全文获取类型
收费全文 | 281篇 |
免费 | 12篇 |
国内免费 | 1篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 20篇 |
2020年 | 12篇 |
2019年 | 12篇 |
2018年 | 20篇 |
2017年 | 11篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 21篇 |
2013年 | 25篇 |
2012年 | 24篇 |
2011年 | 21篇 |
2010年 | 6篇 |
2009年 | 10篇 |
2008年 | 9篇 |
2007年 | 13篇 |
2006年 | 9篇 |
2005年 | 12篇 |
2004年 | 14篇 |
2003年 | 2篇 |
2002年 | 7篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有294条查询结果,搜索用时 15 毫秒
31.
Nazia Riaz Romana Idress Sadia Habib Iqbal Azam El-Nasir MA Lalani 《Translational oncology》2018,11(4):920-929
BACKGROUND: Androgen receptor (AR) has emerged as a significant prognostic marker in early breast cancer (BCa). Association of AR with cancer stem cell (CSC) markers in BCa is unknown. Aim of the present study was to evaluate the immunohistochemical expression of AR, CD44, CD24 and ALDH1 in a cohort of Pakistani patients diagnosed with invasive BCa and to correlate the expression with 5- year disease free survival. PATIENTS AND METHODS: We evaluated immunohistochemical expression AR, CD44, CD24 and ALDH1 in formalin fixed paraffin embedded archival blocks of 166 cases of primary invasive BCa (stage I-III) and correlated the expression with clinicopathological variables and outcome using univariable and multivariable analysis. Survival data was computed by Kaplan Meier curves. RESULTS: Expression of AR was observed in 62.7% tumors whereas CD44, CD24 and ALDH1 were expressed in 61.4%, 44% and 30.1% tumors, respectively. AR expression was significantly associated with T1-T2 tumors, lower grade, estrogen and progesterone receptor expression (P < .05) and remained an independent prognostic indicator in multivariable analysis (adjusted HR 0.33, 95% CI 0.13–0.81; P = .016). Significant association was observed between concordant expression of AR and CD24 (P = .001) with a favorable impact on survival (P = .007) whereas expression of CSC phenotypes (CD44+, CD44+/CD24? and ALDH1+) did not correlate with adverse outcome (P > .05). However, AR expression retained the association with better prognosis even in patients whose tumors exhibited a CSC phenotype. CONCLUSIONS: Expression of AR and CD24 in stage I-III invasive BCa correlates with favorable clinicopathological features and delineates a subgroup of patients with better disease-free survival. 相似文献
32.
Lei Yan Muhammad Riaz Xiuwen Wu Yuhan Wang Chenqing Du Cuncang Jiang 《Acta Physiologiae Plantarum》2018,40(2):33
It has been reported that aluminum (Al) toxicity is a major limiting factor for plant growth and production on acidic soils. Boron (B) is indispensable micronutrient for normal growth of higher plants, and its addition could alleviate Al toxicity. The rape seedlings were grown under three B (0.25, 25 and 500 μM) and two Al concentrations [0 (?Al) and 100 μM (+Al) as AlCl3·6H2O]. The results indicated that Al stress severely hampered root elongation and root activity at 0.25 μM B while the normal (25 μM) and excess (500 μM) B improved the biomass of rape seedlings under Al exposure. Additionally, normal and excess B treatment reduced accumulation of Al in the roots and leaves under Al toxicity, which was also confirmed by hematoxylin with light staining. This indicates that both normal and excess B could alleviate Al toxicity. Furthermore, it also decreased the contents of malondialdehyde and soluble protein under Al toxicity. Likewise, superoxide dismutase activity (SOD) improved by 97.82 and 131.96% in the roots, and 168 and 119.88% in the leaves at 25 and 500 µM B, respectively, while the peroxidase and catalase activities dropped as a result of Al stress. The study results demonstrated that appropriate B application is necessary to avoid the harmful consequences of Al toxicity in rape seedlings. 相似文献
33.
Ehsan Ullah Mughal Amina Sadiq Shahzad Murtaza Hummera Rafique Muhammad Naveed Zafar Tauqeer Riaz Bilal Ahmad Khan Abdul Hameed Khalid Mohammed Khan 《Bioorganic & medicinal chemistry》2017,25(1):100-106
The present study describes efficient and facile syntheses of varyingly substituted 3-thioaurones from the corresponding 3-oxoaurones using Lawesson’s reagent and phosphorous pentasulfide. In comparison, the latter methodology was proved more convenient, giving higher yields and required short and simple methodology. The structures of synthetic compounds were unambiguously elucidated by IR, MS and NMR spectroscopy. All synthetic compounds were screened for their inhibitory potential against in vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Molecular docking studies were also performed in order to examine their binding interactions with AChE and BChE human proteins. Both studies revealed that some of these compounds were found to be good inhibitors against AChE and BChE. 相似文献
34.
A number of new imine derivatives of 5-amino-1, 3, 4-thiadiazole-2-thiol have been synthesized, and their anti-depressant activity was tested using imipramine as reference drug. Two compounds namely 5-{[1-(4-chlorophenyl)-3-(4-methoxy-phenyl)prop-2-en-1-ylidene]-amino}-5-benzylthio-1, 3,4 -thiadiazole 4i(b) and 5-{[1-(4-chlorophenyl)-3-(4-dimethyl-aminophenyl)-prop-2-en-1-ylidene]amino}-5-benzylthio-1,3,4-thiadiazole 4i(c) have shown significant anti-depressant activity, which decreased immobility time by 77.99% and 76.26% compared to the standard imipramine (82%). All the compounds in the series have passed neurotoxicity tests. 相似文献
35.
The root extract of Operculina turpethum (OTE) has been used as an anti-inflammatory, purgative, and hepato-protective agent. N-Nitrosodimethylamine (NDMA) is a potent hepatotoxin that induces fibrosis of the liver. In the present study, we examined the therapeutic effects of OTE root extract against NDMA-induced hepatotoxicity and clastogenicity in rats. Hepatic fibrosis was induced in adult male albino rats through serial intraperitoneal administrations of NDMA at a concentration of 10 mg/kg body weight on three consecutive days of each week over a period of three weeks. A group of rats received OTE orally in doses of 75, 150 and 200 mg/kg body weight at 5 h after the administration of NDMA. The controls and treated animals were sacrificed on days-7, 14 and 21 after the start of the administration of NDMA. The progression of hepatic fibrosis as well as the amelioration effect of OTE was evaluated through histopathologically as well as by immunohistochemical staining for the activation of hepatic stellate cells. Alterations in serum and liver biochemical parameters and LDH isoenzymes were also studied. Serial administration of NDMA resulted in well formed fibrosis in the liver and induction of micronuclei in the bone marrow cells. Staining of α-SMA demonstrated activated stellate cells from day-7 onwards which was dramatically increased on day-21. An elevation of micronuclei count, liver function enzymes, serum hydroxyproline levels and LDH isoenzymes 4 and 5 were also observed. All these changes were remarkably reduced in OTE administered animals and fibrogenesis was completely absent. Our results suggest that OTE has hepatoprotective and anti-clastogenic effects against NDMA-induced hepatic fibrosis. Therefore OTE may be used as a hepatoprotective agent against various liver diseases including toxic liver injury. 相似文献
36.
Francesco Marchetti Massimo Bergamin Susanna Bosi Riaz Khan Erminio Murano Stefano Norbedo 《Carbohydrate polymers》2009,75(4):670-676
Polysaccharides are widely used as carriers in the field of drug delivery. We present a methodology to obtain water soluble drug-conjugates based on scleroglucan. Selective C-6 halogenation gives access to C-6 esters; conjugates between methotrexate and scleroglucan are described, potentially useful for antitumour therapy or in rheumatoid arthritis treatment. 相似文献
37.
Muhammad Tariq Murtaza Memon Asif Jafferani Sana Shoukat Saqib Ali Gowani Rabeeya Nusrat Mehmood Riaz Junaid Patel Bushra Jamil Raymond A. Smego Jr. 《PloS one》2009,4(10)
Background
Cholera is an important infectious cause of secretory diarrhea. The primary symptom of infection is the sudden onset of watery diarrhea with subsequent volume depletion causing renal insufficiency. The objective of this research is to study the level of dehydration at presentation and subsequent fluid management in patients with cholera.Methods
This study was conducted on 191 patients of Cholera admitted at a tertiary care hospital in Karachi, Pakistan during the period of 5 years. Medical charts were evaluated retrospectively for initial hydration status, baseline lab investigations on admission and discharge and fluid therapy given to all the patients while their stay in the hospital and the data was analyzed on SPSS 15.0.Results
Out of the 191 patients, 83(43%) were males and 108 (57%) were females with mean age of 42.3 years (SD±18.34). The average duration of symptoms was 3.75 days (SD±2.04). Of 191 patients, 175 (92.1%) presented with dehydration, 80 (42.3%) were given Ringer''s Lactate (R/L) + Normal Saline (N/S), 45 (24%) patients were given R/L + N/S + Oral Rehydration Therapy (ORS), 27 (14.3%) of the patients were kept on R/L only and remaining were given various combinations of R/L, N/S, ORS and Dextrose Saline (D/S). On admission mean Blood Urea Nitrogen (BUN) was 24.54 (SD±16.6), mean creatinine was 2.47 (SD±2.35) and mean BUN/Creatinine ratio was 11.63 (SD±5.7).Conclusion
Aggressive fluid rehydration remains the cornerstone of management of cholera. Instead of presenting with a classical BUN/Creatinine ratio of >20∶1, patients with pre-renal failure in cholera may present with a BUN/Creatinine ratio of <15∶1. 相似文献38.
Three-dimensional (3D) models for the 79.2 kDa activated Cry1Ib9 and 77.4 kDa activated Cry3A δ-endotoxins from Bacillus thuringiensis (Bt) native isolates that are specifically toxic to Coleopteran insect pests were constructed by utilizing homology modeling online tool. Evidences presented here, based on the identification of structural equivalent residues of Cry1Ib9 and Cry3A toxin through homology modelling indicate that, they share a common Bt toxin tridimensional structure. The main differences observed in Cry1I9 domain I at positions α2b (S56-I60), α4 (F78-l93) and additionally β0 (Q10-L12), α8a (T280-V282) were observed, in domain II at positions α9b (P333-L339), β6(T390-Q393), β7(V398-W404), β8 (V418-W425), β9 (E453-N454), β10 (S470-I479) where as in domain III the changes were observed at positions β19 (R601-F607), β20 (609-L613), β21 (S618-F627) and α11a (K655-F664), α13, α14 components present at downstream sites, where as in Cry3A main differences observed in domain I is at the position of α4 (P105-I152), α5 (Q163-A185), β1A(E190-L192), α6 (F193-Y217), Domain II is not consevered and main variations were observed at β2 (E292-L295), β3(V299-L308), β4(I340-F347), β5(D356-P368), β6(I375-T377), β7(V389-F394), β8(K398-N405), β9(Y416-Y427), β10 (T436-Y439), β12(G476-H495), β12A (M503-I504) where as in domain III main variations observed at positions of β18 (P583-I593), β19(F604-S610), β20(P611-L615), β21(N619-G626). Cry1Ib9 and Cry3A contain the most variable regions in the loops of domain II, which determine the specificity of these toxins. These are the first models of Coleopteran-active protein from native isolates of Bt and its importance can be perceived since members of this group of toxins are potentially important candidates for coleoptera insect pest control programs. 相似文献
39.
Francolinus pondicerianus interpositus (grey francolin, Galliformes) is the only francolin present in the Suleiman Range (central Pakistan), one of the poorest and least developed areas in Pakistan. As a game bird, the francolin is an important income source for the region, but no demographic data are available. Therefore, the aim of this work was to study the polymorphism pattern of the Control Region gene (mitochondrial DNA, mtDNA), in order to obtain some initial information about genetic diversity, possible structure and demographic dynamics in this population. In 29 individuals captured in four sampling areas in the western and the eastern Suleiman Range, we detected nine polymorphic sites in a 511 bp fragment of the mtDNA Control Region gene, resulting in seven haplotypes. Haplotype (h = 0.818 ± 0.032) and nucleotide diversity (π % = 0.308 ± 0.210) values suggested a large population size and a low divergence among the haplotypes. AMOVA (Φ(ST) = 0.005; P = 0.352) did not detect any significant differences among the western and eastern populations; therefore, specimens of both sampled areas could be considered as drawn from a single population. The observed distribution of pairwise mismatches was bimodal, revealing significant departure from a growing-decreasing population model (P = 0.030); these results would point to a demographic equilibrium. Tribal control of hunting might provide an explanation for this situation, but future overhunting would threaten the survival of this population. 相似文献
40.
Faheem M Raheel U Riaz MN Kanwal N Javed F us Sahar Sadaf Zaidi N Qadri I 《Molecular biology reports》2011,38(6):3731-3740
More than one third of the world’s population living in tropical and subtropical areas of the world is at risk of dengue infections
and as many as 100 million people are yearly infected. This disease has reemerged during the past 20 years in the form of
an epidemic. Dengue is caused by one of four related serotypes of dengue virus and often leads to severe forms of the disease,
resulting commonly from secondary infections. Dengue virus is a mosquito borne virus, belongs to the family Flaviviridae and consists of a single stranded positive sense RNA genome. Like other RNA viruses it escapes defense mechanisms and neutralization
attempts by mutations, which make it more resistant and adaptable to its environment. Antiviral strategies and vaccine development
is thus impaired and hence to date there is no licensed vaccine available for dengue virus. Here we discuss various efforts
made towards the identification of potential vaccine targets for dengue as well as various strategies employed by research
groups/pharmaceutical companies towards the development of a successful dengue vaccine. 相似文献