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51.
52.

Background  

High accrual to clinical trials enables new treatment strategies to be tested rapidly, accurately and with generalisability. Ethical standards also must be high so that participation is voluntary and informed. However, this can be difficult to achieve in trials with complex designs and in those which are closely embedded in clinical practice. Optimal recruitment requires a balance of both ethical and accrual considerations. In the context of a trial of stratified treatments for children with acute lymphoblastic leukaemia (UKALL2003) we examined how recruitment looked to an observer and how it felt to the parents, to identify how doctors' communication could promote or inhibit optimal recruitment.  相似文献   
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54.
The doctrine of contributory negligence evolved from 19th century economic legal policy seeking to protect America's fledgling industries from liability for injuries resulting from their activities. These policies resulted in an anti-claimant environment that made it difficult for any plaintiff, including malpractice plaintiffs, to recover for their injuries. Since the onset of the 20th century, courts, spurred by state and federal legislative acts, have become more even-handed, and contributory negligence has become a limited defense in malpractice cases. This article defines some of the situations where courts have found that patient's actions have barred plaintiff recovery because of contributory negligence and offers the limited prediction that contributory negligence may be on the verge of once again becoming a major malpractice defense.  相似文献   
55.
The Emergency Medical Treatment and Labor Act (EMTALA) was enacted to prevent patient dumping. It provides patients a considerable amount of protection and leverage in obtaining care under emergency situations. The reimbursement strictures imposed by managed care organizations have compounded the problems. This article summarizes the Act's definition of role and duties of hospitals and physicians and the regulations to which these parties must adhere or face significant penalties.  相似文献   
56.
A variety of anti-cancer drugs elevate endogenous ceramide, thereby inducing apoptosis in tumor cells. Recently, we have introduced novel ceramide analogs of the beta-hydroxy alkyl amide type, which trigger pro-apoptotic signaling pathways without prior elevation of endogenous ceramide. They induce apoptosis specifically in rapidly dividing neuroblastoma cells, but not in resting or differentiated cells. We characterize new ceramide mimics that have been derived from N-acylation of serinol (S), diethanolamine (B), propanolamine (P), and tris(hydroxy-methyl)methylamine (T) with myristic (14), palmitic (16), or oleic (18) acid. The water solubility of these compounds exceeds that of ceramide by more than 100-fold (up to 5 mM). Apoptosis of human neuroblastoma, glioma, medulloblastoma, and adenocarcinoma cells is induced by N-(2-hydroxy-1-(hydroxymethyl)ethyl)-palmitoylamide, C16-serinol (S16), N-(2-hydroxy-1-(hydroxymethyl)ethyl)-oleoylamide, C18-serinol (S18), N-bis(2-hydroxyethyl)-myristoyl-amide (B16), and N-tris(hydroxymethyl)methyl-oleoylamide (T18) within 60 min of incubation, and is completed even after removal of the compound from the medium. This is most likely due to a rapid uptake of the analogs followed by their slow release from the cells. Alteration of the acyl chain length to less than 14 methylene units, removal of the amino group, or reducing the number of hydroxyalkyl residues to less than two significantly lowers or eliminates the pro-apoptotic potential of these compounds. The target specificity of novel ceramide analogs for tumor cells, their water solubility, and fast pro-apoptotic mechanism indicates a high therapeutic potential for cancer treatment.  相似文献   
57.
Xi  L; Zhang  L; Wang  Y; Smith  MT 《Carcinogenesis》1997,18(9):1687-1693
1,3-Butadiene is a carcinogen in rodents, but its potential carcinogenicity to humans remains controversial. Numerous studies have shown that butadiene and its metabolites cause sister chromatid exchanges in vitro and in vivo. To test for other types of genotoxicity, the micronucleus assay and fluorescence in situ hybridization (FISH) have been used to detect chromosome damage in human lymphocytes caused by two reactive metabolites of butadiene, diepoxybutane (DEB) and monoepoxybutene (MEB). DEB (0.5-5.0 microM) significantly increased micronucleus formation 4- to 6-fold (P <0.01) and MEB (1-500 microM) by 2- to 4-fold (P <0.01) over control levels. The ability of DEB and MEB to induce aneuploidy of chromosomes 7, 8, 12, and X was examined using dual-color FISH in both interphase and metaphase cells. These chromosomes were chosen because of their involvement in leukemogenesis. Both DEB and MEB caused dose-dependent increases in hyperdiploidy of chromosomes 12 and X, but had no discernible effect on chromosomes 7 and 8. These results suggest that DEB and MEB cause chromosome-specific aneuploidy in human cells. If formed in sufficient amounts, DEB and MEB may produce chromosome damage of the type found in leukemia following exposure to butadiene.   相似文献   
58.
Six children presenting with partial growth hormone (GH) deficiency (mean GH peak in two different tests, 8.0 k1.3 μ g/l ) aged 8–10.3 years (mean, 2.7 ± 0.9 years) were treated for 6 months by continuous subcutaneous infusion of GH-releasing hormone(1–29)-NH, (GHRH(1–29)-NH2); 24-hour GH profiles and height velocity were measured. A biphasic effect of GHRH(1–29)-NH2 infusion was observed. After an early substantial increase in the 24-hour integrated concentration of GH, from 1.6 ± 0.1 to 3.5 ± 0.7 μg/l/minute, a subsequent consistent decrease occurred by 3 months, which was more pronounced after 6 months (mean 24-hour integrated concentration of GH, 1.9± 0.9 μg/l/minute). This effect reflects modification of both pulse amplitude and frequency of GH secretion. At the end of the study, one child had complete suppression of GH secretion and two others showed only one peak above 5 μg/1 during a 24-hour period. No correlation was found between these changes and height velocity. Three children did not grow significantly; the other three children who had a growth response to GHRH(1–29)-NH2 were those with the lowest 24-hour integrated GH concentration at the end of the study. The possible mechanisms involved in this biphasic effect, including GHRH antibodies, changes in somatostatin levels and/or desensitization of pituitary GHRH receptors, have been investigated.  相似文献   
59.
Moderate and severe malnutrition are endemic in much of the developing world and in association with pockets of deprivation in the developed world. The cost in terms of individual and social development is high. The principles of effective management are clearly documented. A low cost, community based treatment programme for moderately and severely malnourished children under 3 years of age was established at a health centre in rural Jamaica. Children were followed up monthly and defaulters were rigorously recalled. Management consisted of carefully delivered dietary advice, antibiotics, anthelminthics, and vitamin supplements. All children improved and the response of 36 children, who were treated in the first year, showed an accelerated weight gain, with catch-up growth and the maintenance of length gain. There was a significant increase in the weight for age, at 1.9% per month over six months, which exceeds the rate reported with food supplementation programmes and nutrition rehabilitation centres.  相似文献   
60.
The use of follow up studies was evaluated in 128 patients with coeliac disease during their first visit to a department for adults. The original diagnosis had been made in childhood in all patients. Fifty eight (45%) of the subjects were following a gluten free diet, 23 (18%) were following a gluten free diet but with occasional gluten consumption, and 47 (37%) had adopted an unrestricted, gluten containing diet for a mean of 11.2 years. There was no correlation in individual subjects between the presence of symptoms, biochemical and immunological abnormalities, severity of histological findings, and the amount of dietary gluten, despite the greater frequency of symptoms in the group following an unrestricted diet than in the other two groups. Short stature and epilepsy with cerebral calcifications only occurred in patients following an unrestricted diet. As only diagnosis based on two or three biopsy samples and regular follow up correlated positively with dietary compliance, it is suggested that a histologically confirmed diagnosis of coeliac disease and regular lifelong follow up are essential in the management of these patients.  相似文献   
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