing progesterone formation during the menstrual cycle. In the follicular phase, the positive correlation with conjugated pregnenolone, the independence of progesterone, and the negative age relationships of PI indicate their adrenal origin. The dependence on progesterone and the independence of conjugated pregnenolone suggest a gonadal source of PI in the luteal phase. The neuroactivating PI prevailed over neuroinhibiting PI. 相似文献
28.
29.
The effect of proteins secreted by cultured pre-pubertal rat Sertoli cells (pSCP) on natural killer (NK) cell activity of rat, mice and guinea pig splenocytes and human peripheral blood lymphocytes was estimated. The results indicate that pSCP inhibited, in a dose-dependent manner, NK cell activity of mice, guinea pig and human lymphocytes but did not suppress lysis of YAC-1 target cells by rat NK cells. Species-specific differences in the effect of pSCP on NK cell activity probably result from differences in the binding of proteins within the effector cells. These data indicate that in the pre-pubertal period of gonadal development immature Sertoli cells synthesize a factor/s which might contribute to the maintenance of specific testis immunological environment. 相似文献
30.
Nadia Kancheva Landolt Nittaya Phanuphak Chuleeporn Khongpetch Rosalin Kriengsinyot Somsong Teeratakulpisarn Sasiwimol Ubolyam 《AIDS care》2015,27(5):587-594
The objective of this study was to characterize HIV-serodiscordant heterosexual couples and to evaluate acceptance for HIV testing and HIV prevalence in nonindex partners. We conducted a cross-sectional study with quantitative and qualitative components. Two cohorts of 1767 HIV-positive people were screened to identify heterosexual HIV-serodiscordant couples. HIV-positive partners (index) were administered a questionnaire; CD4, viral load (VL), and antiretroviral therapy (ART) history were gathered from clinical records. HIV-negative/unknown status partners (nonindex) were invited for a similar questionnaire and HIV testing. In-depth interviews with three HIV-serodiscordant couples were conducted. Two hundred and ninety-seven index partners agreed to enroll in this study. The median duration of the relationship was 10 years, and 81% were sexually active. All but two index partners were on ART, and 98% had VL < 1000 copies/mL. Only 111 (37%) nonindex partners came for HIV testing, and all of them tested HIV-negative. In addition, only 41% of nonindex partners had HIV testing in the last one year. The main reasons for the nonindex partners not to come for HIV testing were “no interest” (n = 117, 63%) and “nondisclosure of HIV status” (n = 46, 25%). The latter was substantiated and explained by the qualitative outcome of this study, suggesting relation to stigma against HIV-positive people. Our results support the WHO recommendation for starting ART for treatment and prevention in HIV-serodiscordant couples at any CD4 count. Furthermore, we recommend the dissemination of data showing that no HIV transmission in heterosexual couples through sex practice has been observed provided VL is suppressed. This could be a powerful tool for effective fight against stigma and self-stigma in people living with HIV. 相似文献