全文获取类型
收费全文 | 5833篇 |
免费 | 540篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 70篇 |
儿科学 | 167篇 |
妇产科学 | 121篇 |
基础医学 | 838篇 |
口腔科学 | 124篇 |
临床医学 | 545篇 |
内科学 | 1338篇 |
皮肤病学 | 247篇 |
神经病学 | 466篇 |
特种医学 | 220篇 |
外国民族医学 | 3篇 |
外科学 | 884篇 |
综合类 | 39篇 |
预防医学 | 436篇 |
眼科学 | 123篇 |
药学 | 414篇 |
中国医学 | 21篇 |
肿瘤学 | 342篇 |
出版年
2023年 | 32篇 |
2022年 | 56篇 |
2021年 | 165篇 |
2020年 | 127篇 |
2019年 | 187篇 |
2018年 | 209篇 |
2017年 | 148篇 |
2016年 | 167篇 |
2015年 | 161篇 |
2014年 | 203篇 |
2013年 | 257篇 |
2012年 | 362篇 |
2011年 | 362篇 |
2010年 | 231篇 |
2009年 | 206篇 |
2008年 | 290篇 |
2007年 | 270篇 |
2006年 | 283篇 |
2005年 | 246篇 |
2004年 | 194篇 |
2003年 | 195篇 |
2002年 | 173篇 |
2001年 | 168篇 |
2000年 | 152篇 |
1999年 | 131篇 |
1998年 | 70篇 |
1997年 | 72篇 |
1996年 | 65篇 |
1995年 | 54篇 |
1994年 | 62篇 |
1993年 | 45篇 |
1992年 | 140篇 |
1991年 | 118篇 |
1990年 | 81篇 |
1989年 | 70篇 |
1988年 | 74篇 |
1987年 | 60篇 |
1986年 | 78篇 |
1985年 | 71篇 |
1984年 | 44篇 |
1983年 | 32篇 |
1982年 | 38篇 |
1981年 | 23篇 |
1979年 | 18篇 |
1978年 | 25篇 |
1976年 | 19篇 |
1974年 | 19篇 |
1971年 | 15篇 |
1970年 | 16篇 |
1969年 | 21篇 |
排序方式: 共有6398条查询结果,搜索用时 15 毫秒
21.
I Pascual-Castroviejo M C Roche V Martinez Fernndez M Perez-Romero R M Escudero J J Garcia-Peas M Sanchez 《AJNR. American journal of neuroradiology》1994,15(8):1521
PURPOSETo describe the MR findings in eight girls and women with incontinentia pigmenti, from two families. Four had skin lesions and neurologic disease, and four had only skin lesions.METHODSEight patients had physical examination, family history, electroencephalogram and MR examination of the brain. MR was repeated in the two cases with more severe changes several years after the first study.RESULTSMR revealed brain changes only in the four patients who had neurologic disease associated with the cutaneous lesions of incontinentia pigmenti. Abnormalities were located in the cerebral hemisphere contralateral to the most affected side of the body. In two cases, the MR changes were subjacent to the scalp areas where the most severe cutaneous lesions were located in the neonatal period. Hypoplasia of the corpus callosum, probably secondary to atrophy of one or both cerebral hemispheres, and abnormal signal and atrophy of the lateral regions of one of the cerebellar hemispheres also were found in all four cases. Although the changes were seen in both the T1- and T2-weighted images, they were most evident in the latter. The four patients in the fourth stage who had only cutaneous lesions without neurologic problems did not reveal any MR abnormalities.CONCLUSIONSThis study demonstrates MR signal changes and focal atrophy of the cerebrum, cerebellum, and corpus callosum in patients with incontinentia pigmenti and neurologic disorders. The MR images appear normal in patients with incontinentia pigmenti who have no neurologic abnormalities. 相似文献
22.
23.
J. Sanchez Burson J. Graña Gil M. Rosales Rodriguez A. Atanes Sandoval C. Alonso Blanco F. Galdo Fernandez 《Clinical rheumatology》1992,11(2):261-264
Summary We have studied the characteristics of arthritis present in 32 patients with Behçet's disease (BD), and how this arthritis is related to the HLA markers class I. 84% of the patients presented arthritis, the most common being monoarthritis as the initial presentation, and oligoarthritis in subsequent episodes. In 63% of the cases, the development was in episodes of acute/subacute arthritis. We found statistically significant association between antigens B-5 and B-51, and the group with BD, with a relative risk of 3.89 and 4.71 respectively. The attempt to relate markers B-5, B-51 and B-27 to the presence of arthritis as well as to its manifestation and further development was not conclusive. 相似文献
24.
Fernandez-Aviles Francisco; Sanchez Pedro L.; On behalf of the GRACIA Group 《European heart journal》2007,28(19):2418
We thank Dr Villata et al. for their thought-provoking comments.Their concern about the suitableness to choose combined endpointsin clinical trials deserves some comment. 相似文献
25.
E Del Villar P Vega C Gaule E Sanchez 《European journal of drug metabolism and pharmacokinetics》1990,15(4):279-285
Short or long term diabetes in female rats produced remarkable activation of aminopyrine N-demethylation, inhibition of oestrone and p-nitrophenol glucuronidation and no changes in morphine UDP-glucuronyltransferase activity in vitro. Km and Vmax for these reactions were determined. Insulin treatment partially antagonized diabetes activation of aminopyrine N-demethylation: it restored decreased UDP-glucuronyltransferase activities for oestrone and p-nitrophenol only in long term and short term diabetes, respectively. Insulin also markedly inhibited morphine glucuronidation. Triton X-100 also displayed a differential pattern of activation for the glucuronidation reactions in liver microsomes of diabetic rats. Results suggest that diabetes in female rats may increase the actual amount of enzyme protein for aminopyrine metabolism and to decrease that for oestrone and p-nitrophenol. 相似文献
26.
Quality control of perfusion: monitoring venous blood oxygen tension to prevent hypoxic acidosis 总被引:2,自引:0,他引:2
H Swan M Sanchez M Tyndall C Koch 《The Journal of thoracic and cardiovascular surgery》1990,99(5):868-872
The long-held belief that venous oxygen tension mirrored tissue oxygen tension became suspect in the 1960s when new instrumentation consistently showed that tissue oxygen tension was 10 to 30 torr less than venous oxygen tension. Moreover, a countercurrent of oxygen exchange between terminal arteries and veins was shown to exist. Despite this conflict in scientific theory, however, monitoring venous oxygen tension as a means to control hypothermic cardiopulmonary bypass has been repeatedly urged, since myocardial acidosis is clearly extremely detrimental. This study of the relationship between venous oxygen tension during hypothermic bypass and a concurrent increment in lactacidemia yields strong objective evidence to support the use of on-line venous oxygen tension monitoring to guide perfusion. In a random series of 36 patients, venous blood samples were drawn at five preselected intervals during operation and were analyzed for pH, carbon dioxide tension, oxygen tension, lactic acid, hematocrit, and base excess. Analysis of the data revealed that venous pH and base excess showed no correlation to venous oxygen tension. However, lactic acid showed a strong correlation with venous oxygen tension, with a correlation coefficient of 0.4338 at a confidence level of p less than 0.0001. If the patients were divided into three clinically pertinent groups based on the lowest venous oxygen tension recorded, a strong relationship between venous oxygen tension and lactic acid emerged. If the lowest measurement of venous oxygen tension was greater than 35 mm Hg (group A), the mean rise in lactic acid was only 0.12 microns/ml. If the lowest measurement was between 30 and 34 mm Hg (group B), the mean rise was 0.64 microns/ml. Whereas, if any venous oxygen tension value fell below 30 mm Hg (group C), the mean rise in lactic acid was 2.56 microns/ml. Analysis of variance showed that group C values were significantly different from groups A and B values (p less than 0.0002). A scientific hypothesis relating venous oxygen tension to adequate tissue oxygenation is proposed. Use of venous oxygen tension monitoring with the goal to maintain the level above 35 mm Hg is strongly supported by this study. 相似文献
27.
28.
B M Evers P L Rady K Sandoval I Arany S K Tyring R L Sanchez W H Nealon C M Townsend Jr J C Thompson 《Annals of surgery》1994,219(6):596-604
OBJECTIVE: This study determined whether genomic amplification of HER-2/neu or mutations of the p53 and ras genes were present in gastrinomas. SUMMARY BACKGROUND DATA: Amplification of HER-2/neu, a proto-oncogene related to the epidermal growth factor receptor, and mutation of the ras proto-oncogene and p53 tumor suppressor gene appear to play a role in the pathogenesis of some human cancers. Little is known about possible molecular alterations in gastrinomas, tumors that may be particularly virulent because of gastrin overproduction, resulting in the severe ulcer diathesis, the Zollinger-Ellison syndrome. METHODS: The differential polymerase chain reaction (PCR) procedure was used to detect amplification of the HER-2/neu gene in DNA samples from the novel human gastrinoma cell line (PT) and from paraffin-embedded samples of gastrinomas. Sequencing techniques were used to determine whether mutations of the p53 or ras (Ha-ras, N-ras, Ki-ras) genes were present. RESULTS: Amplification (> twofold) occurred in all gastrinoma tumor samples. Compared with normal pancreas or ileum, a 4- to 12-fold amplification of HER-2/neu was found in 3 gastrinomas, 3 to 3.3-fold in four samples and 2.1- to 2.4-fold in the remaining five tumors. A heterozygous point mutation in the p53 gene (codon 273) was found in a single sample; none of the gastrinomas contained a mutation of the ras genes. CONCLUSIONS: Amplification of the HER-2/neu gene, but not alterations of either p53 or ras, may be involved in the pathogenesis of gastrinomas. The unique PT cell line will be a useful model to further elucidate the molecular mechanisms that contribute to gastrinoma formation and growth. 相似文献
29.
L Naval A Garcia Sanchez R Duran F Rodriguez F Alamillos A Dean J Fernandez 《Revue de stomatologie et de chirurgie maxillo-faciale》1991,92(1):48-50
We present a new case of Pilomatrix Carcinoma after having review the 22 cases previously published. The tumor arisen in a 74 years old male, in the left preauricular region. The lesion was excised with wide margins. A year after there is not any evidence of recurrence or metastases. 相似文献
30.
G R Parr D E Steflik A L Sisk F T Lake L K Gardner R A Sanchez 《The Journal of oral implantology》1992,18(4):372-378
The objectives of this study were: (a) to observe and describe the variability of bone healing in implant receptor sites which were prepared in rabbit femurs by use of different surgical methods; and (b) to determine if the animal model which was used was suitable for the detection of differences in healing reactions in implant receptor sites which were prepared by different surgical methods. Three 3-mm-wide implant receptor sites were prepared in the right and left femurs of four large New Zealand white rabbits. The surgical parameters used in preparation of the different sites included: low speed with no irrigation (LSO); low speed with internal irrigation only (LSI); low speed with external irrigation only (LSE); high speed with no irrigation (HSO); or high speed with external irrigation only (HSE). The sites were randomized so that each animal had one of each type of site in either the right or left femur. A non-treated control site was located in each animal for comparison with experimental sites. The animals were killed at 7, 14, 21, and 28 days post-operatively. The resultant samples were fixed, embedded, sectioned, and stained with basic fuchsin and toluidine blue. The results indicated that this was probably not a suitable animal model, since no discernible differences were detected in the various healed sites. 相似文献