全文获取类型
收费全文 | 830篇 |
免费 | 68篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 11篇 |
妇产科学 | 70篇 |
基础医学 | 89篇 |
口腔科学 | 7篇 |
临床医学 | 40篇 |
内科学 | 118篇 |
皮肤病学 | 4篇 |
神经病学 | 89篇 |
特种医学 | 15篇 |
外科学 | 47篇 |
综合类 | 1篇 |
预防医学 | 52篇 |
眼科学 | 3篇 |
药学 | 135篇 |
肿瘤学 | 204篇 |
出版年
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 14篇 |
2019年 | 10篇 |
2018年 | 15篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 15篇 |
2014年 | 20篇 |
2013年 | 16篇 |
2012年 | 33篇 |
2011年 | 39篇 |
2010年 | 19篇 |
2009年 | 15篇 |
2008年 | 25篇 |
2007年 | 38篇 |
2006年 | 32篇 |
2005年 | 29篇 |
2004年 | 35篇 |
2003年 | 36篇 |
2002年 | 31篇 |
2001年 | 48篇 |
2000年 | 34篇 |
1999年 | 30篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 10篇 |
1993年 | 5篇 |
1992年 | 30篇 |
1991年 | 28篇 |
1990年 | 35篇 |
1989年 | 33篇 |
1988年 | 19篇 |
1987年 | 19篇 |
1986年 | 17篇 |
1985年 | 15篇 |
1984年 | 18篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1974年 | 7篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1966年 | 3篇 |
排序方式: 共有898条查询结果,搜索用时 0 毫秒
51.
Urrutia G Serra C Bonfill X Bastús R;Grupo Trabajo para el Estudio del Cancer de Vejiga Urinaria en la Comarca del Valles Occidental 《Gaceta sanitaria / S.E.S.P.A.S》2002,16(4):291-297
AIM: To identify all incident cases of bladder cancer in the county of Vallès Occidental (Spain), describe their histopathological characteristics, and make comparisons with other Spanish and European areas. METHOD: The study was carried out from the Corporació Parc Taulí (Sabadell). All new cases of bladder cancer in residents of the county Vallès Occidental, a highly industrialised area of Catalonia (Spain), were included between 1992 and 1994. Incidence rates of bladder cancer were adjusted and were compared with adjusted incidence rates reported by registries in other Spanish and European countries. RESULTS: 485 new cases were identified. Transitional cell carcinomas predominated (95.5%). The majority of tumours were diagnosed in their initial stages, 75.9% being superficial and 62.6% well to moderately differentiated. Bladder cancer was more common in men than in women, but women presented tumours of worse prognosis. The mean age at diagnosis was also higher in women than men (71 vs. 66 years, p = 0.03). The adjusted incidence rate in men (52.2 cases/100,000) was among the highest of the observed areas, whereas for women (5.4 cases/100,000) was relatively low. CONCLUSIONS: The incidence of bladder cancer among men in Vallès Occidental is among the highest in Europe, and intermediate for women. The high male/female ratio seen in all Spanish areas could be attributed to the fact that women in Spain have been less exposed than men to the risk factors, or their exposure occurred more recently. 相似文献
52.
Exaggerated impact of ATP-sensitive K(+) channels on afferent arteriolar diameter in diabetes mellitus 总被引:3,自引:0,他引:3
Ikenaga H Bast JP Fallet RW Carmines PK 《Journal of the American Society of Nephrology : JASN》2000,11(7):1199-1207
Experiments were performed to determine the involvement of ATP-sensitive K(+) channels (K(ATP) channels) in the renal afferent arteriolar dilation that occurs during the hyperfiltration stage of insulin-dependent diabetes mellitus (IDDM). IDDM was induced in rats by streptozotocin (STZ) injection, and adequate insulin was provided to maintain moderate hyperglycemia. Sham rats received vehicle treatments. Two weeks later, afferent arteriolar function was assessed using the in vitro blood-perfused juxtamedullary nephron technique. Baseline afferent arteriolar lumen diameter was greater in STZ rats (25.9 +/- 1.1 microm) than in sham rats (20.8 +/- 1.0 microm). Glibenclamide (3 to 300 microM) had virtually no effect on afferent arterioles from sham rats; however, this K(ATP) antagonist caused concentration-dependent afferent arteriolar constriction in kidneys from STZ-treated rats, restoring lumen diameter to 20.6 +/- 1.7 microm (P > 0.05 versus sham baseline). In both groups of rats, pinacidil (a cyanoguanidine K(ATP) agonist; 0.3 to 300 microM) evoked concentration-dependent afferent arteriolar dilation, indicating the functional expression of K(ATP) channels; however, lumen diameter was increased by 73% in STZ kidneys but only by 48% in sham kidneys. The gliben-clamide-sensitive afferent arteriolar dilator response to 1 microM PCO-400 (a benzopyran K(ATP) agonist) was also accentuated in STZ kidneys. These observations suggest that increases in both the functional availability and basal activation of K(ATP) channels promote afferent arteriolar vasodilation during the early stage of IDDM, changes that likely contribute to the etiology of diabetic hyperfiltration. 相似文献
53.
OBJECTIVE: We investigated the effect of Psychological Job Demands (PJD) on the occurrence of the clinical symptoms of common cold. METHODS: Subjects, participating in a large prospective cohort study on psychological determinants of fatigue at work, were asked to fill in a questionnaire on the occurrence of common cold during the previous four months. High PJD were considered as a potential risk factor. Other factors such as age, gender, and having young children were considered as potential confounders. RESULTS: In logistic regression analysis, the adjusted odds ratio (OR) for having a recent cold in subjects reporting high PJD vs. those reporting low PJD was 1.20 (95% confidence interval (CI), 1.08-1.33). A higher risk emerged among those with young children (OR, 1.70; 95% CI, 1.47-1.96), those having a history of asthma (OR, 1.69; 95% CI, 1.28-2.22), or being under the age of 40 (OR, 1.28; 95% CI, 1.14-1.43) and among smokers (OR, 1.23; 95% CI, 1.09-1.38). CONCLUSION: The results support an association between PJD and common cold. In spite of the almost inevitable shortcoming of a large cohort study using questionnaires, this study gave us the opportunity to study the relationship between common cold and work-related factors in a nonexperimental setting with participants observed in a natural environment with all the normal everyday hassles. 相似文献
54.
Serra C Bonfill X Sunyer J Urrutia G Turuguet D Bastús R Roqué M 't Mannetje A Kogevinas M;Working Group on the Study of Bladder Cancer in the County of Vallès Occidental 《Scandinavian journal of work, environment & health》2000,26(6):476-481
OBJECTIVES: This study examined the occupations and industries at high risk for bladder cancer in an area where the textile industry is plentiful and the incidence of the disease is very high. METHODS: A case-referent study concerning 218 incident bladder cancer cases diagnosed during 1993-1995 in the county of Vallès Occidental, Barcelona, was carried out. A reference group (N=344) was selected from municipal lists matched to the cases by age, gender, and area of residence. All the subjects were personally interviewed, and a complete occupational history was abstracted together with other sociodemographic and life-style factors. All odds ratios (OR) and 95% confidence intervals (95% CI) were adjusted for age, gender, and smoking. RESULTS: No overall excess risk was found forever having worked in the textile industry (OR 1.13, 95% CI 0.79-1.63) nor for specific sectors of this industry (ie cotton, wool, silk). An excess risk was observed for spinners and winders employed for more than 20 years (OR 3.28, 95% CI 1.08-9.97) and for machine setters employed between 1960 and 1974 (OR 4.26, 95% CI 1.09-16.7). CONCLUSIONS: The results of this study do not support the findings of some earlier studies for an increased bladder cancer risk in the textile industry. However, some elevated risks were observed among the workers with the highest exposures. 相似文献
55.
ARHI is the center of allelic deletion on chromosome 1p31 in ovarian and breast cancers 总被引:8,自引:0,他引:8
Peng H Xu F Pershad R Hunt KK Frazier ML Berchuck A Gray JW Hogg D Bast RC Yu Y 《International journal of cancer. Journal international du cancer》2000,86(5):690-694
In our previous work, we had characterized ARHI as an imprinted putative tumor-suppressor gene in ovarian and breast cancers. ARHI is expressed in primary breast and ovarian cell lines but largely absent from the corresponding malignant tumors. Moreover, the non-imprinted functional allele is typically deleted in malignant cells. Since ARHI had been mapped to 1p31, a common deletion site in breast and ovarian cancer and male germ-cell tumors, in this study, we set out to define precisely the physical location of ARHI at 1p31 and to determine if this location lies within the smallest common region of deletion in breast and ovarian cancers. To this end, we first carried out radiation hybrid mapping of ARHI and surrounding markers, followed by a high-resolution study of loss of heterozygosity at 1p31 in 49 ovarian and breast cancers. Combining a radiation hybrid map and a physical map of the region encompassing ARHI, 3 discrete regions of minimal deletion were found at 1p31 in breast and ovarian cancers. ARHI is the most common deletion region at 1p31. Two other less common regions of deletion were found centromeric to this gene. One of them centered on D1S207 and the other one included and was proximal to D1S488. We also confirmed the preferential loss of non-imprinted functional allele in 7 of 9 tumor specimens. These data support the possibility that ARHI is a tumor-suppressor gene and suggest that additional tumor-suppressor genes may lie proximal to ARHI at 1p31. The data obtained from our study should aid in the identification and characterization of genes in this novel imprinted region. 相似文献
56.
Abou El Hassan MA Touw DJ Wilhelm AJ Bast A van der Vijgh WJ 《International journal of pharmaceutics》2000,211(1-2):51-56
MonoHER is a semisynthetic flavonoid used successfully in modulating the cardiotoxic effect of doxorubicin but not its antitumor activity. The oral bioavailability of monoHER is <1%. Therefore, it should be prepared as an i.v. formulation for use in clinical trials. The solubility of monoHER in water is highly pH dependent. At pH=8.3 the drug precipitates 4 h after preparation. DMSO was tested for enhancing the solubility of monoHER in aqueous solutions. In all DMSO-based aqueous solutions monoHER recrystalized again at pH<8.3 and room temperature within 4 h after preparation. Moreover, the stability of monoHER was lower in a DMSO stock solution than after dilution with an aqueous solution. The stability of monoHER was tested in alkaline solutions (pH 8.3 and 9.5) using an HPLC-DAD procedure to detect all possible degradation products within 10 min after injection. Minor degradation occurred to monoHER in alkaline solutions when exposed to daylight or 1% H(2)O(2). MonoHER intensively degraded when exposed to a high temperature (80 degrees C). The stability of monoHER was almost the same in saline or 5% glucose when kept at room temperature and an alkaline pH of 8.3 and 9.5. Under shelf-life conditions the stability of monoHER in 5% glucose (pH 8.4), decreased with about 10% during 48 h after preparation. 相似文献
57.
Salim E. Kabawat Robert C. Bast William R. Welch Robert C. Knapp Atul K. Bhan 《International journal of cancer. Journal international du cancer》1983,32(5):547-554
Expression of histocompatibility antigens and the intensity of inflammatory cellular infiltrate were evaluated in frozen tissue sections from 70 human ovarian tumors and six normal ovaries using monoclonal antibodies and an avidin-biotin immunoperoxidase technique. In the normal human ovary, surface epithelial cells, mature granulosa cells and lutein cells reacted with anti-HLA-A, B, C (HLA) and beta2-microglobulin antibodies but not with anti-la (la-like, HLA-DR). Stromal cells and granulosa cells of the primordial follicles did not react with any of the antibodies. Among the neoplasms examined, all benign epithelial tumors, 86% of borderline an 81% of malignant epithelial tumors reacted with anti-HLA and/or beta2-microglobulin antibodies. HLA-negative epithelial tumors were of serous or endometrioid types. Although la was not found in normal ovarian surface epithelium, the antigen could be detected in 44% of benign, and 43% of borderline and malignant epithelial ovarian tumors. Mono-nuclear cellular infiltrate was generally scarce in ovarian tumors and consisted mainly of T cells. Malignant epithelial tumors contained significantly more T cells than did benign tumors. More T cells were observed in HLA-positive ovarian tumors than in HLA-negative neoplasms, but the difference did not achieve statistical significance. No correlation could be found between la expression and the intensity of T-cell infiltrate. Significantly more T8 and Leu-3a-positive cells were found in the tumor stroma than amongst neoplastic cells. HNK-I-positive natural killer cells, OK-MI-positive macrophages and BI-positive B lymphocytes were rarely encountered either in the tumor stroma or between adjacent tumor cells. 相似文献
58.
Product inhibition has been suggested to be a determinant in orphenadrine pharmacokinetics. Two possibilities for the mechanism of product inhibition in orphenadrine metabolism are explored in this study. Orphenadrine and its metabolites may compete for cytochrome P-450 catalytic binding sites. Therefore the interaction of orphenadrine and some of its metabolites with hepatic microsomal ferricytochrome P-450 of the rat was investigated. The spectral dissociation constant for the type I (substrate) interaction of orphenadrine and its metabolites displayed no relationship with the lipophilicity of the compounds. Orphenadrine is only partially displaced from its cytochrome P-450 binding sites by its respective metabolites. For this mechanism to be significant in vivo. the metabolites need to reach concentrations near cytochrome P-450 similar to that of orphenadrine. This is not known yet. The significance of this mechanism for the product inhibition phenomenon is therefore uncertain. In this study it is also established that during both in vitro as well as in vivo metabolism of orphenadrine, a metabolic intermediate is formed, which binds irreversibly to ferrous-cytochrome P-450 (MI complex). In vitro, both the rate and extent of the MI complex formation with orphenadrine and metabolites as precursor, decreased in the order N-hydroxytofenacine >; tofenacine > orphenadrine > bisnororphenadrine. The metabolite orphenadrine-N-oxide did not produce an MI complex, in vitro. Furthermore. in vitro, it was shown that the N-demethylation of tofenacine paralleled the concomitant MI complex formation. Together, the data suggest that the first N-demethylation step of orphenadrine occurs via α-carbon oxidation, whereas the second N-demethylation step mainly comes about via N-oxidation. Both metabolic pathways eventually lead to the MI complex forming species. These two parallel pathways also account for the complicated substrate dependency and concentration dependency in MI complex formation. Finally, the formation of the nitroxide radical (the ultimate ligand for MI complexation) has been shown to be susceptible to inhibition by its precursors.The occurrence of MI complex formation resulting in metabolic inactive cytochrome P-450 is probably the main mechanism for the product inhibition phenomenon in orphenadrine metabolism. 相似文献
59.
60.