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   9968篇
  免费   527篇
  国内免费   40篇
耳鼻咽喉   148篇
儿科学   275篇
妇产科学   185篇
基础医学   1296篇
口腔科学   787篇
临床医学   939篇
内科学   1699篇
皮肤病学   330篇
神经病学   944篇
特种医学   194篇
外科学   816篇
综合类   36篇
一般理论   9篇
预防医学   1321篇
眼科学   143篇
药学   738篇
中国医学   74篇
肿瘤学   601篇
  2023年   83篇
  2022年   138篇
  2021年   262篇
  2020年   178篇
  2019年   252篇
  2018年   274篇
  2017年   216篇
  2016年   276篇
  2015年   309篇
  2014年   411篇
  2013年   544篇
  2012年   814篇
  2011年   981篇
  2010年   515篇
  2009年   427篇
  2008年   668篇
  2007年   760篇
  2006年   654篇
  2005年   591篇
  2004年   523篇
  2003年   428篇
  2002年   389篇
  2001年   82篇
  2000年   62篇
  1999年   78篇
  1998年   62篇
  1997年   54篇
  1996年   40篇
  1995年   40篇
  1994年   41篇
  1993年   40篇
  1992年   25篇
  1991年   27篇
  1990年   20篇
  1989年   34篇
  1988年   15篇
  1987年   25篇
  1986年   27篇
  1985年   16篇
  1984年   18篇
  1983年   20篇
  1982年   15篇
  1981年   13篇
  1980年   8篇
  1979年   12篇
  1978年   7篇
  1974年   6篇
  1973年   6篇
  1971年   6篇
  1967年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Infant rats exhibit sensitive-period odor learning characterized by olfactory bulb neural changes and odor preference acquisitions critical for survival. This sensitive period is coincident with low endogenous corticosterone (CORT) levels and stress hyporesponsivity. The authors hypothesized that low corticosterone levels modulate sensitive-period learning. They assessed the effects of manipulating CORT levels by increasing and removing CORT during (Postnatal Day 8) and after (Postnatal Day 12) the sensitive period. Results show that (a) exogenous CORT prematurely ends sensitive-period odor-shock-induced preferences; (b) adrenalectomy developmentally extends the sensitive period as indicated by odor-shock-induced odor-preference learning in older pups, whereas CORT replacement can reinstate fear learning; and (c) CORT manipulation modulates olfactory bulb correlates of sensitive-period odor learning in a manner consistent with behavior.  相似文献   
32.
The entorhinal cortex of the monkey: I. Cytoarchitectonic organization   总被引:6,自引:0,他引:6  
As an essential preliminary to a series of experimental studies of the afferent and efferent connections of the monkey entorhinal cortex, we have carried out a detailed analysis of its cytoarchitectonic organization. Primarily on the basis of features observed in Nissl- and fiber-stained preparations, supplemented with Golgi-stained material and preparations stained for heavy metals by Timm's method and histochemically for acetylcholinesterase, the entorhinal cortex has been divided into seven fields that are named according to their rostrocaudal and mediolateral positions except for one rostrally located field that is named for the prominent input that it receives from the olfactory bulb. At rostral levels, the entorhinal cortex is marked by a number of morphological inhomogeneities. The neurons tend to be organized in patches that are surrounded by large, thick, radially oriented bundles of fibers. At caudal levels, the entorhinal cortex has a more distinctly laminated appearance, reminiscent of that in the neocortex, and most of the neurons and fiber fascicles are arranged in discrete radial columns. The cortical region adjoining the entorhinal cortex laterally, which is commonly known as the "perirhinal cortex," is in fact composed of two separate fields corresponding to areas 35 and 36 of Brodmann. Area 35 occupies the fundus and part of the lateral aspect of the rhinal sulcus. Area 36 extends from the lateral bank of the rhinal sulcus into the inferior temporal gyrus, where it borders fields TA and TE rostrally, and field TF of the parahippocampal gyrus caudally. The surface extents of each of the entorhinal fields have been determined by making "unfolded" two-dimensional maps of the region and measuring the areas with a computerized digitizing system.  相似文献   
33.
Lasers in Medical Science - Ultraviolet radiation (UVR) is the major etiologic agent of cutaneous photoaging, and different strategies are used to prevent and treat this condition. The...  相似文献   
34.
Neurosurgical Review - A preferred treatment for residual/recurrent pituitary adenomas has not been established. The existence of higher complication rates for revision surgeries remains under...  相似文献   
35.
The two-pore-domain potassium channels TASK-1, TASK-3 and TASK-5 possess a conserved C-terminal motif of five amino acids. Truncation of the C-terminus of TASK-1 strongly reduced the currents measured after heterologous expression in Xenopus oocytes or HEK293 cells and decreased surface membrane expression of GFP-tagged channel proteins. Two-hybrid analysis showed that the C-terminal domain of TASK-1, TASK-3 and TASK-5, but not TASK-4, interacts with isoforms of the adapter protein 14-3-3. A pentapeptide motif at the extreme C-terminus of TASK-1, RRx(S/T)x, was found to be sufficient for weak but significant interaction with 14-3-3, whereas the last 40 amino acids of TASK-1 were required for strong binding. Deletion of a single amino acid at the C-terminal end of TASK-1 or TASK-3 abolished binding of 14-3-3 and strongly reduced the macroscopic currents observed in Xenopus oocytes. TASK-1 mutants that failed to interact with 14-3-3 isoforms (V411*, S410A, S410D) also produced only very weak macroscopic currents. In contrast, the mutant TASK-1 S409A, which interacts with 14-3-3-like wild-type channels, displayed normal macroscopic currents. Co-injection of 14-3-3ζ cRNA increased TASK-1 current in Xenopus oocytes by about 70 %. After co-transfection in HEK293 cells, TASK-1 and 14-3-3ζ (but not TASK-1ΔC5 and 14-3-3ζ) could be co-immunoprecipitated. Furthermore, TASK-1 and 14-3-3 could be co-immunoprecipitated in synaptic membrane extracts and postsynaptic density membranes. Our findings suggest that interaction of 14-3-3 with TASK-1 or TASK-3 may promote the trafficking of the channels to the surface membrane.  相似文献   
36.
Two thousand consecutive children have been evaluated for suspected heart disease in a 27-month period. The main reasons for referral were: murmur (70%), precordial pain (9.5%), suspicion of arrhythmia (8.5%) and breathless (5%). Five hundred and six (25%) cases did not complete the investigation and the results were not computed. A final diagnosis was obtained based on the reason for referral and the main conclusions were: 1) a high incidence of normality was found: murmur (83%), pain (98%), arrhythmia (97%) and breathless (94%); 2) heart disease is unlikely when other referral reasons were analyzed; 3) 14% of the children were considered abnormal and the necessity of therapeutic procedures was 0.8%. A pediatric cardiology outpatient clinic in a public setting seems to be justifiable in the region, due to the high current demand.  相似文献   
37.
38.
The functional restoration approach to treating chronic spinal disability consists of a medically directed, interdisciplinary team approach to physical reconditioning and a cognitive-behavioral crisis intervention procedure for dealing with related psychosocial problems. One- and two-year follow-up studies have demonstrated the clinical efficacy of this approach. The present article describes this approach and summarizes the research documenting its success in treating patients with chronic spinal disability. This article also highlights the pitfalls in misunderstanding and misrepresenting the components of the functional restoration approach when evaluating treatment efficacy.  相似文献   
39.
BACKGROUND: Locally advanced and/or inflammatory breast cancer (LABC) is a heterogeneous disease. Molecular markers may help to understand this heterogeneity. This paper reports the results of a study assessing the potential prognostic or predictive value of HER-2, p53, cyclinD1, MIB1, ER and PgR expression by immunohistochemistry from patients included in an EORTC-NCIC-SAKK trial. PATIENTS AND METHODS: A total of 448 patients with a cytological or histological diagnosis of LABC were randomised into a trial comparing two anthracycline-based neoadjuvant regimens. Chemotherapy was followed by standard locoregional therapy. Survival was comparable in both arms. We collected and analysed centrally paraffin-embedded tumour specimens from 187 (72.5%) of 258 patients that had a histological diagnosis. RESULTS: Of the patients included in this molecular marker study 114 relapsed and 91 died. In the multivariate analysis p53 positivity was associated with a shorter progression-free survival [hazard ratio (HR) = 1.96; 95% CI 1.33-2.91; P = 0.0008) and a shorter overall survival (HR = 1.98; 95% CI 1.28-3.06; P = 0.002). PgR positivity predicted for a longer overall survival (HR = 0.54; 95% CI 0.35-0.83; P = 0.0045). CONCLUSIONS: p53 was an independent factor predicting for survival. In order to clarify whether p53 is a pure prognostic and/or a predictive factor, a phase III trial is being conducted (EORTC 10994/BIG 00-01 study) using functional assay in yeast from frozen tumour samples.  相似文献   
40.
Zusammenfassung Anhand von 3 Fallbeispielen aus der Spina-bifida-Ambulanz der Klinik für Kinder und Jugendliche der Universit?t Erlangen wird über die Problematik von Frakturen bei Patienten mit Meningomyelozele sowie deren Therapiekonzept berichtet. In übereinstimmung mit Literaturberichten zeigen die Kasuistiken, da? schwere Allgemeinreaktionen, lokale und systemische Entzündungsparameter und variable radiologische Befunde mit h?ufig ausgedehnter reaktiver Kallusbildung die Diagnosestellung von Frakturen bei Patienten mit Meningomyelozele, die nicht selten schmerzlos und ohne erinnerliches Trauma verlaufen, erheblich erschweren k?nnen. Differentialdiagnostisch kommen Osteomyelitis, maligne Knochentumoren und aneurysmatische Knochenzysten in Frage. Diskussion: Statische Belastung durch Geh-/ Stehtraining sowie die Verkürzung von Immobilisationsphasen stellen wichtige Faktoren in der Prophylaxe von Frakturen bei Meningomyelozyelepatienten dar. Das Therapiekonzept von Frakturen bei unserer Patientengruppe weist wesentliche Unterschiede zu den allgemeinen unfallchirurgischen und orthop?dischen Richtlinien auf.   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