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   5372篇
  免费   234篇
  国内免费   28篇
耳鼻咽喉   73篇
儿科学   136篇
妇产科学   110篇
基础医学   517篇
口腔科学   121篇
临床医学   391篇
内科学   1496篇
皮肤病学   20篇
神经病学   637篇
特种医学   305篇
外科学   776篇
综合类   11篇
预防医学   176篇
眼科学   55篇
药学   248篇
中国医学   9篇
肿瘤学   553篇
  2024年   8篇
  2023年   69篇
  2022年   117篇
  2021年   228篇
  2020年   117篇
  2019年   128篇
  2018年   197篇
  2017年   119篇
  2016年   158篇
  2015年   168篇
  2014年   256篇
  2013年   276篇
  2012年   458篇
  2011年   423篇
  2010年   215篇
  2009年   245篇
  2008年   347篇
  2007年   337篇
  2006年   349篇
  2005年   327篇
  2004年   270篇
  2003年   252篇
  2002年   191篇
  2001年   36篇
  2000年   29篇
  1999年   34篇
  1998年   33篇
  1997年   27篇
  1996年   18篇
  1995年   21篇
  1994年   11篇
  1993年   15篇
  1992年   17篇
  1991年   19篇
  1990年   11篇
  1989年   9篇
  1988年   12篇
  1987年   6篇
  1986年   7篇
  1985年   12篇
  1984年   11篇
  1983年   3篇
  1982年   3篇
  1980年   5篇
  1979年   5篇
  1978年   4篇
  1976年   2篇
  1972年   4篇
  1971年   2篇
  1967年   2篇
排序方式: 共有5634条查询结果,搜索用时 15 毫秒
101.
BACKGROUND/AIMS: We studied the influence of biochemical and virologic patterns and interferon on the outcome of anti-HBe positive chronic hepatitis B in 164 (103 treated) consecutive patients, followed-up prospectively for a mean of 6 years (21 months-12 years). METHODS: Histology, biochemical and virologic profiles were characterized by monthly monitoring during the first 12 months of follow-up. Thereafter patients underwent blood and clinical controls every 4 and 6 months, respectively. Cirrhosis at follow-up histology or end stage complications of cirrhosis served as end points for the analysis of factors influencing disease progression in patients with baseline chronic hepatitis or cirrhosis, respectively. RESULTS: Disease progression was associated with older age (P<0.001), absence of previous HBeAg history (P=0.017) and higher serum HBV-DNA levels (P=0.009) (more frequently observed in unremitting disease profile, P=0.012) at multivariate analysis. Fluctuations of IgM anti-HBc levels (associated with disease exacerbations, P=0.045) correlated with end stage complications in cirrhotics (P=0.011). Disease improved in 14.6 and 1.6% of treated and untreated patients, respectively (P=0.015): interferon slowed disease progression (P<0.001). CONCLUSIONS: The outcome of anti-HBe positive chronic hepatitis B is worsened by older age and persistent viral replication or hepatitis exacerbations in chronic hepatitis or in cirrhotic patients, respectively. Interferon reduces by 2.5-folds disease progression.  相似文献   
102.
PURPOSE This retrospective study evaluates the effect of abdominal hysterectomy on patients affected by descending perineum syndrome. METHODS Eighty-nine female patients affected by descending perineum syndrome and one group of 10 healthy women with normal bowel habits were studied retrospectively. Thirty-two descending perineum syndrome patients (Group 1) had received an abdominal hysterectomy for benign diseases, while 57 descending perineum syndrome patients (Group 2) had not undergone this surgery. All 99 subjects underwent clinical evaluation, computerized anorectal manometry, and defecography. RESULTS Dyschezia was found predominantly in Group 2 subjects (P < 0.05). Fecal incontinence was significantly higher in Group 1 than in Group 2 (P < 0.05). The worst anal resting pressure was found in the incontinent Group 1 patients (P < 0.01). Rectoanal intussusception was a significant defecographic sign in Group 1 subjects (P < 0.05). CONCLUSIONS Clinical evaluation and instrumental data suggested a possible link between fecal incontinence and abdominal hysterectomy in patients affected by descending perineum syndrome.  相似文献   
103.
To study the effects of sampling through cardiac catheters on indices of platelet function, we measured the levels of platelet factor 4 (PF4), beta thromboglobulin (BTG), and platelet aggregate ratio (PAR) in 10 patients with atrioventricular accessory pathway (AVNAP), six patients with primary pulmonary hypertension (PPH), and six patients with critical narrowing of the left anterior descending artery (LAD). In AVNAP and LAD patients samples were drawn simultaneously from a peripheral vein, coronary sinus, and brachial artery; in AVNAP patients samples were also obtained from the axillary vein before the coronary sinus was entered. In PPH patients samples were drawn from pulmonary artery, aorta, and a peripheral vein; in these patients the effects of an intravenous infusion of prostacyclin (PGl2) (2 to 8 ng/kg/min) on PF4, BTG, and PAR were also studied at all sampling sites. In all patients arterial, coronary sinus, pulmonary arterial, and axillary venous levels of PF4, BTG, and PAR significantly exceeded those measured in the peripheral vein. PGl2 infusion resulted in a significant decrease of PF4 at all sampling sites, while no consistent BTG changes were observed and PAR levels did not decrease in the peripheral vein. Although a considerable interpatient variability in PF4 levels was observed, a significant (r = 0.91) correlation was found in patients with AVNAP between simultaneous coronary sinus and arterial PF4 levels. The value of PF4 coronary sinus-arterial difference in LAD patients was consistently higher than that calculated in AVNAP patients (54.5 ± 28.9 vs 4.2 ± 3.8 ng/ml). In conclusion: (1) a considerable and variable degree of platelet activation occurs with catheter sampling, preventing the measurement of absolute levels of platelet metabolites; (2) among the indices examined PF4 appears the most sensitive for detecting changes in platelet activity; and (3) the measurement of coronary sinus-arterial PF4 differences may provide information on directional changes in transcardiac platelet behavior.  相似文献   
104.
Purpose  Some patients, having undergone sphincter-saving operations for rectal cancer, may suffer from fecal incontinence. This study was designed to evaluate the results of rehabilitative treatment in patients with fecal incontinence after sphincter-saving operations and to identify the negative factors that influence therapeutic success. Methods  Between January 2000 and June 2007, 88 incontinent patients (54 women; age range, 47–73 years; 69 had received a low anterior rectal resection; 19 a straight coloanal anastomosis) were included in the study. After a preliminary clinical evaluation, including the Wexner Incontinence Scale score, anorectal manometry was performed. All 88 patients underwent rehabilitative treatment according to the “multimodal rehabilitative program” for fecal incontinence. At the end of program, all 88 patients were reassessed by means of a clinical evaluation and anorectal manometry; their results were compared with the clinical and manometric data from ten healthy control subjects. Postrehabilitative Wexner Incontinence Scale scores were used for an arbitrary schedule of patients divided into three classes: Class I, good (score ≤3); Class II, fair (score >3 to ≤6); Class III, poor (score >6). Results  After rehabilitation, there was a significant improvement in the overall mean Wexner Incontinence Scale score (P < 0.03) for both surgical operation types (low anterior rectal resection: P < 0.05; coloanal anastomosis: P < 0.02). Only 21 patients (23.8 percent) were symptom-free, and 37 (42 percent) were considered Class III. A significant postrehabilitative direct correlation was found between: 1) Wexner Incontinence Scale score and degree of genital relaxation (rρ s 0.78; P < 0.001); 2) Wexner Incontinence Scale score and irradiation (rρ s 0.72; P < 0.01); and 3) Wexner Incontinence Scale score and pelvic (rρ s 0.65; P < 0.01) or anal surgery (rρ s 0.68; P < 0.01). No significant differences were found between prerehabilitative and postrehabilitative anal pressures in low anterior rectal resection and coloanal anastomosis patients. Conclusions  After rehabilitation, some patients become symptom-free, many patients show an improvement in the Wexner Incontinence Scale score, and others exhibit the highest grades of fecal incontinence. Genital relaxation, radiotherapy, and previous pelvic, and/or anal surgery are impeding factors to rehabilitative success.  相似文献   
105.
106.
Tick-borne encephalitis virus (TBEV) is an emerging human pathogen that causes potentially fatal disease with no specific treatment. Mouse monoclonal antibodies are protective against TBEV, but little is known about the human antibody response to infection. Here, we report on the human neutralizing antibody response to TBEV in a cohort of infected and vaccinated individuals. Expanded clones of memory B cells expressed closely related anti-envelope domain III (EDIII) antibodies in both groups of volunteers. However, the most potent neutralizing antibodies, with IC50s below 1 ng/ml, were found only in individuals who recovered from natural infection. These antibodies also neutralized other tick-borne flaviviruses, including Langat, louping ill, Omsk hemorrhagic fever, Kyasanur forest disease, and Powassan viruses. Structural analysis revealed a conserved epitope near the lateral ridge of EDIII adjoining the EDI–EDIII hinge region. Prophylactic or early therapeutic antibody administration was effective at low doses in mice that were lethally infected with TBEV.  相似文献   
107.
The term "neuronal ceroid lipofuscinosis" (NCL) describes a complex of inherited neurodegenerative conditions associated with storage of lipopigments in brain tissue. In 1989 Dyken proposed a classification of NCL based on the age, clinical symptoms, and ultrastructural aspects of the lipopigments. At the ultrastructural level it is possible to distinguish 5 different patterns of osmiophilic lipopigments: usual lipofuscin, fingerprint deposits, granular profiles, curvilinear bodies, and microtubular aggregates. The concept that each ultrastructural pattern was the counterpart of a specific clinical type has been proved not to be true. Advances in molecular genetic techniques have allowed the identification of defective genes and their protein products in several NCL clinical forms. Ceroid lipofuscin deposits may be ultrastructurally observed not only in neuronal cells, but also in several other sites, such as trophoblastic cells, thus permitting prenatal diagnosis. In spite of recent advances in immunohistochemical identification of biochemical markers, the ultrastructural identification of lipofuscinic pigments remains the gold standard to identify NCL, together with clinical aspects and respective gene defects. This study describes the ultrastructural aspects observed in 8 cases of NCL syndromes (3 juvenile, 3 infantile, 1 late infantile, and 1 congenital clinical form). In these patients, genetic analysis was also performed.  相似文献   
108.
109.
A subgroup of HER2‐overexpressing breast tumours co‐expresses p95 $^{{\rm{HER2}}}$ , a truncated HER2 receptor that retains a functional HER2 kinase domain but lacks the extracellular domain, thus impairing trastuzumab binding. We evaluated p95 $^{{\rm{HER2}}}$ expression in 99 frozen breast carcinoma samples by western blot analysis. The HER2‐positive cell line BT474 treated with pervanadate or pronase was used as a positive control for p95 $^{{\rm{HER2}}}$ expression. Immunohistochemistry was performed on parallel formalin‐fixed, paraffin‐embedded sections of the same case series using antibodies directed against either the intra‐ or extra‐cellular binding domain of HER2. In particular, biotinylated trastuzumab (BiotHER) was used to evaluate the binding capacity of the humanized antibody. To avoid a subjective evaluation of the score values and the percentage of immunostained cells, the slides were scanned and automatically analysed. The number of cases with HER2 overexpression (score 3+) and HER2 gene amplification was higher in the p185 $^{{\rm{HER2}}}$ ‐positive/p95 $^{{\rm{HER2}}}$ ‐positive samples than in the p185 $^{{\rm{HER2}}}$ ‐positive/p95 $^{{\rm{HER2}}}$ ‐negative group. Automated analysis confirmed a significantly higher percentage of 3+ scored cells in p95 $^{{\rm{HER2}}}$ ‐positive cases. Conversely, the percentage of 2+ scored cells was higher in p95 $^{{\rm{HER2}}}$ ‐negative cases. The status of the HER2 extracellular domain was then studied using flow cytometry on BT474 cells after pronase enzymatic digestion using trastuzumab and pertuzumab, while the presence of HER2‐HER3 dimers was studied using a proximity‐ligation assay. In vitro experiments showed that short‐term pronase digestion of BT474 cells produced two HER2 fragments (of 95 and 150 kDa, detectable in tissue specimens as well), increased the binding affinity of trastuzumab, reduced the rate of HER2–HER3 dimers, and did not interfere with pertuzumab‐binding capacity. In conclusion, the presence of p95 $^{{\rm{HER2}}}$ as detected by western blot analysis does not compromise the immunohistochemical detection of HER2. Our data suggest that a reduction of the receptor steric hindrance as induced by enzymatic shedding may facilitate the binding capacity of trastuzumab. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.  相似文献   
110.
This is a case of 62 years old Caucasian treatment‐naïve patient who developed a severe acute hepatitis B infection soon after a trip to Thailand. The infection was due to genotype C HBV which was found to be resistant to lamivudine and telbivudine. The patient was treated with tenofovir resulting in complete suppression of viral replication and complete clinical and laboratory remission of acute hepatitis. Later the patient also developed seroconversion of HBeAg to anti‐HBe and of HBsAg to anti‐HBs. This case demonstrates that mutations of HBV polymerase associated with lamivudine, telbivudine, and adefovir resistance can be present also in untreated patients with severe acute hepatitis B. This suggests that in the clinical context, which represents a life threatening condition, a baseline resistance‐testing should be an additional marker in the diagnostic evaluation process. Finally, this case report seems to support the use of tenofovir for the immediate treatment of severe acute hepatitis B. J. Med. Virol. 85:210–213, 2013. © 2012 Wiley Periodicals, Inc.  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