全文获取类型
收费全文 | 276篇 |
免费 | 17篇 |
国内免费 | 2篇 |
专业分类
儿科学 | 8篇 |
妇产科学 | 4篇 |
基础医学 | 30篇 |
口腔科学 | 6篇 |
临床医学 | 42篇 |
内科学 | 62篇 |
皮肤病学 | 10篇 |
神经病学 | 4篇 |
特种医学 | 7篇 |
外科学 | 24篇 |
综合类 | 7篇 |
预防医学 | 37篇 |
眼科学 | 1篇 |
药学 | 28篇 |
肿瘤学 | 25篇 |
出版年
2022年 | 2篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 10篇 |
2018年 | 17篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 13篇 |
2013年 | 13篇 |
2012年 | 21篇 |
2011年 | 21篇 |
2010年 | 17篇 |
2009年 | 8篇 |
2008年 | 16篇 |
2007年 | 25篇 |
2006年 | 14篇 |
2005年 | 17篇 |
2004年 | 15篇 |
2003年 | 2篇 |
2002年 | 9篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有295条查询结果,搜索用时 15 毫秒
101.
Kumar S Biswas S Mandal D Roy HN Chakraborty S Kabir SN Banerjee S Mondal NB 《Contraception》2007,75(1):71-78
PURPOSE: Aqueous decoction of Chenopodium album seeds (CAD) was assessed for its sperm-immobilizing and contraceptive efficacy in laboratory mammals. METHOD: Spermicidal efficacy was evaluated in vitro by a modified Sander-Cramer test. The mode of spermicidal action was assessed by (a) supravital and double fluoroprobe staining of sperm, (b) hypoosmotic swelling tests and (c) transmission electron microscopy. Contraceptive efficacy was evaluated by intrauterine and vaginal application of CAD in rats and rabbits, respectively, followed by their mating and evaluation of pregnancy outcomes. RESULTS: The minimum effective concentration of CAD that induced instantaneous immobilization of rat spermatozoa in vitro was 2 mg/mL. The mechanism of CAD action involved disintegration of sperm plasma membrane and dissolution of acrosomal cap causing sperm death. Fertilization of oocytes and establishment of implantation were prevented in the uterine horn that was administered with CAD, while these events occurred unhindered in the untreated contralateral side. In rabbit, intravaginal application of CAD significantly blocked the establishment of pregnancy. CONCLUSION: CAD possesses appreciable spermicidal potential, which may be explored as an effector constituent of vaginal contraceptive. 相似文献
102.
Whole grain (WG) foods have been shown to reduce chronic disease risk and overweight. Total dietary fiber is associated with WG and its health benefits. The purpose was to determine whether associations exist between WG intake (no-WG intake, 0 ounce equivalent [oz eq]; low, >0-<3 oz eq; high, ≥3 oz eq) and total dietary fiber intake among Americans 2 years and older. One-day food intake data from the US National Health and Nutrition Examination Survey 2009 to 2010 (n = 9042) showed that only 2.9% and 7.7% of children/adolescents (2-18 years) and adults (≥19 years) consumed at least 3 WG oz eq/d, respectively. For children/adolescents and adults, individuals in the high WG intake group were 59 and 76 times more likely to fall in the third fiber tertile, respectively, compared with those with no-WG intake. Total dietary fiber intake from food sources varied by WG intake group for children/adolescents and adults with more total dietary fiber consumed from ready-to-eat (RTE) and hot cereals and yeast breads/rolls in the high WG intake group compared with the no-WG intake group. Major WG sources for children/adolescents and adults included yeast bread/rolls (24% and 27%, respectively), RTE cereals (25% and 20%, respectively), and oatmeal (12% and 21%, respectively). Among those with the highest WG intake, WG RTE cereal with no added bran was the greatest contributor to total dietary fiber compared with other RTE cereal types. Whole grain foods make a substantial contribution to total dietary fiber intake and should be promoted to meet recommendations. 相似文献
103.
BackgroundWe had shown that dienogest (DNG) + testosterone undecanoate (TU) induced complete sperm suppression in rats when administered together every 45 days. On the other hand, individual drugs given alone in a similar fashion failed to achieve the same result.Study DesignThe present study was therefore undertaken to determine the reason for such a differential sperm suppression and to correlate it with the expression of steroidogenic enzyme genes in the rat testis.ResultsAdministration of DNG (40 mg/kg body weight [bw]) + TU (25 mg/kg bw) every 45 days for a duration of 90 days induced spermatogenic arrest, leading to a significant reduction in testicular weight and number of precursor germ cells. Flow cytometric analysis further confirmed the same result, leading to a significant shift in the distribution of haploid cells. Measurement of testosterone (serum and intratesticular) was significantly low. Complete sperm suppression coincided with significant down-regulation in the expression of upstream steroidogenic enzyme genes represented serially by cytochrome P450 side-chain cleavage, P450 17α-hydroxylase, 3β-hydroxysteroid dehydrogenase and steroidogenic acute regulatory protein (StAR) in the testis. On the other hand, rats administered with either DNG or TU alone demonstrated incomplete sperm suppression in which the expression of all the above genes remained characteristically nonuniform.ConclusionTaken together, the above findings corroborate the fact that regulation of expression of three of the upstream steroidogenic enzymes genes and the StAR protein in rat testis is crucial in leading to complete sperm suppression as observed with DNG+TU treatment. 相似文献
104.
105.
To the editor:Dengue is a mosquito transmitted,newly emerging urban epidemic in tropical and subtropical countries.Usual symptoms are fever,headache,arthralgia and myalgia with severe prostration.Hemorrhagic manifestations as rash and thrombocytopenia are common.The two widely known,potentially fatal,complications are Dengue hemorrhagic fever and Dengue Shock Syndrome. 相似文献
106.
Anirban Banerjee Nandan Kumar Mondal Debangshu Das Manas Ranjan Ray 《Inflammation》2012,35(2):671-683
The possibility of inflammation and neutrophil activation in response to indoor air pollution (IAP) from biomass fuel use
has been investigated. For this, 142 premenopausal, never-smoking women (median age, 34 years) who cook exclusively with biomass
(wood, dung, crop wastes) and 126 age-matched control women who cook with cleaner fuel liquefied petroleum gas (LPG) were
enrolled. The neutrophil count in blood and sputum was significantly higher (p < 0.05) in biomass users than the control group. Flow cytometric analysis revealed marked increase in the surface expression
of CD35 (complement receptor-1), CD16 (FCγ receptor III), and β2 Mac-1 integrin (CD11b/CD18) on circulating neutrophils of biomass users. Besides, enzyme-linked immunosorbent assay showed
that they had 72%, 67%, and 54% higher plasma levels of the proinflammatory cytokines tumor necrosis factor-alpha, interleukin-6,
and interleukin-12, respectively, and doubled neutrophil chemoattractant interleukin-8. Immunocytochemical study revealed
significantly higher percentage of airway neutrophils expressing inducible nitric oxide synthase, while the serum level of
nitric oxide was doubled in women who cooked with biomass. Spectrophotometric analysis documented higher myeloperoxidase activity
in circulating neutrophils of biomass users, suggesting neutrophil activation. Flow cytometry showed excess generation of
reactive oxygen species (ROS) by leukocytes of biomass-using women, whereas their erythrocytes contained a depleted level
of antioxidant enzyme superoxide dismutase (SOD). Indoor air of biomass-using households had two to four times more particulate
matter with diameters of <10 μm (PM10) and <2.5 μm (PM2.5) as measured by real-time laser photometer. After controlling potential confounders, rise in proinflammatory mediators among
biomass users were positively associated with PM10 and PM2.5 in indoor air, suggesting a close relationship between IAP and neutrophil activation. Besides, the levels of neutrophil activation
and inflammation markers were positively associated with generation of ROS and negatively with SOD, indicating a role of oxidative
stress in mediating neutrophilic inflammatory response following chronic inhalation of biomass smoke. 相似文献
107.
108.
Melanoma is the leading cause of death from skin disease due, in large part, to its propensity to metastasize. We have examined the effect of berberine, an isoquinoline alkaloid, on human melanoma cancer cell migration and the molecular mechanisms underlying these effects using melanoma cell lines, A375 and Hs294. Using an in vitro cell migration assay, we show that over expression of cyclooxygenase (COX)-2, its metabolite prostaglandin E? (PGE?) and PGE? receptors promote the migration of cells. We found that treatment of A375 and Hs294 cells with berberine resulted in concentration-dependent inhibition of migration of these cells, which was associated with a reduction in the levels of COX-2, PGE? and PGE? receptors (EP2 and EP4). Treatment of cells with celecoxib, a COX-2 inhibitor, or transient transfection of cells with COX-2 small interfering RNA, also inhibited cell migration. Treatment of the cells with 12-O-tetradecanoylphorbol-13-acetate (TPA), an inducer of COX-2 or PGE?, enhanced cell migration, whereas berberine inhibited TPA- or PGE?-promoted cell migration. Berberine reduced the basal levels as well as PGE?-stimulated expression levels of EP2 and EP4. Treatment of the cells with the EP4 agonist stimulated cell migration and berberine blocked EP4 agonist-induced cell migration activity. Moreover, berberine inhibited the activation of nuclear factor-kappa B (NF-κB), an upstream regulator of COX-2, in A375 cells, and treatment of cells with caffeic acid phenethyl ester, an inhibitor of NF-κB, inhibited cell migration. Together, these results indicate for the first time that berberine inhibits melanoma cell migration, an essential step in invasion and metastasis, by inhibition of COX-2, PGE? and PGE? receptors. 相似文献
109.
110.
The most common malignancy of biliary tract is gallbladder cancer(GBC) which is the third most common cancer in gastrointestinal tract. It is a lethal disease for most patients in spite of growing awareness and improved diagnostic techniques. GBC has a verypoor prognosis and the 5 year survival rate is 10%. Although etiology of the carcinoma of the gallbladder is still obscure, various factors have been implicated, cholelithiasis being the most frequent. The incidence of GBC worldwide is based on the gender, geography and ethnicity which suggest that both genetic and environmental factors can cause GBC. The major route of spread of gallbladder cancer(GC) is locoregional rather than distant. It spreads by lymphatic, vascular, neural, intraperitoneal, and intraductal routes. Sonography is usually the most common imaging test to evaluate symptoms of biliary tract disease including suspected GC. With recent advances in imaging modalities like multi-detector computed tomography(CT) scanners, magnetic resonance imaging-positron emission tomography/CT diagnosis of gallbladder cancer has improved. Studies have also targeted molecular and genetic pathways. Treatment options have included extended and radical surgeries and adjuvant chemotherapy. This review article deals in detail with important aspects of carcinoma gallbladder and its manifestations and challenges. Role of various imaging modalities in characterization and accurate staging has been discussed. The loco-regional spread of this aggressive malignancy is dealt explicitly. 相似文献