全文获取类型
收费全文 | 31805篇 |
免费 | 2030篇 |
国内免费 | 218篇 |
专业分类
耳鼻咽喉 | 333篇 |
儿科学 | 913篇 |
妇产科学 | 782篇 |
基础医学 | 3257篇 |
口腔科学 | 811篇 |
临床医学 | 2885篇 |
内科学 | 7227篇 |
皮肤病学 | 646篇 |
神经病学 | 1517篇 |
特种医学 | 989篇 |
外国民族医学 | 10篇 |
外科学 | 5706篇 |
综合类 | 902篇 |
现状与发展 | 2篇 |
一般理论 | 26篇 |
预防医学 | 2143篇 |
眼科学 | 868篇 |
药学 | 2835篇 |
中国医学 | 305篇 |
肿瘤学 | 1896篇 |
出版年
2023年 | 489篇 |
2022年 | 1460篇 |
2021年 | 2002篇 |
2020年 | 1092篇 |
2019年 | 1371篇 |
2018年 | 1682篇 |
2017年 | 1018篇 |
2016年 | 1069篇 |
2015年 | 1167篇 |
2014年 | 1445篇 |
2013年 | 1763篇 |
2012年 | 2515篇 |
2011年 | 2482篇 |
2010年 | 1261篇 |
2009年 | 1075篇 |
2008年 | 1579篇 |
2007年 | 1629篇 |
2006年 | 1427篇 |
2005年 | 1246篇 |
2004年 | 1124篇 |
2003年 | 979篇 |
2002年 | 804篇 |
2001年 | 368篇 |
2000年 | 342篇 |
1999年 | 310篇 |
1998年 | 176篇 |
1997年 | 121篇 |
1996年 | 111篇 |
1995年 | 110篇 |
1994年 | 75篇 |
1993年 | 63篇 |
1992年 | 136篇 |
1991年 | 126篇 |
1990年 | 118篇 |
1989年 | 108篇 |
1988年 | 103篇 |
1987年 | 97篇 |
1986年 | 98篇 |
1985年 | 91篇 |
1984年 | 75篇 |
1983年 | 90篇 |
1982年 | 41篇 |
1981年 | 56篇 |
1980年 | 35篇 |
1979年 | 79篇 |
1978年 | 49篇 |
1977年 | 55篇 |
1976年 | 44篇 |
1975年 | 46篇 |
1974年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
Gangliosides of cultured astroglia 总被引:3,自引:0,他引:3
Michele Sbaschnig-Agler Henri Dreyfus William T. Norton Monique Sensenbrenner Muhammad Farooq Mary C. Byrne Robert W. Ledeen 《Brain research》1988,461(1):98-106
Cultured astrocytes prepared from newborn rat brain and 13-day-old chick embryonic brain were analyzed qualitatively and quantitatively for ganglioside content. All preparations contained approximately the same total level: 2.4-3.4 micrograms N-acetylneuraminic acid (NeuAc)/mg protein. In contrast, the value for primary cultures of neurons from chick embryonic brain was 5.9. The non-hexosamine-containing species, GM3 and GD3, comprised 75-85% of the total in astroglial cultures, the remainder consisting mainly of structural types other than the gangliotetraose series; choleragenoid assay revealed the latter to be virtually absent or to comprise at most a few percent. Deficiency of gangliotetraose synthesizing ability was indicated by the very low level of UDP-GalNac:GM3 N-acetylgalactosaminyltransferase detected in the cells. Treatment of cultured astrocytes with astroglial growth factor 2 or dibutyryl cyclic AMP caused little if any change in quantity or pattern of gangliosides. The large majority of cells stained in a manner characteristic of astrocytes: positive for glial fibrillary acidic protein, negative for galactosyl ceramides. Staining with cholera toxin and anti-GM1 antibody was essentially negative, as was that with tetanus toxin, A2B5 monoclonal antibody, and antibody to GD3. All evidence thus points to cultured astrocytes of rat and chick brain containing appreciable gangliosides, most of which are GM3 and GD3 with the majority of the remainder comprising structures other than the gangliotetraose type. 相似文献
95.
96.
Khalid Ahmed AL-ANAZI Asma Marzouq AL-JASSER David Alan Price EVANS Nasr Abu DAFF 《Asia-Pacific Journal of Clinical Oncology》2006,2(2):91-97
Background: Surgical intervention in patients with malignant hematological disorders is a major undertaking due to the expected risks of bleeding, infection and poor wound healing. Methods and materials: A retrospective study of patients treated at the Riyadh Armed Forces Hospital, Saudi Arabia between January 1991 and December 2002 was conducted. The results of patients with acute leukemia and lymphoma who underwent surgical procedures (study group) were compared with those of a control group composed of patients with the same spectrum of disorders treated over the same period of time and given the same treatment protocols but never required any surgery. Results: No single death occurred intraoperatively or in the immediate postoperative period due to surgical therapy per se. However, follow up of both groups of patients revealed a shorter long‐term survival and higher rates of relapse and severe invasive infections in the surgical group compared to the control group of patients. The mean survival for the study group was 1871 ± 307 days versus 3094 ± 279 days for the control group of patients (P = 0.0027). Thirty (75%) study patients suffered relapses of their malignant hematological disorders versus 23 (37.1%) control patients. Forty‐five relapses were encountered in the study group of patients (1.5 relapses per relapsed patient) versus 26 relapses in the control group (1.13 relapses per relapsed patient). Various infections occurred in 37 (92.5%) study patients and 32 (51.6%) control patients. Recurrent infections developed in 30 (75%) study patients and 22 (35.5%) control patients (P = 0.00008). Infections causing tissue invasion were encountered in 29 (72.5%) study patients and 22 (35.5%) control patients. Conclusion: Even major surgical procedures can be performed in patients with leukemia or lymphoma provided enough preparatory measures are made to minimize bleeding and infectious complications. Surgery may, however, be associated with long‐term complications such as a high incidence of relapse of the primary malignant hematological disorder and an increased rate of severe and invasive infections. 相似文献
97.
Yasser EMAD Yasser RAGAB Ahmed EL‐MARAKBI Salama MOHAMED HANFI 《International journal of rheumatic diseases》2007,10(4):326-329
A 48‐year‐old male patient with long‐standing ulcerative colitis since February 2001 which was diagnosed by endoscopy, developed acute digital ischemia affecting both hands with fixed colour changes in the left index finger which was followed shortly by digital ulceration. Magnetic resonance angiography (MRA) of both upper limbs showed evidence of vasculitis affecting digital arterioles on both sided and right subclavian occlusion. The patient received pulse methylprednisolone followed by cyclophosphamide pulse therapy, the latter continuing on a monthly basis for 6 months with appreciable improvement and remission of the vasculitic process; follow‐up MRA showed reperfusion of the previously occluded subcalvian artery. To the authors’ knowledge vasculitis complicating the course of ulcerative colitis is a rare association and is only sporadically reported in the literature. This rare entity should be diagnosed early and aggressively treated; MRA is a very promising diagnostic tool that is suitable for both diagnosis and follow‐up of patients with this rare entity. 相似文献
98.
In samples of Kuwaiti (n=460) and American (n=273) college students, the Reynolds Suicide Ideation Questionnaire (SIQ) proved to have good internal consistency and concurrent validity with measures of anxiety, optimism, pessimism, death obsession, obsession-compulsion, and ego-grasping. The SIQ was factorially complex in both samples, but the eight critical items showed a similar two-factor pattern in both samples. It is important to note that in spite of the great differences between Kuwait and US students and their cultures, the findings were quite similar. By and large, the psychological correlates of the SIQ may have cross-cultural generality. 相似文献
99.
Muhammad Al-Kaylani Peter Konrad Barry Lazenby Bennett Blumenkopf Bassel Abou-Khalil 《Seizure》2007,16(2):95-98
Data are limited on seizure recurrence after antiepileptic drug (AED) discontinuation in operated seizure-free patients. We reviewed seizure outcome in patients who came off AEDs after being seizure-free for 2 years following temporal lobe surgery in our center. Thirty-nine (68%) of 57 patients who discontinued AED therapy remained seizure-free. They had a younger age at surgery than the group with seizure recurrence (p=0.01). Earlier surgery may be a favorable predictor for seizure freedom after AED discontinuation. 相似文献
100.
Vicky E Macrae S Faisal Ahmed Talat Mushtaq Colin Farquharson 《Growth hormone & IGF research》2007,17(5):435-439
OBJECTIVE: To determine if glucocorticoids and proinflammatory cytokines inhibit bone growth through a common mechanism involving impaired IGF-I signalling. DESIGN: IGF-I (100 ng/ml), dexamethasone (dex) (10(-6)M) and IL-1beta (10 ng/ml) with inhibitors of the PI3K (LY294002) and Erk 1/2 (PD98059 and UO126) IGF-I pathways (all 10 microM) were studied using the ATDC5 chondrocyte cell line and murine fetal metatarsal cultures. RESULTS: IGF-I stimulated ATDC5 chondrocyte proliferation (322%; P < 0.001 versus control). Addition of PD or LY individually to IGF-I supplemented ATDC5 cultures partially reduced proliferation by 32% (P < 0.001), and 66% (P < 0.001), respectively. PD and LY in combination blocked all IGF-I stimulated ATDC5 proliferation. LY significantly reversed IGF-I stimulatory effects on metatarsal growth (P < 0.001), whereas PD and UO treatment had no effect. IGF-I induced ATDC5 proliferation was further decreased when Dex (24%; P < 0.01) or IL-1beta (33%; P < 0.001) were added to PD but not LY cultures. Metatarsal growth inhibition by LY was unaltered by Dex or IL-1beta addition. CONCLUSIONS: Both the PI3K and Erk 1/2 pathways contributed independently to IGF-I mediated ATDC5 proliferation. However in metatarsal cultures, the Erk 1/2 pathway was not required for IGF-I stimulated growth. Dex and IL-1beta may primarily inhibit IGF-I induced bone growth through the PI3K pathway. 相似文献