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   1281篇
  免费   58篇
  国内免费   4篇
耳鼻咽喉   1篇
儿科学   23篇
妇产科学   12篇
基础医学   108篇
口腔科学   13篇
临床医学   93篇
内科学   261篇
皮肤病学   11篇
神经病学   250篇
特种医学   141篇
外科学   204篇
综合类   12篇
预防医学   111篇
眼科学   8篇
药学   36篇
中国医学   7篇
肿瘤学   52篇
  2021年   19篇
  2019年   9篇
  2018年   20篇
  2017年   11篇
  2016年   17篇
  2015年   25篇
  2014年   27篇
  2013年   36篇
  2012年   44篇
  2011年   56篇
  2010年   43篇
  2009年   28篇
  2008年   57篇
  2007年   52篇
  2006年   59篇
  2005年   54篇
  2004年   35篇
  2003年   52篇
  2002年   58篇
  2001年   44篇
  2000年   54篇
  1999年   39篇
  1998年   26篇
  1997年   24篇
  1996年   20篇
  1995年   20篇
  1994年   16篇
  1993年   11篇
  1992年   28篇
  1991年   20篇
  1990年   29篇
  1989年   30篇
  1988年   20篇
  1987年   25篇
  1986年   23篇
  1985年   24篇
  1984年   21篇
  1983年   14篇
  1982年   11篇
  1980年   13篇
  1979年   13篇
  1978年   7篇
  1977年   7篇
  1976年   10篇
  1974年   7篇
  1973年   9篇
  1972年   8篇
  1971年   8篇
  1969年   8篇
  1968年   7篇
排序方式: 共有1343条查询结果,搜索用时 958 毫秒
1.
Schlu?folgerungen Für die Peritonealkarzinose bei rezidivierendem Ovarialkarzinom sollte die IHCP als Konsolidierungstherapie nach neuerlicher zytoreduktiver Chirurgie in Erw?gung gezogen werden. Bei grobknotiger diffuser Carcinosis peritonei und massivem Aszites kann die IHCP über l?ngerer Zeit dessen Neubildung verhindern und damit zu einer Verbesserung der Lebensqualit?t und Verl?ngerung der überlebenszeit beitragen.  相似文献   
2.
Sequential contrast-enhanced MR imaging of the penis   总被引:1,自引:0,他引:1  
Kaneko  K; De Mouy  EH; Lee  BE 《Radiology》1994,191(1):75
  相似文献   
3.
Three patients presented with giant aneurysms of the intracranial internal carotid artery that became symptomatic with expanding mass effects 4-10 years after severe head trauma accompanied by skull base injuries at the site of aneurysm formation. These aneurysms are therefore considered to be late manifestations of traumatic vessel disruption. Posttraumatic aneurysm growth was documented in one case of a supraclinoidal aneurysm. One intracavernous aneurysm was combined with a traumatic carotid-cavernous sinus fistula. Although the origin of intracranial aneurysms is usually considered to be traumatic only within a period of weeks or months after head injuries, giant aneurysms of the intracranial internal carotid may represent late complications of trauma in a number of cases.  相似文献   
4.
Equating the condition after cardiac arrest with that of medial temporal damage, and consequently medial temporal lobe amnesia, is questioned on the basis of results from a patient who was studied neuropsychologically as well as with static and dynamic imaging methods (MRI, PET) 6–9 months after a heart attack. The patient manifested severe and persistent anterograde and retrograde amnesia, as well as further cognitive deteriorations. While MRI only indicated non-specific cortical atrophy, PET revealed a severe bilateral affection of the thalamus and of both medial and lateral temporal cortices as well as occipito-parietal hypometabolism. The neuropsychological status indicates that patients with a diagnosis of cardiac arrest may suffer very severe and persistent cognitive deficits; the imaging analyses show that cardiac arrests may lead to quite severe and widespread brain damage which, however, may not be visible with current magnetic resonance imaging technology, but which is clearly apparent from positron emission tomography. These data suggest that patients with a condition after a heart attack may not be valid models for pure hippocampal—or even medial temporal lobe—pathology, as they may suffer much more widespread brain damage.  相似文献   
5.
6.
Insemination with donor spermatozoa is an integral part of infertility treatment. For the last 3 years in our unit, intrauterine insemination with donor spermatozoa (IUID) has been used in preference to vaginal insemination. In this retrospective study, patients were offered an initial course of five single intrauterine inseminations with cryopreserved donor spermatozoa and treatment was then reviewed. A total of 389 patients received 1465 inseminations. In all, 1119 cycles were monitored using luteinizing hormone serum analyses and 346 cycles using the urine home test kits. The clinical pregnancy rate per insemination for the cycles monitored by the serum assay was 18.0% (202/1119) compared with the urine cycles (13.7%, 46/346) (P <05). The pregnancy loss rate was not significantly different (14.4%, 29/202 and 21.7%, 10/46) (serum and urine cycles respectively). The viable clinical pregnancy rate was significantly higher (P <03) for the serum cycles than for the cycles using the urinary monitoring (15.5%, 173/1119 and 10.4%, 36/346 respectively). The cycles monitored by serum assay had a significantly higher cumulative viable clinical pregnancy rate (P <0001) of 70.2% after nine inseminations compared with the urine monitored cycles of 54.8%. The majority of patients opted for the serum cycles, with a minority self-selecting the urine cycles mainly for travelling convenience. The explanation for the significant differences between the viable clinical pregnancy rates per insemination and the cumulative viable clinical pregnancy rates may be due to the sensitivity of the urine home test kit or the patients' interpretation of the result.   相似文献   
7.
The glucose metabolic rate of the human brain can be measured with labeled deoxyglucose, using positron emission tomography, provided certain conditions are fulfilled. The original method assumed irreversible trapping of deoxyglucose metabolites in brain during the experimental period, and it further requires that a conversion factor between deoxyglucose and glucose, the "lumped constant," be known for the brain regions of interest. We examined the assumption of irreversible trapping of fluorodeoxyglucose metabolites in brain of four patients in 365 normal and 4 recently infarcted regions. The average net, steady-state rate of fluorodeoxyglucose (KD) accumulation in normal regions of the four patients was 0.025 ml g-1 min-1. We also examined the variability of the lumped constant. We first confirmed that methylglucose is not phosphorylated in the human brain. We then estimated the lumped constant from the regional distribution of labeled methylglucose in brain. The average (virtual) volume of distribution of labeled methylglucose in the normal regions was 0.46 ml g-1 and was the same in both gray and white matter structures. The average brain glucose content corresponding to this value was 1.3 mumol g-1, assuming a Michaelis constant (Kt) of 3.7 mM for glucose transport across the blood-brain barrier. The lumped constant varied insignificantly between 0.4 and 0.5 in most regions, with an overall average of 0.44. It did not vary significantly between the patients and was the same in gray and white matter structures, but was inversely related to the calculated metabolic rate. This observation indicates that metabolic rates calculated with a fixed lumped constant (e.g., 0.40) would be slightly underestimated at high metabolic rates and slightly overestimated at low metabolic rates. The average glucose metabolic rates of the 365 normal regions, in which gray matter regions prevailed by 20:1, was 32 mumol 100 g-1 min-1. The average glucose phosphorylation rate in white matter was 20 mumol 100 g-1 min-1 with a lumped constant of 0.45. In the recently infarcted areas, the lumped constants varied from 0.37 to 2.83, corresponding to glucose metabolic rates varying from 2 to 18 mumol 100 g-1 min-1. Two infarct types were identified. In one type, the phosphorylation-limited type, glucose content and the lumped constant were close to normal (1 mumol g-1 and 0.40, respectively). In the other, the transport/flow-limited type, the glucose content was low (0.2 mumol g-1), and the lumped constant in excess of unity. The evidence from the present study upholds the model of Sokoloff et al. in every detail.  相似文献   
8.
目的 探讨盐酸喹那普利 (QuinaprilHydrochloride)治疗轻、中度原发性高血压的有效性和安全性。方法 全国 6家医院参加的一项多中心、随机、双盲、平行组间对照研究。结果  113例原发性高血压病人治疗 8周后 ,总有效率达 85 84% ,统计学有显著性差异。盐酸喹那普利副反应较轻 ,对肾脏、肝脏、造血系统和心脏未见有害作用。结论 盐酸喹那普利是一种安全、疗效好、副反应小的治疗轻、中度原发性高血压的有效药物。  相似文献   
9.
Progression rates of Alzheimer's disease (AD) vary considerably, and they are particularly difficult to predict in patients with mild cognitive impairment. We performed a prospective multicenter cohort study in 186 patients with possible or probable AD, mostly with presenile onset. In a cross-sectional analysis at entry, impairment of glucose metabolism in temporoparietal or frontal association areas measured with positron emission tomography was significantly associated with dementia severity, clinical classification as possible versus probable AD, presence of multiple cognitive deficits and history of progression. A prospective longitudinal analysis showed a significant association between initial metabolic impairment and subsequent clinical deterioration. In patients with mild cognitive deficits at entry, the risk of deterioration was up to 4.7 times higher if the metabolism was severely impaired than with mild or absent metabolic impairment. Copyrightz1999S.KargerAG, Basel  相似文献   
10.
Summary The effects of antineoplastic treatment on gliomas are related to tumour cell cycle and proliferation kinetics, glioma tissue architecture, and the surrounding environment. Morphological changes induced by radiation and chemotherapy are characterized by cell necrosis and severe alterations in cell and nuclear morphology caused by changes in the cell kinetic parameters which, however, may also occur spontaneously in untreated anaplastic gliomas.Comparative studies of cytological imprints and routine histological preparations of biopsy and autopsy specimens were performed in four groups of anaplastic astrocytomas and glioblastomas (78 cases) with postsurgical irradiation, combination chemotherapy, and CCNU treatment, and without specific postsurgical treatment (control group). Following radiation and chemotherapy, in addition to increased necrosis and vascular response, a variety of characteristic but nonspecific changes were observed in cell and nuclear morphology with prominent formation of multinucleated giant and monstrous cells, irregular and hyperchromatic nuclei, and severe cytoplasmic degeneration indicating both inhibition of cell division and cell damage. Statistically significant findings were a posttreatment increase in the number of multinucleated giant and monstrous cells and a decrease in the number of mitoses. These changes were more pronounced after chemotherapy than after radiation, while no significant dissimilarities were found between combination chemotherapy and CCNU. The implications of these changes on the mechanisms of antitumour treatment in anaplastic gliomas are discussed.
Morphologische Veränderungen in anaplastischen Gliomen nach Strahlen- und Chemotherapie
Zusammenfassung Die Wirkung anuneoplastisdier Behandlung auf Gliome ist abhängig von der Tumorzeil- und Proliferationskinetik, der Gliomarchitektur und dem umgebenden Hirngewebe. Durch Strahlen- und Chemotherapie induzierte morphologische Veränderungen sind gekennzeichnet durch Zellnekrosen sowie schwere Zell- und Kernschäden durch Eingriffe in die Zellkinetik, doch können diese auch spontan in unbehandelten anaplastischen Gliomen auftreten.Vergleichsuntersuchungen von zytologischen Abstrichen und histologischen Routinepräparaten an Biopsie- und Autopsiematerial von 4 Gruppen anaplastischer Astrozytome und Glioblastome (78 Fälle) wurden nach postoperativer Strahlenbehandlung, Polychemotherapie und CCNU-Behandlung sowie ohne spezifische postoperative Therapie (Kontrollgruppe) vorgenommen. Nach Strahlen- und Chemotherapie fanden sich neben gesteigerter Nekrose und Gefäßreaktion verschiedene charakteristische, aber unspezifische Zell- und Kernveränderungen mit gesteigerter Neigung zur Bildung vielkerniger Riesen- und Monsterzellen, Kernhyperchromasie sowie schwerer Zytoplasmadegeneration als Hinweise auf Mitosestörungen und Zellschädigung. Nach antineoplastischer Therapie fand sich eine statistisch signifikante Zunahme von Riesen- und vielkernigen Monsterzellen sowie Abnahme der Mitosen, wobei diese Veränderungen nach Chemotherapie stärker ausgeprägt waren als nach Bestrahlung. Zwischen Polychemo- und CCNU-Behandlung ergaben sich keine wesentlichen Abweichungen. Die Bedeutung dieser zytologischen Spätbefunde auf die Effekte antineoplastischer Behandlung anaplastischer Gliome wird diskutiert.
  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