全文获取类型
收费全文 | 15533篇 |
免费 | 968篇 |
国内免费 | 88篇 |
专业分类
耳鼻咽喉 | 100篇 |
儿科学 | 363篇 |
妇产科学 | 368篇 |
基础医学 | 1918篇 |
口腔科学 | 314篇 |
临床医学 | 1519篇 |
内科学 | 3583篇 |
皮肤病学 | 219篇 |
神经病学 | 1724篇 |
特种医学 | 689篇 |
外科学 | 2300篇 |
综合类 | 66篇 |
一般理论 | 6篇 |
预防医学 | 1091篇 |
眼科学 | 297篇 |
药学 | 890篇 |
中国医学 | 33篇 |
肿瘤学 | 1109篇 |
出版年
2024年 | 22篇 |
2023年 | 192篇 |
2022年 | 285篇 |
2021年 | 500篇 |
2020年 | 382篇 |
2019年 | 449篇 |
2018年 | 527篇 |
2017年 | 411篇 |
2016年 | 496篇 |
2015年 | 488篇 |
2014年 | 666篇 |
2013年 | 844篇 |
2012年 | 1392篇 |
2011年 | 1365篇 |
2010年 | 713篇 |
2009年 | 599篇 |
2008年 | 1063篇 |
2007年 | 1028篇 |
2006年 | 895篇 |
2005年 | 918篇 |
2004年 | 794篇 |
2003年 | 680篇 |
2002年 | 621篇 |
2001年 | 94篇 |
2000年 | 74篇 |
1999年 | 101篇 |
1998年 | 134篇 |
1997年 | 75篇 |
1996年 | 89篇 |
1995年 | 63篇 |
1994年 | 50篇 |
1993年 | 56篇 |
1992年 | 53篇 |
1991年 | 42篇 |
1990年 | 31篇 |
1989年 | 37篇 |
1988年 | 34篇 |
1987年 | 23篇 |
1986年 | 22篇 |
1985年 | 32篇 |
1984年 | 19篇 |
1983年 | 29篇 |
1982年 | 14篇 |
1981年 | 20篇 |
1979年 | 11篇 |
1972年 | 14篇 |
1971年 | 19篇 |
1970年 | 10篇 |
1969年 | 10篇 |
1968年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Friedman D Cuneo S Valenzano M Marinari GM Adami GF Gianetta E Traverso E Scopinaro N 《Obesity surgery》1995,5(3):308-313
Background: 239 pregnancies occurred in 1136 women who had undergone biliopancreatic diversion (BPD). Methods: There were
73 abortions, and 14 pregnancies are presently in their course. The 152 term pregnancies (six twins) occurred in 129 women
2-173 months (mean 42.7) after BPD. Mean age and current excess weight were 31.4 years (20-42) and 29.1% (-6.9-78.2), and
mean excess weight loss was 72.9% (30.4-110.5). Results: Mean weight gain during pregnancy was 6.2 kg (-21-25). In 32 patients
(21%), parenteral nutritional support was needed. In all the other patients (79%), the usual supplementations were given.
Of the newborns, 122 were delivered at term (84.7%) with a mean weight of 2842.4 g (1760-4600 g) and a mean length of 48.5
cm (43-59 cm), while the 22 preterm babies (15.3%) weighed 2151.1 g (1400-3850 g) and had a length of 44.6 cm (33-56 cm).
Forty infants (27.8%) were small for gestational age but 17 of them weighed more than 2500 g. Eleven twins (one abortion at
26th week) were also delivered, with a mean weight of 2088.6 g (1200-3100 g) and a mean length of 45.6 cm (35-50 cm). Delivery
was spontaneous in 85 instances (56%), while vacuum extractor was used in one, and 66 cesarean sections were performed. There
were two birth malformations, one infant died after surgery for meconium obstruction and two died from unknown causes. Of
the 129 women, 35 had been infertile before BPD. Conclusions: Disappearance of infertility and decrease of pregnancy risk
are to be considered among the beneficial effects of weight reduction following BPD. 相似文献
92.
Varrassi G Marinangeli F Agrò F Aloe L De Cillis P De Nicola A Giunta F Ischia S Ballabio M Stefanini S 《Anesthesia and analgesia》1999,88(3):611-616
We assessed the relative morphine consumption in a combined analgesic regimen (on-demand morphine plus the nonopioids propacetamol or ketorolac) after gynecologic surgery. Two hundred women randomly received two i.v. doses of propacetamol 2 g or ketorolac 30 mg in a double-blinded, double-dummy trial. Patients were monitored for 12 h, and the following efficacy variables were assessed: total dose of morphine, pain intensity, and global efficacy. Safety and tolerability were evaluated by the occurrence of adverse events, especially the presence and intensity of gastrointestinal symptoms. Hemostatic variables were measured 30 and 60 min after the first infusion; arterial blood pressure, heart and respiratory rates, sedation scores, and renal and hepatic function were also assessed. Total morphine requirements were not significantly different between the propacetamol (10.6 +/- 4.8 mg) and ketorolac (10.2 +/- 4.4 mg) groups. The evolution of pain intensity and the global efficacy also showed similar patterns in the two groups: 70.2% of patients in the propacetamol group rated the efficacy as "good/ excellent" compared with 68.2% in the ketorolac group. There were no clinically significant changes in vital signs or laboratory values and no observed differences between the two groups, although ketorolac slightly, but not significantly, prolonged the bleeding time. Epigastric pain was present in 9% and 15% of patients receiving propacetamol and ketorolac, respectively. There were two adverse events in the propacetamol group and four in the ketorolac group. Propacetamol demonstrates an efficacy similar to that of ketorolac and has an excellent tolerability after gynecologic surgery. IMPLICATIONS: Propacetamol and ketorolac, combined with patient-controlled analgesia morphine, show similar analgesic efficacy after gynecologic surgery. Morphine consumption and pain scores were comparable in the two studied groups. Propacetamol is as effective as ketorolac and has an excellent tolerability after gynecologic surgery. 相似文献
93.
A multifactorial etiology underlies the majority of cases of Alzheimer's disease (AD). Both ill-defined environmental and genetic factors contribute to the development of the disease. Allele epsilon 4 of ApoE is a genetic risk factor. Its presence increases the risk of developing AD. However, presence of e4 is neither necessary nor sufficient for the disease to arise. Apart from the common multifactorial forms of the disease, there are rare variants which are inherited as Mendelian traits. To date three genes are known that can be mutated in these rare forms of AD. Of these, mutations in the gene presenilin 1 on chromosome 14 are most frequent. In addition, mutations in the gene presenilin 2 on chromosome 1 and in the amyloid precursor protein gene (APP on chromosome 21) occur in autosomal dominant AD. This article reviews our present knowledge of the genetics of AD and discusses its relevance for patients with AD and their relatives. 相似文献
94.
95.
Pietra N Sarli L Maccarini PU Sabadini G Costi R Gobbi S 《World journal of surgery》2000,24(3):345-352
Consensus has never been reached regarding the need or the imaging technique for evaluating the common bile duct (CBD) in
patients considered for cholecystectomy. With the advent of laparoscopic cholecystectomy there has been a resurgence of interest
in the role of preoperative intravenous cholangiography (IVC) as an alternative for evaluating the CBD. The purpose of this
audit was to assess whether a diagnostic workup based on IVC, which permits selective use of intraoperative cholangiography
(IOC) and endoscopic treatment of CBD stones before surgery, could be useful in patients undergoing laparoscopic cholecystectomy
(LC). In patients without jaundice, gallstone pancreatitis, a prior diagnosis of CBD stones, a prior history of contrast allergy,
or a risk of contrast-associated acute renal failure, IVC was performed routinely. Patients suspected to have CBD stones based
on IVC results or with inconclusive IVC and patients with a strong clinical suspicion of CBD stones were referred for endoscopic
retrograde cholangiography (ERC). IOC was carried out in patients who had a history of contrast allergy or risk of contrast-associated
acute renal failure and whenever the surgeon was in doubt as to the biliary anatomy or CBD clearance. IVC was carried out
in 1155 patients, ERC in 225, and IOC in 54. IVC was conclusive in 1132 patients, with a diagnostic accuracy of 99%. Our workup
permitted the sequential endoscopic-laparoscopic treatment of cholecystocholedocholithiasis in 162 cases. During the follow-up
period residual CBD stones were detected in four patients. Our diagnostic workup showed that routine IVC exposes the population
to a large radiation burden, and the cost is high for the small number of patients who benefit. Moreover, it does not seem
helpful in reducing the incidence of CBD injuries during LC. 相似文献
96.
Rebecca J Dearman Catherine J Betts Neil Humphreys Brian F Flanagan Nicola J Gilmour David A Basketter Ian Kimber 《Toxicological sciences》2003,71(2):137-145
Chemical respiratory allergy is an important occupational health problem, but there are currently available no validated methods for hazard identification. This is due in part to the fact that the relevant cellular and molecular mechanisms of sensitization of the respiratory tract have been unclear, with particular controversy regarding the role of IgE. There is now increasing evidence that respiratory sensitization is associated with the preferential activation of type 2 T lymphocytes and the expression of type 2 cytokines interleukin (IL)-4, IL-5, IL-10, and IL-13. Type 2 cell products favor immediate type hypersensitivity reactions, serving as growth and differentiation factors for mast cells and eosinophils, the cellular effectors of the clinical manifestations of the allergic responses, and promoting IgE antibody production. There has been considerable interest in the application of cytokine profiling for the characterization of chemical allergens, with cytokine phenotypes analyzed in freshly isolated tissue, or following culture in the presence or absence of mitogen at the level of protein secretion or mRNA expression. Experience to date suggests that the measurement of induced cytokine secretion profiles shows promise for the hazard identification and characterization of chemical respiratory allergens. The purpose of this brief review article is to consider the approaches available and to highlight key procedural issues. 相似文献
97.
Sabbatini M Sansone G Uccello F De Nicola L Nappi F Andreucci VE 《Transplantation》2000,69(9):1946-1990
The acute effects of cyclosporin (CsA, 20 mg(kg i.v.) and rapamycin (RAPA, 5 mg(kg i.v.) on glomerular dynamics were separately investigated by renal micropuncture in two groups of intact rats (group CsA and RAPA, respectively) and compared with vehicle-treated rats, used as controls (group CON). Left kidney glomerular filtration rate (GFR) was decreased by CSA (-35% vs. CON, P<0.05), but was not affected by RAPA (-14% vs. CON, NS), whereas the single-nephron GFR (SNGFR) was significantly decreased in both groups (-40% in CsA, P<0.01 and -26% in RAPA, P<0.05 vs. CON). In both groups glomerular plasma flow (GPF) was significantly reduced vs. CON (CsA: -48%, and RAPA: -25%) due to the increase in both afferent (Ra) and efferent (Re) glomerular resistances: group CSA showed a prevalent rise in Re (+98% vs. CON, P<0.001) than in Ra (+66%, P<0.001); in group RAPA the increment was modest and similar in Ra and Re (+33 and +32%, respectively, NS versus CON). A further group of rats was studied in which L-Arginine (ARG), the precursor of nitric oxide (NO), was administered (2.5 mg/Kg/min iv) with RAPA (group ARG). ARG limited the rise in Ra and Re, thereby preserving GPF; nevertheless, SNGFR remained low (-26% vs. CON, P<0.05) due to the decrease in the effective filtration pressure (-26% vs. CON). These data demonstrate that: (1) CsA is nephrotoxic at immunosuppressive doses; (2) RAPA, even at huge doses, has marginal effects on renal and glomerular dynamics; (3) the ARG-NO pathway is only partially involved in the vasoconstriction of superficial nephrons after RAPA administration. 相似文献
98.
Prognostic value of CD40 in adult soft tissue sarcomas. 总被引:4,自引:0,他引:4
Alessandro Ottaiano Anna De Chiara Francesco Perrone Gerardo Botti Flavio Fazioli Vincenzo De Rosa Nicola Mozzillo Vincenzo Ravo Brunello Morrica Ciro Gallo Carmela Pisano Maria Napolitano Paolo Antonio Ascierto Rosario Vincenzo Iaffaioli Gaetano Apice 《Clinical cancer research》2004,10(8):2824-2831
PURPOSE: The purpose is to evaluate the expression of CD40, a membrane protein predominantly expressed on B cells, dendritic cells, and macrophages, in a series of adult soft tissue sarcomas and to test its possible prognostic value. EXPERIMENTAL DESIGN: CD40 expression was studied by immunohistochemistry. Correlations with other baseline characteristics of patients and tumors were analyzed with chi(2) test. The prognostic value was studied with univariable and multivariable analysis adjusted by age, sex, tumor size, grade, location, and distant metastases. RESULTS: Eighty-two patients, between January 1994 and May 2001, were analyzed. Membrane or cytoplasmic staining for CD40 protein was absent in 30% of the tumors but present in <10% of cells in 22 (27%), in 10% to 50% in 23 (28%), and in >50% of cells in 12 (15%) tumors. There was no correlation between CD40 expression and age, sex, size, grade, and location of the primary tumor and distant metastases. With 61 patients (74.4%) progressed and 31 (37.8%) dead, CD40 expression was a significant prognostic factor for disease-free and overall survival at univariable and multivariable analysis. Patients with tumors expressing CD40 in >50% of cells had a dramatically unfavorable prognosis with median disease-free and overall survival of 7 and 17 months, respectively, and hazard ratios of relapse and death as compared with patients with CD40-negative tumors of 2.89 (95% confidence interval: 1.26-6.60) and 6.92 (95% confidence interval: 2.18-22.0), respectively. CONCLUSIONS: These data suggest that expression of CD40 protein in >50% of cells might indicate an unfavorable prognosis in adult soft tissue sarcomas. 相似文献
99.
Bradley R Pieters Augustinus A M Hart Nicola S Russell Edwin P M Jansen Johannes L Peterse Jacques Borger Emiel J Th Rutgers 《Radiotherapy and oncology》2003,67(2):159-164
BACKGROUND AND PURPOSE: Interstitial implants for brachytherapy boost in the breast conserving therapy of breast cancer can be performed in two ways; implants during the tumor excision (per-operative implants) or after the external beam therapy (delayed interstitial implants). Differences in cosmetic outcome were investigated. PATIENTS AND METHODS: Cosmetic results in 47 patients having a per-operative implant were compared to 123 patients having a delayed interstitial implant in a matched case-control study. Cosmesis was scored on a four-point-scale varying from 0 (excellent) to 3 (poor). RESULTS: After mean follow-up of 63 months, three observers found no difference in cosmetic outcome between the two groups after adjustment for variables found to be related with cosmesis (difference in mean score 0.50, P=0.26). Implant volume at 100% isodose was not found to differ (P=0.084) between the per-operative group (mean 102 cm3, S.D. 34 cm3) and the delayed group (mean 93 cm3, S.D. 29 cm3). CONCLUSIONS: Performing per-operative implants has not led to smaller implants. The method of performing brachytherapy does not result in marked differences in cosmetic outcome. 相似文献
100.
Valeria Masciullo Tommaso Susini Alessandra Zamparelli Alessandro Bovicelli Corrado Minimo Daniela Massi Gianluigi Taddei Nicola Maggiano Pierandrea De Iaco Marcello Ceccaroni Luciano Bovicelli Gianni Amunni Salvatore Mancuso Giovanni Scambia Antonio Giordano 《Clinical cancer research》2003,9(14):5332-5338
PURPOSE: p27(Kip1) is a member of the Cip1/Kip1 family of cyclin-dependent kinase inhibitors and is a potential tumor suppressor gene. Low levels of p27 are associated with poor prognosis in a variety of gynecological tumors, including breast, ovarian, and cervical carcinomas. The role of p27 in endometrial cancer remains controversial. EXPERIMENTAL DESIGN: In the present study, p27 protein expression was investigated by immunohistochemistry in a series of 217 endometrial adenocarcinomas and, where present, in synchronous normal endometrium, simple and complex hyperplasia (with or without atypia), and cystic atrophy. The relationship between p27 expression and clinical outcome was also evaluated. RESULTS: Immunohistochemical analysis revealed a significant loss of p27 expression from normal (33%) through hyperplastic endometrium (50%) to endometrial adenocarcinomas (71%; P = 0.001). In addition to nuclear staining, cytoplasmic localization of p27 was noted in 193 (91%) of 217 specimens examined. When the clinical outcome of the patients was evaluated in relation to p27 status, we found no significant correlation between the presence of p27 staining and clinicopathological parameters or survival. CONCLUSIONS: These data indicate that p27 expression could progressively decrease from normal endometrium through hyperplastic endometrium to invasive endometrial carcinomas, suggesting that loss of this tumor suppressor may represent a novel and distinct molecular alteration involved in estrogen-related endometrial adenocarcinomas (type I). Despite the suggested role of the p27 protein in determining the prognosis of several human tumors, it was not found to be a predictor of clinical outcome in this large group of patients with endometrial cancer. 相似文献