全文获取类型
收费全文 | 902篇 |
免费 | 52篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 47篇 |
妇产科学 | 12篇 |
基础医学 | 89篇 |
口腔科学 | 6篇 |
临床医学 | 37篇 |
内科学 | 198篇 |
皮肤病学 | 18篇 |
神经病学 | 26篇 |
特种医学 | 163篇 |
外科学 | 150篇 |
综合类 | 15篇 |
一般理论 | 2篇 |
预防医学 | 35篇 |
眼科学 | 44篇 |
药学 | 43篇 |
中国医学 | 3篇 |
肿瘤学 | 66篇 |
出版年
2023年 | 6篇 |
2022年 | 15篇 |
2021年 | 39篇 |
2020年 | 13篇 |
2019年 | 28篇 |
2018年 | 33篇 |
2017年 | 29篇 |
2016年 | 33篇 |
2015年 | 32篇 |
2014年 | 45篇 |
2013年 | 41篇 |
2012年 | 66篇 |
2011年 | 80篇 |
2010年 | 60篇 |
2009年 | 44篇 |
2008年 | 73篇 |
2007年 | 60篇 |
2006年 | 61篇 |
2005年 | 59篇 |
2004年 | 52篇 |
2003年 | 34篇 |
2002年 | 23篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有959条查询结果,搜索用时 15 毫秒
71.
Hydrophytes lack potential to exhibit cadmium stress induced enhancement in lipid peroxidation and accumulation of proline 总被引:1,自引:0,他引:1
Investigations were carried out to evaluate if hydrophytes (viz. Ceratophyllum, Wolffia, and Hydrilla) can be used as markers to assess the level of heavy metal pollution in aquatic bodies. The potential of these hydrophytes for lipid peroxidation and accumulation of proline in response to cadmium (Cd2+) pollution was studied. Hydrophytes were raised in artificial pond water (APW) supplemented with various levels of Cd2+. Interestingly, unlike mesophytes none of the hydrophytes showed ability to accumulate proline. Infact, in response to Cd2+ pollution hydrophytes exhibited a decline in proline levels in comparison to controls but mesophytes (viz. Brassica juncea, Vigna radiata and Triticum aestivum) showed progressive increase in the level of proline with increase in the extent of Cd2+ pollution. Mesophytes showed six to nine-fold increase in the level of proline in response to 1 mM Cd2+. The potential of the above hydrophytes for lipid peroxidation was also low under Cd2+ stress. In contrast, as expected a significant enhancement in the lipid peroxidation was observed in all three mesophytes in response to their exposure to Cd2+. About two-fold increase in production of malondialdehyde (a cytotoxic product of lipid peroxidation) was recorded in mesophytes exposed to 1 mM Cd2+. However, a decline in chlorophyll (Chl a and Chl b) levels was recorded in response to Cd2+pollution both in hydrophytes as well as mesophytes. In summary, hydrophytes neither have potential to accumulate proline nor have ability to accelerate lipid peroxidation under heavy metal stress. This suggests that the adaptive mechanism(s) existing in hydrophytes to tackle heavy metal stress is distinct from that in mesophytes. 相似文献
72.
Effects of Vitamin C and E on PCB (Aroclor 1254) induced oxidative stress, androgen binding protein and lactate in rat Sertoli cells 总被引:6,自引:0,他引:6
Senthil kumar J Banudevi S Sharmila M Murugesan P Srinivasan N Balasubramanian K Aruldhas MM Arunakaran J 《Reproductive toxicology (Elmsford, N.Y.)》2004,19(2):201-208
The effect of Aroclor 1254 and the ameliorative effect of Vitamin C and E on Sertoli cell function were studied in adult male rats. The rats were administered Aroclor 1254 at a dose of 2 mg/kg bw/day intraperitoneally for 30 days. One group of rats received Vitamin C (100 mg/kg bw/day) while the other group received Vitamin E (50 mg/kg bw/day) orally simultaneously with Aroclor 1254 for 30 days. Necropsy was performed at 24 h after the last injection. Sertoli cells were isolated for the estimation of enzymatic antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GST), and gamma-glutamyl transpeptidase (gamma-GT). Lipid peroxidation (LPO), hydrogen peroxide and hydroxyl radical were estimated. Sertoli cellular androgen binding protein (ABP) and lactate were also quantified. Whereas body weight, testis weight, relative weight of testis, ABP, lactate and specific activities of SOD, CAT, GPx, GR, GST, gamma-GT were all decreased, the levels of hydrogen peroxide, hydroxyl radical and LPO were significantly increased in the Sertoli cells of Aroclor 1254 treated rats. Simultaneous administration of Vitamin C or E restored these parameters to a normal range. Thus, the present study suggests that Aroclor 1254 exposure induces oxidative stress in rat Sertoli cells and furthermore that simultaneous administration of Vitamin C or E ameliorated these effects. 相似文献
73.
Human papillomavirus and risk factors for cervical cancer in Chennai,India: a case-control study 总被引:6,自引:0,他引:6
Franceschi S Rajkumar T Vaccarella S Gajalakshmi V Sharmila A Snijders PJ Muñoz N Meijer CJ Herrero R 《International journal of cancer. Journal international du cancer》2003,107(1):127-133
To evaluate the role of human papillomavirus (HPV) and other risk factors in the aetiology of invasive cervical carcinoma (ICC), we conducted a hospital-based case-control study in Chennai, Southern India. A total of 205 ICC cases (including 12 adenocarcinomas) and 213 frequency age-matched control women were included. HPV DNA in cervical cells was evaluated by means of a polymerase chain-reaction assay. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were computed by means of unconditional multiple logistic regression models. HPV infection was detected in all but one ICC cases and in 27.7% of control women (OR = 498). Twenty-three different HPV types were found. HPV 16 was the most common type in either cases or controls, followed by HPV 18 and 33. The association of ICC with HPV 18 and HPV 16-associated types was somewhat stronger than the one with HPV 16. Multiple HPV infections did not show a higher OR for ICC than single infections. Other than HPV infection, high parity (OR for >4 vs. =2 births = 7.3), a woman's report of her husband's extramarital sexual relationships (OR = 10.0) and early menopause (OR for <45 vs. >/=45 years = 4.2) were significantly associated with ICC, also after restricting the analysis to HPV-positive cases and controls. Poor hygienic conditions were associated with an increased risk of HPV infection among control women but not with ICC risk among HPV-positive women. A vaccine against HPV 16 and 18 may be effective in more than three-quarters of ICC in the study area. 相似文献
74.
Ramesh C. Dhiman Sharmila Pahwa G. P. S. Dhillon Aditya P. Dash 《Parasitology research》2010,106(4):763-773
It is unequivocal that climate change is happening and is likely to expand the geographical distribution of several vector-borne
diseases, including malaria and dengue etc. to higher altitudes and latitudes. India is endemic for six major vector-borne
diseases (VBD) namely malaria, dengue, chikungunya, filariasis, Japanese encephalitis and visceral leishmaniasis. Over the
years, there has been reduction in the incidence of almost all the diseases except chikungunya which has re-emerged since
2005. The upcoming issue of climate change has surfaced as a new threat and challenge for ongoing efforts to contain vector-borne
diseases. There is greater awareness about the potential impacts of climate change on VBDs in India and research institutions
and national authorities have initiated actions to assess the impacts. Studies undertaken in India on malaria in the context
of climate change impact reveal that transmission windows in Punjab, Haryana, Jammu and Kashmir and north-eastern states are
likely to extend temporally by 2–3 months and in Orissa, Andhra Pradesh and Tamil Nadu there may be reduction in transmission
windows. Using PRECIS model (driven by HadRM2) at the resolution of 50 × 50 Km for daily temperature and relative humidity
for year 2050, it was found that Orissa, West Bengal and southern parts of Assam will still remain malarious and transmission
windows will open up in Himachal Pradesh and north-eastern states etc. Impact of climate change on dengue also reveals increase
in transmission with 2 C rise in temperature in northern India. Re-emergence of kala-azar in northern parts of India and reappearance
of chikungunya mainly in southern states of India has also been discussed. The possible need to address the threat and efforts
made in India have also been highlighted. The paper concludes with a positive lead that with better preparedness threat of
climate change on vector-borne diseases may be negated. 相似文献
75.
76.
Sharmila M. Reddy P. Balakrishnan S. Uma S. P. Thyagarajan Suniti Solomon 《Clinical and Vaccine Immunology : CVI》2005,12(2):359-360
For 93 stored serum samples tested by HerpeSelect2 and the Euroimmun enzyme-linked immunosorbent assay for detection of herpes simplex virus type 2-specific immunoglobulin G antibodies, the concordance of positive and negative results was 100%. Moreover, all the results that were equivocal by HerpeSelect2 (negative by Euroimmun) were confirmed as being negative by a Western blot assay. 相似文献
77.
Kiranjit Sekhon Galateia J. Kazakia Andrew J. Burghardt Bryan Hermannsson Sharmila Majumdar 《BONE》2009,44(3):473-479
Accurate bone mineral density (BMD) quantification is critical in clinical assessment of fracture risk and in the research of age-, disease-, and treatment-related musculoskeletal changes. The development of high-resolution peripheral quantitative computed tomography (HR-pQCT) imaging has made possible in vivo assessment of compartmental volumetric BMD (vBMD) and bone micro-architecture in the distal radius and tibia. HR-pQCT imaging relies on a polychromatic X-ray source and therefore is subject to beam hardening as well as scatter artifacts. In light of these limitations, we hypothesize that the accuracy of HR-pQCT vBMD measurement in the trabecular compartment (vBMDtrab) is not independent of bone density and geometry, but rather influenced by variations in trabecular bone volume fraction and cortical thickness. The goal of this study, therefore, was to evaluate the accuracy of HR-pQCT vBMDtrab measurement in the radius and tibia, and to determine the dependence of this measurement on geometric and densitometric parameters. Our approach was to use a series of idealized hydroxyapatite (HA) phantoms with varying densities and geometries to quantify the accuracy of HR-pQCT analysis. Two sets of custom-made HA phantoms designed to mimic the distal tibia and distal radius were manufactured. Geometric and densitometric specifications were based on a dataset of healthy volunteers and osteopenic patients. Multiple beam hardening correction (BHC) algorithms were implemented and evaluated in their ability to reduce measurement error. Substantial errors in measured vBMDtrab were found. Overestimation of vBMDtrab increased proportional to cortical shell thickness and decreased proportional to insert density. The most pronounced vBMDtrab overestimation therefore occurred in the phantoms with the lowest insert densities and highest shell thickness, where error was as high as 20 mg HA/cm3 (33%) in the radius phantom and 25 mg HA/cm3 (41%) in the tibia phantom. Error in vBMDtrab propagates to the calculation of micro-architectural measures; 41% error in vBMDtrab will produce 41% error in volume fraction (BV/TV) and trabecular thickness (Tb.Th), and 5% error in trabecular separation (Tb.Sp). BHC algorithms supplied by the manufacturer failed to eliminate these errors. Our results confirm that geometric and densitometric variations influence the accuracy of HR-pQCT vBMDtrab measurements, and must be considered when interpreting data across populations or time-points. 相似文献
78.
Civilian Prehospital Tourniquet Use Is Associated with Improved Survival in Patients with Peripheral Vascular Injury 总被引:1,自引:0,他引:1
79.
80.
Ramen Goel Madhu Goel Amrit Manik Nasta Sharmila Vyas Shefali Dharia Shireen Hamrapurkar 《Obesity surgery》2018,28(12):3738-3743