全文获取类型
收费全文 | 29065篇 |
免费 | 1343篇 |
国内免费 | 164篇 |
专业分类
耳鼻咽喉 | 245篇 |
儿科学 | 558篇 |
妇产科学 | 394篇 |
基础医学 | 3855篇 |
口腔科学 | 534篇 |
临床医学 | 1873篇 |
内科学 | 7664篇 |
皮肤病学 | 701篇 |
神经病学 | 2282篇 |
特种医学 | 1392篇 |
外科学 | 4820篇 |
综合类 | 131篇 |
一般理论 | 4篇 |
预防医学 | 686篇 |
眼科学 | 534篇 |
药学 | 1931篇 |
中国医学 | 105篇 |
肿瘤学 | 2863篇 |
出版年
2023年 | 150篇 |
2022年 | 289篇 |
2021年 | 487篇 |
2020年 | 279篇 |
2019年 | 373篇 |
2018年 | 475篇 |
2017年 | 401篇 |
2016年 | 525篇 |
2015年 | 562篇 |
2014年 | 742篇 |
2013年 | 896篇 |
2012年 | 1382篇 |
2011年 | 1555篇 |
2010年 | 921篇 |
2009年 | 787篇 |
2008年 | 1413篇 |
2007年 | 1510篇 |
2006年 | 1476篇 |
2005年 | 1557篇 |
2004年 | 1417篇 |
2003年 | 1354篇 |
2002年 | 1437篇 |
2001年 | 796篇 |
2000年 | 817篇 |
1999年 | 788篇 |
1998年 | 434篇 |
1997年 | 341篇 |
1996年 | 375篇 |
1995年 | 307篇 |
1994年 | 284篇 |
1993年 | 231篇 |
1992年 | 592篇 |
1991年 | 586篇 |
1990年 | 555篇 |
1989年 | 512篇 |
1988年 | 408篇 |
1987年 | 371篇 |
1986年 | 391篇 |
1985年 | 359篇 |
1984年 | 267篇 |
1983年 | 215篇 |
1982年 | 127篇 |
1981年 | 120篇 |
1980年 | 134篇 |
1979年 | 190篇 |
1978年 | 130篇 |
1977年 | 122篇 |
1974年 | 106篇 |
1972年 | 111篇 |
1969年 | 102篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
M Hayashi J Kimura K Yamaki Y Suwabe M Dozen Y Imai S Oh-ishi 《Thrombosis research》1987,48(3):299-310
PAF-likely activity, detected as aggregation of washed platelets, was found in the exudate of rats with pleurisy induced by phorbol myristate acetate (PMA, 1 nmol). At 30 min after the injection of PMA, 400-500 pg of PAF was detected in the pleural exudate. An extract of the exudate was made and analysed by HPLC and by rabbit platelet aggregation. The activity was characterized as that of PAF as a result of the inhibition seen with the PAF-antagonist CV-3988 and the loss of activity by treatment with phospholipase A2. Indirect evidence was previously reported in that CV-3988 suppressed the pleural fluid accumulation in the pleurisy induced by PMA. Taken together these facts it indicates that PAF could be an important mediator of acute inflammation, especially of the plasma exudation resulting from an increase in vascular permeability. Evidence that pleural cells produce PAF was also examined in an in vitro experiment. PAF was found in the supernatant and cellular fractions of the incubation mixture of the pleural cells from normal rats when stimulated by PMA (1 microM) or A23187 (5 microM), and the results indicate that the pleural cells produce PAF and release a portion of it. 相似文献
102.
Immunostaining patterns of two glia-associated proteins, glial fibrillary acidic protein (GFAP) and S-100 protein (S100P), were compared using the peroxidase-antiperoxidase (PAP) method on adjacent paraffin sections in 100 brain tumors including 52 astroglial tumors, 13 oligodendrogliomas, 14 ependymomas, 13 choroid plexus papillomas and 8 medulloblastomas. Most astroglial tumors showed similar immunoreactivity for both proteins. Fibrillary processes, however, showed a stronger and more crisp staining with anti-GFAP than with anti-S100P, whereas cell nuclei were labeled only for S100P. Focal dissociation of immunoreactivities for the two proteins was prominent in several malignant astroglial tumors including giant cell glioblastoma, and in subependymal giant cell astrocytoma. In oligodendrogliomas, GFAP-positive neoplastic oligodendrocytes also showed immunoreactivity for S100P; a smaller number of tumor cells were immunoreactive only for S100P, comparable to normal mature oligodendroglia. Most ependymomas were characterized by a similar distribution of cells immunoreactive for both proteins. In choroid plexus papilloma, absent or only focal immunoreactivity for GFAP contrasted with diffuse labeling for S100P in all cases; this seems of value for a differential diagnosis of papillary CNS tumors. In medulloblastoma, some tumor cells of a classical type were immunoreactive only for S100P; on the contrary, GFAP positive tumor cells with sparse or absent immunoreactivity for S100P were found in desmoplastic medulloblastomas. Similar immunoreactivities for both proteins in most tumors suggest a generally parallel production of both proteins by glial tumor cells.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
103.
104.
105.
Atsuhiko Chiba Tatsuo Akema Masayuki Iigo Yuta Nagami Fukuko Kimura Jun-ichi Toyoda 《Journal of neuroendocrinology》1998,10(2):79-84
It has been recently reported that acute immobilization stress almost completely suppresses the luteinizing hormone (LH) release induced by naloxone, a μ-opioid antagonist, in ovariectomized estrogen-primed rats. The present study examined the possible involvement of the pineal gland in the acute immobilization-related suppression of the naloxone-induced LH release. An intraventricular (ICV) injection of 15 μg naloxone produced an abrupt increase in circulating LH concentrations in non-stressed rats. The naloxone-induced LH release was completely eliminated when tested 60 min after the end of a 30 min session of acute immobilization. The same stress conditions did not affect LH-releasing hormone (LHRH)-induced LH release, suggesting that the stress-related suppression of the naloxone-induced LH release was a suprapituitary event. In chronically-pinealectomized rats, but not in sham-pinealectomized rats, naloxone injected 60 min after the end of the stress session evoked a significant increase in serum LH concentrations. However, naloxone injected ICV during the acute immobilization did not elicit LH release in either pinealectomized or sham-operated rats. Under non-stressed conditions, the LH secretory response to naloxone was similar in pinealectomized and sham-operated animals. The same stress (30 min immobilization) significantly increased pineal melatonin content as well as plasma melatonin concentrations in rats bearing intact pineal glands, indicating that stress actually affected the pineal function. These results provide evidence for a role of the pineal in the suppression of the LH response to naloxone after stress, but not during stress. 相似文献
106.
Toshifumi Gabata Masumi Kadoya Osamu Matsui Masashi Yamashiro Tsutomu Takashima Donald G. Mitchell Yasutaka Nakamura Kazuo Takeuchi Yasuni Nakanuma 《Journal of magnetic resonance imaging : JMRI》1998,8(2):503-504
We reported a case of the biliary cystadenoma of the liver. The cystic mass had labulation and septation and showed marked hyperintensity on T1-weighted images and hypointensity on T2-weighted images; MR findings were very unusual for cystadenoma. The content of the cystic mass was jelly-like, thick mucinous fluid without intracystic hemorrhage. We concluded that these unusual signal intensities of the cyst were due to hyperproteinous mucinous fluid. 相似文献
107.
Yoshiro Tanizaki Hikaru Kitani Morihiro Okazaki Takashi Mifune Fumihiro Mitsunobu Ikuro Kimura 《The Journal of asthma》1993,30(4):309-318
The effects of long-term glucocorticoid therapy on airway inflammation were examined in 84 asthma patients. The proportion of lymphocytes in bronchoalveolar lavage (BAL) fluid was significantly decreased in patients with steroid-dependent intractable asthma (SDIA) compared to results in non-SDIA patients, while BAL neutrophils were significantly increased in SDIA patients compared to results in non-SDIA patients. Regarding age, in patients under the age of 69 (except those between 30 and 39), BAL lymphocyte number was significantly decreased in SDIA compared with non-SDIA subjects, and in patients between 50 and 69, BAL neutrophils were significantly increased in SDIA compared with non-SDIA subjects. The number of BAL lymphocytes was significantly lower in patients with serum cortisol levels of less than 5.0 μg/dl than in those with levels of more than 5.1 μg/dl. BAL lymphocyte number was also significantly lower in patients who had received glucocorticoid therapy for more than 6 years than in those who had received such therapy for 2 years. These results show that long-term glucocorticoid therapy decreases the number of lymphocytes and increases neutrophil numbers in the airways. 相似文献
108.
Osamu Ozaki M.D. Kunihiko Ito M.D. Kaoru Kobayashi M.D. Akira Suzuki M.D. Yoshitaka Manabe M.D. Yasuhiro Hosoda M.D. 《World journal of surgery》1988,12(4):565-571
Familial occurrence of differentiated, nonmedullary thyroid carcinoma in 23 patients from 11 families is reported. Five patients were male and 18 were female. The familial relationship of patients was parent and child in 12 cases from 6 families, and siblings in 11 cases from 5 families. Carcinoma of other organs was noted in other members in 8 families. Histological examination revealed 18 papillary, 2 follicular, and 2 anaplastic carcinomas (the 2 anaplastic carcinomas were considered to be transformed from preexisting differentiated carcinoma). In 1 case, the histological type was unknown. The average diameter of the primary lesion was 29.9 mm. Cervical lymph node metastasis was found in 77.8% and local recurrence in 28.6% of the patients. Solid and invasive growth was dominant. On HLA typing, phenotypes of B7 and DR1 were significantly redominant in familial patients compared with nonfamilial patients and normal Japanese. Moreover, the haplotype of B7-Cw7-DR1 was observed in 5 of 13 patients tested.
It is suggested from these observations that some types of differentiated, nonmedullary thyroid carcinoma may show familial occurrence and that they may have common factors with regard to the genetic and immunologic basis of the disease.
Presented at the International Association of Endocrine Surgeons in Sydney, Australia, September, 1987. 相似文献
Resumen Se informa la ocurrencia familiar de carcinoma bien diferenciado, no medular, de tiroides en 23 pacientes provenientes de 11 familias, 5 hombres y 18 mujeres. La relación familiar fue padre e hijo en 12 casos de 6 familias, y hermanos en 11 casos de 5 familias. Se observé la presencia de carcinoma de otros órganos en otros miembros de 8 familias. El examen histopatológico reveló 18 carcinomas papilares, 2 foliculares, y 2 anaplásicos (los 2 fueron considerados como transformación de carcinomas diferenciados preexistentes). En un caso no fue conocido el tipo histológico. El diámetro promedio de la lesión primaria fue 29.9 mm. Se hallaron metástasis en ganglios cervicales en 77.8% de los pacientes y recurrencia local en 28.6%. El crecimiento sólido e invasivo apareció como característica dominante. En la tipificación HLA aparecieron como significativamente predominantes los fenotipos de B7 y DR1 en pacientes familiares en comparación con pacientes no familiares y japoneses normales. Por otra parte, el halotipo de B7-CW7-DR1 fue observado en 5 de 13 pacientes investigados.Como resultado de estas observationes se sugiere que algunos tipos de carcinomas diferenciados, no medulares, pueden demostrar ocurrencia familiar y que pueden poseer factores comunes relacionados con las bases genéticas e inmunológicas de la enfermedad.
Résumé On a étudié les caratéristiques du cancer de la thyroïde, dans sa variété différenciée non médullaire, survenu chez 23 patients provenant de 11 familles. Cinq patients étaient des hommes, 18 des femmes. La relation familiale était parent/enfant dans 12 cas provenant de 6 familles, et frère/soeur dans 11 cas provenant de 5 familles. Des membres de 8 autres familles présentaient un cancer d'un autre organe. Il y avait 18 cancers papillaires, 2 cancers folliculaires, et 2 cancers anaplasiques (on a considéré que les 2 cancers anaplasiques étaient des transformations à partir de cancers différenciés préexistants). Dans un cas, le type histologique était inconnu. Le diamètre moyen de la lésion primitive était de 29.9 mm. On a retrouvé des métastases ganglionnaires cervicales chez 77.8% des patients et une récidive locale chez 28.6%. Les tumeurs étaient principalement solides et invasives. Par rapport aux cancéreux non familiaux et à la population japonaise normale, il y avait plus de phénotypes B7 et DR1 au système HLA. L'haplotype B7-CW7-DR1 était observé chez 5 des 13 patients testés.On suggère que certains types de cancer différenciés, non médullaires, ayant des facteurs communs génétiques et immunologiques, peuvent survenir dans une même famille.
Presented at the International Association of Endocrine Surgeons in Sydney, Australia, September, 1987. 相似文献
109.
K Takeuchi K Matsubayashi S Kimura A Kawamoto T Ozawa K Shimada 《Nihon Ronen Igakkai zasshi. Japanese journal of geriatrics》1992,29(7-8):549-553
Lacunes on brain MRI, causal blood pressure, 24-hour ambulatory blood pressure and common carotid blood flow measured by the doppler method were studied in 31 elderly patients with Parkinson's disease (mean age 67.5 +/- 7.3 years). Nineteen patients with Parkinson's disease (61%) had at least one lacune. Patients with lacunes (P(+)) were significantly higher in age than patients without lacune (P(-)). The difference of casual blood pressure between patients in the two groups was not significant. On the other hand, the average of ambulatory blood pressure measurements during a 24-hour period was significantly higher in the P(+) group than in the P(-) group. The average of carotid blood flow was also significantly lower in the P(+) group than in the P(-) group, however, after adjustment for age, the difference between them became insignificant. In conclusion, the incidence of silent lacunes on brain MRI was fairly common in elderly patients with Parkinson's disease. A high average 24-hour ambulatory blood pressure was suggested to be one of the risk factors of lacunar stroke in elderly cases of Parkinson's disease. The concept of "combine type" in Parkinsonism was supposed to be suitable as well as in senile dementia of Alzheimer type. 相似文献
110.
Right-hand superiority for throwing but not for intercepting 总被引:2,自引:0,他引:2
In humans, the organization of movements performed by both upper limbs, relies significantly on a left hemisphere "praxis" system that also subsumes speech function. Right hand preference may also be an expression of this left hemisphere dependence, arising from the preferential connections of the right hand to the left hemisphere. Consequently, a manual task that maximizes the spatial complexity of a target (presumably engaging right hemisphere mechanisms), while concurrently minimizing motor-programming demands, was expected to yield a diminished disparity in preference and performance between the hands. Left and right hand accuracy were measured independently for two motor tasks in 48 normal right-handed university students. In the first task, darts were thrown overhand at a stationary target. For the second task, subjects were asked to use the open hand to block (but not catch) projectiles launched at varying trajectories and velocities. ANOVA yielded a significant Hand x Task interaction, in which the left hand did not differ from the right hand in intercepting ability, but was significantly less accurate than the right hand for throwing. A sex difference favouring males was found for both tasks; this difference was not reducible to differences in physique or athleticism. 相似文献