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   1500篇
  免费   117篇
  国内免费   8篇
耳鼻咽喉   7篇
儿科学   83篇
妇产科学   8篇
基础医学   185篇
口腔科学   36篇
临床医学   113篇
内科学   203篇
皮肤病学   24篇
神经病学   128篇
特种医学   358篇
外科学   134篇
综合类   47篇
预防医学   45篇
眼科学   32篇
药学   156篇
中国医学   1篇
肿瘤学   65篇
  2021年   8篇
  2020年   11篇
  2019年   11篇
  2018年   27篇
  2017年   8篇
  2016年   46篇
  2015年   42篇
  2014年   48篇
  2013年   62篇
  2012年   56篇
  2011年   48篇
  2010年   70篇
  2009年   76篇
  2008年   56篇
  2007年   49篇
  2006年   58篇
  2005年   69篇
  2004年   52篇
  2003年   64篇
  2002年   53篇
  2001年   37篇
  2000年   48篇
  1999年   28篇
  1998年   50篇
  1997年   53篇
  1996年   50篇
  1995年   38篇
  1994年   32篇
  1993年   34篇
  1992年   17篇
  1991年   20篇
  1990年   23篇
  1989年   35篇
  1988年   28篇
  1987年   20篇
  1986年   23篇
  1985年   21篇
  1984年   14篇
  1983年   16篇
  1982年   10篇
  1981年   18篇
  1980年   9篇
  1979年   6篇
  1978年   6篇
  1977年   13篇
  1976年   12篇
  1971年   6篇
  1970年   4篇
  1969年   6篇
  1966年   6篇
排序方式: 共有1625条查询结果,搜索用时 15 毫秒
61.
The absorptive activity of ameloblasts during the maturation of enamel   总被引:1,自引:0,他引:1  
  相似文献   
62.
63.
64.
The aim of this study was to evaluate the influence of intraoperative monitoring on the function of the facial nerve after surgical treatment of acoustic neurinomas, classified according to the grading system of Stennert. One hundred thirty patients were divided into two groups. The first group underwent surgery without intraoperative facial monitoring; the second group included intraoperative facial monitoring. Concerning degree of paresis, preoperatively there was no statistically significant difference between the two groups (group 1: 0.77+/-1.5; group 2: 0.4+/-1.2). Despite structural preservation of the facial nerve, postoperative deterioration of its function was observed which consecutively improved postoperatively. Postoperatively, the mean degree of paresis increased to 4.4+/-3.0 in group 1 and 2.4+/-2.3 in group 2. For better understanding of the role of intraoperative monitoring, we investigated the outcome of patients with acoustic neurinomas who underwent surgery over the following 6 months postoperatively. At that time, function improved by 4.1+/-3.2 (group 1) and 2.0+/-2.3 (group 2). We could show that intraoperative monitoring of the facial nerve was a significant factor for better postoperative function in patients undergoing microsurgical excision of neurinomas (P=0.001) .  相似文献   
65.
Reith W 《Der Radiologe》2005,45(9):797-806
Depending on the problems, CT or MRI should be used in the differential diagnosis of conditions affecting the nasal sinuses. In particular, when chronic sinusitis is present, computed tomography should be performed before surgery to ascertain the condition of the bones. In most cases spiral CT with a decidedly lowered tube voltage and power (MAS product) is now used for this purpose. This means that the patient is exposed to about 70% less radiation than in other CT investigations. To avoid artefacts attributable to dental fillings, whenever possible the spiral should be tilted in such a way that the dental artefacts are not within the mass imaged. When an isotropic voxel is selected secondary reformatting is possible with no loss of quality. Diagnostic MRI should include both T1- and T2-weighted sequences before and after the administration of contrast agent. For the differential diagnosis of a space-occupying tumour coronal cuts about 2 mm apart are advised, whether the spiral or the conventional technique is used. A T2-weighted and fat-suppressed sequence or a STIR (short tau inversion recovery) sequence can also be helpful in the recognition and visualization of lymph nodes. If orbital involvement seems possible it is advisable to use a T1-weighted and fat-suppressed sequence in the coronal plane in addition to check this.  相似文献   
66.
Intraarterielle Lyse der A. cerebri media: ein Überblick   总被引:3,自引:0,他引:3  
Zusammenfassung Bis 1996 bedeutete Schlaganfalltherapie die Verhinderung weitere ischämischer Insulte. Durch die Entwicklung der intravenösen und intraarteriellen Lysetherapie mit rt-PA wurde erstmals eine kausale Therapie möglich. In diesem Beitrag soll der Stand der intravenösen Lysetherapie kurz dargestellt werden, um dann den Stellenwert der lokalen intraarteriellen Lysetherapie zu bewerten.  相似文献   
67.
Reith W 《Der Radiologe》2005,45(4):327-339
Zusammenfassung Seit der Entdeckung der Röntgenstrahlen gab und gibt es rasante und wichtige Entwicklungen in der Bildgebung, v. a. in der Neuroradiologie. Meilensteine waren der Einsatz von Kontrastmitteln, die digitale Subtraktionsangiographie, die Computer- und Magnetresonanztomographie. Letzte Errungenschaften sind die Darstellung von Hirnaktivierung sowie der Fasersysteme im Hirnparenchym. Mit neuen Kontrastmittel scheint es auch möglich zu sein, Bildgebung auf molekularer Ebene durchzuführen.  相似文献   
68.
The SLC6 family is a diverse set of transporters that mediate solute translocation across cell plasma membranes by coupling solute transport to the cotransport of sodium and chloride down their electrochemical gradients. These transporters probably have 12 transmembrane domains, with cytoplasmic N- and C-terminal tails, and at least some may function as homo-oligomers. Family members include the transporters for the inhibitory neurotransmitters GABA and glycine, the aminergic transmitters norepinephrine, serotonin, and dopamine, the osmolytes betaine and taurine, the amino acid proline, and the metabolic compound creatine. In addition, this family includes a system B(0+) cationic and neutral amino acid transporter, and two transporters for which the solutes are unknown. In general, SLC6 transporters act to regulate the level of extracellular solute concentrations. In the central and the peripheral nervous system, these transporters can regulate signaling among neurons, are the sites of action of various drugs of abuse, and naturally occurring mutations in several of these proteins are associated with a variety of neurological disorders. For example, transgenic animals lacking specific aminergic transporters show profoundly disturbed behavioral phenotypes and probably represent excellent systems for investigating psychiatric disease. SLC6 transporters are also found in many non-neural tissues, including kidney, intestine, and testis, consistent with their diverse physiological roles. Transporters in this family represent attractive therapeutic targets because they are subject to multiple forms of regulation by many different signaling cascades, and because a number of pharmacological agents have been identified that act specifically on these proteins.  相似文献   
69.
Blood-brain barrier (BBB) breakdown is a feature of cerebral ischaemia, multiple sclerosis, and other neurodegenerative diseases, yet the relationship between astrocytes and the BBB integrity remains unclear. We present a simple in vivo model in which primary astrocyte loss is followed by microvascular damage, using the metabolic toxin 3-chloropropanediol (S-alpha-chlorohydrin). This model is uncomplicated by trauma, ischaemia, or primary immune involvement, permitting the study of the role of astrocytes in vascular endothelium integrity, maintenance of the BBB, and neuronal function. Male Fisher F344 rats given 3-chloropropanediol show astrocytic damage and death at 4-24 h in symmetrical brainstem and midbrain nuclear lesions, while neurons show morphological changes at 24-48 h. Fluorescent 10 kDa dextran tracers show the BBB leaking from 24 h, progressing to petechial haemorrhage after 48-72 h, with apparent repair after 6 days. BBB breakdown, but not the earlier astrocytic death, is accompanied by a delayed increase in blood flow in the inferior colliculus. An ED1 inflammatory response develops well after astrocyte loss, suggesting that inflammation may not be a factor in starting BBB breakdown. This model demonstrates that the BBB can self-repair despite the apparent absence of direct astrocytic-endothelial contact. The temporal separation of pathological events allows pharmacological intervention, and the mild reversible ataxia permits long-term survival studies of repair mechanisms.  相似文献   
70.
OBJECTIVE: To analyze the risk factors for suicide, premature death and all-cause death in a representative population of hospital-treated deliberate self-poisoning patients. METHOD: A prospective cohort study using data-linkage between the Hunter Area Toxicology Service Database and the National Death Index of the Australian Institute of Health and Welfare, from January 1991 to December 2000. RESULTS: There were 4105 subjects, of whom 228 (5.6%) died, 122 (2.9%) by premature death and 58 (1.4%) by suicide. The probability of suicide after 10 years follow-up was 2%. The adjusted hazard ratios (95% CI) for suicide were: 'disorders usually diagnosed in infancy, childhood and adolescence', 5.28 (95% CI = 2.04-13.65): male gender, 4.25 (95% CI = 2.21-8.14); discharge to involuntary psychiatric hospital admission, 3.20 (95% CI = 1.78-5.76); and increasing age, 1.02 (95% CI = 1.01-1.04). Men and women showed different patterns of multivariate risks, although increased risk with increasing age and discharge to an involuntary psychiatric admission was true for both. The standardized all-cause mortality ratio (95% CI) was: for men, 6.42 (95% CI = 5.44-7.57), and for women 4.39 (95% CI = 3.56-5.41). The standardized suicide mortality ratio (95% CI) was: for men, 20.55 (95% CI = 15.24-27.73), and for women 22.95 (95% CI = 13.82-38.11). CONCLUSIONS: Men and women have different risk factors for subsequent suicide after self-poisoning. Hospital-treated self-poisoning patients have increased risk of subsequent suicide, premature and all-cause death. Psychiatric assessment, leading to discharge decisions, is worthwhile in identifying patients at long-term risk of suicide, premature and all-cause death.  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