全文获取类型
收费全文 | 1330795篇 |
免费 | 95952篇 |
国内免费 | 2898篇 |
专业分类
耳鼻咽喉 | 19762篇 |
儿科学 | 40221篇 |
妇产科学 | 38655篇 |
基础医学 | 186874篇 |
口腔科学 | 39762篇 |
临床医学 | 112143篇 |
内科学 | 261067篇 |
皮肤病学 | 30165篇 |
神经病学 | 106234篇 |
特种医学 | 53642篇 |
外国民族医学 | 435篇 |
外科学 | 207820篇 |
综合类 | 30988篇 |
现状与发展 | 6篇 |
一般理论 | 436篇 |
预防医学 | 91681篇 |
眼科学 | 31306篇 |
药学 | 99987篇 |
2篇 | |
中国医学 | 2987篇 |
肿瘤学 | 75472篇 |
出版年
2018年 | 11737篇 |
2015年 | 11872篇 |
2014年 | 16684篇 |
2013年 | 25244篇 |
2012年 | 32999篇 |
2011年 | 34866篇 |
2010年 | 20736篇 |
2009年 | 20231篇 |
2008年 | 33580篇 |
2007年 | 36678篇 |
2006年 | 37258篇 |
2005年 | 36013篇 |
2004年 | 35091篇 |
2003年 | 34070篇 |
2002年 | 33593篇 |
2001年 | 63627篇 |
2000年 | 65329篇 |
1999年 | 55395篇 |
1998年 | 14653篇 |
1997年 | 13467篇 |
1996年 | 12940篇 |
1995年 | 12219篇 |
1994年 | 11395篇 |
1992年 | 42710篇 |
1991年 | 41280篇 |
1990年 | 40539篇 |
1989年 | 39529篇 |
1988年 | 36933篇 |
1987年 | 36398篇 |
1986年 | 34876篇 |
1985年 | 33094篇 |
1984年 | 24786篇 |
1983年 | 20990篇 |
1982年 | 12612篇 |
1981年 | 11504篇 |
1980年 | 10710篇 |
1979年 | 23873篇 |
1978年 | 17023篇 |
1977年 | 14768篇 |
1976年 | 13339篇 |
1975年 | 15229篇 |
1974年 | 18054篇 |
1973年 | 17547篇 |
1972年 | 16793篇 |
1971年 | 15705篇 |
1970年 | 14887篇 |
1969年 | 14330篇 |
1968年 | 13440篇 |
1967年 | 11990篇 |
1966年 | 11247篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Adjuvant radiotherapy in carcinomas of the uterine cervix: the prognostic value of hemoglobin levels
K. Münstedt P. Johnson M.K. Bohlmann M. Zygmunt R. von Georgi† & H. Vahrson 《International journal of gynecological cancer》2005,15(2):285-291
Anemia has been associated with a poorer treatment response and reduced survival in women undergoing primary radiotherapy (RT) or radiochemotherapy for advanced cervical carcinoma. This study aimed to determine the influence of anemia on outcome in patients with cervical carcinoma undergoing adjuvant RT. Medical records were reviewed for 183 cervical cancer patients who had received adjuvant RT because of risk factors after radical surgery (n= 109) or inadequate primary surgery (simple hysterectomy; n= 74). Kaplan-Meier and Cox regression analyses were used to study hemoglobin levels before and during adjuvant RT in relation to recurrence-free and overall survival. Hemoglobin values > or =11 g/dL were considered normal, while those <11 g/dL indicated anemia. Hemoglobin levels before RT influenced significantly overall survival and recurrence-free survival across the whole group (overall survival--log rank(all patients)= 7.5; df = 1; P= 0.006). However, subgroup analysis showed that the observed difference was mainly due to the group of women who had undergone inadequate primary surgery (overall survival--log rank(inadequate surgery)= 10.8; df = 1; P= 0.001). Multifactorial regression analyses comparing hemoglobin before RT with grading and tumor stage confirmed the prognostic value of hemoglobin values. Maintaining normal hemoglobin values before and during adjuvant RT seems to be important, especially in patients who have had inappropriate simple hysterectomy, which may resemble a therapeutic situation. 相似文献
952.
953.
Williamson Kathleen A.; Hever Ann M.; Rainger Joe; Rogers R. Curtis; Magee Alex; Fiedler Zdenek; Keng Wee Teik; Sharkey Freddie H.; McGill Niolette; Hill Clare J.; Schneider Adele; Messina Mario; Turnpenny Peter D.; Fantes Judy A.; van Heyningen Veronica; FitzPatrick David R. 《Human molecular genetics》2006,15(12):2030
Table 1 相似文献
954.
H. S. Tilney R. E. Lovegrove S. Purkayastha A. G. Heriot A. W. Darzi P. P. Tekkis 《Colorectal disease》2006,8(5):441-450
AIM: The present meta-analysis aims to compare short-term and long-term outcomes in patients undergoing laparoscopic or open subtotal colectomy for benign and malignant disease. METHODS: A literature search of Medline, Ovid, Embase and Cochrane databases was performed to identify studies published between 1992 and 2005, comparing laparoscopic (LSC) and open (OSC) subtotal colectomy. A random effect meta-analytical technique was used and sensitivity analysis performed on studies published since the beginning of 2000, higher quality papers, those reporting on more than 40 patients, and those studies reporting on adult cases or acute colitis. RESULTS: A total of eight studies satisfied the criteria for inclusion. These included outcomes on 336 patients, 143 (42.6%) of whom had undergone laparoscopic resection, with an overall conversion rate to open surgery of 5% (range 0-11.8%). Operative time was significantly longer in the laparoscopic group by 86.2 min (P < 0.001) and throughout subgroup analysis, although it was only in patients with acute colitis that this finding was without significant heterogeneity. Operative blood loss was less in the laparoscopic group by 57.5 millilitres in high quality and studies published since 2000, and 65.3 millilitres in those reporting on more than 40 patients. There was no significant difference in early or long-term complications between the groups. A statistically significant reduction in length of postoperative stay was observed in the laparoscopic groups by 2.9 days (P < 0.001). CONCLUSION: Laparoscopic subtotal colectomy was associated with longer operating times but a reduced length of stay compared to open surgery. Although short-term outcomes were equivalent in both groups, the suggested benefits in terms of reduced long-term obstructive complications were not supported by this meta-analysis. 相似文献
955.
C. J. M. Antens M. Oldenwening A. Wolse U. Gehring H. A. Smit R. C. Aalberse M. Kerkhof J. Gerritsen J. C. de Jongste B. Brunekreef 《Clinical and experimental allergy》2006,36(12):1525-1531
BACKGROUND: Studies of the association between indoor allergen exposure and the development of allergic diseases have often measured allergen exposure at one point in time. OBJECTIVE: We investigated the variability of house dust mite (Der p 1, Der f 1) and cat (Fel d 1) allergen in Dutch homes over a period of 8 years. METHODS: Data were obtained in the Dutch PIAMA birth cohort study. Dust from the child's mattress, the parents' mattress and the living room floor was collected at four points in time, when the child was 3 months, 4, 6 and 8 years old. Dust samples were analysed for Der p 1, Der f 1 and Fel d 1 by sandwich enzyme immuno assay. RESULTS: Mite allergen concentrations for the child's mattress, the parents' mattress and the living room floor were moderately correlated between time-points. Agreement was better for cat allergen. For Der p 1 and Der f 1 on the child's mattress, the within-home variance was close to or smaller than the between-home variance in most cases. For Fel d 1, the within-home variance was almost always smaller than the between-home variance. Results were similar for allergen levels expressed per gram of dust and allergen levels expressed per square metre of the sampled surface. Variance ratios were smaller when samples were taken at shorter time intervals than at longer time intervals. CONCLUSION: Over a period of 4 years, mite and cat allergens measured in house dust are sufficiently stable to use single measurements with confidence in epidemiological studies. The within-home variance was larger when samples were taken 8 years apart so that over such long periods, repetition of sampling is recommended. 相似文献
956.
Sodium MRI of the human kidney at 3 Tesla. 总被引:6,自引:0,他引:6
Nimrod Maril Yael Rosen Glenn H Reynolds Alex Ivanishev Long Ngo Robert E Lenkinski 《Magnetic resonance in medicine》2006,56(6):1229-1234
The sodium concentration gradient in the kidney (from the cortex to the medulla) serves to regulate fluid homeostasis and is tightly coupled to renal function. It was previously shown that renal function and pathophysiology can be characterized in rat kidneys by measuring the sodium gradient with (23)Na MRI. This study demonstrates for the first time the ability of (23)Na MRI to map the distribution of sodium in the human kidney and to quantify the corticomedullary sodium gradient. The study was performed on a 3T Signa LX scanner (GE) using an in-house-built quadrature surface coil. (23)Na images of volunteers were acquired using a 3D coronal gradient-echo sequence at a spatial resolution of 0.3 x 0.3 x 1.5 cm(3) in a 25-min scan time. The signal intensity (relative to the noise) increased linearly from the cortex to each of the medullae with a mean slope of 1.6 +/- 0.2 in relative arbitrary units per mm (Rel.u./mm, N = 6) and then decreased, as expected, toward the renal pelvis. Water deprivation (12 hr) induced a significant increase of 25% (P < 0.05) in this gradient. Based on these results, we suggest that sodium MRI can serve as a valuable noninvasive method for functional imaging of the human kidney. 相似文献
957.
958.
959.
The inhibitory effect of polysaccharide on mumps virus multiplication 总被引:12,自引:12,他引:0
Polysaccharides derived from type-specific Friedl?nder bacilli cause inhibition of the multiplication of mumps virus in the allantoic sac of the chick embryo. As little as 5 microg. of polysaccharide is effective as an inhibitor. Inhibition of multiplication is obtained when polysaccharide is injected as long as 4 days after inoculation of virus. Chemical studies have shown that the structural configurations of the polysaccharide responsible for specific serological activity are not identical with those which determine the inhibitory effect relative to mumps virus. The possible mechanisms of the inhibition of viral multiplication by means of polysaccharides are discussed. 相似文献
960.
The intravenous injection into rabbits of suspensions of dead T. pallidum derived from rabbit testicular chancres regularly caused the appearance of Wassermann and flocculation antibodies in significantly increased titer. Control suspensions of cultured treponemes (Reiter strain) added to extracts of normal testes were ineffective. This suggests that the Wassermann and flocculation reagin elaborated during syphilitic infection may be an antibody to T. pallidum which happens to cross-react with alcoholic extracts of mammalian tissue. The antisera did not cause the agglutination of suspensions of pathogenic T. pallidum, living or dead, did not give specific complement fixation with those suspensions, and did not usually cause the living treponemata to lose their infectiousness. Animals immunized with such aqueous suspensions for as long as 4 months, or with organisms suspended in a water-in-oil emulsion, were not demonstrably resistant to infection. As few as ten living organisms inoculated intradermally into animals "immunized" with as many as 38 billion dead treponemata regularly produced typical darkfield positive infections; and two of five animals inoculated intratesticularly with ten organisms were also infected. The contradiction involved in the production of antibodies cross-reacting with a non-specific antigen, and the non-appearance of specific antibodies against the organism used as antigen, is discussed in the text. 相似文献