全文获取类型
收费全文 | 182507篇 |
免费 | 1483篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 1226篇 |
儿科学 | 6817篇 |
妇产科学 | 3225篇 |
基础医学 | 17581篇 |
口腔科学 | 1687篇 |
临床医学 | 13259篇 |
内科学 | 32190篇 |
皮肤病学 | 848篇 |
神经病学 | 17209篇 |
特种医学 | 9129篇 |
外科学 | 29450篇 |
综合类 | 2375篇 |
一般理论 | 1篇 |
预防医学 | 18734篇 |
眼科学 | 2835篇 |
药学 | 9910篇 |
中国医学 | 664篇 |
肿瘤学 | 16881篇 |
出版年
2023年 | 98篇 |
2022年 | 208篇 |
2021年 | 378篇 |
2020年 | 254篇 |
2019年 | 273篇 |
2018年 | 22154篇 |
2017年 | 17547篇 |
2016年 | 19736篇 |
2015年 | 1196篇 |
2014年 | 1125篇 |
2013年 | 1215篇 |
2012年 | 7588篇 |
2011年 | 21615篇 |
2010年 | 19130篇 |
2009年 | 11811篇 |
2008年 | 19947篇 |
2007年 | 22083篇 |
2006年 | 945篇 |
2005年 | 2555篇 |
2004年 | 3689篇 |
2003年 | 4606篇 |
2002年 | 2752篇 |
2001年 | 296篇 |
2000年 | 427篇 |
1999年 | 186篇 |
1998年 | 261篇 |
1997年 | 237篇 |
1996年 | 119篇 |
1995年 | 127篇 |
1994年 | 127篇 |
1993年 | 76篇 |
1992年 | 50篇 |
1991年 | 95篇 |
1990年 | 135篇 |
1989年 | 91篇 |
1988年 | 68篇 |
1987年 | 51篇 |
1986年 | 29篇 |
1985年 | 36篇 |
1984年 | 34篇 |
1983年 | 32篇 |
1982年 | 43篇 |
1980年 | 49篇 |
1969年 | 22篇 |
1938年 | 61篇 |
1937年 | 30篇 |
1935年 | 24篇 |
1934年 | 30篇 |
1932年 | 58篇 |
1930年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Stephen J. Hanna Oz Barakat Simon Watkin 《Journal of hepato-biliary-pancreatic sciences》2004,11(3):190-192
We report the case of a 54-year old woman who presented with a persistent right lower lobe pneumonia followed by cholelithoptysis, 11 months after a laparoscopic cholecystectomy. It is postulated that this was a result of the formation of a subphrenic abscess secondary to intraoperative spillage of gallstones. It is concluded that spillage of gallstones at laparoscopic cholecystectomy is not as benign as previously thought and that efforts to prevent spillage should include scrupulous operative technique, especially in the presence of gallbladder inflammation, and especial care when removing the gallbladder from the abdominal cavity. 相似文献
992.
Brundell S Tsopelas C Chatterton B Touloumtzoglou J Blefari C Hewett PJ 《Diseases of the colon and rectum》2003,46(5):637-642
INTRODUCTION: We have reported previously on an in vitro model to examine tumor cell adherence to metal and plastic laparoscopic ports and to port sites through which they had been passed. This demonstrated that increased numbers of tumor cells were found both on metal ports compared with plastic ports and on the port sites through which metal ports had passed. In this study, the in vivo adherence of such cells to ports and port sites was investigated.
METHODS: LIM 1215 tumor cells were injected under direct vision into the pelvises of 16 30-kg female pigs (range, 15–70 × 106 cells). A total of 12 ports were inserted through each anterior abdominal wall (6 metal and 6 plastic), and these were either left in situ for 30 minutes (nondisplaced) or were removed twice and replaced through the original wound (displaced).
RESULTS: Increasing the tumor cell inoculum resulted in increased deposition of tumor cells on both ports (P = 0.002) and on the port sites (P = 0.017). Significantly more tumor cells adhered to metal ports than to plastic ports (P = 0.04), although this failed to reach significance for the sites through which metal ports had been passed (P = 0.066). Although displacement of ports did not increase the number of tumor cells that adhered to ports (P = 0.45), this did result in more tumor cells being deposited on the port sites (P = 0.01).
CONCLUSIONS: These data suggest that minimizing the number of tumor cells within the abdominal cavity, using plastic ports, and securing ports to prevent inadvertent displacement would be expected to reduce the number of tumor cells deposited in port sites during operative laparoscopy. This may be beneficial in reducing the incidence of port-site metastases after laparoscopic surgery for gastrointestinal malignancies. 相似文献
993.
Antonio De Sisti Joelci Tonet Sonia Marrakchi Denis Raguin Robert Frank 《Journal of interventional cardiac electrophysiology》2008,22(3):189-193
Limited information is available on the efficacy of cryoablation in the coronary venous system in humans. A patient with a lateral accessory pathway was referred to our center after several unsuccessful endocardial and epicardial (within the coronary sinus) attempts using standard radiofrequency energy. Ablation was subsequently performed successfully by applying cryoenergy distally into the coronary sinus, using a temperature of -50 degrees C and a freezing application time of 45 s. There were no complications. Angiography of the left coronary circumflex artery and coronary venous system was performed at 12 months follow-up using cardiac multislice computed tomography, and no coronary stenosis or anatomic anomaly was found. Neither pre-excitation or any arrhythmia recurred during follow-up. This experience suggests that ablating in the distal coronary sinus can be safely performed using cryoenergy. 相似文献
994.
Insulin aspart (NovoLog, NovoRapid), a rapid-acting human insulin analog, provides more rapid absorption than regular human insulin after subcutaneous administration. In most randomized, nonblind clinical trials in patients with type 1 diabetes mellitus, insulin aspart administered immediately before meals resulted in significantly lower mean glycosylated hemoglobin (HbA1c) levels than regular human insulin (usually administered 30 minutes before a meal). Insulin aspart also significantly improved postprandial glycemic control compared with regular human insulin. The efficacy of insulin aspart was similar to that of insulin lispro when administered to patients with type 1 diabetes mellitus via continuous subcutaneous infusion in a randomized, nonblind trial. Preliminary data from randomized, nonblind trials suggest insulin aspart had a trend towards lower HbA1c levels compared with regular human insulin in patients with type 2,diabetes mellitus. Biphasic insulin aspart (30% soluble [rapid-acting] and 70% protamine-bound insulin aspart [BIAsp30]) [NovoLog Mix 70/30, NovoMix 30(2)] generally provided significantly better postprandial glucose control than a similar mixture of biphasic regular human insulin (BHI30) in a randomized, nonblind trial in patients with type 1 or 2 diabetes mellitus. However, the long-term efficacy of BIAsp30 was similar to that of BHI30 after 2 years in a randomized, nonblind trial in patients with type 2 diabetes mellitus. Patients with type 1 or 2 diabetes mellitus reported greater treatment satisfaction with insulin aspart or BIAsp30 than with regular human insulin or BHI30. The overall incidence of hypoglycemia with insulin aspart was lower than, or similar to, that of regular human insulin. Moreover, insulin aspart tended to be associated with a lower occurrence of nocturnal hypoglycemia and severe hypoglycemic events than regular human insulin. Conclusion: The standard preparation of insulin aspart has the potential to better mimic the physiological response to meals than regular human insulin. Insulin aspart when combined with a suitable basal insulin improved overall glycemic control and led to a similar or lower number of hypoglycemic episodes compared with a similar regular human insulin regimen. Insulin aspart was generally as effective and well tolerated as insulin lispro when administered by continuous subcutaneous infusion in a single comparative trial. The efficacy of biphasic insulin aspart has been documented in a small number of trials. Both insulin aspart and biphasic insulin aspart provide for flexible and convenient administration. Insulin aspart is now well established as an effective and convenient means of providing glycemic control which offers clinical and practical advantages over regular human insulin. 相似文献
995.
Breitmeier D Becker N Weilbach C Albrecht K Scheinichen D Panning B Schneider U Jüttner B 《Alcoholism, clinical and experimental research》2008,32(10):1708-1713
Background: Polymorphonuclear, neutrophil granulocytes (PMN) play a major role in the control of infections, and people who abuse alcohol are susceptible to infections. Resistance against infections ensues intracellularly following initial phagocytosis of microorganisms with the oxygen‐dependent respiratory burst, the key enzyme of which is the respiratory burst oxidase, whereby oxygen radicals are produced for microbial destruction. To date there is insufficient information available in connection with the process of impaired defence against infection in patients suffering from alcohol dependence. Therefore, our investigation was carried out to determine the influence of alcohol exposition on the formation of oxygen radicals and the respiratory burst. Methods: 4.5 ml of whole blood was taken from 10 healthy adults and 10 patients suffering from alcohol dependence. An additional 3.5 ml of whole blood was taken from the alcoholic patients for determination of the blood alcohol concentration. The respiratory burst of PMN was tested using the Four‐Colour‐Continuous Flow Cytometer. Each experimental procedure consisted of 4 test samples [negative controls, Escherichia coli, FMLP‐supplement (N‐formyl‐l‐methionyl‐l‐leucyl‐l‐phenylalanin), PMA‐supplement (phorbol‐12‐myristate‐13‐acetate)]. Differing concentrations of ethanol were also introduced to each of the tests performed (0.20 to 4.00 g/l). Results: Ethanol revealed a marked decrease of burst activity in those patients suffering from alcoholism with increased alcohol concentration. A dependence between the burst activity and the ethanol concentration was seen to be statistically significant. This effect was only evident after stimulation with E. coli and FMLP in those patients with alcohol dependence. Conclusion: The results presented in this study show an impairment in the function of PMN in those patients addicted to alcohol due to the decrease in burst activity. In view of the results of the different stimuli, the second‐messenger effects were not evident. A clarification of this phenomenon could well be assumed as an allosteric receptor effect on the burst oxidase, namely, a direct effect on the phagocytosis interaction between circulating granulocytes and causative organisms. 相似文献
996.
Expression of vascular endothelial growth factor and receptor flk-1 in colon cancer liver metastases
Jun Cheng Richard E. Slavin Jennifer A. Gallagher Guojing Zhu Thomas R. Biehl Lee L. Swanstrom Paul D. Hansen 《Journal of hepato-biliary-pancreatic sciences》2004,11(3):164-170
Background/Purpose
This study investigated vascular endothelial growth factor (VEGF) and flk-1 expression in hepatic metastases from colon carcinoma, and their associations with tumor angiogenesis, proliferation, and apoptosis.Methods
Immunohistochemical studies were performed for VEGF/flk-1, Ki-67, p53, and bcl-2 expression, and microvessel density (MVD) in surgical specimens from 35 patients who underwent hepatectomy for colon cancer liver metastases between 1986 and 2001.Results
VEGF and flk-1 were expressed mainly in the cytoplasm of tumor cells. High VEGF expression was associated with high flk-1 expression (P = 0.043). MVDs of less than 15 and 15 or more were found in 5 (14.3%) and 30 (85.7%) of 35 hepatic metastases, respectively. A Ki-67 index (KI) of 50% or more was detected in 33/35 (94.3%) of tumors, and 23 of these (65.7%) showed a KI of 85% or more. A KI of less than 50% was present in 2/35 (5.7%) of tumors. The expression of VEGF/flk-1 was related to elevated MVD (P ≤ 0.026). VEGF was also associated with an increased KI (P = 0.025). Mutant p53 and bcl-2 expressions were detected in 26/35 (74.3%) and 17/35 (48.6%) of liver metastases, respectively. Mutant p53 was not related to VEGF/flk-1 expression, but bcl-2 was highly associated with flk-1 (P = 0.007). The incidences of high flk-1 expression and a KI of 85% or more were significantly higher in tumors which were both p53- and bcl-2-positive (93.3% and 73.3%) than in tumors which were negative for both (42.9% and 14.3%; P ≤ 0.021).Conclusions
The VEGF-flk-1 system takes part in tumor angiogenesis, proliferation, and apoptosis in colon liver metastases. The bcl-2 pathway may upregulate VEGF activity via the flk-1 receptor. These findings are preliminary, requiring a larger sampling in order to elucidate the role of VEGF/flk-1 in metastatic colon cancer.997.
Neuromyelitis optica (NMO), characterised by longitudinally extensive transverse myelitis (LETM), was previously thought to be a variant of multiple sclerosis. Transverse myelitis may be a manifestation of autoimmune connective tissue diseases and NMO is now recognised to be a humorally mediated autoimmune disease. We present a case of NMO associated with non-organ-specific autoantibodies and the absence of the characteristic NMO-IgG antibody. Our case provides an opportunity to review the diagnostic criteria of NMO and its distinction from other autoimmune and demyelinating conditions. We report successful treatment with plasmapheresis and rituximab in NMO-IgG-negative relapsing disease. 相似文献
998.
999.
The stylopharyngeus plays a critical role in the clearance of the piriform recess. We dissected 78 sides of the pharynx from 55 donated cadavers and observed histology of another seven sides of the pharynx from seven cadavers. The stylopharyngeus consistently comprised (1) a descending muscle bundle surrounding the piriform recess and (2) an additional short sheet inserting into the tonsillar bed. Histologically, the former bundle connected to a thick fascia providing the lateral glossoepiglottic fold, extending along the submucosa of the piriform recess, and covering the thyroid cartilage, whereas the latter sheet intermingled with other pharyngeal wall muscles at and near the tonsillar bed. Notably, in 44.4% of female specimens, the additional sheet occupied a greater proportion in cross section than the descending muscle bundle. Given the different directions, the additional sheet seemed to check clearance function of the descending bundle for the piriform recess. Thus, particularly in women, interindividual differences in pharyngeal clearance were likely to depend on whether the additional sheet is strong or weak. Chin down in combination with tilting and rotating the head may represent effective exercises of the stylopharyngeus that could compensate for the disadvantages of additional insertion. 相似文献
1000.
Background We developed and evaluated the clinical usefulness of a scoring system that subclassified type Vi pit patterns.
Methods We studied 119 colon cancer lesions (pTis, n = 26; pT1, n = 93) and 22 tubular adenoma lesions with severe atypia in which a type Vi pit pattern was visible under a stereomicroscope. Four type Vi pit pattern formation appearances (existing pits, marginal irregularities of the gland duct, narrowing of the gland duct
lumen, and unclear outline of the gland duct) were defined, and the relationship between each appearance and the invasive
depth of the cancer was evaluated.
Results When the four type Vi pit pattern appearances were considered in a logistic regression analysis, the odds of a more invasive submucosal cancer
were significantly increased by the appearance of marginal irregularities, a narrowed lumen, and an unclear outline. In the
logistic regression analysis results, when 0.63 was used as the cutoff score for prediction of a more invasive submucosal
cancer, 80 cases in the less invasive group were classified correctly (specificity, 1.0), whereas 53 (86.9%) of the 61 cases
in the more invasive group were classified correctly (sensitivity, 0.869).
Conclusions It is important first to understand the usability and limitations of objective scoring of type V pit pattern findings and
then to apply this score to the determination of cancer depth in order to accurately identify lesions suitable for endoscopic
treatment. 相似文献