首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5806篇
  免费   289篇
  国内免费   35篇
耳鼻咽喉   53篇
儿科学   82篇
妇产科学   82篇
基础医学   667篇
口腔科学   118篇
临床医学   339篇
内科学   1732篇
皮肤病学   158篇
神经病学   446篇
特种医学   241篇
外科学   913篇
综合类   26篇
预防医学   161篇
眼科学   69篇
药学   398篇
中国医学   28篇
肿瘤学   617篇
  2024年   14篇
  2023年   43篇
  2022年   65篇
  2021年   131篇
  2020年   92篇
  2019年   83篇
  2018年   121篇
  2017年   111篇
  2016年   133篇
  2015年   155篇
  2014年   169篇
  2013年   194篇
  2012年   353篇
  2011年   410篇
  2010年   211篇
  2009年   199篇
  2008年   332篇
  2007年   373篇
  2006年   336篇
  2005年   339篇
  2004年   343篇
  2003年   397篇
  2002年   361篇
  2001年   98篇
  2000年   66篇
  1999年   102篇
  1998年   74篇
  1997年   48篇
  1996年   64篇
  1995年   44篇
  1994年   73篇
  1993年   43篇
  1992年   70篇
  1991年   60篇
  1990年   47篇
  1989年   40篇
  1988年   37篇
  1987年   52篇
  1986年   27篇
  1985年   28篇
  1984年   21篇
  1983年   11篇
  1982年   21篇
  1981年   17篇
  1980年   17篇
  1979年   16篇
  1977年   13篇
  1975年   7篇
  1971年   9篇
  1969年   9篇
排序方式: 共有6130条查询结果,搜索用时 15 毫秒
141.
Pharmacists active in health care venues need to be able to evaluate generic drugs in terms of effectiveness, safety, and economy to ensure that they are used appropriately. As part of the ongoing study of these factors, we carried out an objective evaluation of information provided for generics. A minimum of 20 commercially available products was considered for each pharmaceutical ingredient. The information subjected to evaluation consisted of the text of drug package inserts and information noted on interview forms. Using our own criteria for evaluating drug information, we attempted to quantify the amounts of information provided. Then, based on the numerical values obtained, we calculated information quantities with reference to drug prices to study the relationship between prices and available information for original drugs and their later-developed, generic equivalents. A total of 14 different pharmaceutical ingredients (327 product items) were considered, with the information quantity for generics amounting to 27.9+/-17.8-46.3+/-21.4% (Mean+/-S.D.) that for the original drugs. Examined on the basis of individual pharmaceutical companies, the corresponding ratio came to 15.1+/-7.8-62.4+/-6.4% (Mean+/-S.D.). For generics, the relationship between drug price (expressed against a value of 1.0 for original drugs) and information quantity (Qua(i)) came to 0.79+/-0.46-1.90+/-0.79% (Mean+/-S.D.). These results clearly point to the importance of evaluating information quantity for generic drugs on a maker-by-maker basis.  相似文献   
142.
143.
Of all distant metastases from carcinoma of the papilla of Vater (CPV), the liver is the most frequent site (more than 60%) and should be specifically targeted in the effort to improve the prognosis. However, the optimal chemotherapy regimen for nonresectable liver metastasis has not been clearly established. In this preliminary report, we note a patient with multiple hepatic metastases from CPV successfully treated using intrahepatic infusion of 5-fluorouracil (FU) with low-dose cisplatin. A 62-year-old woman underwent curative pylorus-preserving pancreaticoduodenectomy for CPV. Four months after surgery, followup computed tomography (CT) demonstrated multiple liver metastases. Weekly intrahepatic arterial infusion chemotherapy of 5-FU, 350 mg/m2, with low-dose cisplatin (7 mg/m2) was started. Ten months after starting chemotherapy, a complete response was obtained. To date, the patient continues to receive this weekly hepatic arterial infusion chemotherapy without any side effects, and she has successfully maintained a long-term complete response for 20 months. The patient remains well and was able to proceed with daily activity at the last follow up 30 months after starting this chemotherapy regimen. This regimen is safe and effective and is recommended as one of the treatment choices for liver metastases from CPV.  相似文献   
144.
145.
PURPOSE: To propose a new surgical technique for optimized visualization of the chamber angle using scleral indentation under an operating microscope in goniosynechialysis (GSL). PATIENTS AND METHODS: Six volunteers with normal chamber angle and five patients with synechial angle closure glaucoma were examined. Scleral indentation 2 mm posterior to the limbus was performed during observation of chamber angle. Width of trabecular meshwork in images was recorded through a CCD camera mounted on an operating microscope. Trabecular-iris angle and trabecular-corneal angle obtained by ultrasound biomicroscopy were used for the parameters for the angle configuration. GSL with scleral indentation was performed in the patients. RESULTS: According to the visibility of the chamber angle, width of trabecular meshwork in images significantly increased from 0.34 +/- 0.08 mm equivalent (mean +/- SD) to 0.67 +/- 0.14 mm equivalent (P = 0.0001) with scleral indentation. According to the angle configurations, trabecular-iris angle significantly increased from 39.6 +/- 3.8 degrees to 47.5 +/- 6.6 degrees (P = 0.0016), and trabecular-corneal angle significantly decreased from 169.8 +/- 5.5 degrees to 158.7 +/- 5.4 degrees (P < 0.0001). All patients were successfully treated with GSL using scleral indentation. CONCLUSION: Scleral indentation provided the surgeon an optimized visualization of the anterior chamber angle. Deepening of the chamber angle and steeping in trabecular-corneal curvature probably induced the plane of the trabecular meshwork less oblique to the surgeon's visual axis. This enhanced visualization promises the accuracy and safety of GSL.  相似文献   
146.
Tetanus is characterized by tetanic convulsions related to the actions of tetanospasmin produced by Clostridium tetani. Another important characteristic of tetanus is the instability of the cardiovascular system related to sympathetic hyperactivity in the autonomic nervous system, and it may be an important prognostic factor. We report a patient with tetanus in whose unstable circulatory kinetics made circulation management difficult. A 77-year-old woman who injured in a fall, 11 days after trismus appeared and 3 day after convulsion appeared. It was not severe case in the acuity classification. However, repeated generalized convulsions and autonomic imbalance involving the cardiovascular system were observed clinically, suggesting a severe case. Because of the unstable circulatory kinetics, the patient was carefully managed was performed in the intensive care unit (ICU), and she improved. ICU management may be essential for treating severe tetanus with cardiovascular complications. Acquired immunity is not achieved after the onset of tetanus, and since elderly people, in particular, as in our own caset, are easily injured when they fall, we recommend vaccination.  相似文献   
147.
Selective cleavage of the Glu395-Ser396 bond of brevican, one of the major proteoglycans in adult brain tissues, is thought to be important for glioma cell invasion. Our previous biochemical study demonstrated that ADAMTS-4, a member of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family, has such an activity. In the present study, we examined brevican-degrading activities of ADAMTS-1, -4 and -5 at the cellular level, and their expression and localization in human glioma tissues. In 293T transfectants expressing ADAMTS-4 or ADAMTS-5, brevican was cleaved into two major fragments in an identical pattern, but no such degradation was observed with ADAMTS-1 transfectants. When the expression levels of these ADAMTS species were examined by real-time quantitative PCR, only ADAMTS-5 was found to be overexpressed in glioblastoma tissues compared to control normal brain tissues (P <0.05). In situ hybridization and immunohistochemistry demonstrated that ADAMTS-5 is expressed predominantly in glioblastoma cells. Forced expression of ADAMTS-5 in glioma cell lines stimulated cell invasion. These results demonstrate for the first time that ADAMTS-5 is capable of degrading brevican and is overexpressed in glioblastoma cells, and suggest that ADAMTS-5 may play a role in glioma cell invasion through the cleavage of brevican.  相似文献   
148.
Two novel classes of diphenyloxazole and Ndelta-Z-ornithine derivatives as highly potent and selective EP(4) antagonists have been discovered. The optimized diphenyloxzole 8 and Ndelta-Z-ornithine 11 effectively competed with [(3)H]PGE(2) binding to human recombinant EP(4), with K(i) values of 0.30 nM and 0.91 nM, respectively, and were selective for all members of the human prostanoid receptor family. 8 was shown to exhibit good pharmacokinetic properties in rats and dogs and potent inhibitory activity toward in vitro PGE(2)-promoted IgE synthesis.  相似文献   
149.
150.
New experimental model of crush injury of the hindlimbs in rats   总被引:11,自引:0,他引:11  
BACKGROUND: Crush injury (CI) remains a life-threatening condition. Because there is a shortage of animal models of CI, we purposed to develop a reproducible model of CI of hindlimbs in rats and to evaluate correlation between the volume of muscles traumatized and the severity of CI. METHODS: The right or both hindlimbs of anesthetized rats were compressed for 6 hours under blocks weighing 3 kg. This was followed by 3 hours of reperfusion. Serum lactate, base excess (BE), and potassium (K) were measured at 10 minutes after cannulaton (baseline), immediately before release (compression), and 3 hours after release (reperfusion). Serum creatine phosphokinase (CK), lactate dehydrogenase (LDH), aspartate transferase (AST) and alanine transferase (ALT) were measured at baseline and reperfusion. Muscles and kidneys were evaluated morphologically. In a separate group of animals treated in the same way, survival rate was monitored for 168 hours. RESULTS: Unilateral CI did not induce serious systemic impairment. Bilateral CI resulted in severe lactic acidosis. Serum K levels increased similarly and significantly in both groups. Serum CK levels correlated strongly with the volume of muscles traumatized. Bilateral CI produced a sharp increase in serum LDH, AST and ALT levels by the end of experiment. Signs of direct cellular damage and ischemia-reperfusion injury were found in histology specimens. In bilaterally crushed rats there were patent signs of acute tubular necrosis at 24 hours after insult. All rats with unilateral CI survived, whereas mortality rate reached 58.3% in rats with bilateral CI. The majority of these animals died within 24 hours after compression. CONCLUSIONS: We developed a valid experimental model of severe CI of the hindlimbs in rats. Systemic responses to CI and the severity of CI appeared to correlate strongly with the volume of muscle traumatized.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号