全文获取类型
收费全文 | 9708篇 |
免费 | 432篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 125篇 |
儿科学 | 194篇 |
妇产科学 | 204篇 |
基础医学 | 1211篇 |
口腔科学 | 1202篇 |
临床医学 | 568篇 |
内科学 | 2130篇 |
皮肤病学 | 222篇 |
神经病学 | 770篇 |
特种医学 | 176篇 |
外科学 | 1342篇 |
综合类 | 27篇 |
一般理论 | 5篇 |
预防医学 | 772篇 |
眼科学 | 259篇 |
药学 | 559篇 |
中国医学 | 69篇 |
肿瘤学 | 362篇 |
出版年
2024年 | 5篇 |
2023年 | 95篇 |
2022年 | 216篇 |
2021年 | 359篇 |
2020年 | 217篇 |
2019年 | 259篇 |
2018年 | 371篇 |
2017年 | 246篇 |
2016年 | 255篇 |
2015年 | 375篇 |
2014年 | 462篇 |
2013年 | 526篇 |
2012年 | 867篇 |
2011年 | 975篇 |
2010年 | 470篇 |
2009年 | 403篇 |
2008年 | 708篇 |
2007年 | 707篇 |
2006年 | 599篇 |
2005年 | 505篇 |
2004年 | 474篇 |
2003年 | 391篇 |
2002年 | 342篇 |
2001年 | 43篇 |
2000年 | 28篇 |
1999年 | 40篇 |
1998年 | 40篇 |
1997年 | 24篇 |
1996年 | 24篇 |
1995年 | 9篇 |
1994年 | 17篇 |
1993年 | 15篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 14篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1965年 | 5篇 |
1963年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
Daniela N Amora Ticiana M Sousa Alice M C Martins Paulo S F Barbosa Marta R Magalh?es Marcus H Toyama Manassés C Fonteles Dalgimar B de Menezes Helena S A Monteiro 《Toxicon》2006,47(3):260-264
Ophidian accidents caused by the subspecies Crotalus durissus are responsible for high morbity and mortality rates. Acute renal failure is a common complication observed in these accidents. The aim of the present study was to investigate the renal effects promoted by the venom of C. d. collilineatus and its fractions, crotoxin and phospholipase A2. C. d. collilineatus (Cdc; 30 microg mL(-1)), crotoxin (CTX; 10 microg mL(-1)) and phospholipase A2 (PLA2; 10 microg mL(-1)) were tested in isolated rat kidney. The first 30 min of each experiment were used as an internal control and Cdc or its fractions, CTX and PLA2 were added to the system after this period. All experiments lasted 120 min. The venom of Cdc decreased perfusion pressure (PP; control120 = 110.3 +/- 3.69 mmHg; Cdc120 = 96.7+/-8.1 mmHg), renal vascular resistance (RVR; control120 = 6.42+/-0.78 mmHg mL g(-1) min(-1); Cdc120 = 4.8+/-0.56 mmHg/mL g(-1) min(-1)), urinary flow (UF; control120 = 0.19+/-0.03 mL g(-1) min(-1); Cdc120 = 0.12 +/- 0.01 mL g(-1) min(-1)), and glomerular filtration rate (GFR; control120 = 0.79 +/- 0.07 mL g(-1) min(-1); Cdc120 = 0.53 +/- 0.09 mL g(-1) min(-1)), but had no effect on the percent of sodium tubular transport (%TNa+), percent of chloride tubular transport (%TK+) and percent of potassium tubular transport (%TCl-). CTX and PLA2 reduced the GFR, while UF, PP and RVR remained stable during the full 120 min of perfusion. Crotoxin administration also diminished the %TK+ (control120 = 69.94 +/- 6.49; CTX120 = 33.28 +/- 4.78) and %TCl- (control120 = 79.53 +/- 2.67; CTX120 = 64.62 +/- 6.93). PLA2 reduced the %TK+, but exerted no effect on the %TNa+ or on that of TCl-. In conclusion, the C. d. collilineatus venom altered the renal functional parameters evaluated. We suggest that crotoxin and phospholipase A2 were involved in this process, since the renal effects observed would be due to the synergistic action of the components of the venom. 相似文献
72.
Barros MP Lemos M Maistro EL Leite MF Sousa JP Bastos JK Andrade SF 《Journal of ethnopharmacology》2008,120(3):372-377
Aim of the study
In a previous study, our group described the gastric protective effect of the hydroalcoholic extract of Brazilian green propolis. The main compounds found in Brazilian green propolis include phenolic acids, such as: caffeic, ferulic, p-coumaric and cinnamic acids. This study was therefore carried out to evaluate the antiulcerogenic property of the main phenolic acids found in Brazilian Green Propolis.Material and methods
The anti-ulcer assays were performed using the following protocols: nonsteroidal-antiinflammatory drug (NSAID)-induced ulcer, ethanol-induced ulcer, and stress-induced ulcer. The effects of the phenolic acids on gastric content volume, pH and total acidity, using the pylorus ligated model, were also evaluated.Results
It was observed that treatment using doses of 50 and 250 mg/kg of caffeic, ferulic, p-coumaric and cinnamic acids and positive controls (omeprazol or cimetidine) significantly diminished the lesion index, the total area of the lesion and the percentage of lesion in comparison with the negative control groups. In addition, the percentage of ulcer inhibition was significantly higher in the groups treated with the different phenolic acids, cimetidine or omeprazol, in all the protocols used, compared with the negative control groups. In the model to determine gastric secretion, using ligated pylorus, treatment with phenolic acids and cimetidine reduced the volume of gastric juice and total acidity and significantly increased the gastric pH (p < 0.05), compared with the control group, with the exception of the group treated with 50 mg/kg of p-coumaric acid, in which no significant difference was observed, compared with the control. In relation to the acute toxicity, none sign of toxicity was observed when phenolic acids, used in this study, were administered for rats in dose of 2000 mg/kg.Conclusions
In conclusion, the results of this study show that caffeic, ferulic, p-coumaric and cinnamic acids display antiulcer activity. 相似文献73.
Paulo A Martins S Branco P Dias T Borges C Rodrigues AI Costa Mdo C Teixeira A Mota-Filipe H 《Phytotherapy research : PTR》2008,22(4):539-543
The effect of an aqueous extract of Pterospartum tridentatum on the blood glucose levels of normal Wistar rats was investigated in a situation of oral glucose challenge. The extract at 300 mg/kg showed an antihyperglycaemic effect in the first 30 min after glucose challenge but then the blood glucose levels rose above those of the control group, indicating the presence of compounds with different effects on glucose tolerance. Nine compounds of isoflavone and flavonol skeletons were identified in the extract by HPLC-ESI-MS(n), four of them being identified for the first time in this species. The isoflavone sissotrin and the flavonol derivative, isoquercitrin, were selected for the oral glucose tolerance test. Isoquercitrin (100 mg/kg) showed time-dependent antihyperglycaemic activity by delaying the post-oral glucose load glycaemic peak at 30 min, as did the sodium-dependent glucose transporter inhibitor phloridzin (100 mg/kg). In contrast, sissotrin (100 mg/kg) showed an opposite effect, impairing glucose tolerance. In conclusion, these preliminary results indicate that the effect of the extract on blood glucose may be either antihyperglycaemic or hyperglycaemic. Additionally, as far as is known, these are the first in vivo results on the acute antihyperglycaemic potential of isoquercitrin. 相似文献
74.
Delmanto A Nahas-Neto J Nahas EA de Oliveira ML Fernandes CE Traiman P 《European journal of obstetrics, gynecology, and reproductive biology》2008,139(2):187-192
OBJECTIVE: The objective was to analyze the effect of raloxifene on the vaginal epithelium of postmenopausal women. STUDY DESIGN: In this non-randomized clinical trial, 80 women (mean age = 60.6 years) were prospectively studied. Forty patients received 60 mg/day of raloxifene (RG), and 40 women constituted a non-treated control group (CG), paired by age and time since menopause. The treated group consisted of patients with osteoporosis of the lumbar spine. Those with a diagnosis of infection in the lower genital tract and using hormone therapy (HT) up to 6 months prior to the study were excluded. Vaginal smears were collected at baseline and after 6 months of intervention. The vaginal maturation value (VMV) was determined, and counts of superficial, intermediate and parabasal cells were performed. Smears were analyzed by only one cytopathologist who was blinded to patient data. The t-test, Wilcoxon test, and Chi-Squared test were used in the statistical analysis. RESULTS: The study groups were homogeneous regarding age, time since menopause, parity, HT use, smoking, and body mass index. No statistically significant differences were observed in VMV median values (RG, 39.7 and 35.7; CG, 50.0 and 50.0, respectively) or in the percentage of superficial, intermediate and parabasal cells between the groups at baseline and after 6 months (p>0.05). There was no significant correlation between VMV and age, time since menopause, previous HT use, or body mass index, in either of the groups. CONCLUSION: Treatment with raloxifene for 6 months has no effect on the maturation of the vaginal epithelium in postmenopausal women with osteoporosis. 相似文献
75.
Giraldo PC Eleutério J Cavalcante DI Gonçalves AK Romão JA Eleutério RM 《European journal of obstetrics, gynecology, and reproductive biology》2008,137(1):88-91
OBJECTIVES: The objectives were to assess the prevalence of high-risk HPV in the male sexual partners of women with HPV-induced lesions, and correlate it with biopsies guided by peniscopy. STUDY DESIGN: Fifty-four asymptomatic male sexual partners of women with low-grade squamous intra-epithelial lesions (LSIL) associated with high-risk HPV were examined between April 2003 and June 2005. The DNA-HPV was tested using a second-generation hybrid capture technique in scraped penile samples. Peniscopy identified acetowhite lesions leading to biopsy. RESULTS: High-risk HPV was present in 25.9% (14 out of 54) of the cases. Peniscopy led to 13 biopsies (24.07%), which resulted in two cases of condyloma, two cases of intra-epithelial neoplasia (PIN) I, one case of PIN II, and eight cases of normal tissue. The high-risk HPV test demonstrated 80% sensitivity, 100% specificity, 100% positive predictive value, and 88.9% negative predictive value for the identification of penile lesions. There was a greater chance of finding HPV lesions in the biopsy in the positive cases of high-risk HPV with abnormal peniscopy (p=0.007); OR=51 (CI 1.7-1527.1). CONCLUSION: Among asymptomatic male sexual partners of women with low-grade intra-epithelial squamous lesions, those infected by high-risk HPV have a higher chance of having abnormal penile tissue compared with male partners without that infection. 相似文献
76.
Giraldo PC Babula O Gonçalves AK Linhares IM Amaral RL Ledger WJ Witkin SS 《Obstetrics and gynecology》2007,109(5):1123-1128
OBJECTIVE: To evaluate associations between polymorphisms in the gene coding for mannose-binding lectin (MBL) and the diagnosis of acute or recurrent vulvovaginal candidiasis and bacterial vaginosis METHODS: Women at two outpatient clinics in Brazil filled out a questionnaire and were examined for the presence of vulvovaginal candidiasis or bacterial vaginosis. A buccal swab was blindly tested for codons 54 and 57 MBL2 gene polymorphisms by polymerase chain reaction and endonuclease digestion. RESULTS: A total of 177 women were enrolled. Vulvovaginal candidiasis was identified in 78 (44.1%) women, 33 (18.6%) had bacterial vaginosis, and 66 (37.3%) were normal controls. Recurrent vulvovaginal candidiasis was present in 50 (64.1%) of the women with vulvovaginal candidiasis; 20 (60.6%) of the bacterial vaginosis patients had recurrent disease. Vulvovaginal candidiasis was associated with white race (P=.007), bacterial vaginosis was associated with nonwhite race (P=.05), and both were associated with a history of allergy (P< or =.02) and having sexual intercourse at least three times a week (P<.001). Carriage of the variant MBL2 codon 54 allele B was more frequent in women with recurrent vulvovaginal candidiasis (25.0%) than in the women with acute vulvovaginal candidiasis (17.9%) or controls (10.6%) (P=.004). Allele B was also more prevalent in women with recurrent bacterial vaginosis (22.5%) than in those with acute bacterial vaginosis (0%) (P=.009). The MBL2 codon 57 polymorphism was infrequent and not associated with vulvovaginal candidiasis or bacterial vaginosis. CONCLUSION: The incidence of vulvovaginal candidiasis and bacterial vaginosis differs by ethnicity in Brazilian women. The MBL2 codon 54 gene polymorphism is associated with both recurrent vulvovaginal candidiasis and recurrent bacterial vaginosis. 相似文献
77.
78.
Hammes LS Tekmal RR Naud P Edelweiss MI Kirma N Valente PT Syrjänen KJ Cunha-Filho JS 《Gynecologic oncology》2007,105(1):157-165
OBJECTIVE: To evaluate the population of macrophages during the cervical malignant transformation and its influence in CIN outcome. METHODS: Biopsies from 26 normal cervix, 28 low-grade (LSIL), 30 high grade squamous intraepithelial lesions (HSIL) and 28 squamous cell carcinomas (SCC) were stained by H&E to assess inflammation and by immunohistochemistry with anti-CD68 to detect macrophages. The macrophage count was corrected for the epithelial and stromal compartments using appropriate software. Clinical and prospective follow-up data were also available. RESULTS: We identified that macrophage count increased linearly with disease progression (median count per case at x200 magnification: normal, 5.1; LSIL, 5.5; HSIL, 9.9; SCC, 14.5; P<0.001), that inflammation also increased (moderate-intense inflammation present in 25%, 46.1%, 58.4% and 89.3% of normal, LSIL, HSIL and SCC, respectively; P<0.001) and that macrophage count was independently associated with the lesion grade (P<0.001). Moreover, macrophages showed an increasing migration into the epithelium along with the progression of CIN to invasive cancer. Of the 24 LSIL cases with information available, followed-up for 805+/-140 days, 16 regressed, 6 persisted and 2 progressed. Age, high-risk HPV or inflammation were not risk factors for persistent/progressed LSIL in our cohort. However, LSIL that persisted or progressed showed a higher macrophage count (median of 10.8) than lesions that regressed (7; P=0.031). CONCLUSIONS: The study on macrophages offers a potential approach for cervical cancer treatment, since macrophages are closely related to progression of CIN, and can be used as an applicable marker of such a risk. 相似文献
79.
Cecatti JG Souza JP Parpinelli MA de Sousa MH Amaral E 《Reproductive Health Matters》2007,15(30):125-133
The occurrence of complications during pregnancy depends less on the degree of human development than differences in the way complications in pregnancy are detected and managed. It is the quick diagnosis and correct management that really contribute to the enormous differences in maternal mortality ratios between countries and regions. Understanding of the determinants of maternal mortality may be improved by studying cases of severe maternal morbidity. In this paper, various approaches to the concept of severe maternal morbidity and near-misses are discussed, and the relationship between these and maternal deaths. Although no consensus has been reached on a strict definition of near-miss or severe maternal morbidity, we show that the definitions used may be tailored to support diverse objectives, including monitoring progress, epidemiological surveillance and auditing of health care. We conclude that the versatility of the concept, the greater frequency of cases available for study and the possibility of interviewing the survivors of severe complications all support the value of studying severe maternal morbidity to help guide local efforts to reduce maternal mortality. Although this may almost be a reality in developed countries, it continues to represent an important and difficult challenge to overcome in places where its benefits would be most evident. 相似文献
80.
Joana Costa Vieira Antnio de O. Mendes Marcelo Leite Ribeiro Andr Costa Vieira Ana Margarida Carta Paulo Torro Fiadeiro Ana Paula Costa 《Materials》2022,15(12)
Embossing is a converting process in which the surface of a tissue paper sheet is changed under high pressure, allowing different functions. In this work, the authors intend to study how the embossing pressure affects the main properties of tissue paper, using a laboratory embossing system. An optimum pressure was achieved at 2.8 bar to this embossing laboratory set-up. The effect of pressure when densifying the paper sheet gives it a gain in mechanical strength but no differences in terms of liquid absorbency. The two embossing patterns present different behaviors but both evidence losses in mechanical and softness properties. On the other hand, the finite element method (FEM) does not show clear evidence of how the pressure affects the paper strength. For the deco die, it is possible to observe that the amount of yielding is slightly higher for lower pressure (2.4 bar), but this plasticity state parameter is very similar for 2.8 bar and 3.2 bar. For the micro die, FEM simulations of the manufacturing pressure do not show a considerable impact on the amount of plasticity state of the material; only for 3.2 bar, it shows a change in the pattern of the plasticity state of the paper during the embossing processes. In the end, to achieve a final product with excellent quality, it is important to make a compromise between the various properties. 相似文献