全文获取类型
收费全文 | 181127篇 |
免费 | 9741篇 |
国内免费 | 175篇 |
专业分类
耳鼻咽喉 | 2634篇 |
儿科学 | 5950篇 |
妇产科学 | 4142篇 |
基础医学 | 27042篇 |
口腔科学 | 6033篇 |
临床医学 | 15288篇 |
内科学 | 34391篇 |
皮肤病学 | 4687篇 |
神经病学 | 18105篇 |
特种医学 | 7544篇 |
外国民族医学 | 11篇 |
外科学 | 26637篇 |
综合类 | 785篇 |
现状与发展 | 1篇 |
一般理论 | 101篇 |
预防医学 | 12099篇 |
眼科学 | 3665篇 |
药学 | 11597篇 |
中国医学 | 246篇 |
肿瘤学 | 10085篇 |
出版年
2023年 | 964篇 |
2022年 | 804篇 |
2021年 | 1844篇 |
2020年 | 1643篇 |
2019年 | 2107篇 |
2018年 | 3767篇 |
2017年 | 3219篇 |
2016年 | 4087篇 |
2015年 | 3721篇 |
2014年 | 4305篇 |
2013年 | 7078篇 |
2012年 | 9490篇 |
2011年 | 10366篇 |
2010年 | 5808篇 |
2009年 | 4420篇 |
2008年 | 10150篇 |
2007年 | 10661篇 |
2006年 | 10330篇 |
2005年 | 10121篇 |
2004年 | 9364篇 |
2003年 | 9323篇 |
2002年 | 8991篇 |
2001年 | 6726篇 |
2000年 | 8040篇 |
1999年 | 5034篇 |
1998年 | 1998篇 |
1997年 | 1718篇 |
1996年 | 1435篇 |
1995年 | 1164篇 |
1994年 | 1130篇 |
1993年 | 1079篇 |
1992年 | 1743篇 |
1991年 | 1570篇 |
1990年 | 1523篇 |
1989年 | 1470篇 |
1988年 | 1319篇 |
1987年 | 1283篇 |
1986年 | 1178篇 |
1985年 | 1321篇 |
1984年 | 1090篇 |
1983年 | 917篇 |
1982年 | 780篇 |
1981年 | 750篇 |
1980年 | 676篇 |
1979年 | 799篇 |
1978年 | 611篇 |
1977年 | 639篇 |
1976年 | 532篇 |
1975年 | 597篇 |
1974年 | 564篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
11.
F Boomsma F A van der Hoorn A J Man in 't Veld M A Schalekamp 《Clinica chimica acta; international journal of clinical chemistry》1988,178(1):59-69
We report a reliable method for determining DOPA levels in plasma and cerebrospinal fluid. The method is based on complete conversion of DOPA to dopamine and quantification by HPLC-ECD of the dopamine formed. Lower limit of detection was 0.5 nmol/l. No differences in plasma DOPA levels were found between normal children (0-15 yr, n = 60), normal adults (n = 39) and patients with essential hypertension (n = 40) or Parkinson's disease (no DOPA therapy, n = 30). In normal individuals and in patients with essential hypertension venous plasma levels were higher than arterial levels (10.2 vs 9.3 nmol/l, p less than 0.001, V/A ratio 1.11 (SD 0.08), n = 15). Sympathetic stimuli (standing, tilting, bicycle exercise, tyramine) did not influence DOPA levels. In untreated depressed patients (n = 10) and in non-parkinsonian neurological patients (n = 12) cerebrospinal fluid levels of DOPA were 4.5 (SD 2.4) and 5.2 (SD 1.3) nmol/l respectively. A direct method for the measurement of DOPA by HPLC-ECD after deproteinization of plasma is also described and compared with the conversion method. Good agreement was found when plasma DOPA levels exceeded 0.25 mumol/l (y(conversion method) = 0.943x (direct method) + 0.118; n = 60; r = 0.985). The direct method, because of greater simplicity and the possibility of simultaneous measurement of the DOPA metabolite 3-O-methyldopa, is the method of choice with plasma samples from DOPA-treated patients. In non-DOPA treated individuals the conversion method is superior and has proved to be an accurate and sensitive method for the determination of DOPA levels in plasma and cerebrospinal fluid. 相似文献
12.
T F Kruger J P Van der Merwe H J Odendaal F S Stander G M Grobler V A Hulme E L Erasmus K Coetzee M L Windt Y Swart 《Suid-Afrikaanse tydskrif vir geneeskunde》1990,77(12):634-636
The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate. 相似文献
13.
A E van der Merwe F J Mattheyse M Bedford P D van Helden D J Rossouw 《Burns : journal of the International Society for Burn Injuries》1990,16(3):193-197
Cultured keratinocytes were used as allografts on burn wounds in two patients. In both patients successful covering of the wounds was obtained. DNA fingerprinting of the epidermis covering the wounds 21 days later showed that the cultured keratinocytes were replaced by the patients' cells. 相似文献
14.
15.
The simultaneous determination of cerebrospinal fluid and plasma adenosine deaminase activity as a diagnostic aid in tuberculous meningitis 总被引:1,自引:0,他引:1
P R Donald C Malan A van der Walt J F Schoeman 《Suid-Afrikaanse tydskrif vir geneeskunde》1986,69(8):505-507
The simultaneous determination of cerebrospinal fluid (CSF) and plasma adenosine deaminase (ADA) activity was evaluated as a diagnostic aid in tuberculous meningitis (TBM). CSF and plasma ADA activity were determined in four groups of patients: (i) a 'no meningitis' group of 174 children investigated for possible meningitis, but found to be uninfected; (ii) an aseptic meningitis group of 40 children; (iii) a bacterial meningitis group of 31 children; and (iv) a TBM group of 27 patients (24 children and 3 adults). CSF ADA alone was determined in a further 23 children with aseptic meningitis, 19 with bacterial meningitis and 13 children and 7 adults with TBM. Both the CSF/plasma ADA ratio and the absolute CSF ADA activity were raised in TBM (mean values 0,24 and 12,61 U/I respectively) and bacterial meningitis (mean values 0,59 and 15,43 U/I respectively), but not in the aseptic meningitis group (mean values 0,06 and 2,00 U/I) or the 'no meningitis' group (mean values 0,04 and 1,51 U/I). Both values will distinguish TBM from aseptic meningitis, but do not appear to hold any marked advantages over conventional CSF criteria in the diagnosis of TBM. 相似文献
16.
In comparative histological and cytological studies on 270 prostatic carcinoma patients highly and moderately differentiated tumors were found to be more frequent histologically than cytologically. An early and reliable sign of response to hormone therapy proved to be reticularization and vacuolization of the nuclear chromatin. Follow-up studies by means of multiple aspiration biopsies with cytologic examinations seem to be more reliable in prognostic terms than examination of the histological tumor structure. 相似文献
17.
18.
Å. Öst P. Lindström B. Christensson H. Gyllenhammar L. Engstedt 《European journal of haematology》1984,33(2):160-170
A consecutive series of patients (1978–1981) comprising all patients with acute leukaemia from a population of 475000 inhabitants was reviewed. Thus, 94 patients were diagnosed as having acute leukaemia. No patients were lost from follow-up. The incidence figures of ALL and AML differed significantly from those of Sweden as a whole. 9 patients were < 15 years old. The median age of adult patients was 64 years, 60.8% being ≥ 60 years old. Of adult patients with AML, 20% had a preleukaemic history (chronic myeloproliferative disorders, myelodysplastic syndromes and others). None of 6 patients with leukaemia as a metamorphosis of a chronic myeloproliferative disorder achieved a complete remission. The overall remission rate of the remaining adult patients was 25%. Treated patients, 15–39 years old, with AML without any preleukaemic history, had a complete remission rate of 80% compared to 12% for patients ≥ 60 years old with the same diagnosis. Of 60 patients with ‘primary’ AML, 14 were not treated, mainly because of advanced age and complicating diseases. Most of these patients died within a week of admission. 相似文献
19.
We found that thirteen per cent of all head and neck malignomas are malignant lymphomas. In 75% of these cases the Non-Hodgkin type could be found. The major salivary glands were involved by the lymphoma in 55% out of 104 patients. Paraglandular lymph nodes of the parotid gland were affected as well as intraglandular lymph nodes and the lymphoid tissue within the gland proper. The submandibular gland normally shows an involvement only with its paraglandular lymph nodes. Two thirds of the Non-Hodgkin lymphomas located in the salivary glands were low-grade. In case of clinical suspicion of a malignant lymphoma, fine needle biopsy is required for cytological diagnosis. However, surgery is mandatory for histological diagnosis, not as a therapeutic measure. 相似文献
20.
Andrology was included as a further subject for continuing education in the Model Ordinance on Continuing Education at the 106th German Physicians’ Meeting in Cologne in 2003. In addition to fertility disorders, this discipline comprises medical care for men with fertility disorders, erectile dysfunction, disorders of libido, ejaculation, and coitus, various forms of hypogonadism, and delayed puberty. Furthermore, this field also covers questions concerning male contraception, gynecomastia, and male senescence. Diagnostic procedures in andrology require close interdisciplinary cooperation with practitioners of gynecology, human genetics, and psychosomatic medicine. It includes medical history, clinical examination, and laboratory analyses. Except to confirm azoospermia, it is not possible to make a definitive prognosis for fertility based on semen analysis. Functional tests allow a better assessment of the spermatozoa’s fertility since 25–30% of men desiring a child exhibit reduced spermatozoal functions, which cannot be verified on routine semen analysis. 相似文献