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Monomethylarsonic acid (MMA) was administered in the diet of male and female Fischer F344 rats and B6C3F1 mice in 2-year feeding studies according to US EPA guidelines. Rats were treated with 50, 400, or 1300 ppm MMA and mice were treated with 10, 50, 200, or 400 ppm MMA based on preliminary short-term studies. The highest dose in the male and female rat groups was reduced to 1000 ppm during week 53 and then further reduced to 800 ppm during week 60 due to high mortality in the male rats. There was no treatment-related mortality in the mice. The primary target organ for MMA-induced toxicity in rats and mice was the large intestine. Toxicity was more severe in rats compared to mice and in male rats compared to female rats. The maximum tolerated dose for chronic dietary administration of MMA in rats and mice was assessed as 400 ppm, and the no effect level with regard to intestinal toxicity was assessed as 50 ppm for rats and female mice and 200 ppm for male mice. There were no treatment-related neoplastic effects detected in either the rat or the mouse. 相似文献
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Cystoenteric conversion and reduction cystoplasty for treatment of bladder dysfunction after pancreas transplantation 总被引:7,自引:0,他引:7
Black PC Plaskon LA Miller J Bakthavatsalam R Kuhr CS Marsh CL 《The Journal of urology》2003,170(5):1913-1917
PURPOSE: Bladder drainage of pancreatic exocrine secretions during pancreas transplantation can lead to significant urological complications. Our experience with cystoenteric conversion (CEC) is reviewed with respect to safety and efficacy. Select patients underwent concurrent reduction cystoplasty. MATERIALS AND METHODS: A total of 255 pancreas transplantations were performed at the University of Washington between 1990 and 2001, of which 236 were bladder drained and 33 required enteric conversion of bladder drainage. An additional patient from an outside institution required conversion. These cases were reviewed retrospectively. Of the patients 21 with large capacity (greater than 500 ml) bladders underwent concurrent reduction cystoplasty. RESULTS: Mean age of the 20 male and 14 female patients was 44 years (range 33 to 60) and mean interval between transplantation and CEC was 4.3 years (0.6 to 9). The most frequent indication for CEC was recurrent urinary tract infections (15 of 34 cases, 44%). Mean followup after CEC was 2.5 years (range 0.3 to 6.5). Six complications requiring reoperation were seen in 5 of the 34 patients (15%), one of which led to death (3%). Normal pancreatic graft function persisted in 30 of the 34 cases (88%). After reduction cystoplasty mean bladder capacity in all 34 cases decreased from 900 to 465 ml intraoperatively (p <0.0001) and from 650 to 362 ml in 9 according to urodynamics (p <0.015). Of the patients 30 (88%) experienced resolution of symptoms, while 3 (9%) experienced improvement and 1 (3%) continued to have recurrent infections. CONCLUSIONS: Although we advocate maximal conservative treatment of the urological complications of pancreas transplantation, CEC offers safe and effective management of these complications, and can easily be combined with reduction cystoplasty in select cases to optimize postoperative voiding function. 相似文献
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The effects of enforced expression of p53 on the sensitivity of p53(-/-) human monocytic leukemia cells (U937) to apoptosis following exposure to the S-phase-specific antimetabolite 1-[beta-D-arabinofuranosyl]cytosine (ara-C) were examined. Cells were stably transfected with a plasmid containing a chimeric DNA construct encoding a temperature-sensitive p53 variant (135(ala-->val)), which transactivates at 32 degrees but is non-functional at 37 degrees. A significant reduction in the S-phase population was observed in ptsp53 mutants incubated at 32 degrees. Nevertheless, while vector controls did not exhibit differential sensitivity to ara-C at 32 degrees versus 37 degrees, temperature-sensitive p53 mutants displayed a significant increase in apoptosis at the permissive temperature. This was not accompanied by increased ara-CTP formation, DNA incorporation of [3H]ara-C, or altered expression of Bcl-2 or Bax. Enhanced sensitivity was associated with increased mitochondrial injury (e.g. cytochrome c release), caspase activation, and loss of clonogenic survival. Significantly, ptsp53 cells synchronized in S phase were markedly more sensitive to ara-C-mediated mitochondrial injury and apoptosis at 32 degrees, indicating that wild-type p53 specifically enhances the susceptibility of this subpopulation to ara-C lethality. Consistent with these results, transient transfection of human wild-type p53 cDNA rendered parental U937 cells more sensitive to ara-C-mediated cell death. Collectively, these findings indicate that p53 expression renders S-phase U937 cells more susceptible to ara-C-mediated mitochondrial dysfunction, cytochrome c release, apoptosis, and loss of clonogenic survival without enhancing ara-C metabolism. Such findings raise the possibility that loss of functional p53 activity allows leukemia cells to circumvent ara-C lethality. 相似文献
55.
We report 4 cases of malignant peripheral nerve sheath tumors (MPNST) with neurofibromatosis type 1 (NF1). Mean age was 29.5. Two of them had a family history. Three of them were male. All of them had enlarging mass and pain in the background of neurofibromas. Locations were popliteal, thigh and forearm. The masses were greater than 5 cm in diameter in each case. In two cases the mass was showing continuity with a nerve. One patient had a nonossifying fibroma as well as a MPNST. Wide excision and radiotherapy were applied to three of the patients. One of them did not take any therapy after surgical resection. Two of the patients died of lung metastases after a mean period of 12.5 months. In a majority of NF1 patients MPNST emerges from a preexisting neurofibroma. The patients with NF1 are at greatest risk for developing sarcomas, so they should be followed closely. 相似文献
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Burke LE Hudson AG Warziski MT Styn MA Music E Elci OU Sereika SM 《The American journal of clinical nutrition》2007,86(3):588-596
BACKGROUND: A vegetarian diet may lead to numerous health benefits, including weight loss. OBJECTIVE: We examined the joint effects of personal preference of dietary treatment and a calorie-restricted, low-fat lactoovovegetarian diet (LOV-D) compared with a standard calorie-restricted, low-fat omnivorous diet (STD-D) on changes in weight, total cholesterol, ratio of LDL to HDL cholesterol (LDL:HDL cholesterol), triacylglycerols, insulin resistance, and macronutrient intake during an 18-mo study. DESIGN: This was a randomized clinical trial of 176 overweight and obese adults who were recruited and randomly assigned first to 1 of 2 preference conditions (yes or no). If assigned to Preference-No, they were randomly assigned to 1 of the 2 diet conditions (STD-D or LOV-D). If assigned to Preference-Yes, they were assigned to the diet they indicated as preferred at screening. The 12-mo intervention was followed by a 6-mo maintenance phase. RESULTS: Participants were mainly women (86.9%) and white (70.5%); 75% completed the 18-mo study. A significant interaction between preference and dietary treatment was not observed for any of the outcome variables. However, participants in the Preference-No groups significantly decreased their triacylglycerols (P = 0.04). The only effect observed for diet was a borderline significant decrease in LDL:HDL cholesterol for the LOV-D group (P = 0.06). Within the LOV-D groups, those who were 100% adherent to the LOV-D had significant and marginally significant reductions in monounsaturated fat (P = 0.02) and total fat (P = 0.05) intakes at 18 mo. CONCLUSIONS: Our findings suggest that neither prescribing a vegetarian diet nor allowing persons to choose their preferred diet had a significant effect on outcome measures. However, all participants had a significant reduction in total energy and fat intakes and an increase in energy expenditure, which was reflected in reduced body weight. This clinical trial was registered at www.clinicaltrials.gov as NCT00330629. 相似文献
60.
Mitscheli S. Da Rocha Lora L. Arnold Puttappa R. Dodmane Karen L. Pennington Fang Qiu João Lauro V. De Camargo Samuel M. Cohen 《Toxicology》2013,303(2-3):238-246
Diuron is carcinogenic to the rat urinary bladder at high dietary levels. The proposed mode of action (MOA) for diuron is urothelial cytotoxicity and necrosis followed by regenerative urothelial hyperplasia. Diuron-induced urothelial cytotoxicity is not due to urinary solids. Diuron is extensively metabolized, and in rats, N-(3,4-dichlorophenyl)urea (DCPU) and 4,5-dichloro-2-hydroxyphenyl urea (2-OH-DCPU) were the predominant urinary metabolites; lesser metabolites included N-(3,4-dichlorophenyl)-3-methylurea (DCPMU) and trace levels of 3,4-dichloroaniline (DCA). In humans, DCPMU and DCPU have been found in the urine after a case of product abuse. To aid in elucidating the MOA of diuron and to evaluate the metabolites that are responsible for the diuron toxicity in the bladder epithelium, we investigated the urinary concentrations of metabolites in male Wistar rats treated with 2500 ppm of diuron, the urothelial cytotoxicity in vitro of the metabolites and their gene expression profiles. DCPU was found in rat urine at concentrations substantially greater than the in vitro IC50 and induced more gene expression alterations than the other metabolites tested. 2-OH-DCPU was present in urine at a concentration approximately half of the in vitro IC50, whereas DCPMU and DCA were present in urine at concentrations well below the IC50. For the diuron-induced MOA for the rat bladder, we suggest that DCPU is the primary metabolite responsible for the urothelial cytotoxicity with some contribution also by 2-OH-DCPU. This study supports a MOA for diuron-induced bladder effects in rats consisting of metabolism to DCPU (and 2-OH-DCPU to a lesser extent), concentration and excretion in urine, urothelial cytotoxicity, and regenerative proliferation. 相似文献