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   11336篇
  免费   552篇
  国内免费   56篇
耳鼻咽喉   193篇
儿科学   124篇
妇产科学   232篇
基础医学   1589篇
口腔科学   269篇
临床医学   750篇
内科学   2715篇
皮肤病学   147篇
神经病学   991篇
特种医学   462篇
外国民族医学   1篇
外科学   1845篇
综合类   78篇
一般理论   1篇
预防医学   374篇
眼科学   117篇
药学   908篇
中国医学   36篇
肿瘤学   1112篇
  2023年   57篇
  2022年   108篇
  2021年   151篇
  2020年   82篇
  2019年   108篇
  2018年   146篇
  2017年   113篇
  2016年   107篇
  2015年   130篇
  2014年   207篇
  2013年   230篇
  2012年   465篇
  2011年   512篇
  2010年   306篇
  2009年   292篇
  2008年   494篇
  2007年   522篇
  2006年   522篇
  2005年   522篇
  2004年   574篇
  2003年   500篇
  2002年   555篇
  2001年   445篇
  2000年   497篇
  1999年   422篇
  1998年   149篇
  1997年   118篇
  1996年   116篇
  1995年   93篇
  1994年   87篇
  1993年   93篇
  1992年   337篇
  1991年   281篇
  1990年   303篇
  1989年   276篇
  1988年   245篇
  1987年   231篇
  1986年   201篇
  1985年   193篇
  1984年   143篇
  1983年   113篇
  1979年   78篇
  1978年   63篇
  1977年   74篇
  1975年   54篇
  1974年   60篇
  1973年   52篇
  1972年   60篇
  1969年   51篇
  1968年   61篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
We evaluated the respiratory functions of patients with pulmonary emphysema who underwent lung volume reduction surgery (LVRS) by the mean transit time (MTT) with Xe-133 lung ventilation scintigraphy, forced expiration volume in 1 sec (FEV1.0), residual volume (RV), distance walked in 6 min (6-min walk), and the Hugh-Jones classification (H-J classification) before and after LVRS. In 69 patients with pulmonary emphysema (62 men, 7 women; age range, 47-75 years; mean age, 65.4 years +/- 6.1, preoperative H-J classification, III (two were II)-V) who underwent LVRS, all preoperative and postoperative parameters (MTT 3 weeks after LVRS and the others 3 months after LVRS) were judged statistically by the Wilcoxon signed-ranks test and Odds ratio. Every postoperative parameter was improved with a significant difference (P < 0.05) compared to preoperative parameters. MTT at 3 weeks after LVRS was not associated with %FEV1.0 and the H-J classification at 3 months after LVRS, but was associated with RV and a 6-min walk at 3 months after LVRS. MTT was useful for the clinical evalution of aerobic capability after LVRS.  相似文献   
103.
K Hanada  H Katoh  T Hosokawa  M Hosono    T Takeda 《Immunology》1991,74(1):160-164
Short-lived SAMP-P/1 mice are low responders in in vitro antibody responses because of a selectively impaired helper T(Th)-cell activity. After crossing with high responders (B10.BR mice), about 12% of (B10.BR x SAM-P/1) (BRP)F2 mice showed low responsiveness, as did SAM-P/1 mice, against two T-dependent antigens, sheep and horse red blood cells (RBC), both of which were not cross-reactive to each other at helper T- and B-cell levels. The immune activities against the two antigens in individual BRPF2 mice showed a good correlation (r = 0.81), thereby suggesting that SAM-P/1 mice have an antigen non-specific Th cell dysfunction. Based on the incidence of the low responders in F2 generation and statistical analyses, the hypo-responsiveness was postulated to be controlled by two genes. To survey the location of these genes, linkage analyses were performed in the F2 mice using a large set of genetic markers. Low responders in the F2 generation showed a significantly higher incidence of SAM-P/1 genotype at the Gpi-1 as well as c locus on chromosome 7 (Chr.7). However, no linkage of low responsiveness to the Hbb locus was evident, an area present at a more distal site to the centromere on the same chromosome. These results suggest that one of the genes controlling the hypo-responsiveness of SAM-P/1 mice is linked to both Gpi-1 and c loci and that it locates at a more proximal site on Chr.7.  相似文献   
104.
In order to simplify the testing-method of blood groups (ABO, Rh, MN, Ss, P, I, Lewis, Duffy, Kidd and Diego) and the assay of glycosyl transferases activity, we have developed a new method using Terasaki plate (T-plate method), and examined its usefulness in the routine examination. As results followings were obtained: 1) The sensitivity of T-plate method was equal or superior than that of the common method using test-tube. 2) Samples used for T-plate method were smaller in volume compared with those for the common tube test method. 3) The percent of coincidence between T-plate method and tube test method was 100% for ABO, Rh, MN, Ss, P, I, Duffy, Kidd and Diego grouping. They were 98% for Lewis(a) and 96% for Lewis(b) grouping, respectively. These results indicate the superiority of T-plate method than the common method using test-tubes in respects of smaller volume of samples, lower price and handling of a large amount of samples.  相似文献   
105.
106.
Immunocytochemical analysis with antibodies raised against aspartate, glutamate, gamma-aminobutyrate (GABA), choline acetyltransferase (ChAT), and substance P (SP) have allowed the transmitter characterisation and distribution of cells of the lateralis medialis-nucleus suprageniculatus (LM-SG) complex to be made at the level of the light microscope. We have found that the intranuclear distributions of aspartate and glutamate differed substantially from that of GABA, as well as there being specific and, in some cases, major differences in the respective populations of cells labelled with all three amino-acid-sensitive antibodies. ChAT-labelled elements were disposed very similarly to acetylcholinesterase (AChE)-positive subregions of the nuclear complex, while SP labelling was comparatively weak, albeit present, throughout the region. These data provide an important first step towards the further understanding of the details of the neurochemical and functional identity of the LM-SG complex.  相似文献   
107.
Induced ischemic tolerance in rat hippocampus was investigated in a forebrain ischemia model of repeated 4-vessel occlusion (4-VO). Ischemic insult variability was reduced by the use of dc potential measurements to determine the duration of ischemic depolarization in hippocampus. The results demonstrate a depolarization threshold for ischemic injury to CA1 neurons of 4-6 min and a window for optimal preconditioning of 2.5-3.5 min. Levels of induced mRNAs encoding hsp72 and several immediate-early genes were also shown to vary with depolarization interval. Immediate-early genes were maximally induced after depolarization periods inducing optimal preconditioning, while hsp72 expression increased with insult severity over the range leading to neuron loss. These results are similar to those obtained in gerbil studies indicating that preconditioning does not require large increases in hsp72 expression, and demonstrate the fundamental comparability of rodent global ischemia models when monitored by this approach.  相似文献   
108.
Most of "so-called" posterior communicating artery aneurysms previously reported, originated from the internal carotid-posterior communicating junction. Aneurysms arising from the posterior communicating artery itself are very rare. The abducens nerve palsy caused by cerebral aneurysm is also very rare. We are reporting a case with the saccular aneurysm arising directly from the distal half of the posterior communicating artery presenting the abducens nerve palsy. This 73-year-old woman who had no treatment with hypertension for several years was admitted for sudden onset of severe headache, vomitting and unconsciousness on March 1, 1984. She opened her eyes when addressed and had disorientation, urinary incontinence, right-hemiparesis and left-abducens nerve palsy. A 4-vessel angiography revealed the saccular aneurysm originating directly from the distal half of the posterior communicating artery. The patient underwent left-frontotemporal craniotomy on the 27th day after subarachnoid hemorrhage under Hunt & Kosnic Grade 3. The aneurysm originated directly from the distal half of the posterior communicating artery and directed inferior-posterior-laterally below the oculomotor nerve. The neck was successfully clipped. Immediate post-operative course was uneventful until the 7th day after surgery. On the 8th day she had hypertensive intraventricular hemorrhage and expired. The autopsy could not be obtained. The saccular "true" posterior communicating artery aneurysm with isolated unilateral abducens nerve palsy as seen in our case has not been reported. Considering the operative findings, we thought the aneurysmal dome contacted directly with the abducens nerve.  相似文献   
109.
Ten patients with advanced bladder cancer were treated with intra-arterial infusion therapy. The patients consisted of nine males and one female between 55 and 82 years old (median: 70 years). In all patients, cisplatinum (CDDP) (2 mg/kg), aclacinomycin (ACR) (0.5 mg/kg) and Angiotensin II (25 mg) were infused via the internal iliac artery for a period of about 30 minutes. Seven patients also received X-ray therapy with a linac. The efficacy of this therapy was assessed by computed tomographic scanning, sonography and cystoscopy. As a result of this assessment, 2 patients were rated complete response "(CR)", 6 partial response (PR) (showing 50% or more reduction in the lesion) and 2 no change "(NC)". To compare the efficacy of this therapy for two histopathologically defined groups of patients (patients with grades 2 and 3 cancer), one patient was rated "CR", four "PR" and two "NC" in the grade 3 group (total 7 patients), while one was rated "CR" and two "PR", in the grade 2 group (total 3 patients). In effective cases, pollakiuria and miction pain disappeared shortly following intra-arterial infusion therapy. As for side effects of the therapy, mild nausea or vomiting was observed in all patients, while leukopenia was noted in one patient.  相似文献   
110.
Purpose

Intravesical bacillus Calmette–Guérin (BCG) is the standard of care for bladder carcinoma in situ (CIS). The response to BCG therapy against CIS is generally assessed by random bladder biopsy (RBB). In this study, we examined the necessity of routine RBB after BCG therapy.

Methods

We retrospectively identified 102 patients who were initially diagnosed with CIS with or without papillary tumor and received subsequent 6–8-week BCG therapy. Thereafter, all patients underwent voiding cytology analysis, cystoscopy, and RBB to evaluate the effects of BCG therapy. We evaluated the association between clinical parameters (voiding cytology and cystoscopy findings) and the final pathological results by RBB specimens.

Results

According to the pathological results of RBB, 30 (29%) patients had BCG-unresponsive disease (remaining urothelial carcinoma was confirmed pathologically) and 20 were diagnosed with CIS. Positive/suspicious voiding cytology and positive cystoscopy findings were well observed in patients who had BCG-unresponsive disease compared with their counterparts (p?=?0.116, and p?<?0.001, respectively). The sensitivity (Sen.), specificity (Spe.), positive predictive value (PPV), and negative predictive value (NPV) of voiding cytology were 50%, 68%, 39%, and 77%, respectively. The values for cystoscopy findings were as follows: Sen.: 87%, Spe.: 57%, PPV: 46%, and NPV: 91%. The values for their combination (having either of them) were as follows: Sen.: 100%, Spe.: 44%, PPV: 43%, and NPV: 100%.

Conclusion

RBB after BCG therapy for patients with negative voiding cytology and negative cystoscopy may be omitted because their risk of BCG-unresponsive disease is significantly low (NPV: 100%).

  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