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91.
Activation of cytotoxic nucleoside analogues in vivo depends primarily on their cell-specific phosphorylation. Anticancer chemotherapy using nucleoside analogues may be significantly enhanced by intracellular administration of active phosphorylated drugs. However, the cellular transport of anionic compounds is very ineffective and restricted by many drug efflux transporters. Recently developed cationic nanogel carriers can encapsulate large amounts of nucleoside 5'-triphosphates that form polyionic complexes with protonated amino groups on the polyethylenimine backbone of the nanogels. In this paper, the 5'-triphosphate of an antiviral nucleoside analogue, 3'-azido-2',3'-dideoxythymidine (AZT), was efficiently synthesized and its complexes with nanogels were obtained and evaluated as potential cytotoxic drug formulations for treatment of human breast carcinoma cells. A selective phosphorylating reagent, tris-imidazolylphosphate, was used to convert AZT into the nucleoside analogue 5'-triphosphate using a one-pot procedure. The corresponding 3'-azido-2',3'-dideoxythymidine 5'-triphosphate (AZTTP) was isolated with high yield (75%). Nanogels encapsulated up to 30% of AZTTP by weight by mixing solutions of the carrier and the drug. The AZTTP/nanogel formulation showed enhanced cytotoxicity in two breast cancer cell lines, MCF-7 and MDA-MB-231, demonstrating IC50 values 130-200 times lower than those values for AZT alone. The exact mechanism of drug release from nanogels remains unclear. One mechanism could involve interaction with negatively charged counterions. A high affinity of nanogels to isolated cellular membranes has been observed, especially for nanogels made of amphiphilic block copolymer, Pluronic P85. Cellular trafficking of nanogel particles, contrasted by polyethylenimine-coordinated copper(II) ions, was studied by transmission electron microscopy (TEM), which revealed membranotropic properties of nanogels. A substantial release of encapsulated drug was observed following interactions of drug-loaded nanogels with cellular membranes. A drug release mechanism triggered by interaction of the drug-loaded nanogels with phospholipid bilayer is proposed. The results illustrate therapeutic potential of the phosphorylated nucleoside analogues formulated in nanosized cross-linked polymeric carriers for cancer chemotherapy. 相似文献
92.
93.
Virological and pharmacological parameters predicting the response to lopinavir-ritonavir in heavily protease inhibitor-experienced patients
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Marcelin AG Cohen-Codar I King MS Colson P Guillevic E Descamps D Lamotte C Schneider V Ritter J Segondy M Peigue-Lafeuille H Morand-Joubert L Schmuck A Ruffault A Palmer P Chaix ML Mackiewicz V Brodard V Izopet J Cottalorda J Kohli E Chauvin JP Kempf DJ Peytavin G Calvez V 《Antimicrobial agents and chemotherapy》2005,49(5):1720-1726
The genotypic inhibitory quotient (GIQ) has been proposed as a way to integrate drug exposure and genotypic resistance to protease inhibitors and can be useful to enhance the predictivity of virologic response for boosted protease inhibitors. The aim of this study was to evaluate the predictivity of the GIQ in 116 protease inhibitor-experienced patients treated with lopinavir-ritonavir. The overall decrease in human immunodeficiency virus type 1 (HIV-1) RNA from baseline to month 6 was a median of -1.50 log(10) copies/ml and 40% of patients had plasma HIV-1 RNA below 400 copies/ml at month 6. The overall median lopinavir study-state C(min) concentration was 5,856 ng/ml. Using univariate linear regression analyses, both lopinavir GIQ and the number of baseline lopinavir mutations were highly associated with virologic response through 6 months. In the multivariate analysis, only lopinavir GIQ, baseline HIV RNA, and the number of prior protease inhibitors were significantly associated with response. When the analysis was limited to patients with more highly mutant viruses (three or more lopinavir mutations), only lopinavir GIQ remained significantly associated with virologic response. This study suggests that GIQ could be a better predictor of the virologic response than virological (genotype) or pharmacological (minimal plasma concentration) approaches used separately, especially among patients with at least three protease inhibitor resistance mutations. Therapeutic drug monitoring for patients treated by lopinavir-ritonavir would likely be most useful in patients with substantially resistant viruses. 相似文献
94.
Kohli V 《Indian journal of pediatrics》2005,72(2):181
In some children of Tetralogy of Fallot's (TOF) presenting with progressive cyanosis, are palliative Blalock-Taussing (BT) shunt may be required. There are no reports of this modality of management in India, though this has been practiced in the other countries. The author reports an infant with Tetralogy of Fallot's who successfully underwent ballon dilatation of the pulmonary valve. Review of literature shows 332 patients with TOF undergoing pulmonary valve balloon dilatation as an alternative to BT shunt in 12 studies with significant increase in pulmonary artery 'Z' score and low incidence of conversion to shunt. This modality of management should be considered in selected patients to change a palliative surgery to an intervention. 相似文献
95.
96.
Fungal arthritis and osteomyelitis are uncommon diseases and generally present in an indolent fashion. The incidence of fungal bone and joint dis-ease is increasing with an increase in the prevalence of factors predisposing to invasive fungal disease, such as the use of central venous catheters, broad spectrum antibiotics, immunosuppression, and abdominal surgery. Definitive diagnosis relies on bone or synovial culture or biopsy. Successful management has traditionally consisted of amphotericin B in combination with surgical debridement. Given the rarity of this disease, treatment is not well defined, but reports of success with the use of azole antifungal agents, including itraconazole, fluconazole, voriconazole, and posaconazole, are promising. 相似文献
97.
Protozoal infections of the gastrointestinal tract occur worldwide and have substantial morbidity and mortality. Prevalence
is higher in the economically deprived regions of the world, especially the developing countries. Infections like amoebiasis
and giardiasis have a worldwide distribution, being endemic in India. Apart from producing GI symptoms, growth and development
of children is also impaired. It is seen that protozoa multiply rapidly in their hosts and as there is a lack of effective
vaccines, chemotherapy has been the only practiced way to treat individuals and reduce transmission. The current treatment
modalities for protozoal diarrhoea include 5-nitrosoimidazoles, iodoquinol, diloxanide furoate, paromomycin, chloroquine,
and trimethoprim-sulphamethoxazole. 相似文献
98.
Sud K Swaminathan S Varma N Kohli HS Jha V Gupta KL Sakhuja V 《Nephrology (Carlton, Vic.)》2004,9(6):422-425
Combined liver and kidney transplantation is the ideal treatment for patients with end-stage renal failure secondary to primary hyperoxaluria and systemic oxalosis, with a functioning liver providing replacement of the deficient enzyme and a functioning kidney providing the route of excretion for the oxalate crystals. Pancytopenia from bone marrow infiltration of oxalate crystals is a rare complication of primary hyperoxaluria, and its reversal following transplant has not been described. We report the first case of pancytopenia from marrow infiltration by oxalate crystals reversing following a successful kidney transplant alone. Although kidney alone transplants do not provide the best chance of survival or quality of life as compared to a combined kidney and liver transplant, a well functioning kidney transplant is able to take care of the systemic oxalate load and ameliorate, at least for a period of time, the systemic complications of oxalosis. 相似文献
99.
Dietary L-arginine supplementation enhances endothelial nitric oxide synthesis in streptozotocin-induced diabetic rats 总被引:5,自引:0,他引:5
This study tested the hypothesis that dietary arginine supplementation increases endothelial tetrahydrobiopterin (BH(4)) availability for nitric oxide (NO) synthesis in diabetic rats. Streptozotocin-induced diabetic rats either were given unrestricted access to a casein-based diet (Expt. 1) or were pair-fed the diet on the basis of the food intake per kg of body weight of nondiabetic rats (Expt. 2). Beginning 1 d after vehicle or streptozotocin injection, arginine-HCl (1.51%) or alanine (isonitrogenous control, 2.55%) was added daily to the drinking water for nondiabetic rats, whereas concentrations were adjusted (0.43% arginine-HCl and 0.73% alanine) in the drinking water for diabetic rats (which consumed more water) to ensure isonitrogenous provision. At 2 wk after the initiation of arginine supplementation, coronary endothelial cells and plasma were obtained for the measurement of NO synthesis and metabolites. In both experiments, plasma and endothelial concentrations of N(G)-monomethylarginine, asymmetric dimethylarginine, and symmetric dimethylarginine increased, but those of arginine as well as endothelial BH(4) availability and NO synthesis decreased in diabetic rats, compared with nondiabetic rats. In both diabetic and nondiabetic rats, arginine supplementation increased plasma concentrations of arginine and insulin, endothelial concentrations of arginine and BH(4), and endothelial NO synthesis, but did not affect plasma and endothelial concentrations of methylarginines or plasma concentrations of homocysteine. Dietary arginine supplementation or provision of a BH(4) precursor normalized endothelial NO synthesis in diabetic rats. Arginine supplementation did not affect plasma glucose levels in nondiabetic rats, but reduced body weight loss and plasma glucose levels in diabetic rats. Thus, dietary L-arginine supplementation stimulates endothelial NO synthesis by increasing BH(4) provision, which is beneficial for vascular function and glucose homeostasis in diabetic subjects. 相似文献
100.
Molecular characterization of isolates of waterborne Cryptosporidium spp. collected during an outbreak of gastroenteritis in South Burgundy,France
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Dalle F Roz P Dautin G Di-Palma M Kohli E Sire-Bidault C Fleischmann MG Gallay A Carbonel S Bon F Tillier C Beaudeau P Bonnin A 《Journal of clinical microbiology》2003,41(6):2690-2693
In September 2001, a waterborne outbreak of gastroenteritis occurred in eastern France. Of 31 fecal samples from symptomatic individuals, 19 tested positive for Cryptosporidium with two PCRs targeting the Hsp70 and the 18S rRNA genes of CRYPTOSPORIDIUM: Sequencing of the PCR fragments produced sequences identical to that of Cryptosporidium parvum genotype 1. 相似文献