全文获取类型
收费全文 | 21516篇 |
免费 | 1067篇 |
国内免费 | 127篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 282篇 |
妇产科学 | 241篇 |
基础医学 | 2749篇 |
口腔科学 | 547篇 |
临床医学 | 1442篇 |
内科学 | 5346篇 |
皮肤病学 | 323篇 |
神经病学 | 1816篇 |
特种医学 | 1076篇 |
外科学 | 4247篇 |
综合类 | 77篇 |
预防医学 | 522篇 |
眼科学 | 420篇 |
药学 | 1565篇 |
中国医学 | 53篇 |
肿瘤学 | 1908篇 |
出版年
2023年 | 102篇 |
2022年 | 205篇 |
2021年 | 408篇 |
2020年 | 198篇 |
2019年 | 301篇 |
2018年 | 416篇 |
2017年 | 324篇 |
2016年 | 363篇 |
2015年 | 365篇 |
2014年 | 484篇 |
2013年 | 635篇 |
2012年 | 959篇 |
2011年 | 1079篇 |
2010年 | 589篇 |
2009年 | 502篇 |
2008年 | 912篇 |
2007年 | 1036篇 |
2006年 | 1084篇 |
2005年 | 1027篇 |
2004年 | 957篇 |
2003年 | 924篇 |
2002年 | 914篇 |
2001年 | 795篇 |
2000年 | 808篇 |
1999年 | 745篇 |
1998年 | 263篇 |
1997年 | 234篇 |
1996年 | 190篇 |
1995年 | 155篇 |
1994年 | 151篇 |
1993年 | 168篇 |
1992年 | 540篇 |
1991年 | 481篇 |
1990年 | 448篇 |
1989年 | 435篇 |
1988年 | 424篇 |
1987年 | 361篇 |
1986年 | 362篇 |
1985年 | 357篇 |
1984年 | 205篇 |
1983年 | 169篇 |
1982年 | 87篇 |
1981年 | 88篇 |
1979年 | 172篇 |
1978年 | 125篇 |
1977年 | 91篇 |
1974年 | 125篇 |
1973年 | 113篇 |
1970年 | 84篇 |
1969年 | 101篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
T Tsuji T Yamamuro Y Kotoura M Matsumoto H Tanaka C Tanaka J Toguchida K Endo H Sakahara M Koizumi 《Nuclear medicine communications》1988,9(12):947-954
Bone scintigraphy was performed in 17 patients with previously known lung metastases of osteosarcoma. 99Tcm-MDP uptake was observed in all primary bone lesions but lung metastatic lesions were positive in only six patients (35%). 99Tcm-MDP uptake by lung metastases was significantly correlated with bone and osteoid formation in the metastatic lesions and preoperative serum ALPase values. These clinical observations were confirmed by using nude mice transplanted with human lung metastatic osteosarcoma. 99Tcm-MDP scintigraphy appears to be useful for detecting lung metastases of osteosarcoma only in a selected group of patients. 相似文献
82.
83.
S Tadera N Oka M Sako M Sugino G Hamami O Matsumoto S Kamidono 《Hinyokika kiyo. Acta urologica Japonica》1986,32(3):462-467
A case of a 19-year-old male with leiomyosarcoma of the prostate is reported. He visited our hospital with the chief complaint of urinary retention in December, 1983. Following overall examination, needle biopsy of the prostate gland was performed with the suspicion of sarcoma. Histology of the prostate revealed leiomyosarcoma. Two courses of combined chemotherapy were given, but the tumor continued to enlarge. The patient died in April, 1984, 5 months after the appearance of the first symptom. 相似文献
84.
85.
Kazuo Kitagawa Masayasu Matsumoto Keisuke Kuwabara Masafumi Tagaya Toshiho Ohtsuki Ryuji Hata Hirokazu Ueda Nobou Handa Kazufumi Kimura Takenobu Kamada 《Brain research》1991,561(2)
We investigated the effects of mild and non-lethal ischemic insult on neuronal death following subsequent lethal ischemic stress in various brain regions, using a gerbil model of bilateral cerebral ischemia. Single 10-min ischemia consistently caused neuronal damage in the hippocampal CA1, CA2, CA3 and CA4, layer III/IV of the cerebral cortex, dorsolateral part of the caudoputamen and ventrolateral part of the thalamus. On the other hand, in double ischemia groups, 2-min ischemic insult 2 days before 10-min ischemia exhibited significant protection in the CA1 and CA3 of the hippocampus, the cerebral cortex, the caudoputamen and the thalamus. Five-min ischemic insult 2 days before 10-min ischemia also showed protective effect in the same areas as those of 2-min ischemia except for the CA1 region of the hippocampus, while 1-min ischemic insult exhibited no protective effect in any brain regions. In the immunoblot analysis, both 2- and 5-min ischemia caused increased synthesis of heat shock protein 72 (HSP 72) in the hippocampus, but 1-min ischemia did not. The present study demonstrated that the ‘ischemic tolerance’ phenomenon was widely found in the brain and also suggested that ischemic treatment severe enough to cause HSP 72 synthesis might be needed for induction of ‘ischemic tolerance’. 相似文献
86.
T Oda S Yoshimura T Hara S Hara M Yahagi C Matsumoto T Ohno Y Nakamura Y Sumi K Sueoka 《Nippon Sanka Fujinka Gakkai zasshi》1987,39(1):113-120
To examine the effects of transient hyperprolactinemia on in vitro fertilization and embryo transfer, 61 cycles in 50 euprolactinemic ovulatory women with irreparable tubal diseases were stimulated with clomiphene (CC) alone or CC and human menopausal gonadotropin followed by human chorionic gonadotropin (hCG). Serum prolactin (PRL) increased after hCG administration with peak values of 45.4 +/- 4.2 ng/ml on the day of laparoscopic oocyte aspiration. The highest serum estradiol (E2) concentration was found on the day before PRL peak and serum progesterone (P) began to increase after hCG injection concomitant with the PRL rise. The group having 50 ng/ml or more of PRL (34 cycles) had significantly higher levels of E2 during preovulatory and early luteal phase compared to those of the group having less than 50 ng/ml of PRL (27 cycles) but there was no significant difference between the P levels in the two groups. In the higher PRL group 72 (62.1%) of 116 collected oocytes were fertilized and 6 (20.0%) conceived. In the lower PRL group 45 oocytes (58.4%) of 77 were fertilized and 3 (12.5%) became pregnant. These data suggest that elevated serum PRL concentrations may have no effect on fertilization of oocytes in vitro or embryonic development. 相似文献
87.
A G Hohmann R R Matsumoto M K Hemstreet S L Patrick J E Margulies R P Hammer J M Walker 《Brain research》1992,593(2):265-273
The 2-deoxy-D-[1-14C]glucose ([14C]DG) method was used to examine the effects of the relatively selective sigma ligand 1,3-di-o-tolylguanidine (DTG) on cerebral metabolism in freely moving rats. Each animal received an i.p. injection of DTG (0.2, 1, or 5 mg/kg) or normal saline 20 min prior to the infusion of [14C]DG. DTG induced dose-dependent changes in local cerebral glucose utilization (LCGU) in several motor and limbic structures. Most structures showed increases in LCGU, with a maximum effect at 1 mg/kg. The most profound increases in LCGU were observed in brain regions that are rich in sigma receptors. These included cerebellar and related nuclei (interpositus, lateral and medial cerebellar n., vestibular n., olivary n.), ambiguus n., superior colliculus (superior layers), hippocampus (CA2, CA3, DG), n. basalis of Meynert interpeduncular n., and the substantia nigra pars compacta and pars reticulata. No significant decreases in glucose utilization were observed at any dose. Although the areas affected by DTG are similar to those previously reported for other sigma ligands, future studies employing a range of doses for additional selective sigma ligands must be carried out in order to confirm whether these changes in LCGU were sigma-mediated. 相似文献
88.
Central cholinergic hypofunction causes the disruption of spatial cognition, while cholinomimetics improve this disruption in rats. Scopolamine (0.5 mg/kg, i.p.) has also been reported to disrupt radial maze performance in rats. Nebracetam (WEB 1881 FU), a new nootropic candidate, was able to correct this scopolamine-induced disruption of spatial cognition at the dose of 10 mg/kg, p.o. Furthermore, nebracetam enhanced oxotremorine-induced tremors in mice. These results indicate that nebracetam has a cholinergic enhancing effect. The scopolamine-induced disruption of spatial cognition has been previously reported to improve not only by cholinomimetics but also by brain noradrenergic drugs such as L-threo-DOPS and amantadine. Nebracetam reversed the change of brain noradrenaline contents in the frontal cortex and hippocampus in which the noradrenaline content decreased by treatment with scopolamine. Nebracetam also decreased the delta 9-tetrahydrocannabinol (6 mg/kg, i.p.)-induced disruption of spatial cognition, which was reported to be related to the lymbic noradrenergic function. These results suggest that the cognitive enhancing effect of nebracetam involves not only cholinergic mechanisms but also involves lymbic and hippocampal noradrenergic mechanisms. 相似文献
89.
S Higano S Takahashi K Ishii K Matsumoto H Ikeda K Sakamoto 《AJNR. American journal of neuroradiology》1994,15(8):1435
PURPOSETo describe MR and CT features of germinoma originating in the basal ganglia and thalamus and to discuss the roles of each modality for its diagnosis.METHODSMR and CT studies of six cases of germinomas, five of which were histologically proved, were retrospectively reviewed. T1-weighted, T2-weighted, and contrast-enhanced T1-weighted conventional spin-echo images, and unenhanced and contrast-enhanced CT images were evaluated.RESULTSTypically, the tumor consisted of an irregular solid area with contrast enhancement and various-size cysts. Cystic components were found in five cases and calcification in four. Intratumoral hemorrhage was noted in one. Ipsilateral cerebral hemiatrophy and brain stem hemiatrophy were noted in three cases each. MR was superior to CT in evaluating precise tumor extension, cystic components, and intratumoral hemorrhage, although in one case, extension of the tumor was better defined on CT in its early stage. Calcification was difficult to identify by MR alone. The solid components of the tumors generally showed slightly high density on CT, which seemed to be characteristic compared with nonspecific intensity pattern on MR.CONCLUSIONThe combination of CT and MR findings allows early detection and appropriate diagnosis of the mass in the basal ganglia and/or thalamus. 相似文献
90.
Hiroshi Yamada Shizuo Oi Norihiko Tamaki Satoshi Matsumoto Katsuko Sudo 《Child's nervous system》1992,8(7):394-398
Primary aqueductal stenosis is one of the main causes of congenital hydrocephalus in humans and experimental models. The congenitally hydrocephalic rat strain LEW/Jms is one such model. In this report, we describe further detailed histological features of periaqueductal structure, including the posterior commissure, subcommissural organ (SCO), and ependyma, and discuss the changes in these structures in relation to the cause of hydrocephalus. Coronal sections of the aqueduct in normal rats showed that the usual ependyma was absent in the center of the base facing the dorsal side, which was replaced by tall columnar cells. On the other hand, in hydrocephalic rats the ependyma encircled the aqueductal cavity. In midline sagittal sections, normal and hydrocephalic rats showed the SCO, although the SCO in hydrocephalic rats was shorter than in normal rats. There was also a marked difference between normal and hydrocephalic rats in the dorsoventral dimension of the rostral midbrain. In hydrocephalus, this dimension was large in comparison with normal rats. The superior collicular commissure located caudal to the posterior commissure ran along the ventral side of the midbrain in rats with hydrocephalus, and there was a cell-depleted area just dorsal to the superior collicular commissure. The same findings were observed from the 17th day of gestation until the postnatal period. Although the role of the SCO has been widely discussed from the viewpoint of secretory function, the present study indicated that this organ might be involved in the formation of the shape of the aqueduct. 相似文献