全文获取类型
收费全文 | 25342篇 |
免费 | 1202篇 |
国内免费 | 126篇 |
专业分类
耳鼻咽喉 | 334篇 |
儿科学 | 409篇 |
妇产科学 | 481篇 |
基础医学 | 3181篇 |
口腔科学 | 638篇 |
临床医学 | 1847篇 |
内科学 | 6996篇 |
皮肤病学 | 466篇 |
神经病学 | 1897篇 |
特种医学 | 788篇 |
外科学 | 4192篇 |
综合类 | 105篇 |
一般理论 | 1篇 |
预防医学 | 760篇 |
眼科学 | 404篇 |
药学 | 1688篇 |
中国医学 | 44篇 |
肿瘤学 | 2439篇 |
出版年
2022年 | 179篇 |
2021年 | 416篇 |
2020年 | 236篇 |
2019年 | 280篇 |
2018年 | 402篇 |
2017年 | 303篇 |
2016年 | 374篇 |
2015年 | 388篇 |
2014年 | 542篇 |
2013年 | 689篇 |
2012年 | 1068篇 |
2011年 | 1172篇 |
2010年 | 649篇 |
2009年 | 586篇 |
2008年 | 1142篇 |
2007年 | 1227篇 |
2006年 | 1182篇 |
2005年 | 1130篇 |
2004年 | 1133篇 |
2003年 | 1135篇 |
2002年 | 1165篇 |
2001年 | 917篇 |
2000年 | 951篇 |
1999年 | 835篇 |
1998年 | 339篇 |
1997年 | 257篇 |
1996年 | 239篇 |
1995年 | 226篇 |
1994年 | 189篇 |
1993年 | 165篇 |
1992年 | 614篇 |
1991年 | 639篇 |
1990年 | 549篇 |
1989年 | 552篇 |
1988年 | 536篇 |
1987年 | 505篇 |
1986年 | 429篇 |
1985年 | 437篇 |
1984年 | 324篇 |
1983年 | 248篇 |
1979年 | 236篇 |
1978年 | 136篇 |
1977年 | 143篇 |
1974年 | 132篇 |
1973年 | 120篇 |
1972年 | 138篇 |
1971年 | 130篇 |
1970年 | 115篇 |
1969年 | 137篇 |
1967年 | 128篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
141.
142.
The histochemical demonstration of iron and the iron content was examined in the brain of a case of the special type of hepatocerebral encephalopathy (HCE). The patient had suffered from a liver disease since 36 years old. At 44 years old, she experienced the first attack of twilight state with flapping tremor. She had predilection for eating beans. Her personality gradually became euphoric with the recurrent episodes of unconsciousness. At 54 years old, she died of the complication of melena, renal insufficiency and pneumonia. The liver showed cirrhotic changes and iron content of liver was 0 or 1 after MacDonald's criterion scale. The histopathological findings of the brain showed the characteristic changes of HCE, which were incomplete softening and spongy state pseudolaminarilly extending in the deep layer of the cerebral cortex, the proliferation of the severely changed Alzheimer 2 type glia with or without intranuclear carmine positive substance. The deparaffinized sections, 20 mu in thickness, which were not fastened on slides were used for the histochemical study of iron, because iron deposits displaced inside of the brain tissues when the paraffin sections were fastened on slide glasses in the constant-temperature bath. The iron deposition was found in the central gyrus, superior temporal gyrus, medial and lateral occipito-temporal gyrus and middle temporal gyrus of occipital lobe. The iron accumulated in the ground substance, glia cell bodies, glia nuclei and unknown bodies in the 3-6 layers of cerebral cortex of these gyri. The iron accumulation demonstrated histochemically in other parts of the brain were group 1, 2 by Spatz, mammillary body, glia cell bodies in cerebellar white matter and pons.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
143.
144.
145.
Toshikazu Saito M.D. Hideaki Ishizawa M.D. Fumiaki Tsuchiya M.D. Hiroki Ozawa M.D. Naohiko Takahata M.D. 《Psychiatry and clinical neurosciences》1986,40(2):189-194
Abstract: Monoamine and their acid metabolites were determined in the CSF of 18 drug-treated chronic schizophrenic patients with the symptoms of tardive dyskinesia and neuroleptic-induced Parkinsonism (Parkinsonism). Six healthy volunteers were used as the control group.
The norepinephrine (NE) levels were found to be significantly higher in the patients with tardive dyskinesia than in the controls. Furthermore, elevated CSF NE levels were also observed in the patients with Parkinsonism. Epinephrine (E) and Dopamine (DA) were not present in the CSF of the control group, whereas measurable levels of DA could be detected in 4 out of 9 and E was found in 8 out of 9 patients with tardive dyskinesia. The mean concentration of HVA was slightly but not significantly elevated in the patients with tardive dyskinesia and Parkinsonism. The mean values of CSF 5-HIAA were all within the normal range in both patient groups. From the above results, it was suggested that abnormal adrenergic activity rather than abnormal dopaminergic activity may play an important role as a mechanism in the etiopathogenesis of extrapyramidal disorders. Furthermore, in the patients with Parkinsonism, CSF neurochemical observations were similar to those of the patients with tardive dyskinesia in this study. It may help to explain the clinical coexistence of tardive dyskinesia and neuroleptic-induced Parkinsonism. 相似文献
The norepinephrine (NE) levels were found to be significantly higher in the patients with tardive dyskinesia than in the controls. Furthermore, elevated CSF NE levels were also observed in the patients with Parkinsonism. Epinephrine (E) and Dopamine (DA) were not present in the CSF of the control group, whereas measurable levels of DA could be detected in 4 out of 9 and E was found in 8 out of 9 patients with tardive dyskinesia. The mean concentration of HVA was slightly but not significantly elevated in the patients with tardive dyskinesia and Parkinsonism. The mean values of CSF 5-HIAA were all within the normal range in both patient groups. From the above results, it was suggested that abnormal adrenergic activity rather than abnormal dopaminergic activity may play an important role as a mechanism in the etiopathogenesis of extrapyramidal disorders. Furthermore, in the patients with Parkinsonism, CSF neurochemical observations were similar to those of the patients with tardive dyskinesia in this study. It may help to explain the clinical coexistence of tardive dyskinesia and neuroleptic-induced Parkinsonism. 相似文献
146.
The apolipoprotein(a) (apo[a]) gene encodes a protein component of lipoprotein(a) [Lp(a)] whose plasma levels vary widely among individuals. Hyper-Lp(a)-emia constitutes a risk factor for thromboembolic disease. We previously subclassified the apo(a) gene into four allelic types (A-D) by polymorphisms in the 5''-flanking region. To elucidate whether these polymorphisms affect the expression of apo(a), we measured plasma Lp(a) concentrations in vivo by ELISA and examined expression of the gene by an in vitro assay using its 5''-flanking region. Homozygotes of type C had significantly higher Lp(a) levels than those of type D. The relative expression of type C was also about three times higher than that of type D, which was consistent with the in vivo results. Deletion analysis revealed that the substitution of C by T (+93) led to negative regulation in expression of the gene, while the change of G to A (+121) led to positive regulation. These results indicate that the polymorphisms in the 5''-flanking region of the apo(a) gene affect the efficiency of its expression and, in part, play a role in regulating plasma Lp(a) levels. 相似文献
147.
Seigo Kinuya Shiro Takahashi Motoyasu Saito Yohei Tofuku Takatoshi Michigishi Norihisa Tonami 《Annals of nuclear medicine》1996,10(2):261-264
Thallium-201 SPECT was performed to evaluate a pulmonary lesion in a 73-year-old male which had been considered to be an inflammatory lesion for two years. The lesion has slowly increased in size on x-CT. Tl-201 was intensely taken up and retained in the lesion, suggesting a malignant lesion. Histological examination revealed that the lesion was bronchioloalveolar carcinoma. This case suggested that Tl-201 uptake of pulmonary carcinoma would not be necessarily related to cell growth rate. 相似文献
148.
The retino-collicular neuron terminals containing type A monoamine oxidase (MAO-A) in the stratum griseum superficiale of the rat superior colliculus were analyzed to provide a morphologic basis for the physiologic role of these neurons in the visual pathway. A computer-assisted, three-dimensional re-construction of the terminal complex associated with the MAO-A-positive terminals was performed. MAO-A-positive terminals originated in the retina and terminated in the stratum griseum superficiale. This was confirmed by tract tracing and enucleation experiments. The terminals were densely grouped in clusters of irregularly shaped swellings. Electron microscopy revealed that the MAO-A-positive terminals were located in a glomerulus-like structure. In this terminal complex, a significant proportion of the axonal profiles (42.96%) synapsed with the MAO-A-positive terminals. Most of the profiles (24.16%) resembled presynaptic dendrites, which represent intermediate elements between the retinal terminals and conventional dendrites. Unlike the glomerulus in the dorsal lateral geniculate body, the MAO-A-positive terminal swellings were not located in the central part of the terminal complex. The terminals had an irregular shape and were located in the complex. The terminal complex was partially ensheathed by glial processes. Furthermore, the membrane surfaces exhibiting synaptic specializations were very small compared with the total surface of the terminal swellings. The membrane length of the synaptic specialization was 5.38% of the total perimeter of the MAO-A-positive terminals. 相似文献
149.
Hajime ISOMOTO Yohei MIZUTA Keiichiro MATSUNAGA Michio TOMONAGA Isao SHIMOKAWA Katsuhisa OMAGARI Fuminao TAKESHIMA Kunihiko MURASE Shigeru KOHNO 《Digestive endoscopy》1998,10(2):135-141
Abstract: We report a case of glucagonoma syndrome with liver metastasis, who responded completely to dacarbazine chemotherapy. A 77-year-old woman complained of itching skin eruptions (diagnosed as necrolytic migratory erythema) and weight loss. She was found to have glucose intolerance, anemia, hypoproteinemia and hyperglucagonemia. Abdominal CT and celiac arteriography showed a hypervascular tumor in the pancreatic tail and a metastatic tumor in the left hepatic lobe. Immunohistochemical examination of the metastatic liver tumor obtained by laparoscopic biopsy revealed the tumor cells to be positive for glucagon. The patient was treated with 20 courses of 300 mg/day intravenous dacarbazine for 5 consecutive days followed by a 4 week drug-free interval. No major side effects were noted. Treatment resulted in disappearance of the skin lesions and correction of anemia, glucose intolerance, hypoproteinemia and hyperglucagonemia. Follow-up abdominal CT showed complete resolution of both the primary pancreatic tumor and the metastatic liver tumor. We suggest that dacarbazine be considered as the treatment of choice for metastatic glucagonoma. 相似文献
150.
The Basomedial and Basolateral Amygdaloid Nuclei Contribute to the Induction of Long-term Potentiation in the Dentate Gyrus In Vivo 总被引:1,自引:0,他引:1
Recent behavioural studies have provided evidence that the amygdala modulates hippocampal-dependent memory. To test the possibility that the amygdala modulates hippocampal synaptic plasticity, we investigated the effects of surgical lesions of the amygdaloid nuclei on the induction of long-term potentiation (LTP) in the dentate gyrus of anaesthetized rats. Previously we reported that LTP in the dentate gyrus was attenuated by lesion of the basolateral amygdala, but was not affected by lesion of the central amygdala. In the present study, dentate gyrus LTP was significantly attenuated by basomedial amygdala lesion but not by medial amygdala lesion. These results suggest that, among the amygdaloid nuclei, the basomedial and basolateral nuclei are involved in the modulation of hippocampal plasticity. The roles of the basomedial and basolateral amygdala were further supported by experiments examining the effects of electrical stimulation of these nuclei. High-frequency stimulation of the basomedial amygdala alone did not induce dentate gyrus LTP, but when applied at the same time as tetanic stimulation of the perforant path increased the magnitude of the dentate gyrus LTP. Similarly, high-frequency stimulation of the basolateral amygdala enhanced LTP induced by tetanic stimulation of the perforant path. Furthermore, facilitation of dentate gyrus LTP by basomedial or basolateral amygdala stimulation was observed even in rats lesioned in either amygdala, suggesting that neurons in the basomedial and basolateral amygdala can modulate dentate gyrus LTP independently. Activity-dependent facilitation of hippocampal plasticity by the basomedial and basolateral amygdala may underlie memory processing associated with emotion. 相似文献