全文获取类型
收费全文 | 1504107篇 |
免费 | 113400篇 |
国内免费 | 6371篇 |
专业分类
耳鼻咽喉 | 17804篇 |
儿科学 | 49378篇 |
妇产科学 | 39457篇 |
基础医学 | 199236篇 |
口腔科学 | 37756篇 |
临床医学 | 132175篇 |
内科学 | 307344篇 |
皮肤病学 | 32539篇 |
神经病学 | 125935篇 |
特种医学 | 64062篇 |
外国民族医学 | 274篇 |
外科学 | 237487篇 |
综合类 | 33779篇 |
现状与发展 | 2篇 |
一般理论 | 414篇 |
预防医学 | 123608篇 |
眼科学 | 30807篇 |
药学 | 102730篇 |
5篇 | |
中国医学 | 2860篇 |
肿瘤学 | 86226篇 |
出版年
2018年 | 33939篇 |
2017年 | 26887篇 |
2016年 | 31104篇 |
2015年 | 15165篇 |
2014年 | 20684篇 |
2013年 | 30451篇 |
2012年 | 42744篇 |
2011年 | 58720篇 |
2010年 | 42109篇 |
2009年 | 34737篇 |
2008年 | 54776篇 |
2007年 | 59229篇 |
2006年 | 40365篇 |
2005年 | 40473篇 |
2004年 | 39910篇 |
2003年 | 39914篇 |
2002年 | 36183篇 |
2001年 | 66337篇 |
2000年 | 68337篇 |
1999年 | 56774篇 |
1998年 | 16928篇 |
1997年 | 15217篇 |
1996年 | 16096篇 |
1995年 | 16336篇 |
1994年 | 15201篇 |
1993年 | 14213篇 |
1992年 | 47154篇 |
1991年 | 45853篇 |
1990年 | 44120篇 |
1989年 | 41914篇 |
1988年 | 38823篇 |
1987年 | 38137篇 |
1986年 | 35896篇 |
1985年 | 34679篇 |
1984年 | 26378篇 |
1983年 | 22138篇 |
1982年 | 13881篇 |
1981年 | 12454篇 |
1980年 | 11756篇 |
1979年 | 23562篇 |
1978年 | 17093篇 |
1977年 | 14407篇 |
1976年 | 13205篇 |
1975年 | 13741篇 |
1974年 | 16129篇 |
1973年 | 15421篇 |
1972年 | 14195篇 |
1971年 | 13061篇 |
1970年 | 11913篇 |
1969年 | 11139篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
An improved method for determining 89Sr and 90Sr in urine 总被引:1,自引:0,他引:1
A method has been developed for the rapid isolation and quantitation of 89Sr and 90Sr in urine samples. The radiostrontium is concentrated from the bulk urine sample by coprecipitation with calcium phosphate. The precipitate is then wet ashed with nitric acid, and a solution of the resulting residue in 2 M HNO3-0.5 M Al(NO3)3 is passed through an extraction chromatographic column containing a supported crown ether that preferentially retains strontium. Sorbed strontium may then be eluted from the column with either dilute HNO3 or water and counted via liquid scintillation. A new counting scheme that permits quantitation of both 89Sr and 90Sr on the same day the separation is performed is described. 相似文献
992.
P. H. B. Willemse J. G. Aalders J. Bouma N. H. Mulder R. C. J. Verschueren E. G. E. de Vries D. Th. Sleijfer 《Gynecologic oncology》1987,28(3):268-277
Thirteen patients with a malignant germ cell tumor of the ovary have been treated with a combination of vinblastine, bleomycin, and cisplatin (VBP). In 12 patients a complete remission was reached, which was maintained in 10 of these patients. One patient with large tumor residues and a partial remission became CR after surgery. The tumor recurred in 2 patients after 6 and 27 months. Overall, 11 of these patients are in long-term remission, from 14 to 84 months after the start of treatment. VBP is an effective treatment for malignant germ cell tumors of the ovary, even in patients with large tumor residuals. 相似文献
993.
994.
995.
996.
P Van Houtte M Roelandts D Devriendt M Minsat H Laharie G Kantor 《Cancer radiothérapie》2005,9(6-7):427-434
The authors present an update version of the indications for radiotherapy in the management of benign diseases. This is based on available randomized trials and recent international meetings. Validated indications remain the prevention of resected heterotopic bone ossifications, kelo?ds scars and pterygium and also treatment of arteriovenous malformations; the place of radiotherapy for malignant exophtalmia is more and more restricted. Randomized trials have demonstrated the efficacy of endobrachytherapy in the prevention of restenosis after angioplasty but the use of embedded stent has replaced this indication. Macular degeneration is no more an indication of radiotherapy. Quality requirements for radiotherapy are identical for benign or malignant indications. 相似文献
997.
G Oberhuber T Schmid R Erdk?nig W Thaler D Ofner G K?r?szi G Klima R Margreiter 《European surgical research. Europ?ische chirurgische Forschung. Recherches chirurgicales européennes》1991,23(3-4):206-213
The effect of ciclosporin (CS) and methotrexate (MTX) on the development of graft-versus-host (GvH) disease was examined after small bowel allotransplantation in the rat. The drugs were tested either alone or in combination. Lewis small bowel allografts were transplantated into Brown Norway recipients in a heterotopic position. The native small bowel, spleen, liver, skin, mesenteric lymph nodes and the kidney of the recipients were examined histologically 5, 10 and 20 days after allotransplantation. Intraepithelial lymphocyte numbers were determined quantitatively in the native small bowel. The relative spleen weight of the host was determined after sacrifice for estimation of the severity of GvH disease. Grade I GvH reaction of the native small bowel occurred in the animals without immunosuppression, but graft rejection predominated in this group. Treatment with CS was effective in the early postoperative periods; after 10 and 20 days GvH lesions in the native small bowel were comparable to those observed in the allogeneic combinations. MTX had a detrimental effect on the allografts and the GvH reaction was augmented. When CS and MTX were combined, GvH lesions were comparable to those in the animals treated solely with CS. Animals, however, suffered from heavy side effects. The spleen, liver, lymph nodes and kidney exhibited only unspecific histologic changes, which could not unequivocally be recognized as a GvH reaction. This was true for all groups. As a conclusion it can be said that GvH reaction occurs in the early postoperative period in a fully allogeneic model and cannot be prevented by CS in the dosae used. MTX was not seen to be of any value in this regard. 相似文献
998.
C Baumgartner W W Sutherling S Di D S Barth 《Electroencephalography and clinical neurophysiology》1991,79(1):27-35
We measured somatosensory evoked magnetic fields during median nerve stimulation in 6 normal subjects. We applied multiple dipole models to study the spatiotemporal structure of early somatosensory evoked magnetic fields (SEFs), as well as the number, 3-dimensional location and time activity of their underlying neuronal sources. Two dipole sources were necessary to model the first 40 msec of SEFs explaining 85% of the data variance. Source 1 was located deeper than source 2, showed primarily a tangential orientation, and accounted for a larger part of the variance; source 2 showed no consistent orientation across subjects. Both sources showed biphasic time activities corresponding to the previously described N20-P30 and P25-N35 components. Spatiotemporal modeling could identify sources which could not be modeled consistently above noise by single moving dipoles (P25 component), revealed small latency differences of the two sources in some subjects suggesting parallel activation of these sources, and allowed separation of sources overlapping considerably both in space and time. We conclude that spatiotemporal modeling of SEFs may be useful to study functional anatomy of human sensorimotor cortex non-invasively. 相似文献
999.
Breuer J.; Moniz C.; Baldwin D.; Parsons V. 《Nephrology, dialysis, transplantation》1987,2(5):347-350
The effect of oral magnesium carbonate aluminium hydroxide onserum ionised calcium, total calcium, aluminium and magnesium,was assessed in 31 patients with chronic renal failure, duringand after one haemodialysis. The behaviour of ionised calcium and total calcium was the samein both groups. Each showed a slight fall during dialysis, whichwas not significant. Serum total calcium was 0.20.3 mmol/l(0.81.2 mg/dl) greater throughout the period of dialysisin the group taking aluminium hydroxide. Serum magnesium andaluminium were both lower in the group treated with magnesiumcarbonate. In the group taking magnesium carbonate, serum magnesium concentrationsfell markedly during dialysis, but otherwise were maintainedwithin the reference range by the use of a magnesium-free dialysate.These results show the effectiveness of magnesium carbonateoral phosphate-binding agents and zero magnesium dialysate inreducing serum aluminium without affecting the behaviour ofserum calcium fractions during dialysis. 相似文献
1000.
J R Voelker D Cartwright-Brown S Anderson J Leinfelder D A Sica J P Kokko D C Brater 《Kidney international》1987,32(4):572-578
Furosemide and bumetanide share a number of characteristics including reduced natriuretic effects in azotemic patients. It has been presumed that this condition affects each drug equally. Previous studies, however, suggest dissimilar pathways of delivery to their sites of action. Though not rigorously tested, this potential disparity might cause them to differ when used in azotemia. We, therefore, assessed the pharmacokinetic and pharmacodynamic characteristics of intravenously administered furosemide and bumetanide in ten adult patients with stable, chronic renal insufficiency (mean creatinine clearance = 14.1 +/- 2.0 ml/min/1.73 m2) in a randomized, cross-over study during controlled sodium intake. Our goals were to assess differences in diuretic effectiveness and in so doing to determine the dose required to produce a maximal response. The mean diuretic doses of 172 and 4.3 mg for furosemide and bumetanide, respectively (ratio = 40:1) were sufficient to produce a maximum response. Despite similarities in maximal fractional excretion of sodium (18.2 +/- 2.6% with furosemide vs. 19.4 +/- 4.5% with bumetanide, P = 0.687) demonstrating an equal tubular responsiveness to both drugs, overall response as quantified by cumulative natriuresis in the initial eight hour period was 52% greater with furosemide (108 +/- 17 vs. 71 +/- 7 mEq; P = 0.042). The difference in total excreted sodium was accounted for by a preserved nonrenal clearance of bumetanide (113 +/- 12 compared to 53 +/- 5 ml/min for furosemide, P = 0.001) which resulted in relatively less bumetanide in serum available to be delivered into the urine.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献