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81.
通过粘度的测量,考察了壳聚糖在不同条件下经不同剂量γ射线辐照所引起的分子量的变化,并分别计算了真空和空气中壳聚糖辐射裂解的G(S)值。  相似文献   
82.
Female mosquitofish (Gambusia affinis) were collected from two sites located on the US Department of Energy's Oak Ridge Reservation that are contaminated with 137Cs, 90Sr, other radionuclides and chemical genotoxicants. Fish from non- radionuclide contaminated environments located off the reservation were also collected. DNA, extracted from liver tissue and blood cells, was examined by gel electrophoresis for structural damage in the form of strand breakage. In general, the level of DNA strand breaks was elevated in fish from radionuclide-contaminated sites with observed differences in the number and type of strand breaks between liver tissue and blood cells. The number of malformed embryos was higher in fish at the contaminated sites, and varied with season. Fecundity was negatively correlated with the level of double strand breaks in the DNA of fish from one contaminated site. Females with broods that included malformed embryos had more DNA strand breakage than those that did not; and furthermore, a threshold effect was observed between the occurrence of malformed embryos and the presence of double strand breaks in the DNA of the mother. These findings have implications for both ecological risk assessment and evolutionary ecology  相似文献   
83.
脉冲式电磁辐射对大鼠血脑屏障影响的量效关系   总被引:6,自引:1,他引:5  
目的 研究脉冲式电磁辐射(EMR)对大鼠血脑屏障(BBB)影响的量效关系。方法 采用伊思蓝静脉注射,荧光显微镜下观察不同脉冲次数的EMR辐照对大鼠BBB开放的影响。结果 伊思蓝在EMR诱发的大鼠BBB开放局部呈现荧光斑;随着EMR脉冲次数(0~200次)的增加,荧光斑数量增加、面积增大;荧光斑在EMR组全脑的分布,以皮质、丘脑、下丘脑、小脑、尾壳核和延髓较多。结论 不同脉冲次数EMR诱发大鼠BBB开放程度不同,随脉冲次数增加,血管通透性增强,200次时达开放高峰,皮质区BBB开放最明显。  相似文献   
84.
Sixty-two cases of breast pathology were randomly selected from the files of the Dunedin Public Hospital for evaluation of mean epithelial nuclear volume. The cases were comprised of both benign and malignant ductal epithelial disease, diagnosed in cytological smears or in histological sections. Nuclear volume in histological preparations was estimated by the stereological technique of point-line intercept measurements to derive volume-weighted mean volumes (vV). An index of the nuclear volume (Vi) of cytology smears was calculated from measurements of nuclear areas by either image analysis Vi(e) or point-line intercepts Vi(p). By all methods of analysis a clear distinction of nuclear volume was found between the benign [means for the cytology were 148 microns 3 (Vi(e)) or 246 microns 3 (Vi(p)), and 203 microns 3 (Vv) for the histology specimens] and malignant diseased cases [means for cytology: 524 microns 3 (Vi(e)) or 886 microns 3 (Vi(p)), and 587 microns 3 (vV) for the histology specimens].  相似文献   
85.
电磁辐射对神经行为和生物电的影响   总被引:3,自引:0,他引:3  
随着经济的发展和信息时代的来临,各种频段的电磁波充盈整个生活空间,人们暴露于电磁辐射的机会与日俱增,电磁辐射环境污染已经成为继大气污染、水污染、噪声污染之后的新的第四大公害,给职业接触者和居民的健康带来潜在的危害。电磁辐射对人们健康和生活的影响是多方面的,该文就电磁辐射对神经行为、脑电、心电等方面的影响作一综述,以期对电磁辐射的危害作进一步的了解。  相似文献   
86.
Summary Thirty adult patients presenting with medulloblastoma between 1974 and 1991 were studied and treated at Puerta de Hierro Clinic. After diagnosis, all patients were treated by surgery followed by radiotherapy and eight of them received adjuvant chemotherapy. We have studied the influence of some factors such as age, sex, location of tumour in the cerebellum, amount of surgical resection and histological variants on survival and recurrence of the disease. Only the histological type has a statistically significant influence on survival and recurrence: we have found that patients presenting classic medulloblastoma have a long survival and a long relapse-free interval.  相似文献   
87.
Abstract: Between 1970 and 1990, 1,008 patients with early-stage breast cancer were treated by conservative surgery without axillary dissection followed by radiation therapy to the intact breast in the Department of Therapeutic Radiology at Yale-New Haven Hospital. The patient population, broken down by histologic subtype, was as follows: 761 patients presented with infiltrating ductal carcinoma, 70 patients with pure intraductal, 38 intraductal with focal invasion, 54 infiltrating lobular, 21 tubular, 17 medullary, 16 mucinous, and 29 with other various histologic subtypes. Patients were followed on a regular basis by the referring physicians and radiation oncologists. Diagnostic studies for distant metastases were performed as clinically indicated. Annual mammography was a routine component of the follow-up program. As of 3/96, with a median follow-up of 10.5 years, 83 patients developed an ipsilateral breast tumor recurrence, and 109 patients developed distant metastases resulting in an overall 10-year breast recurrence-free rate of 84%, and a 10-year distant metastasis-free rate of 78%. There were significant differences in clinical stage, pathological nodal involvement, and administration of systemic therapy between various histologic subtypes. As expected, those patients with histologies of low metastatic potential (such as intraductal, tubular, and mucinous) had significantly superior distant recurrence-free survival rates. With respect to breast relapse rates, there were no statistically significant differences in the 5- and 10-year breast recurrence-free rates between any of the histologic subtypes. Patients with intraductal carcinoma with or without focal invasion had similar breast relapse rates as those with other histologic subtypes. Patients with lobular carcinoma in situ as a histologic component also had a similar overall breast relapse-free recurrence rate. In conclusion, long-term follow-up of conservatively treated breast cancer patients demonstrates no significant differences in ipsilateral breast tumor recurrence rates between various histologic subtypes. There are no histologies which had a statistically significantly higher breast-relapse rate than infiltrating ductal carcinomas and therefore no primary histologic subtype represents a relative contraindication to breast conservation therapy.  相似文献   
88.
目的对1例192Ir极不均匀外照射局部极重度放射损伤病人进行临床观察。方法系统观察了病变的临床过程和应用红外线热成像技术测定了损伤部位的温度变化。结果照射后2小时出现肢体麻木、抽搐,最早照后4小时出现红斑、肿胀,54小时出现水疱,第5天出现坏死和剧痛,最晚出现红斑、肿胀是照射后41天,47天出现水疱和糜烂创面。红外线热成像显示:损伤早期温度升高,水疱、坏死区和损伤后期温度降低,温度升高越早,损伤越重,温度改变区域与损伤范围相一致。结论大剂量极不均匀外照射放射损伤的初期反应早,放射病与局部损伤相互加重病情,症状先后不一,轻重不等,致残率高和疼痛剧烈,红外线热成像温度变化可以作为临床诊断的指标之一。  相似文献   
89.
自体造血干细胞移植 (ASCT)是治疗复发性、难治性和侵袭性恶性淋巴瘤的有效方法 ,但因存在体内肿瘤细胞负荷过多和移植物被肿瘤细胞污染 ,使移植后的复发率增高。为了提高ASCT的疗效 ,可采取 :①移植前美罗华体内净化 ,除去外周血B细胞 ,清除移植物的肿瘤细胞污染 ;②移植后用美罗华和非交叉耐药药物交替联合化疗 ,以杀伤体内肿瘤细胞 ;③移植前或后累及野放射治疗 (IFRT)辅助 ,降低原发灶的复发率  相似文献   
90.
Summary In an autopsied case of a 37-year-old man with acquired immune deficiency syndrome (AIDS), multinucleated giant cell encephalopathy was noted in close proximity to multiple nodules of primary lymphoma of the brain. Some multinucleated giant cells and macrophages contained HTLV-III-like viral particles. Nuclear bridges, thin strands connecting individual nuclei with one another, were observed with both light and electron microscopes within some of the multinucleated giant cells. There were also thin tapering nuclear processes, which were probably part of nuclear bridges. The possibility that the nuclear bridges and processes represent amitotic nuclear division is discussed.  相似文献   
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