全文获取类型
收费全文 | 23603篇 |
免费 | 1802篇 |
国内免费 | 96篇 |
专业分类
耳鼻咽喉 | 259篇 |
儿科学 | 446篇 |
妇产科学 | 279篇 |
基础医学 | 3237篇 |
口腔科学 | 444篇 |
临床医学 | 2969篇 |
内科学 | 5374篇 |
皮肤病学 | 447篇 |
神经病学 | 2313篇 |
特种医学 | 728篇 |
外国民族医学 | 3篇 |
外科学 | 3449篇 |
综合类 | 243篇 |
现状与发展 | 1篇 |
一般理论 | 10篇 |
预防医学 | 1570篇 |
眼科学 | 374篇 |
药学 | 1547篇 |
中国医学 | 68篇 |
肿瘤学 | 1740篇 |
出版年
2023年 | 145篇 |
2022年 | 321篇 |
2021年 | 566篇 |
2020年 | 385篇 |
2019年 | 605篇 |
2018年 | 695篇 |
2017年 | 507篇 |
2016年 | 535篇 |
2015年 | 659篇 |
2014年 | 838篇 |
2013年 | 1115篇 |
2012年 | 1782篇 |
2011年 | 1952篇 |
2010年 | 939篇 |
2009年 | 897篇 |
2008年 | 1474篇 |
2007年 | 1488篇 |
2006年 | 1388篇 |
2005年 | 1415篇 |
2004年 | 1270篇 |
2003年 | 1129篇 |
2002年 | 1155篇 |
2001年 | 278篇 |
2000年 | 249篇 |
1999年 | 278篇 |
1998年 | 232篇 |
1997年 | 191篇 |
1996年 | 134篇 |
1995年 | 135篇 |
1994年 | 104篇 |
1993年 | 104篇 |
1992年 | 184篇 |
1991年 | 170篇 |
1990年 | 152篇 |
1989年 | 140篇 |
1988年 | 142篇 |
1987年 | 137篇 |
1986年 | 143篇 |
1985年 | 145篇 |
1984年 | 116篇 |
1983年 | 97篇 |
1982年 | 101篇 |
1981年 | 98篇 |
1980年 | 84篇 |
1979年 | 78篇 |
1978年 | 72篇 |
1977年 | 65篇 |
1976年 | 51篇 |
1975年 | 47篇 |
1974年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
David G Biron Cécile Joly Laurent Marché Nathalie Galéotti Vincent Calcagno Andreas Schmidt-Rhaesa Lionnel Renault Frédéric Thomas 《Infection, genetics and evolution》2005,5(2):167-175
The proteome of most parasite species is currently unknown. Hairworms (Nematomorpha), 300 species distributed around the world, are parasitic in arthropods (mainly terrestrial species) when juveniles, but they are free-living in aquatic environments when adult. Most aspects of their systematics and biology are currently unknown. The aim of this paper was (i) to report a novel and reproducible protocol for the analysis of the proteome of hairworms using two-dimensional gel electrophoresis (2-DGE) and mass spectrometry (matrix laser desorption ionization-time of flight mass spectrometry (MALDI-TOF)) and (ii) to determine the level of proteomic divergence between two sympatric but taxonomically unrelated nematomorph species in the adult stage, Paragordius tricuspidatus Dufour (Nematomorpha, Gordiidae) and Spinochordodes tellinii Camerano (Nematomorpha, Gordiidae). In total, 689 protein spots were observed for P. tricuspidatus, 575 for S. tellinii. Only 36.2% spots were shared between the two species. Quantitative analysis of the proteins which are common to both parasite species reveals substantial differences in the pattern of protein expression. These results suggest a rapid evolutionary divergence between these two nematomorph families. Also, to test the value of our MALDI-TOF protocol, we used Actin-2 (Act-2), a protein highly conserved in the course of evolution. Peptide mass fingerprint (PMF) data obtained for Act-2 of P. tricuspidatus and S. tellinii suggest a very high homology with Act-2 of different worms species belonging to the Bilateria phylum (Annelida and Nematoda) and more specifically to Lumbricus terrestris (Annelida, Lumbricidae) and Caenorhabditis elegans (Nematoda, Rhabditidae). We discuss our results in relationship with current ideas concerning the use of proteomics in systematics. 相似文献
72.
Philippe Chauveau Benot Vendrely Wael El Haggan Nicole Barthe Vincent Rigalleau Christian Combe Michel Aparicio 《Journal of renal nutrition》2003,13(4):282-287
BACKGROUND: It has been reported that patients on a very-low-protein diet (VLPD) maintain a satisfactory nutritional status because of a conserved adaptive metabolic response. However, only few studies have examined the course of nutritional status and body composition in the long term (2 years). METHODS: Thirteen stable patients (8 men; age, 55 +/- 12 years; glomerular filtration rate (GFR), 15 +/- 5 mL/min) receiving a VLPD (0.3 g/kg/day protein) supplemented with amino acids and ketoanalogues (SVLPD) were studied for 2 years. A joint visit with a physician and a dietitian and routine blood and urine analyses were performed every month. Dual-energy x-ray absorptiometry (DEXA), which was used to assess modification of body composition, and GFR (urinary 51Cr-EDTA) and urinary urea and creatinine excretion, which were used to assess nutritional status and compliance to the diet, were assessed every 3 months. RESULTS: GFR, albumin, and prealbumin levels remained stable. Urea urinary excretion decreased at 3 months and then slightly increased at 2 years, but the calculated protein intake remained low at 0.38 +/- 0.1 g/kg/day. Energy intake remained close to 30 kcal/kg/day. No significant change was observed for total fat mass or percent fat mass. After an initial decrease, lean body mass stabilized at 6 months and then increased significantly from 6 to 24 months (P =.02, paired t-test); the mean increase during this period was of 2 kg, that is, 4.6%. Urinary creatinine excretion showed the same profile. Total bone mass, lumbar or hip site bone mass, and Z-score significantly decreased from T0 to 1 and 2 years (P <.05). CONCLUSION: This study confirms that a supplemented VLPD is nutritionally safe for a long period, but attention must be paid to bone mass. 相似文献
73.
Cordula C M Pitz Aart Brutel de la Rivière Henry A van Swieten Vincent A M Duurkens Jan-Willem J Lammers Jules M M van den Bosch 《European journal of cardio-thoracic surgery》2004,26(1):202-208
Due to its localisation in the apex of the lung with invasion of the lower part of the brachial plexus, first ribs, vertebrae, subclavian vessels or stellate ganglion, a superior sulcus tumour causes characteristic symptoms, like arm or shoulder pain or Horner's syndrome. If rib invasion is the only feature, lysis of the rib must be evident on the chest radiograph; otherwise the tumour cannot be defined as a Pancoast tumour. It is important to adequately stage the tumour, because staging significantly influences survival. Survival is better for T3 than T4 tumours and mediastinal lymph node involvement has been found to be a negative prognostic factor. Also Horner's syndrome and incompleteness of resection worsen survival. The management of superior sulcus tumours has evolved over the past 50 years. Before 1950 it was considered to be inoperable and uniformly fatal. Shaw and Paulson introduced combined modality treatment and for many years, this combination of radiotherapy and surgery was the treatment of choice with a mean 5-year survival of approximately 30%. Postoperative radiotherapy or brachytherapy does not improve survival in patients with complete or incomplete resection. The tumour can be resected through the classic posterior Shaw-Paulson approach or the newer anterior transcervical approach, introduced by Dartevelle. This method facilitates better exposure of the extreme apex of the lung, brachial plexus and subclavian vessels. Regarding the extent of pulmonary resection, en bloc resection of the involved ribs with a lobectomy is recommended. Recent multimodality studies, involving chemoradiotherapy and surgical resection, show promising results regarding completeness of resection, local recurrence and survival, provided that appropriate staging has been carried out. However, careful patient selection and adequate perioperative management with protection of the bronchial stump or anastomosis are important to achieve reasonable rates of morbidity and mortality. As brain metastases remain one of the most common forms of relapse, further studies are needed to examine the role of prophylactic cranial irradiation in patients with complete resection. Also the addition of other chemotherapy agents or biologic agents such as angiogenesis inhibitors or tyrosine kinase inhibitors gives a new perspective in the treatment of Pancoast tumours. 相似文献
74.
Cathy Charles Jonathan Lomas Mita Giacomini Vandna Bhatia & Victoria A. Vincent 《The Milbank quarterly》1997,75(3):365-394
Four meanings of medical necessity have emerged, evolved, and dominated past and current health policy debates about the appropriate level of service coverage under Canada's health insurance program. To explore the shift in definition, provincial government and national health care association position papers responding to federal legislative and policy reviews of Canada's health insurance program from 1957 to 1984 were examined, as were more current reports on medical necessity. Four meanings of medical necessity predominated: "what doctors and hospitals do"; "the maximum we can afford"; "what is scientifically justified"; and "what is consistently funded across all provinces." These meanings changed with time as different stakeholder associations and governments redefined the concept of medical necessity to achieve different policy objectives for health service coverage under Canada's health insurance program. 相似文献
75.
Vincent R. Hentz M.D. Philip S. Green M.S. Marcel Arditi Ph.D. 《Skeletal radiology》1987,16(6):474-480
Ultrasonic transmission imaging has already demonstrated potential for evaluating structures in the hand. In this study, a cadaver hand was imaged using a transmission scanner with improved imaging capability. The hand was then frozen and serially sectioned and comparisons were made between the sectional anatomy and the corresponding image. Bone (in silhouette), muscle, cartilage, and tendon were visualized with high resolution. 相似文献
76.
Howard B. Yeon Jacob Weinberg Vincent Arlet Jean A. Ouelett Kirkham B. Wood 《European spine journal》2007,16(9):1379-1385
Fifteen skeletally immature patients with double major adolescent idiopathic scoliosis with large lumbar curves and notable L4 and L5 coronal plane obliquity were retrospectively studied. Seven patients who underwent anterior release and fusion of the lumbar curve with segmental anterior instrumentation and subsequent posterior instrumentation ending at L3 were compared with eight patients treated with anterior release and fusion without anterior instrumentation followed by posterior instrumentation to L3 or L4. At 4.5 years follow-up (range 2.5-7 years), curve correction, coronal balance and fusion rate were not statistically different between the two groups; however, the group with anterior instrumentation had improved coronal plane, near normalangulation in the distal unfused segment compared with the group without anterior instrumentation. In cases involving severe lumbar curvatures in the context of double major scoliosis, when as a first stage anterior release is chosen, the addition of instrumentation appears to restore normal coronal alignment of the distal unfused lumbar segment, and may in certain cases save a level compared with traditional fusions to L4. 相似文献
77.
78.
79.
Istvn . Mrocz Kullervo Hynynen HLkon Gudbjartsson Sharon Peled Vincent Colucci Ferenc A. Jlesz 《Journal of magnetic resonance imaging : JMRI》1998,8(1):136-142
The aim of this study was to investigate a potential technique for image-guided minimally invasive neurosurgical interventions. Focused ultrasound (FUS) delivers thermal energy without an invasive probe, penetrating the dura mater, entering through the cerebrospinal fluid (CSF) space, or harming intervening brain tissue. We applied continuous on-line monitoring by MRI to demonstrate the effect of the thermal intervention on the brain tissue. For this, seven rabbits had a part of their skull removed to create access for the FUS beam into the brain through an acoustic window of 11 mm in diameter. Dura was left intact and skin was sutured. One week later, the rabbits were sonicated for 3 seconds with 21 W acoustic power, and the FUS focus was visualized with a temperature-sensitive T1-weighted MRI pulse sequence. The tissue reaction was documented over 7 days with T2-weighted images of the brain. The initial area of the central low signal intensity in the axial plane was .4 ± .3 mm2, and for the bright hyperintensity surrounding the lesion, it was 2.3 ± .6 mm2 (n = 7). In the coronal plane, the corresponding values were .4 ± .1 mm2 and 3.4 ± .9 mm2 (n = 5). The developing brain edema culminated 48 hours later and thereafter diminished during the next 5 days. Histology revealed a central necrosis in the white matter surrounded by edematous tissue with inflammatory cells. In summary, the image-guided thermal ablation technique described here produced a relatively small lesion in the white matter at the targeted location. This was accomplished without opening the dura or the need for a stereotactical device. MRI allowed on-line monitoring of the lesion setting and the deposition of thermal energy and demonstrated the tissue damage after the thermal injury. 相似文献
80.
The Proceedings of the Round Table Conference will be published as volume 19, in the series Update in Intensive Care and Emergency Medicine (Springer Verlag) in January, 1995. 相似文献