全文获取类型
收费全文 | 3929528篇 |
免费 | 293093篇 |
国内免费 | 6743篇 |
专业分类
耳鼻咽喉 | 56435篇 |
儿科学 | 124461篇 |
妇产科学 | 105522篇 |
基础医学 | 565095篇 |
口腔科学 | 112363篇 |
临床医学 | 361098篇 |
内科学 | 750607篇 |
皮肤病学 | 83421篇 |
神经病学 | 319411篇 |
特种医学 | 151304篇 |
外国民族医学 | 1277篇 |
外科学 | 590286篇 |
综合类 | 89533篇 |
现状与发展 | 13篇 |
一般理论 | 1601篇 |
预防医学 | 317300篇 |
眼科学 | 93796篇 |
药学 | 294064篇 |
14篇 | |
中国医学 | 7545篇 |
肿瘤学 | 204218篇 |
出版年
2018年 | 42151篇 |
2017年 | 31979篇 |
2016年 | 35678篇 |
2015年 | 40296篇 |
2014年 | 57637篇 |
2013年 | 87685篇 |
2012年 | 119236篇 |
2011年 | 126767篇 |
2010年 | 75401篇 |
2009年 | 71365篇 |
2008年 | 119348篇 |
2007年 | 127158篇 |
2006年 | 128371篇 |
2005年 | 124771篇 |
2004年 | 120035篇 |
2003年 | 115494篇 |
2002年 | 113125篇 |
2001年 | 175006篇 |
2000年 | 180519篇 |
1999年 | 152750篇 |
1998年 | 45572篇 |
1997年 | 40420篇 |
1996年 | 40004篇 |
1995年 | 38313篇 |
1994年 | 35716篇 |
1993年 | 33533篇 |
1992年 | 121564篇 |
1991年 | 118592篇 |
1990年 | 115259篇 |
1989年 | 111028篇 |
1988年 | 102907篇 |
1987年 | 101056篇 |
1986年 | 95408篇 |
1985年 | 91682篇 |
1984年 | 69236篇 |
1983年 | 59070篇 |
1982年 | 35782篇 |
1981年 | 32029篇 |
1979年 | 64950篇 |
1978年 | 46065篇 |
1977年 | 38657篇 |
1976年 | 36861篇 |
1975年 | 39071篇 |
1974年 | 47643篇 |
1973年 | 45355篇 |
1972年 | 42864篇 |
1971年 | 40110篇 |
1970年 | 37345篇 |
1969年 | 35143篇 |
1968年 | 32280篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Probable gas embolism during operative hysteroscopy caused by products of combustion 总被引:8,自引:0,他引:8
Ngozi Imasogie Ron Crago Nicholas A. Leyland Frances Chung 《Journal canadien d'anesthésie》2002,49(10):1044-1047
PURPOSE: Gas embolism is a rare but well documented entity during operative hysteroscopy, with an incidence of 10-50%. Catastrophic outcomes occur at a rate of three in 17,000 procedures. The purpose of this report is to present a non-fatal case of gas embolism probably caused by the gaseous products of combustion. CLINICAL FEATURES: A 50-yr-old woman with a history of menorrhagia was scheduled for hysteroscopy and endometrial ablation and polypectomy. Fifteen minutes into the procedure, with the patient in lithotomy position, 20 degree head down tilt, and breathing spontaneously, a sudden oxygen desaturation occurred from 97% to 87%. The patient's end-tidal carbon dioxide dropped from 46 mmHg to 27 mmHg. The patient's breathing pattern remained normal, respiratory rate remained 11-12 breaths x min(-1) but amplitude of the reservoir bag movement was increased. Cardiovascular variables remained stable. She responded rapidly to 100% oxygen and made an uneventful recovery. Having ruled out other possible causes, we concluded gas embolism was responsible for the fall in oxygen saturation and end-tidal CO(2). CONCLUSION: With all the precautions in place to minimize the likelihood of fluid overload and ambient air embolism occurring, we surmised that products of combustion were the cause of the gas embolism. During endometrial ablation, gaseous products of combustion, mainly carbon dioxide, accumulate. The gases may then contribute to the rise in uterine pressure that occurs as irrigation fluid enters the uterus and this rise in pressure in turn encourages passage of gas into the open venous sinuses. 相似文献
993.
Ignacio Lopez Escolastico Aguilera-Tejero Arnold J Felsenfeld Jose Carlos Estepa Mariano Rodriguez 《Journal of bone and mineral research》2002,17(9):1691-1700
Because both metabolic (Met Acid) and respiratory acidosis (Resp Acid) have diverse effects on mineral metabolism, it has been difficult to establish whether acidosis directly affects parathyroid hormone (PTH) secretion. Our goal was to determine whether acute Met Acid and Resp Acid directly affected PTH secretion. Three groups of dogs were studied: control, acute Met Acid induced by HCl infusion, and acute Resp Acid induced by hypoventilation. EDTA was infused to prevent acidosis-induced increases in ionized calcium, but more EDTA was needed in Met Acid than in Resp Acid. The PTH response to EDTA-induced hypocalcemia was evaluated also. Magnesium needed to be infused in groups receiving EDTA to prevent hypomagnesemia. The half-life of intact PTH (iPTH) was determined during hypocalcemia when PTH was measured after parathyroidectomy. During normocalcemia, PTH values were greater (p < 0.05) in Met Acid (92 +/- 19 pg/ml) and Resp Acid (77 +/- 22 pg/ml) than in controls (27 +/- 5 pg/ml); the respective pH values were 7.23 +/- 0.01, 7.24 +/- 0.01, and 7.39 +/- 0.02. The maximal PTH response to hypocalcemia was greater (p < 0.05) in Met Acid (443 +/- 54 pg/ml) than in Resp Acid (267 +/- 37 pg/ml) and controls (262 +/- 48 pg/ml). The half-life of PTH was greater (p < 0.05) in Met Acid than in controls, but the PTH secretion rate also was greater (p < 0.05) in Met Acid than in the other two groups. In conclusion, (1) both acute Met Acid and Resp Acid increase PTH secretion when the ionized calcium concentration is normal; (2) acute Met Acid may increase the bone efflux of calcium more than Resp Acid; (3) acute Met Acid acts as a secretogogue for PTH secretion because it enhances the maximal PTH response to hypocalcemia. 相似文献
994.
The triphalangeal thumb-brachyectrodactyly syndrome is a very rare autosomal dominant disorder of unknown etiology characterized by an unusual pattern of limb malformations: triphalangeal thumbs and brachyectrodactyly in the hands, and ectrodactyly in the feet. In a previous report, we described the clinical and radiographical features of three related subjects with the disease and suggest that due to the unusual combination of limb defects and to its phenotypic similarity with the limb malformative pattern induced by disrupting the Hoxd13 gene in mouse, the triphalangeal thumb-brachyectrodactyly syndrome might be caused by mutations in a HOX gene. After sequencing the entire coding region of HOXD13 and the highly conserved homeodomain encoding region of HOXA13, we do not detect any deleterious mutation in any of the patients excluding that alterations at these sequences are responsible for the disease. Mutations in regulatory regions of these genes or in other genes involved in limb development might be responsible for the disease. 相似文献
995.
996.
C. Sch?fer H. H. Klünemann B. Ibach J. Mueller A. Putzhammer I. Trender-Gerhard G. Schuierer H. E. Klein 《Der Nervenarzt》2002,24(1):879-882
Wir berichten über den ersten Fall von polyzystischer lipomembran?ser Osteodysplasie oder “brain, bone and fat disease” in
Deutschland. Die nach dem Erstbeschreibern auch als Morbus J?rvi-Hakola-Nasu bezeichnete Erkrankung ist bisher vor allem in
Japan und in Finnland beschrieben worden. Einzelne F?lle wurden aus Schweden, Norwegen, Italien, Südafrika, Belgien und den
USA berichtet. Im deutschsprachigen Raum ist bisher ein Fall aus ? ver?ffentlicht worden. 相似文献
997.
998.
Interaction of the leucine-rich repeats of polycystin-1 with extracellular matrix proteins: possible role in cell proliferation. 总被引:3,自引:0,他引:3
Ashraf N Malhas Ramadan A Abuknesha Robert G Price 《Journal of the American Society of Nephrology : JASN》2002,13(1):19-26
Polycystin-1, the product of the PKD1 gene, is a membrane-bound multidomain protein with a unique structure and a molecular weight of approximately 460 kD. The purpose of this study is to investigate the binding of the cystein-flanked leucine-rich repeats (LRR) of polycystin-1 to extracellular matrix (ECM) components. These interactions may play a role in normal renal development as well as the pathogenesis of autosomal-dominant polycystic kidney disease (ADPKD). In vitro assays were used to assess the binding of a fusion protein containing the LRR of polycystin-1 and that of affinity purified polycystin-1 to a number of ECM components. The results showed that the LRR modulate the binding of polycystin-1 to collagen I, fibronectin, laminin, and cyst fluid-derived laminin fragments. The addition of the LRR fusion protein to cells in culture resulted in a significant dose-dependent reduction in the rate of proliferation. Cyst fluid-derived laminin fragments had a stimulatory effect on cell proliferation, which was reversed by the LRR fusion protein. These results suggest that the LRR of polycystin-1 act as mediators of the polycystin-1 interaction with the ECM. The observed suppression effect of the LRR on cell proliferation suggests a functional role of the LRR-mediated polycystin-1 involvement in cell-matrix and cell-cell interactions. These interactions may result in the enhanced cell proliferation that is a characteristic feature of ADPKD. 相似文献
999.
1000.
The authors report the association of erythroleukemia (FAB M6) and fetal hemoglobin (HbF) level of at least 65% after therapy for ovarian carcinoma. The patient's erythrocytes had many signs of reversion to fetal-like erythropoiesis including: elevated HbF with a fetal G gamma/A gamma (gly/ala) of 3/1, low hemoglobin A2 (HbA2), macrocytosis, and increased i antigen. These data and data from other case reports suggest that elevation of HbF to greater than 25% with reversion to fetal-like erythropoiesis is useful in differentiating erythroleukemia from other preleukemic disorders. 相似文献